Accepted by P. Alderslade: 10 Oct. 2012; published: 14 Jan. 2013 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition)Copyright ? 2013 Magnolia Press Zootaxa 3602 (1): 001?105 www.mapress.com/zootaxa/ Monograph http://dx.doi.org/10.11646/zootaxa.3602.1.1 http://zoobank.org/urn:lsid:zoobank.org:pub:10304FBF-3969-4EFA-83F1-BB8A5E2B37F3 ZOOTAXA A revision of the genus Thouarella Gray, 1870 (Octocorallia: Primnoidae), including an illustrated dichotomous key, a new species description, and comments on Plumarella Gray, 1870 and Dasystenella, Versluys, 1906 TAYLOR, M.L.1,2,3, CAIRNS, S. D. 4, AGNEW, D.J.2,5 & ROGERS, A.D. 3 1Zoological Society of London, Institute of Zoology, Regent?s Park, London, NW1 4RY, UK 2Department of Natural Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK 3Department of Zoology, Univerity of Oxford, Tinbergen building, South Parks Road, Oxford, UK, OX1 3PS 4Department of Invertebrate Zoology, MRC 163, P.O. Box 37012, National Museum of Natural History, Smithsonian Institution, Washington, D.C., USA 5Marine Resources Assessment Group LtD, 18 Queen Street, London, UK Corresponding author: michelle.taylor@zoo.ox.ac.uk Magnolia Press Auckland, New Zealand 3602 TAYLOR ET AL.2 ? Zootaxa 3602 (1) ? 2013 Magnolia Press TAYLOR, M.L., CAIRNS, S. D., AGNEW, D. & ROGERS, A.D. A revision of the genus Thouarella Gray, 1870 (Octocorallia: Primnoidae), including an illustrated dichotomous key, a new species description, and comments on Plumarella Gray, 1870 and Dasystenella, Versluys, 1906 (Zootaxa 3602) 105 pp.; 30 cm. 14 Jan. 2013 ISBN 978-1-77557-084-4 (paperback) ISBN 978-1-77557-085-1 (Online edition) FIRST PUBLISHED IN 2013 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: zootaxa@mapress.com http://www.mapress.com/zootaxa/ ? 2013 Magnolia Press All rights reserved. No part of this publication may be reproduced, stored, transmitted or disseminated, in any form, or by any means, without prior written permission from the publisher, to whom all requests to reproduce copyright material should be directed in writing. This authorization does not extend to any other kind of copying, by any means, in any form, and for any purpose other than private research use. ISSN 1175-5326 (Print edition) ISSN 1175-5334 (Online edition) Zootaxa 3602 (1) ? 2013 Magnolia Press ? 3REVISION OF OCTOCORAL GENUS THOUARELLA Table of contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 History of Thouarella systematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Biology and reproduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Historical summary of the Thouarella species groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Antarctica gruppe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 K?llikeri-gruppe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Hilgendorfi-gruppe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Species groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Thouarella morphology and characters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Branching structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Polyp shape, arrangement, and distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Sclerites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Species synonymisations and removals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Reliability of some of the morphological characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Did Thouarella originate in the Antarctic? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Species descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Illustrated dichotomous key to Thouarella species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Systematic Account . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Group 1?isolated polyps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. Thouarella antarctica (Valenciennes, 1846) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. Thouarella variabilis Wright and Studer, 1889. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3. Thouarella brevispinosa Wright and Studer, 1889, new rank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4. Thouarella affinis Wright and Studer, 1889 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 5. Thouarella koellikeri Wright and Studer, 1889 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 6. Thouarella brucei Thomson and Ritchie, 1906. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 7. Thouarella striata K?kenthal, 1907 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 8. Thouarella crenelata K?kenthal, 1907 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 9. Thouarella clavata K?kenthal, 1908. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10. Thouarella pendulina (Roule, 1908) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 11. Thouarella chilensis K?kenthal, 1908. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 12. Thouarella hicksoni Thomson, 1911 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 13. Thouarella bipinnata Cairns, 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 14. Thouarella viridis Zapata-Guardiola and L?pez-Gonz?lez, 2010a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 15. Thouarella minuta Zapata-Guardiola and L?pez-Gonz?lez, 2010a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 16. Thouarella andeep Zapata-Guardiola and L?pez-Gonz?lez, 2010b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 17. Thouarella parachilensis sp. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Species Group 2?polyps in pairs or whorls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 18. Thouarella hilgendorfi (Studer, 1878). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 19. Thouarella moseleyi Wright and Studer, 1889 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 20. Thouarella laxa Versluys, 1906. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 21. Thouarella tydemani Versluys, 1906. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 22. Thouarella coronata Kinoshita, 1908 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 23. Thouarella parva Kinoshita, 1908 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 24. Thouarella biserialis (Nutting, 1908) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 25. Thouarella grasshoffi Cairns, 2006. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 New species combinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Plumarella diadema (Cairns, 2006), new combination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Plumarella recta (Nutting, 1912), new combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Plumarella alternata (Nutting, 1912), new combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Plumarella superba (Nutting, 1912) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Plumarella bayeri (Zapata-Guardiola and L?pez-Gonz?lez, 2010b), new combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Plumarella undulata (Zapata-Guardiola and L?pez-Gonz?lez, 2010b), new combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Dasystenella acanthina (Wright and Studer, 1889) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 TAYLOR ET AL.4 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Abstract A comprehensive revision of the genus Thouarella is presented. Thirty-five holotypes of the 38 nominal Thouarella species, two varieties, and one form were examined. The number of original Thouarella species has been reduced to 25, mostly through synonymy or new genus combinations. In the process several new species have also been identified, one of which is described here as Thouarella parachilensis nov. sp. The genus is split into two groups based on polyp arrangement: Group 1 with isolated polyps and Group 2 with polyps in pairs or whorls. An illustrated dichotomous key and detailed character table of the 25 Thouarella species are presented alongside an up-to-date account of all species described in the 19th and 20th centuries and summaries of the few described from 2000 onwards. We propose that Thouarella longispinosa is synonymous with Dasystenella acanthina, T. versluysi with T. brucei, and, T. tenuisquamis, T. flabellata, and T. carinata are synonymous with T. laxa. Lastly, we propose that T. bayeri and T. undulata be placed in Plumarella and support recent suggestions that T. alternata, T. recta, T. superba, and T. diadema are also Plumarella. Key words: Cnidaria, taxonomic revision, sub-Antarctic, octocoral Introduction Thouarella Gray, 1870 is a genus of primnoid octocorals within the class Anthozoa. Octocorals usually have small calcium carbonate sclerites over or within their tissue (with a few notable exceptions, discussed in Alderslade & McFadden 2007). Within octocorals there are a wide variety of sclerite shapes and sizes (Bayer et al. 1983) serving different functions, such as limiting adjacent sclerite movement, giving rigidity and support, as well as flexibility (Lewis & Wallis 1991). Primnoids, with the exception of one species of Mirostenella Bayer, 1988, which has a jointed axis, have solid continuous, calcified gorgonin axes (Cairns & Bayer 2009). They are found worldwide but are especially common in the Antarctic seas and Southern Ocean (Thouarella is no exception) and predominantly occur deeper than 400 m, with the deepest record from 5850 m (although primnoids have been recorded from 8 m depth; Cairns & Bayer 2009). Thouarella is an architecturally delicate genus in which the majority of species have flower-like, open operculate polyps covered with thin sclerites. Species of Thouarella are locally abundant in many areas of the deep sea, especially in the sub-Antarctic, and play an important ecological role, providing habitat for many other animals from a variety of phyla. Although relatively common, little research has focused on species identifications beyond the original type descriptions, many of which are from the turn of last century. Often considered the ?bottlebrush? genus, Thouarella spp. in fact have a range of branching forms, similar to several other genera, resulting in specimens being frequently misidentified. Thouarella is a group of very closely related species; their morphology and many characters historically used to separate species and subgenera are variable and the genus is in need of further revision. Having reviewed all available holotypes we present the most thorough review of this ecologically important genus to date. This has resulted in significant changes to the understanding of several species within this genus and the key characters used for species identification. Abbreviations NHM?Natural History Museum, London, UK. NMNH?National Museum of Natural History, Smithsonian Institution, Washington DC, USA. MNHN?Mus?um National d?Histoire Naturelle, Paris, France. MNHWU?Museum of Natural History, Wroclaw University. SMF?Senckenberg Forschungsinstitut und Museum Frankfurt. UMUT?University Museum, University of Tokyo. ZMA?Zoological Museum, University of Amsterdam. ZMH?Zoological Museum, University of Hamburg. ZMB?Zoologisches Museum, Berlin. ZSL?Zoological Society of London, Institute of Zoology. MYA?million years ago ZGR?Zapata-Guardiola, Rebeca SJ?Schleyer, Jon Zootaxa 3602 (1) ? 2013 Magnolia Press ? 5REVISION OF OCTOCORAL GENUS THOUARELLA History of Thouarella systematics The type species of Thouarella Gray, 1870 was originally described as a species of Primnoa Lamouroux, 1812 by Valenciennes in the report from the 1836?1839 Venus expedition (1846). A brief mention of P. antarctica appears in Valenciennes (1855a) although merely as a referenced example of one of the five gorgonian forms??the fifth form consist[ing] of larger or smaller scales, more or less covered with small spines? (taken from the English translation of Valenciennes, 1855b; p. 179). When the classification of gorgonians was reorganised by John Edward Gray in 1857, primnoids were placed under Lithophyta. Two species of Primnoa were described in Gray?s 1859 paper: P. lepadifera Gray, 1859 (now P. resedaeformis) and P. antarctica Gray, 1859. These species were separated by their branching morphology with the former described as ?tree-like? and the latter with ?spreading branches? (p. 483). Primnoa antarctica was then listed in K?lliker?s 1865 gorgonian descriptions under Primnoaceae, but it wasn?t until 1870 that Thouarella was established by Gray who named the genus after the captain of the Venus expeditions, Abel Du Petit-Thouars. At this point the description was of a bottlebrush morphology but the finer details of morphology were unclear as ?polyp-cells smooth, bell-shaped, scattered on upper side of branches, covered with four or five series of imbricate scales? (Gray 1870: 45) are listed as defining characters. Gray described and illustrated a new specimen of Thouarella antarctica in 1872 (catalogue number NHM1872.4.29.1). It is unclear if he ever sought out the holotype from Paris Museum because, having studied Gray?s 1872 specimen, it appears to be T. brucei Thomson & Richie, 1906. FIGURE 1. First illustration of Thouarella antarctica (from Valenciennes 1846): a) full colony; b) close up of polyps. TAYLOR ET AL.6 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The next major work concerning Thouarella was Wright & Studer (1889) whose descriptions of samples from the H.M.S. Challenger expedition included four new species (T. moseleyi Wright and Studer, 1889, T. affinis Wright and Studer, 1889, T. koellikeri Wright and Studer, 1889, and T. variabilis Wright and Studer, 1889, the latter including three varieties) and a reclassification of Plumarella hilgendorfi Studer, 1878 to T. hilgendorfi. They listed a specimen of Thouarella antarctica, however, the sclerites (Wright and Studer 1889, pl. 11, fig. 6) of the specimen only loosely resemble those of T. antarctica (Figs 4, 5 herein). Versluys (1906: 36) expressed some doubt over Wright and Studer?s T. antarctica identification, although he still classified the sample as T. antarctica putting any physical differences down to depth variation. Several Thouarella species were described from 1906 to 1912: Thomson and Richie (1906) described T. brucei; Versluys (1906) described T. laxa and T. tydemani, and split Thouarella into three groups (?Hilgendorfi?, ?isolated? and ?Antarctic?); in 1907 Kinoshita described T. typica, and in 1908 Roule described T. pendulina; Kinoshita (1908a) assessed Primnoidae and subsequently (1908c,d) added two new species, T. coronata and T. parva, and a new subgenus, Diplocalyptra, as well as placing Amphilaphis biserialis Nutting, 1912 within Thouarella (1908c). K?kenthal began work on Thouarella between 1907 and 1915, describing nine new species (see Table 1) and two new subgenera, Epithouarella and Euthouarella (K?kenthal 1907, 1908, 1912, 1915). Thomson described T. hicksoni in 1911 and finally, Nutting (1912) described T. alternata, T. recta, and T. superba. Thomson and Henderson (1906) published a comparison table for Thouarella species, however, it was K?kenthal (1915; 1919; 1924) who wrote the major diagnostic keys for this genus. The subgenera of Thouarella in 1915 stood as: Amphilaphis Studer, 1887?differentiated on dichotomous branching mode; Euthouarella K?kenthal, 1915?polyps in pairs or whorls of up to four; Parathouarella K?kenthal, 1915?isolated polyps with spined, leaf-shaped marginals; Epithouarella K?kenthal, 1915?isolated polyps with marginals lacking a long spine. K?kenthal did not discuss the subgenus Diplocalyptra (species with dichotomous branching), described by Kinoshita (1908a), presumably not knowing of its existence as most of Kinoshita?s work was written in Japanese. As Parathouarella included the type species T. antarctica it was thus redundant and from 1956 Parathouarella was simply called Thouarella (Thouarella) (see Bayer 1956). Amphilaphis was removed from Thouarella by Kinoshita (1908b), however this removal was not mentioned or followed in later papers by K?kenthal (1912; 1915; 1924). In 1981 Bayer treated Amphilaphis as a valid genus on the basis that it has eight full rows of body-wall scales rather than the six rows of body-wall scales plus two reduced adaxial rows, as found in Thouarella (Cairns & Bayer 2009). Brito (1993) merged Amphilaphis with Thouarella based on Bayer?s exclusion of the genus in a purported 1988 paper that we cannot locate and is not listed in the references. Thus, although Amphilaphis is very similar to Thouarella in many respects (discussed in the Thouarella genus description), in this study we consider only the so-called ?original? Thouarella species and those incorporated into Thouarella in peer-review journals up to the end of 2010 (see Table 1). The genus Amphilaphis has recently been revised by Zapata-Guardiola & L?pez-Gonz?lez (2012). Aurivillius (1931) described T. hilgendorfi forma plumatilis after which there was a 60 year hiatus in Thouarella descriptions until Cairns (2006) provided a revised species list and described three new species. Additionally, in the last few years, five new species of Thouarella have been described from Antarctica (Zapata- Guardiola & L?pez-Gonz?lez 2010a,b). As exploitation of the deep sea (fisheries, oil and gas production, mining resources etc) and scientific exploration spread to wider geographical locations and depths, there shall likely be more Thouarella species described. Biology and reproduction Octocoral reproduction, environmental/biological cues, and factors affecting reproduction have been studied extensively in shallow water tropical and temperate latitudes but less study has focused on octocoral reproduction in the deep ocean, e.g. Bayer (1996), Brito et al. (1997), Cordes et al. (2001), Slattery and McClintock (1997), Orejas et al. (2002, 2007). Considering only Antarctica, reproductive patterns across many animals are mostly defined by characteristics such as prolonged gametogenesis, delayed maturation, low fecundity, large yolky eggs, and in many cases, predominance of non-pelagic or at least lecithotrophic development, brooding, brood protection, viviparity, slow embryonic development, advanced newly hatched juvenile stages, and slow growth (Pearse et al. 1991). A recent study of three primnoid species suggested that morphology may play a role in Zootaxa 3602 (1) ? 2013 Magnolia Press ? 7REVISION OF OCTOCORAL GENUS THOUARELLA reproductive output, with bottlebrush-shaped Dasystenella acanthina (Wright and Studer, 1889) and a Thouarella species having over-lapping generations of more than one a year, and fan-shaped Fannyella rossi Gray, 1872 and F. spinosa (Thomson and Rennet, 1931) having annual reproduction (Orejas et al. 2007). A relationship between morphology and reproductive output has also been suggested by studies on gorgonians from lower latitudes (Brazeau & Lasker 1989). These studies, however, represent a very limited sample size and phylogenetic representation. Much more research is required on reproduction, life histories, and molecular ecology of octocorals to help understand patterns of population connectivity and factors effecting reproductive success. Materials and Methods We (MT) examined all available type specimens (35 of the 38 holotypes were procured and examined) and hundreds of additional specimens, the majority of which were from the USNM and the SMF. The unseen holotypes are those of: T. tydemani Versluys, 1906, which was not seen first hand but detailed images of the remaining three slides of material (taken by ZGR) were examined; the colony T. parva Kinoshita, 1908d, is missing from the University of Tokyo museum and unsuccessful attempts were made to locate non-type material, and thus the description relies entirely on original hand drawings of one polyp and sclerites (Kinoshita 1908d); the colony of T. crenelata K?kenthal, 1907 was not able to be sent from ZMB, however this species has some distinct and recognisable characters (K?kenthal 1907) so scanning electron microscopy (SEM) images were obtained from voucher specimens held within USNM collections. Methods When viewing primnoid polyps under a stereo dissecting light microscope it is useful to dye them using a permanent light-coloured marker pen that highlights sclerite texture and outline. Flattened art clay provides a tacky surface for rolling polyps across so it is possible to view all sides and count the number of scales. To view individual sclerites a polyp was first submerged in ethanol, held gently between tweezers, and a small, soft paintbrush swiped gently over surfaces to remove sand, tissue and other items that may obscure the viewing of sclerites. Polyps were then dissolved in a drop of sodium hypochlorite (bleach). Once free, sclerites were washed with distilled water several times to remove all remnants of bleach. Sclerites were then washed with 70% ethanol and several successively stronger ethanol solutions, up to 95%, before being air-dried. These dried sclerites were placed on stubs for SEM. An eyelash or piece of hair embedded in a lump of art clay on the end of a pencil was useful for manoeuvring individual sclerites onto SEM stubs (similar to methods described in Alderslade 1998). Similarly, a fine-hair brush with all but two hairs removed was equally useful for this task. Modern morphological studies of primnoids rely on SEM images. All images within this publication were taken from stubs coated in gold:palladium 60:40 alloy, to a thickness of between 30?40 nm, at the Smithsonian Institution SEM Laboratory on an Amray 1810 SEM with Lanthanumhexaboride electron source and at Cambridge University Department of Materials, on a JEOL GSM?6340F Field Emission SEM. Results Historical summary of the Thouarella species groups Versluys (1906) first grouped Thouarella species into the ?Hilgendorfi-Gruppe? (species with polyps in pairs and whorls), species with isolated polyps (without a group name), and the ?Antarctica-Gruppe?, which also has isolated polyps. K?kenthal (1912) again grouped Thouarella species (?Hilgendorfi-gruppe?, ?Antarctica-gruppe? and ?K?llikeri-gruppe?, with the latter having isolated polyps but being differentiated by having a longer marginal scale spine than those remaining in the ?Antarctica-gruppe?) and later elevated these groups to subgenera (1919). With Amphilaphis removed (Kinoshita 1908a; Bayer 1981) and Diplocalyptra incorporated (Kinoshita 1908c), Thouarella had subgenera separated according to colony branching, polyp placement (whorled, paired, isolated), and the elongation of the distal edge of the marginal scales (Cairns & Bayer 2009). TAYLOR ET AL.8 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Antarctica gruppe Within Group 1 (isolated polyps) there are a number of very closely related species separated by the smallest of variations in characters. In particular the ?Antarctica-gruppe? (Versluys 1906) deserves mention because some of these species could be considered a single, variable species. Versluys originally only listed T. antarctica (Valenciennes, 1846), T. affinis Wright and Studer, 1889, and T. variabilis Wright and Studer, 1889, of which we disregard T. variabilis as it has very long marginal scales making it distinct from the remaining species. Versluys (1906) grouped these species as they had isolated polyps and a bottlebrush colony arrangement. K?kenthal (1912) considered the ?Antarctica-gruppe? to include: T. antarctica, T. affinis, T. chilensis K?kenthal, 1908, and T. crenelata. He mentioned that isolated polyp arrangement was a more conservative character than branching arrangement, something with which we agree. K?llikeri-gruppe This includes T. koellikeri Wright & Studer, 1889, T. variabilis, T. versluysi K?kenthal, 1907, T. striata K?kenthal, 1907, T. clavata K?kenthal, 1908, T. brucei Thomson and Richie, 1906, and T. hicksoni, Thomson, 1911?species with isolated polyps and foliate, elongated marginal scales. In 1919, K?kenthal rearranged the entire genus, moving T. antarctica into the ?K?llikeri group?, as it has relatively tall marginal scales, leaving T. crenelata, T. chilensis, and T. affinis in the ?Antarctica gruppe? with isolated polyps and shorter marginal scales. It is this latter group where there are now a number of very similar species. As described in detail in the species comparisons after the description of T. antarctica, there are relatively small, but apparently consistent, differences separating these species and it will be interesting to investigate their genetic relatedness, work that is currently underway. Hilgendorfi-gruppe On a species level there are many changes within Thouarella in this paper. One deserving special mention is the Hilgendorfi complex of species (?hilgendorfi-gruppe? sensu, K?kenthal 1912). In 1906, Versluys placed T. hilgendorfi (Studer, 1878), T. laxa Versluys, 1906, T. moseleyi, and T. tydemani into the T. hilgendorfi group. In 1912, T. typica Kinoshita, 1907, T. longispinosa K?kenthal, 1912, T. carinata K?kenthal, 1908, T. tenuisquamis K?kenthal, 1908, and T. flabellata K?kenthal, 1907 were added to this group by K?kenthal. Some 100 years later we find ourselves approaching a similar task in assessing these species whose identifying feature is their paired or whorled polyp arrangement. Disregarding T. longispinosa, which is now considered to be Dasystenella acanthina (see species description), this group now looks quite different because of several synonymisations. Thouarella laxa was described from Japan by Versluys (1906). The following year K?kenthal (1907) described T. flabellata from Somalia, and T. tenuisquamis (originally described as Thouarella regularis K?kenthal, 1907) from Nicobar, northwest of Sumatra, briefly stating the latter could be similar to T. laxa. K?kenthal did not specifically compare these species to each other or T. laxa, perhaps because of the large distance between their type localities. In 1908, K?kenthal described T. carinata from Okinawa and subsequently remarked that it differed from T. laxa in having branchlets and polyp whorls that were more densely placed, as well as different sclerite shapes (K?kenthal 1919). The differences seen between these species in this study are very minor (as discussed in species descriptions) and for this reason we conclude that these species (T. laxa, T. tenuisquamis, T. flabellata, and T. carinata) are conspecific and propose their synonymisation under the senior synonym T. laxa. K?kenthal (1924) separated T. tydemani and T. laxa based on the number of whorls per cm (4?6), which is a variable character, but polyps of T. laxa (Fig. 32c) look very similar to those of T. tydemani (see Zapata-Guardiola & L?pez-Gonz?lez 2010a). A recent paper (Zapata-Guardiola & L?pez-Gonz?lez 2010a) shows that T. tydemani polyps have toothed ridges on the inner surface of body-wall scales; these are absent in T. laxa. Thouarella moseleyi has similar body-wall scale morphology, however, the reduced height of marginal scales and the clavate polyp shape make T. moseleyi distinct from both T. tydemani and T. laxa. Thouarella laxa has bottlebrush-shaped colonies and colonies of T. tydemani are pinnate. The former has polyps that are more inclined to the branchlet than the latter species (whose polyps are almost perpendicular to the branchlet) that also has longer, more flexible branchlets, and less pairs/whorls per cm, making these distinct species. The sclerites, number of whorls per cm, and number of polyps per whorl of T. hilgendorfi and T. typica are nearly identical, and as these character differences can vary widely within colonies and species, we agree with Cairns (2010) that these two species should also be synonymised. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 9REVISION OF OCTOCORAL GENUS THOUARELLA The ?hilgendorfi? group thus includes: ? T. hilgendorfi (synonym: T. typica) ? T. laxa (synonyms: T. tenuisquamis, originally described as T. regularis, T. flabellata, T. carinata) ? T. moseleyi ? T. tydemani In essence, the polyps and sclerites of all of ?Hilgendorfi? species (with the exception of T. moseleyi, whose polyps are clavate) have nearly identical shapes and sizes. It is astounding that species looking so similar are found from Hawaii (T. hilgendorfi) to east Africa (T. laxa, formerly T. flabellata). We have kept these species separate based on branching structure but would be interested to see if genetic studies support this distinction; this research is currently underway. New Thouarella species groups As already mentioned, before this revision Thouarella had subgenera separated according to colony branching (Diplocalyptra), polyp placement (whorled and paired?Hilgendorfi group, isolated?Antarctica and K?llikeri groups), and the elongation of marginal scale distal edges (with the K?llikeri group having longer marginals than Antarctica group species; Cairns & Bayer 2009). We query the reliability of two of these characters as colony branching can vary within a species (Thouarella seems particularly variable in this respect, making this character unsuitable for subgeneric separation), and the entire spectrum of elongation of the distal edge of marginal scales, from rounded to spinose, can be found in Thouarella making this character also a poor choice for assigning species to subgenera. Polyp placement, however, is a more reliable character; species with isolated polyps are easily distinguished from those with paired or whorled polyps and, although some species with paired polyps infrequently have whorls of three and even four polyps, this is very rare in species with isolated polyps. Consequently, given that Thouarella species are very closely related, we acknowledge this close relationship by splitting Thouarella into species groups rather than subgenera. Furthermore, as discussed above, the most reliable character available to group Thouarella species is polyp placement and it is on this character that we, as partially done by Versluys (1906), base our species group delineations (Table 1): Group 1?species with isolated polyps and Group 2?species with polyps in pairs or whorls. Group 1 would thus include both Antarctica and K?llikeri groups. The Hilgendorfi group is now in Group 2. Within Group 1 the number of abaxial body-wall scales, polyp size, number of polyps per cm, and polyp shape are equally important when determining species. Group 2 species have very similar polyps and differentiation is based primarily on branching arrangement and branchlet rigidity. See Table 3 for more details. Thouarella morphology and characters Branching structure The most common Thouarella branching structure is a bottlebrush form, with branchlets arranged on all sides of the main stem in at least three directions. Thouarella species are also pinnate (featherlike branching with branchlets on each side of branch), pinnate to bipinnate (pinnate branching where branchlets are also pinnately branched), dichotomous (repeated bifurcation of branching; Bayer et al. 1983) and bilateral to bottlebrush (where branchlets occur in at least three directions, and are thus technically bottlebrush, however branchlets can curve into one plane creating a bilateral appearance). Part of the colony of T. coronata is also considered to be sympodially branched (the main axis being formed by the basal sections of lateral branches, often forming a zigzag). In some instances, overall colony structure can be one shape and branching structure different, for example, T. hilgendorfi has a uniplanar, flabellate colony shape yet individual bottlebrush branches and branchlets. The complex morphological structure of Thouarella makes these octocorals ideal habitat for many species of epifauna. In this study specimens of Thouarella were often found harbouring polychaetes along their stem between branchlet planes, brittlestars clinging to branchlet tips, amphipods wedged between polyps, and egg cases and ascidians attached to stems and branchlets (Fig. 2). TAYLOR ET AL.10 ? Zootaxa 3602 (1) ? 2013 Magnolia Press TABLE 1. Thouarella species?Groups 1 and 2. Species Synonym(s) Distribution Group 1? Isolated polyps 1. T. antarctica (Valenciennes, 1846) Falkland Islands, SW Atlantic 2. T. variabilis Wright and Studer, 1889 T. variabilis var. gracilis Wright and Studer, 1889 Circum-Antarctic 3. T. brevispinosa Wright and Studer, 1889 SW Atlan., S. Indian Ocean 4. T. affinis Wright and Studer, 1889 SW to S. Atlantic 5. T. koellikeri Wright and Studer, 1889 SE Pacific, SW Atlan. Antarctic Peninsula 6. T. brucei Thomson and Richie, 1906 T. versluysi K?kenthal, 1907 Mid-S. Atlan., SE Pacific, Antarctic Peninsula 7. T. striata K?kenthal, 1907 Bouvet Isl., SW Atlan., Patagonian shelf 8. T. crenelata K?kenthal, 1907 Circum sub-Antarctic 9. T. clavata K?kenthal, 1907 South Africa 10. T. pendulina (Roule, 1908) Circum-Antarctic 11. T. chilensis K?kenthal, 1908 Chile, S/SW Atlantic, S. Indian Ocean, Antarctic Peninsula 12. T. hicksoni Thomson, 1911 South Africa 13. T. bipinnata Cairns, 2006 SW Atlantic 14. T. viridis Zapata-Guardiola and L?pez- Gonz?lez, 2010 South Georgia Island, Patagonian shelf 15. T. minuta Zapata-Guardiola and L?pez- Gonz?lez, 2010 Circum-Antarctica 16. T. andeep Zapata-Guardiola and L?pez- Gonz?lez, 2010 SW Atlan., circum-Antarctica 17. T. parachilensis nov. sp. South Georgia Island, Antarctic Peninsula Group 2? Paired or / whorled polyps 18. T. hilgendorfi (Studer, 1878) T. typica Kinoshita, 1907 Hawaii, Indonesia, Indian Ocean, Japan 19. T. moseleyi Wright and Studer, 1889 Kermadec, New Zealand, and Indonesia 20. T. laxa Versluys, 1906 T. tenuisquamis K?kenthal, 1908 T. flabellata K?kenthal, 1907 T. carinata K?kenthal, 1908 T. regularis K?kenthal, 1907 East Africa to east Asia 21. T. tydemani Versluys, 1906 ?Hookerella pulchella Gray, 1870 Indonesia 22. T. coronata Kinoshita, Japan 23. T. parva Kinoshita, 1908 Japan 24. T. biserialis (Nutting, 1912) Amphilaphis biserialis Hawaii 25. T. grasshoffi Cairns, 2006 N. Atlantic Zootaxa 3602 (1) ? 2013 Magnolia Press ? 11REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 2. Animals found within the branchlets of Thouarella specimens: a) Polychaete found along stem of the holotype of T. affinis; b) crinoid arboreal cup in branchlets of T. crenelata (ZSL AE57); c) anemone attached to branchlet of specimen of T. variabilis (SMF, MD42, sta. 22). TAYLOR ET AL.12 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Polyp shape, arrangement, and distribution Polyps of Thouarella are generally flared distally (this ranges from modest to widely flared) or clavate (having a tall, rounded operculum, visible from side view e.g., T. koellikeri, Fig. 12c, or a rounded polyp where the operculum is beneath encasing marginals and thus not visible, e.g., T. parachilensis nov. sp, Fig. 28c). Polyps open widely to take in food and this function, and the associated change in polyp shape, should be remembered when undertaking species identifications; polyps are not fixed in shape when alive. Thouarella polyps occur individually (isolated, e.g. T. crenelata, Fig. 18b), in pairs (e.g. T. laxa, Fig. 32c; T. laxa polyps also occur in whorls), or in whorls (e.g. T. coronata, Fig. 34c) of up to five. The density of polyps (number of polyps per cm) is often related, in some degree, to polyp size; there will be more 1 mm long polyps per cm than those 2.5 mm long. This is an important point to consider and the reason why we did not use the number of polyps/pairs/whorls per cm in the dichotomous key. However, this is still sometimes a useful factor in species identifications and can be useful as long as the polyp length in the species description is indicated. Polyp length is the length measured abaxially from polyp tip to base. Sclerites The variation and differences of size, shape, and arrangement of sclerites is used in species diagnosis. Review of the original literature pertaining to the identification of Thouarella indicated that the terms ?opercular?, ?circumopercular? and ?marginal? have been used in different ways at different times. To avoid confusion, all sclerite categories are defined below: Operculars (Fig. 3f?i) fulfill the functional role of covering and thus protecting the polyp head. There are eight operculars in Thouarella and they can be arrowhead-shaped (with a dented proximal edge, Fig. 3h,i), acute isosceles triangle/lanceolate-shaped (Fig. 3f) or tongue-shaped (rounded distal edge, Fig. 3g). They may or may not have a distinctive keel on their inner face. Accessory operculars (Fig. 3a?e) have been found in several Thouarella species. Originally noted by Kinoshita (1908b, pl. 5), they are smaller (250?500 ?m) than operculars, often of a similar shape, and usually adhere to the inner surface of typical operculars (and against the polyp body/tentacle-base); they tend to be found in one ring, although two rings have been described in Plumarella (formerly Thouarella) bayeri (Zapata-Guardiola & L?pez-Gonz?lez, 2010), and are often less than eight in number. Similar small operculars are found in Convexella Bayer, 1996 and Digitogorgia Zapata-Guardiola & L?pez-Gonz?lez, 2010. Marginals (Fig. 3j?l), or circumoperculars, are the transverse circle of scales most proximal to the operculars and tend to be the same size or larger than the operculars and usually fold over the operculars, forming a protective cone when the polyp contracts. There are eight marginals and the inner surface is keeled. These keels are diagnostic at the genus level; their presence is the only character that separates Thouarella from Plumarella (Cairns, 2010). Submarginals (Fig. 3m?o) are the next most proximal transverse circle of scales below the marginals. They are sometimes differentiated from body-wall scales in having a more pointed distal edge and occasionally a reduced keel on the inner surface and are thus often specifically included in species descriptions. Body-wall scales (Fig. 3p?s) generally form the majority of scales covering the polyp body in longitudinal rows beneath the submarginals to the polyp base. Body-wall scales usually progressively reduce in size from the abaxial side of a polyp to adaxial. Body-wall scales have tubercles covering the inner surface, as is common for the proximal third to two-thirds of most sclerites. From the marginals to the polyp base the number of scales in each transverse circle often decreases as the polyp diameter attenuates. Coenenchymal scales form one or two layers along branches. Most sclerites within the categories described above are generally the same shape however, in contrast, coenenchymal scales are often a range of shapes: circular, oval and elliptical, possibly because all edges are free to grow. Other commonly used terms and structures include: Keels are an important characteristic in Thouarella species. They are found on the inner surface of the operculars, marginals, and sometimes submarginals. Plumarella and Thouarella may look very similar but the presence of a keel on the marginals determines that a species is in the genus Thouarella, not Plumarella (Cairns 2010). Within Thouarella there are simple keels (Fig. 3k), complex multi-keels (Fig. 3l), channelled keels (Fig. 3j), keels with lateral projections (visible from the outer surface e.g. Fig. 5h), and, unsurprisingly with the high level of variability in Thouarella, there are specimens that can span two of these forms. The text below is provided to enable the reader to understand our descriptions of keeled marginals (although operculars and submarginals also bear keels): Zootaxa 3602 (1) ? 2013 Magnolia Press ? 13REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 3. Examples of sclerite categories. Accessory operculars: a) Thouarella chilensis; b,c) T. hicksoni; d,e) T. coronata. Operculars: f) T. clavata; g) T. affinis; h) T. koellikeri; i) T. antarctica. Marginals: j) T. variabilis; k) T. affinis; l) T. crenelata. Submarginals: m) T. coronata; n) T. koellikeri; o) T. hicksoni. Body-wall scales: p) T. clavata; q) T. hicksoni; r,s) T. parachilensis sp. nov. Coenenchymal scales: t) T. laxa; u) T. crenelata; v) T. antarctica. TAYLOR ET AL.14 ? Zootaxa 3602 (1) ? 2013 Magnolia Press T. brucei marginals have a multi-keel (Fig. 15f), the most common type amongst Thouarella species, often with small lateral projections visible from the outer surface, as with the marginals of T. antarctica (Fig. 5h). T. affinis has marginals with a simple, single keel (Fig. 11h). T. variabilis has marginals that are spinose but flat, with a channelled keel (Fig. 3j). Plumarella diadema (Cairns 2006) (formerly Thouarella diadema) has a long spine (circular in cross-section), which is unkeeled but has longitudinal parallel channels (a bifurcate example of which is seen in Fig. 36d). The term serrated is often applied to the distal edge of sclerites (see distal edges of T. brucei, Fig. 15g). In Thouarella most sclerite edges are actually finely serrate (see Figs 3g,n,o). Coarsely or roughly lobate (e.g. Fig. 3j,p,r) has been used to describe the uneven, sometimes tuberculate proximal edges of most Thouarella sclerites. Pectinate is truly comb-like and only found in Plumarella recta (Nutting, 1912) and P. alternata (Nutting, 1912), which were both formerly placed in Thouarella. Species synonymisations and removals As of 2010, we consider there to be 25 species within Thouarella (Table 1). In the dichotomous key, scale bars are included and are usually the same within each couplet (e.g. 6a and 6b). This was not possible with colony images as their size differed enormously, thus colony/branchlet lengths are listed. Several species of Thouarella are proposed for synonymisation within this study. Thouarella laxa Versluys, 1906, T. tenuisquamis K?kenthal, 1908, T. flabellata K?kenthal, 1915 and T. carinata K?kenthal, 1915 are proposed as conspecific and thus synonymised with the senior synonym T. laxa. In addition, Thouarella variabilis var. a Wright and Studer, 1889 and T. variabilis var. gracilis Wright and Studer, 1889 are proposed as synonymised under T. variabilis, and T. variabilis var. brevispinosa Wright and Studer, 1889 raised to species level (T. brevispinosa). We also propose that Thouarella versluysi K?kenthal, 1907 is synonymised with T. brucei Thomson and Ritchie, 1906. Plumarella sardana (formerly Thouarella sardana) (Zapata-Guardiola & L?pez-Gonz?lez, 2010) and P. diadema (formerly T. diadema) (Cairns, 2006) are conspecific and thus synonymised as P. diadema; in agreement with Cairns (2011). Lastly, mostly as a result of the clarification of the difference between Plumarella and Thouarella (Cairns 2010), the species listed in Table 2 have been removed from Thouarella. TABLE 2. Species removed from Thouarella genus. Reliability of some of the morphological characters K?kenthal created his last key for Thouarella species in 1924. In it the number of abaxial scales and whorls of polyps per cm are used to differentiate between the many species. We believe that these characters are far from fixed and can vary substantially within a colony making K?kenthal?s key unreliable, as he did not allow for ranges within these characters. That said, the number of polyps per cm is still important in species identification with the consideration that this value can be modestly variable. Colony formation can be altered by the presence of annelid commensals that induce branchlets to flatten and curve to form tube-like tunnels along axes (Brito 1993); this must be considered when looking at specimens. However, by examining where branchlets depart the stem, the arrangement can be recognised. Colonies of Thouarella encapsulate a range of forms including: pinnate, dichotomous, bottlebrush, bottlebrush but appearing Old combination/ name New combination / synonym T. diadema Cairns, 2006 T. recta Nutting, 1912 T. alternata Nutting, 1912 T. superba Nutting, 1912 T. bayeri Zapata-Guardiola and L?pez-Gonz?lez, 2010b T. undulata Zapata-Guardiola and L?pez-Gonz?lez, 2010b T. longispinosa K?kenthal, 1912 Plumarella diadema Plumarella recta Plumarella alternata Plumarella superba Plumarella bayeri n. comb. Plumarella undulata n. comb. Dasystenella acanthina (Wright and Studer, 1889) Zootaxa 3602 (1) ? 2013 Magnolia Press ? 15REVISION OF OCTOCORAL GENUS THOUARELLA planar. This range of variation is unusual in just one octocoral genus (Bayer 1956; 1981). We consider polyp morphology (usually distally flared with 8 operculars and 8 keeled marginals) as the defining character for this genus. The range in number of abaxial polyp scales given in the species descriptions of Thouarella is necessary because polyps enlarge as they brood and coenenchymal scales at the polyp base appear to become part of the lower polyp body. Without this consideration, brooding specimens could be regularly misconstrued as different or new species. We suggested that many polyps of a colony, from the tip to the base of branchlets and from the tip to the base of the colony, be examined in species identification as variability within a colony is common. Generally, polyp placement (isolated, paired, whorled), the number of abaxial scales (which usually has a small range), the number of polyps per cm, and the colony form are the most important characters in identifying Thouarella species as they are relatively fixed and thus reliable. Beyond this, marginal scale shape, including the elongation of marginal distal edges, and average polyp size are also informative. A character that is considered less important within this study is the outer surface texture of sclerites. Around commensal tubes, polyps tend to have thicker, calcified sclerites (Brito 1993), as is commonly noted in other primnoids (Bayer 1964; Eckelbarger et al. 2005). Therefore, making use of sclerite texture alone for the purposes of taxonomy is ill-advised. Did Thouarella originate in the Antarctic? Several authors have discussed primnoid character evolution (Kinoshita 1908a; Versluys 1906; Cairns & Bayer 2009). Both Versluys (1906) and Kinoshita (1908a) thought it evolutionary advantageous for there to be fewer and larger scales on polyps, and this holds true in recent primnoid morphological studies. For instance, Primnoeides, with its simple opercular and numerous small body-wall scales not arranged in rows, is considered basal to all other primnoid genera (see Cairns 2006; Cairns & Bayer 2009). Many genera compared to Thouarella in this revision are unsurprisingly from within the same grouping in the phylogenetic analysis of morphological characters undertaken in Cairns and Bayer (2009). Most genera within this grouping occur in Antarctica, where the earliest clade within the Primnoidae, according to morphological analysis, also occurs, suggesting Antarctica could be the origin of the family (Cairns & Bayer 2009). Antarctica cooled around c. 42 MYA in the Eocene with a permanent ice sheet established from around 34 MYA (Tripati et al. 2005). These low temperatures and the break-up of the former supercontinent of Gondwana created an isolation that has made Antarctica?s present-day marine biota the world?s most distinctive and one of three centres of species origin globally (Briggs 2003). Prehistoric dispersals from Antarctica to other ocean basins and trenches have been proposed for other invertebrates, e.g. holothurians (Gebruk 1990, noted in Briggs 2003) and cephalopods (Strugnell et al. 2008). However, molecular phylogenetic analyses are required to confirm the origins of Primnoidae. It is noteworthy that population fragmentation and isolation in times of glacial maxima could have been important mechanisms for allopatric speciation in Antarctic fauna, increasing taxonomic diversity (Clarke & Crame 1989; 2010; Rogers 2007, 2012). Seventeen species of Thouarella are found in the Antarctic, sub-Antarctic and south Atlantic waters whereas just nine are known from the rest of the world (three from Japan, one from Asia to the Pacific, another from Asia to East Africa, one each from the North Atlantic, Indonesia, Hawai?i and South Africa). With high numbers of species from high latitudes of the southern hemisphere one could speculate that this region is the centre for radiation of Thouarella, however, as already mentioned, genetic studies are required to clarify this. Interestingly, all non-sub-Antarctic/Antarctic/southern Atlantic species, with the exception of T. hicksoni (from South Africa), fall within Group 2 (species with polyps in pairs/whorls). Polyps of Group 2 species look very similar, with species differing mostly in branching morphology (this is a tentative comment on branching morphology, as such small fragments of some holotypes remain). Group 2 species, as already mentioned, occur from East Africa to Hawaii, crossing the Indian and Pacific Oceans. It remains to be seen how important branching structure is in the evolution of Thouarella. Within primnoids at least, it does not appear to be very informative in determining phylogeny (Cairns & Bayer 2009). TAYLOR ET AL.16 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Illustrated dichotomous key to Thouarella species Zootaxa 3602 (1) ? 2013 Magnolia Press ? 17REVISION OF OCTOCORAL GENUS THOUARELLA TAYLOR ET AL.18 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Zootaxa 3602 (1) ? 2013 Magnolia Press ? 19REVISION OF OCTOCORAL GENUS THOUARELLA TA B LE 3 .T ab ul ar k ey f or th e sp ec ie s of T ho ua re ll a. G R O U P 1 Is ol at ed p ol yp s B ra nc hi ng p at te rn P ol yp a rr an ge m en t & d is tr ib ut io n ( po ly ps /c m ) P ol yp a ng le fr om b ra nc hl et P ol yp s ha pe P ol yp he ig ht (m m ) N o. o f sc al es in LA B O pe rc ul ar k ee le d? O pe rc ul ar s ha pe M ar gi na l k ee l M ar gi na l s ha pe U ni qu e ch ar ac te rs / C om m en ts T. b ip in na ta U ni pl an ar , p in na te to bi pi nn at e Is ol at ed , r ou gh ly al te rn at e 10 ?1 3 80 ?9 0? M od es tl y cl av at e 2. 4 3? 5 Y es , s im pl e w it h m ul ti pl e st ri at io ns L an ce ol at e to ar ro w he ad C om pl ex w it h la te ra l ex te ns io ns R ou nd ed b as e, p oi nt ed di st al ly C la va te , l ar ge p ol yp s, w it h ta ll o pe r. T. c la va ta bb ./ bi la te ra l a pp ea ra nc e Is ol at ed 45 ?6 0? D is ta ll y fl ar ed 1. 7? 2 6? 7 Y es , s im pl e, la rg e L an ce ol at e to tr i. S im pl e, f la t f ac ed tr i., a ng ul ar p ro xi m al ed ge V er y si m il ar to T . b ru ce i, re qu ir e m or e sp ec im en s T. k oe ll ik er i B us hy , b b. / b il at er al ap pe ar an ce Is ol at ed , 1 2? 15 45 ?6 0? C la va te , t al l, co ne d op er . 1. 6? 2. 5 7? 10 Y es , s in gl e, la rg e A rr ow -h ea de d/ is os ce le s tr i. L ar ge w it h sm al l la te ra l p ro je ct io ns S ho rt tr i., r ou nd ed la te ra lly R ou nd ed s ub m ar g. w it h sm al l k ee l T. a ff in is bb ./ bi la te ra l a pp ea ra nc e Is ol at ed , 7? 9 45 ?6 0? C la va te , r ar el y m od es tl y fl ar ed 1. 1? 2. 1 6? 7 Y es ,l ow m ul it -k ee l To ng ue / t ri . A b. s ca le w it h ke el ; ad . n o ke el o r st ri at io ns W id el y tr i. to d ia m on d C la va te /r ar e m od es t d is ta ll y fl ar ed p ol yp , d ia m on d m ar g. , to ng ue -s ha pe o pe rc ul ar s T. v ir id is B us hy , b b. / b il at er al ap pe ar an ce Is ol at ed , 1 4? 15 45 ?6 0? C la va te , t al l c on e 1. 5? 2. 5 6? 7 Y es , s in gl e, la rg e L an ce ol at e/ ar ro w he ad M ul ti- ch an ne l, ad ja ce nt s tr ia tio ns W id e tr i./ p en ta go na l O ft en g re en w he n al iv e T. b ru ce i B us hy , b b. / b il at er al Is ol at ed , 9? 12 40 ?4 5? D is ta ll y fl ar ed 1. 5? 2. 3 4? 5 Y es , s in gl e, la rg e tr i./ a rr ow he ad C om pl ex , m ul ti -k ee l, sm oo th la te ra ll y to ke el D ia m on d 4? 5 ab . s ca le s, o pe rc ul ar s ke el ed & tr i. T. a nd ee p B us hy , b b. / a lt er na te ly pi nn at e ap pe ar an ce Is ol at ed , 1 0? 11 80 ?9 0? D is ta ll y fl ar ed , t al l co ni ca l o pe r. 1. 9? 3. 4 4? 5 N o To ng ue -s ha pe d M ul ti -k ee l, ch an ne ll ed W id e tr i. L ar ge p ol yp , t al l o pe r. T. b re vi sp in os a bb . Is ol at ed , 7? 11 60 ? D is ta lly fl ar ed , o pe r. lo w er th an m ar gi na ls 2. 5? 3 6? 7 Y es , s im pl e, la rg e Is os ce le s tr i./ la nc eo la te C ha nn el le d ke el Ta ll tr i. S im il ar to T . b ru ce i, bu t m or e sc al es in L A B T. s tr ia ta bb ., co lo ny f la be ll at e Is ol at ed , 1 4? 20 45 ?8 0? D is ta ll y fl ar ed 1. 5? 2. 2 4? 6 Y es , m ul tip le lo ng itu di na l s tri at io ns L an ce ol at e W id e, f la t, ch an ne ll ed tr i. di st al ly , s qu ar e pr ox im al ly St ri at ed o ut er s ca le s ur fa ce *T . a nt ar ct ic a bb . Is ol at ed , 2 5? 30 a t ti p, 1 1? 23 o n br an ch le ts 60 ?8 0? M od es t d is ta l f la re 1. 6? 2. 3 5? 7 Y es , s im pl e, la rg e A rr ow he ad M ul ti -k ee l, w id e la te ra l p ro je ct io ns Ta ll tr i. T ig ht p ol yp p la ce m en t, tr ue bb ., la te ra l p ro je ct io ns to m ar g. k ee l T. c hi le ns is bb . Is ol at ed , 1 1? 23 45 ?8 0? M od es t d is ta l f la re , st ou t 2. 5? 2. 75 6? 8 Y es , m ul ti -k ee l tr i. to a rr ow he ad L at er al p ro je ct io ns tr i. C lu st er ed p ol yp s, o rn at e sc al e di st al e dg es T. c re ne la ta bb ., un ip la na r ap pe ar an ce Is ol at ed , 5 ?1 1, 8 ?1 9 at ti p 60 ?9 0? C la va te 2. 3? 3 6? 10 Y es , s in gl e. la rg e L an ce ol at e to ar ro w -h ea de d M ul ti -r id ge d, la te ra l ri dg es Fa n w it h cu rv ed o r po in te d di st al e dg e L ar ge s er ra te d is ta l e dg es o n sc le ri te s T. p ar ac hi le ns is bb ., co lo ny f la be ll at e Is ol at ed , 1 8? 48 a t ti p 45 ?9 0? C la va te , b ul bo us 2. 5? 2. 8 8? 15 Y es , s im pl e, m ul ti- ke el A rr ow he ad / la nc eo la te S im pl e w it h ad ja ce nt ri dg es E ll ip ti ca l w it h po in te d di st al e dg e B ul bo us p ol yp s in ? ba rr el ? cl us te rs a t t ip T. v ar ia bi li s bb . Is ol at ed , 5? 10 60 ? D is ta ll y fl ar ed 1. 5? 1. 85 4? 5 Y es , s im pl e, f la t fa ce d Is os ce le s tr ia ng le s C ha nn el le d Ta ll tr i., s pi no se S pi no se k ee le d m ar g. T. h ic ks on i bb . Is ol at ed , 1 6? 22 30 ? to ap pr es se d M od es tl y fl ar ed , op er . p oi nt ed 1? 1. 25 4? 5 Y es , s tr ia ti on s or si m pl e ke el To ng ue -s ha pe d C ha nn el le d Te ar -s ha pe d S m al l, cl us te re d po ly ps , to ng ue o pe rc ul ar s T. p en du li na bb . Is ol at ed , 2 7? 41 A pp re ss ed M od es tl y cl av at e, po in te d op er cu lu m 0. 9? 1. 2 4? 5 Y es , s im pl e tr i./ la nc eo la te M od es t s im pl e ke el S ho rt tr i. to d ia m on d S m al l, cl us te re d po ly ps , po in te d op er cu la rs T. m in ut a bb . Is ol at ed , 11 ?1 8 A pp re ss ed Ta pe re d di st al ly 0. 7? 1 3? 4 Y es , s im pl e Is os ce le s tr i./ sp oo n- sh ap ed S im pl e to s in gl e ch an ne ll ed R ou nd to di am on d- sh ap ed V er y sm al l p ol yp s G R O U P 2 Pa ir ed / w ho rl ed p ol yp s C ol on y sh ap e P ol yp a rr an ge m en t & d is tr ib ut io n P ol yp a ng le fr om b ra nc hl et P ol yp s ha pe P ol yp he ig ht N o. sc al es in L A B O pe rc ul ar k ee le d? O pe rc ul ar s ha pe M ar gi na l k ee l U ni qu e ch ar ac te rs / C om m en ts T. h il ge nd or fi U ni pl an ar fl ab el la te co lo ny , i rr eg ul ar d ic ho t. br an ch in g, b b. b ra nc he s P ai rs / w ho rl s of 3 45 ? D is ta ll y fl ar ed 1? 1. 4 6? 7 N o T ri . C ha nn el le d Ta ll tr ia ng le , s pi no se B ra nc he s bb ., sh or t, st ur dy br an ch le ts T. g ra ss ho ff i C ol on y ta ll er th an w id e, tr ue b b. Pa ir ed / r ar e w ho rl s of 3 , 7 ?8 45 ?6 0? M od es t d is ta l f la re m ax . 1 .3 5 Y es , r id ge s/ st ri at io ns Is os ce le s tr i. S im pl e, s om et im es w it h la te ra l p ro je ct io ns B ro ad b as e, te ar -s ha pe d T ru e bb . T. la xa bb ., ap pe ar s un ip la na r pi nn at e P ai re d/ w ho rl s of 3 , 5? 7 45 ?6 0? D is ta ll y fl ar ed 1. 2? 1. 5 5? 6 N o, r ar e st ri at io ns tr i., a pp ea r to ng ue -s ha pe d S im pl e, s in gl e ch an ne ll ed Ta ll tr i., c ir cu la r to di am on d ba se B ra nc he s bb ., fl ex ib le , l on g br an ch le ts T. m os el ey i U ni pl an ar p in na te P ai re d 90 ? C la va te w it h ta ll co ni ca l o pe r. 1. 5 4? 5 Y es , s im pl e T hi n to w id e la nc eo la te K ee le d ab ax ia l m ar gi na l, re m ai nd er w it h ri dg es D ia m on d P ol yp s cl av at e, 9 0? f ro m br an ch le ts T. ty de m an i U ni pl an ar , a lt er na te ly pi nn at e P ai re d/ , r ar e w ho rl s of 3 , 6 /c m 80 ?9 0? D is ta ll y fl ar ed ~1 .5 ~5 ? ? ? si m pl e, c ha nn el le d Ta ll tr i., s pi no se R id ge d di st al e dg e of bo dy -w al l s ca le s T. p ar va U ni pl an ar , d ic ho t. P ai re d, 6/ cm 45 ? Ta pe re d di st al ly , co ni ca l ~1 5? 6 Y es ? L an ce ol at e ? Ir re gu la rl y tr ia ng ul ar ? P ol yp s ta pe re d di st al ly , in cl in ed 4 5? T. c or on at a U ni pl an ar , d ic ho t./ sy m po di al b ra nc hi ng Pa ir ed / r ar e w ho rl s of 3 , 5 ?7 90 ? D is ta ll y fl ar ed 1. 9? 2. 1 5? 6 N o tr i./ la nc eo la te S m al l, m ul ti -k ee l E qu il at er al tr i. P ol yp s di st al ly f la re d, in cl in ed 9 0? T. b is er ia li s U ni pl an ar , d ic ho t.? P ai re d/ r ar e w ho rl s of 3 45 ? C la va te 1. 2? 1. 5 6? 7 N o L an ce ol at e to w id e tr i. M ul ti -k ee l tr i. P ol yp s cl av at e, 4 5? to br an ch le t *t yp e sp ec ie s of g en us L A B ? lo ng it ud in al a ba xi al r ow A bb re vi at io ns : s m . ? sm al l, op er . ? o pe rc ul um , m ar g. ? m ar gi na l, su bm ar g. ? s ub m ar gi na l, ab . ? a ba xi al , b b. ? b ot tl eb ru sh c ol on y m or ph ol og y (3 o r m or e di re ct io ns o f br an ch in g) , d ic ho t. ? di ch ot om ou s br an ch in g, tr i. ?t ri an gu la r. ?T ip ? r ef er s to b ra nc hl et ti p. TAYLOR ET AL.20 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Species descriptions All species descriptions are based on the holotype unless otherwise stated. Species are ordered first by group and then according to chronological precedence. All images of sclerites are of the holotype, paratypes, or syntypes, unless otherwise noted. Systematic Account Subclass Octocorallia Order Alcyonacea Suborder Calcaxonia Grasshoff, 19991 Family Primnoidae Milne-Edwards, 1857 Thouarella Gray, 1870 Primnoa Valenciennes, 1846: pl. 12, figs 2, 2a (only images); Milne-Edwards 1857: 140; Gray 1857: 286; 1859: 483; K?lliker 1865: 135 Thouarella Gray, 1870: 45; 1872: 746; Studer 1878: 649; 1887: 50; (in part), Wright & Studer 1889: 59?61 pl. 11, 14; Versluys 1906: 22?24; Thomson & Henderson 1906: 38?41 (comparison table); K?kenthal 1907: 202?208; 1908: 10?11; 1912: 292; (in part) Bayer 1961: 294 (key to genus); 1981: 936 (key to genus); Broch 1965: 24; Stibane 1987: 17?26, pl. 1(4), 2(4); Williams 1992: 277 Rhopalonella Roule, 1908: 2?3, pl. 1, figs 5?8 ?Hookerella Gray, 1870: 45 Thouarella (Diplocalyptra) Kinoshita 1908b: 454, 457 (key to subgenus), pl. 17, fig. 2 (in Japanese, English translation at USNM); 1908c: 517?519 (in Japanese, English translation at USNM); 1908d: 52 (key to subgenus, in German) Not Primnodendron Nutting 1912: 71?72, pl. 9, fig. 2, 2a; pl. 19, fig. 4 Thouarella (Epithouarella) K?kenthal 1915: 150?151 (key to subgenus and species); 1919: 435 (key to subgenus and species); 1924: 299 (key to subgenus and species); Bayer 1956: F220 Thouarella (Euthouarella) K?kenthal 1915: 149?150 (key to subgenus and species); 1919: 414?415 (key to subgenus and species); 1924: 292 (key to species); Bayer 1956: F220; Bayer & Stefani 1989: 455 (key to subgenus); Cairns 2006: 176, 187?188 Thouarella (Parathouarella) K?kenthal 1915: 150 (key to species); 1919: 425?426 (key to species); 1924: 296?297 (key to subgenus and species) Thouarella (Thouarella): Bayer 1956: F220; Bayer & Stefani 1989: 455 (key to subgenus); Cairns 2006: 176 Definition The colony consists of a main stem, generally simple with rare divisions. Branching is either pinnate, dichotomous, or in a bottlebrush manner (where it is branched in at least 3 directions). Polyps are isolated, paired, or in whorls, generally upwardly inclined at 45?90? from the branchlet. Polyp heads are wider than the base and completely protected by 5-8 rows of longitudinally arranged scales each of 5?15 (generally 5?8) scales. Adaxial body-wall scales are often reduced in size and number. A well-developed, conical operculum consists of 8 operculars; on rare occasions accessory operculars are found beneath the operculum. Opercular scales are lanceolate, arrowhead-shaped, or tongue-shaped, often with a keel. The operculum is surrounded by 8 marginals, often in 2 alternating rings of 4 because the operculum circumference is not large enough to accommodate 8 adjacent marginals. Marginals are keeled on their inner surface; keels are simple, channelled, or a complex multi-keel. Marginals often fold over the operculum, with the keel fitting into the concave outer opercular surface. Opercular scales are lanceolate, arrowhead-shaped, or tongue- shaped, often with a keel. Distribution A wide global distribution: South Africa, Chile, western Atlantic from Burdwood Bank to northern Florida, Japan, Aleutian Islands, Australia, Tasman Sea, New Zealand, especially common around Antarctica/sub-Antarctic. Found from 60?2100 m depth. 1. Calcaxonia are not monophyletic in recent phylogenetic studies (McFadden et al. 2006; Taylor et al., in prep), however a taxonomic revision has not been completed. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 21REVISION OF OCTOCORAL GENUS THOUARELLA Comparisons Thouarella was placed close to three genera within the most recent phylogenetic morphological analysis of Primnoidae (Cairns & Bayer 2009): Pyrogorgia Cairns and Bayer, 2009; Amphilaphis Studer and Wright, in Studer, 1887; and Convexella Bayer, 1996. The bottlebrush form of Thouarella can also be easily mistaken for several other genera with similar branching morphologies. Species of Convexella have marginal scales with a smooth inner surface whereas those of Thouarella have a keel. The only species of Thouarella that may be described as having the distinctive ?radiating spinose ridges? (Cairns & Bayer 2009) found on the outer surface of body-wall scales of Pyrogorgia, is T. striata. However, the polyps of the latter are isolated and the colonies bushy, which is very unlike the uniplanar, dichotomous colony shape and polyp whorls of Pyrogorgia species, making Thouarella and Pyrogorgia clearly distinct. According to Cairns and Bayer (2009) Amphilaphis differs from Thouarella in having polyps with eight ?complete? rows of body-wall scales, whereas the two adaxial rows of body-wall scales in Thouarella are relatively reduced in size. This scale size reduction is a particularly difficult character to quantify. Amphilaphis species are not considered within this revision as it was written prior to the recent revision of the genus Amphilaphis (Zapata- Guardiola & L?pez-Gonz?lez, 2012). Thouarella is most closely related, in terms of polyp morphology, to Plumarella and Amphilaphis. Species of Plumarella are uniplanar, often plumose, whereas only six species of Thouarella are truly uniplanar, although some bottlebrush arrangements are compressed giving a uniplanar appearance (e.g. T. brucei). The polyps of Plumarella species are usually placed in an alternately biserial manner (there are a few species with isolated polyps), whereas within Thouarella only T. bipinnata Cairns, 2006, T. minuta, and T. koellikeri have polyps that are approximately biserial. Marginal scales of Plumarella species are fixed, i.e. do not fold over the operculars (although this is a difficult character to judge, especially in species with long marginals, e.g. T. variabilis). Species of Plumarella have eight rows of body-wall scales; the number of scales in a row can be reduced adaxially, which is very similar to Thouarella. Polyps of Plumarella often stand at 90? to the branchlet, whereas those of Thouarella are mostly at 45?80?. All of these characters are not exclusive to either Thouarella or Plumarella. The only diagnostic character to separate the two genera is the presence or absence of keeled marginals; a keeled marginal is considered a character of Thouarella, unkeeled is Plumarella (Cairns 2010). As already mentioned, there are a number of genera with bottlebrush colonies that are often mistaken for Thouarella. The similarities and differences between these genera and Thouarella are listed below: Colonies of Dasystenella Versluys, 1906 have a bottlebrush formation and are often misidentified as Thouarella. Dasystenella primarily differs from Thouarella in having polyps with just five marginal scales, compared to eight in the latter. Only one species of Dasystenella has been described (D. acanthina) yet much variation was observed amongst specimens seen throughout this study. Dasystenella requires further investigation as there is likely more than one species (Cairns 2006). Although it has a bottlebrush colony shape, the newly described genus Tauroprimnoa Zapata-Guardiola & L?pez-Gonz?lez, 2010 differs from Thouarella in having polyps with only four marginals. The recently described bottlebrush genus Digitogorgia Zapata-Guardiola & L?pez-Gonz?lez, 2010 has marginals with a smooth inner surface and numerous irregular longitudinal rows of body-wall sclerites and is thus distinct from Thouarella. Fannyella (Scyphogorgia) Cairns and Bayer, 2009 also has a bottlebrush form and is separated from Fannyella (Cyathogorgia) Cairns and Bayer, 2009 only by branching morphology (the latter being dichotomously branched, verging on pinnate). Fannyella Gray, 1872 has ascus-type body-wall scales, which have a distinct boundary separating their exposed distal area from the covered proximal area, whereas Thouarella has even, unsectioned, non-ascus body-wall scales. Colonies of Parastenella Versluys, 1906 are mostly uniplanar, however, they can be bushy with isolated, paired, or whorled polyps and could be easily mistaken for Thouarella. The most distinctive difference between these two genera is the morphology of the distal border of the marginal scales of the polyps; marginal scales of Parastenella polyps have a fluted hollow structure whereas those of Thouarella are unfluted. TAYLOR ET AL.22 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Species Group 1?isolated polyps 1. Thouarella antarctica (Valenciennes, 1846) Figs 4, 5. Primnoa antarctica Valenciennes, 1846: pl. 12, figs 2, 2a (only images); Milne-Edwards 1857: 140; Gray 1857: 286; 1859: 483; K?lliker 1865: 135; Bayer 1956: F220 (list). Thouarella antarctica Gray 1870: 69; Wright & Studer 1889: 65?66, pl. 21 fig. 1; Thomson & Henderson 1906: 38 (list); Gravier 1914: 48?56, pl. 7 figs 31?34, pl.10 figs 52?55 (samples not seen); Molander 1929: 75 (samples not seen) Not Thouarella antarctica Hickson 1907: 9?10, pl. 2, figs 19, 24 (= unknown) Thouarella (Parathouarella) antarctica K?kenthal 1915: 150 (key); 1919: 433?435; 1924: 299 Not Thouarella (Euthouarella) antarctica Broch 1965: 24?26, pl. 2, figs 5?7 (= T. pendulina) Not Thouarella (Thouarella) antarctica Cairns & Bayer 2009: 27 (listed), 33?34, fig. 6g?l (= T. chilensis) Material examined: Holotype, MNHN, Oct.0000?208, 1836?1839 Venus expedition, Malouine Islands, Falkland Islands, depth unknown. Other material: ZMH, R/V W. Herwig, sta. 270, south of Falkland Islands, SW Atlantic, 53?00?S, 60?00?W, 375 m, 9 Feb 1971; ZMH, R/V W. Herwig, sta. 256, Burdwood Bank, SW Atlantic, 53?56?S, 63?40?W, 400 m, 6 Feb 1971; ZMH, R/V W. Herwig, sta. 311, off Patagonia, SW Atlantic, 46?54?S, 60?28?W, 480 m, 18 Feb 1971; ZMH, R/V W. Herwig, sta. 361, west of Falkland Islands, SW Atlantic, 51?55?S, 61?50?W, 200 m, 12 Jul 1966; NHM89.5.27.43, H.M.S. Challenger, sta. 148A, off Crozet Island, 46?53?S, 51?52?E, 1005 m, 3 Jan 1874; USNM 97965, R/V Hero, cruise 715, sta. 870, 54?34?S, 64?W, 84 m, 24 Oct 1971. Thouarella antarctica is the type species of Thouarella. Unfortunately, the holotype, held in MNHN, is in very poor condition. F.M. Bayer studied the holotype and identified one NMNH catalogued specimen as T. antarctica (USNM 97966). Having studied the holotype we disagree with Cairns and Bayer (2009) that USNM 97966 is T. antarctica; this is in fact T. chilensis as it has more scales in the abaxial row than is usual for T. antarctica, wider and thicker operculars, and marginal scales that are not smooth edged. Some additional specimens of T. antarctica, listed above, were found at SMF (belonging to ZMH). Description of sclerites and images herein are from three holotype polyps; no SEM images of whole polyps were taken as the specimen is too fragile and thus only an opercular view without a full complement of marginal scales was possible (Fig. 4e,f). Colony and polyp descriptions are from the specimens listed above. Description Colonies are sparsely branched. Branchlets depart the main stem in up to 5 directions from all sides of branches in a typical bottlebrush arrangement. The branchlets are generally simple, however some secondary branching occurs. The axis is yellow, tough, horny, and can be brittle towards the apex. The holdfast is calcareous. Polyps are isolated, 1.6?2.3 mm high (average 2 mm), and modestly flared distally; they project from all sides of the branchlet at 60?80?, and are tightly placed at 11?23 polyps per cm (such that, in lateral view, most polyps overlap), and are more clustered at branchlet tip (25?30). Some polyps occur on the main stem. There are 5?7 scales in each abaxial row (Fig. 4c), 5?6 scales in lateral rows and 8 longitudinal rows reducing to 5 at the polyp base. There are 2 circles of 4 operculars: one upper, one lower (Fig. 4e), and they can join to form a full cone, although sometimes there are gaps. Operculars are arrowhead-shaped (Fig. 5a-f), 415?820 ?m high (average 650 ?m), 200?480 ?m wide (330 average ?m), with a H:W of 1.7?2.1 (average 2) and have a longitudinally concave outer surface with granules radially arranged from a proximal centre, fading towards the distal edges. The inner opercular surface has a large, simple keel with several longitudinal striations, and the proximal half has densely arranged, small tubercles in the centre and serrated striations towards the distal edge. Lateral and distal edges are finely serrate; the proximal edge is coarsely lobate. Marginal scales are triangular (Fig. 5g?i), broader than operculars, 645?870 ?m high (average 760 ?m), 390?750 ?m wide (average of 600 ?m), and with a lower average H:W than the operculars (1.3, ranging from 1?1.7). The inner surface of marginals bears a complex multi-keel with lateral extensions (Fig. 5j), which can project beyond the scale edges, and thus be visible from the outer surface; tubercles cover the inner surface proximally and are found across the keel base. The outer surface is covered with granules radially arranged from the central proximal area. The distal area of the keel and the lateral edge of marginals are finely serrated; proximal edges are coarsely lobate and covered with tubercles. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 23REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 4. Thouarella antarctica. SMF, R/V W. Hertwig 1971, sta. 256: a) 21 cm colony; d) close up of branchlet. Holotype, MNHN, Oct.0000-208: b) holotype colony; c) abaxial polyp view; e) stereo opercular view of polyp, some marginals missing; f) opercular view of polyp with all marginals. TAYLOR ET AL.24 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 5. Thouarella antarctica, holotype, MNHN, Oct.0000-208: a,c) outer and b,d?f) inner surface of opercular scales; g,h) outer and i,j) inner surface of marginal scales; k,l) inner and m,n) outer surface of submarginal scales; o?q,s,t) inner and r,u,v) outer surface of body-wall scales; w) coenenchymal scales?inner surface top row first and second left, bottom row second left, remainder are of the outer surface. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 25REVISION OF OCTOCORAL GENUS THOUARELLA Submarginals are circular to widely elliptical in shape (Fig. 5k?n), 430?650 ?m high (average 760 ?m), 370?750 ?m wide (average 600 ?m), with a H:W of 1?1.7 (average 1.3), and tend to have a pointed distal edge, and a small median distal keel (Fig. 5m) or teeth on the inner surface. The scales directly beneath the submarginals are also sometimes modified in the same manner. Body-walls scales (Fig. 5o?v) form a variety of shapes from circular to elliptical. They are 380?460 ?m high, 440?530 ?m wide (average 420 and 500 ?m respectively), usually wider than high, having an average H:W of 0.85 (range from 0.7?1), with small and sometimes strong ridges on the distal edge of the inner surface (Fig. 5o,t). Sometimes the abaxial body-wall scale at the polyp base is very wide (Fig. 5o). The inner body-wall scale surfaces are covered with dense tubercules and the outer surfaces sparsely covered with granules sometimes arranged radially from the central area. The coenenchymal scales (Fig. 5w) are small, 160?330 ?m high, 190?380 ?m wide (average of 220 and 300 ?m respectively), with a H:W of 0.4?1 (average 0.75), irregularly circular to oval in shape with a regular distribution of peaked granules on the outer surface, and a dense arrangement of tubercules on the inner surface. All polyp sclerites usually have an irregularly coarse, lobate proximal edge and a finely serrate distal edge. Distribution This species is known from 500 km north of the Falkland Islands to the southern tip of South America, from 200?480 m depth. An unseen sample has been described from Crozet Island (1005 m depth, Wright & Studer 1889), so the bathymetric range may extend deeper and the geographic range further east. Remarks The holotype is from the Falkland Islands and consists of one branch broken off mid-stem (Fig. 4b). The original description of Thouarella antarctica (as Primnoa antarctica) by Valenciennes has a beautiful illustration of the colony and polyps (see Fig. 1). Through a microscope, the operculars do appear elongated and the illustration reflects this, although it is exaggerated; the image is otherwise a good likeness. Descriptions thereafter rely heavily upon this drawing as well as Milne-Edwards? (1857) short description. K?lliker (1865) did give further details of body-wall scale dimensions (still under the name of P. antarctica,) but Gray?s (1870, p. 45) redescription as T. antarctica only gave a general description: ?Coral simple, with long, simple filiform branches, spreading on all side of the stem. Bark formed in large imbricated scales. Polyp-cells smooth, bell-shaped, scattered on upperside of branches, covered with four or five series of imbricate scales.? Wright and Studer?s (1889) description of Thouarella, alongside several new species, gives the first moderately detailed definition of the genus and more information about T. antarctica. K?kenthal (1915, 1919) correctly described T. antarctica as having marginal scales with lateral projections off the keel, and this remains one of the defining characteristics. In 1924 K?kenthal listed T. antarctica as having nine or ten scales in the abaxial row but we believe this is a mistake, as he listed 4?6 abaxial scales in both his 1915 and 1919 keys. A bottlebrush colony form, distally flared polyps, and complex multi-keeled marginal scales make T. antarctica just as representative of Thouarella as any species found within Group 1. Thus, T. antarctica is considered to be its type species. Comparisons As mentioned in the historical summary, the ?K?llikeri? (K?kenthal 1912) and ?Antarctica? groups (Versluys 1906; K?kenthal 1912) have very similar species. This includes T. koellikeri Wright & Studer, 1889, T. variabilis, T. versluysi K?kenthal, 1907, T. striata K?kenthal, 1907, T. clavata K?kenthal, 1908, T. brucei Thomson and Richie, 1906, and T. hicksoni, Thomson, 1911?the ?K?llikeri? group including species with isolated polyps and foliate, elongated marginals. In 1919, K?kenthal rearranged the entire genus, moving T. antarctica into the ?K?llikeri group?, as it has relatively tall marginals, leaving T. crenelata, T. chilensis and T. affinis in the ?Antarctica? group. The polyps of Thouarella crenelata have marginal scales with distinctively serrate distal borders and a high number of scales in the longitudinal abaxial row and are thus quite different from the remaining ?Antarctica?/ ?K?llikeri? group species. Thouarella koellikeri, T. viridis Zapata-Guardiola and L?pez-Gonz?lez, 2010, T. antarctica, and T. chilensis are all very similar, having isolated polyps larger than 1.5 mm and low triangular marginals. All of these species have very small differences in the number of body-wall scales in the abaxial row of the polyps and the complexity of the marginal keel. Although all species have a similar polyp size they vary in polyp density; the number of polyps per cm splits this group into two as T. antarctica and T. chilensis have very TAYLOR ET AL.26 ? Zootaxa 3602 (1) ? 2013 Magnolia Press clustered polyps, more than 15 per cm (up to double this in fact), whereas the remaining two species have lower polyp densities. Thouarella antarctica and T. chilensis are considered distinct from each other as the latter has polyps with operculars and marginals that have a heavily striated outer surface and a full opercular cone, all absent in T. antarctica. Thouarella chilensis also tends to have more scales in the abaxial row than T. antarctica. Both T. koellikeri and T. viridis have tall opercular cones and the latter has protruding toothed submarginals. Thouarella koellikeri generally has longer polyps than T. antarctica due to the greater number of body-wall scales in the abaxial row (7?10 as against 5?7), and the operculars of the latter have simple keels whereas in the former there are several small striations adjacent to the keel. Also, the branchlets of the former leave the stem in mainly two directions, whereas T. antarctica has a true bottlebrush form. The scales of the opercular cone of the polyps of T. viridis are more closely fitted than those of T. antarctica; and the former has shorter marginals that are less elongated, with wide lateral extensions of the keel that are rarely visible when viewed from the abaxial side of the polyp, something that is normal in T. antarctica. Also, the operculars of T. viridis have a larger, more pronounced keel than those of T. antarctica, the keel of the latter operculars being complex and spread laterally. Several species have a similar number of longitudinal abaxial body-wall scales as T. antarctica and many were in the original ?K?llikeri? group and are thus compared here: Thouarella variabilis differs from T. antarctica in having longer marginals, polyps that are more flared, and smaller, narrower, lanceolate operculars. The polyps of Thouarella brevispinosa are generally longer than those of T. antarctica, and have more scales in the abaxial row. The marginals of polyps of T. brevispinosa are larger and have a longer, simple keel, lacking the lateral extensions common in T. antarctica. The polyps of Thouarella brucei and T. antarctica are similarly shaped, but the marginal keels of the former are simpler with the inner and outer opercular scale surfaces tending to be smoother, the abaxial row with fewer scales, and colonies that can appear bilateral rather than bottlebrush, as in T. antarctica. Thouarella striata has distinctive striations on the marginal scale inner surface that are absent in T. antarctica. In addition, the marginal scales of T. striata have a less complex keel (although not markedly), where the keel is not visible from an abaxial side view, and there are generally fewer scales in the abaxial row. Thouarella clavata and T. bipinnata have polyps of a similar size as T. antarctica (the polyps of T. bipinnata are only slightly larger), however, polyps of T. bipinnata are clavate (T. antarctica has more splayed polyps) and its colony is uniplanar (whereas T. antarctica is bottlebrush). Thouarella clavata is bottlebrush (although branchlets sometimes bend creating a bilateral appearance) and has a similar number of abaxial scales as polyps of T. antarctica. However, the polyps of T. bipinnata are less densely arranged and branchlets are longer, narrower, and less rigid than those of T. antarctica. Thouarella minuta polyps are under 1 mm tall making them considerably smaller than those of T. antarctica. 2. Thouarella variabilis Wright and Studer, 1889 Figs 6, 7 Thouarella variabilis var. a Wright & Studer, 1889: 68?69, pl. 21, fig. 1 (incorrectly listed as pl. 14, figs 1?2); Thomson & Henderson 1906: 40 (list) Thouarella variabilis var. c gracilis Wright & Studer, 1889: 70; Thomson & Henderson 1906: 40 (list) Thouarella variabilis Menneking 1905: 260?262, pl. 9, figs 9, 10, 21, 22 (samples not seen); Versluys 1906: 37?38; Gravier 1914: 56?61, pl. 1 fig. 6, pl. 3 fig. 13?14 (samples not seen); K?kenthal 1915: 150 (key); Molander 1929: 74?5 (samples not seen); Broch 1965: 30?31, pl. 6, figs 17?19; Brito, Tyler & Clarke 1997: 63?69 Not Thouarella variabilis Thomson 1927: 33, pl. 1, fig. 10 (=unknown) Thouarella (Parathouarella) variabilis K?kenthal 1919: 428, fig. 202 (in text); 1924: 297 (key); Thomson & Rennet 1931: 27?30, pl. 7, fig. 3, pl. 9, figs 4?5 (samples not seen) Thouarella aff. variabilis K?kenthal 1912: 305?306, figs 9?12 (in text), pl. 20, fig. 2 Thouarella (Thouarella) variabilis typica Cairns & Bayer 2009: 27 (listed) Material examined: Syntype of Thouarella variabilis var. a, NHM 89.5.27.56, H.M.S. Challenger, sta. 145, SE of Prince Edward Island, 46?43?S, 38?4?30?E, 256 m, 27 Dec 1873, 3.5 cm fragment seen; Holotype, T. variabilis var. gracilis, NHM 1889.5.27.55?56, sta. 145, SE of Prince Edward Island, 46?43?S, 38?4?30?E, 256 m, 27 Dec 1873, 3.5 cm fragment seen. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 27REVISION OF OCTOCORAL GENUS THOUARELLA Other material: USNM 76897, R/V Eltanin, Antipodes Island, New Zealand, 49?51?S, 178?35?E, 2010?2100 m, 26 Feb 1968, 1 colony; USNM 98226, R/V Hero, cruise 731, sta. 1842, west of Renaud Island, Biscoe Islands, Antarctic Peninsula, 65?30?S, 67?31?W, 180 m, 24 Feb 1973; USNM 1130283, R/V Glacier, cruise 1, sta. 5, 76?00?S, 55?00?W, 457 m, 9 Feb 1968, 2 colonies; SMF, EPOS 03, sta. 281, AGT21, 402 m, 18 Feb 1989; SMF, Am Twist, D. Sudpolar Expedition, 385 m, 1902. Description of var. a typical The main stem is simple. Wright and Studer (1889: pl. 21, fig. 1) recorded a specimen 300 mm long (which must have been damaged since as it now stands at 220 mm); its axis is brown-yellow and firm but brittle towards the base and more flexible distally. Branchlets leave the main stem in 3 to 4 directions; the fourth branch in a series is often in line with the first, in a spiral formation. Branchlets occur at intervals of 1.5?2.0 mm, at near right angles to the main stem; branchlets are 50?150 mm long, narrow, flexible, and frequently branched 2 or 3 times (usually dividing close to the stem in the proximal one third). On the branchlets and stem there are wide, distally flared isolated polyps (Fig. 6b,d?f) which are upwardly inclined at 60? and arranged in irregular short spirals of 3 or 4 with 5?10 polyps per cm on the branchlets (sometimes more closely spaced at branchlet base). Polyps are 1.50?1.85 mm high (average 1.70 mm) including the long marginal point, with 4?5 scales in the abaxial row and 2?3 in adaxial rows; the number of longitudinal rows reduces quickly from 8 at the marginals to 4 or 5 at the base. The polyps are sheathed in scales of 4 categories: 8 operculars, 8 marginals, 1 or 2 circlets of pointed submarginals and a variable number of body-wall scales. The operculars do not form a perfect opercular cone and there are gaps into the opercular cavity (Fig. 6e). They are shaped like an isosceles triangle (Fig. 7a?c), range in size from 330?650 ?m high (average 470 ?m) and 150?370 ?m wide (average 250 ?m), with a H:W of 1.1?2.4 (average 1.9), which is just over half the size of marginals. The proximal half of the inner surface of the operculars are tuberculate; a flat-surfaced, relatively simple keel is present on the inner surface (Fig. 7c). The outer surfaces of the scales are covered with granules that extend radially from the central point in the proximal half. The marginals are long, spinose (Fig. 7e?g), 650?960 ?m in height (average 800 ?m), 430?580 ?m wide (average 520 ?m), with an average H:W of 1.6, usually splayed out and too long to fold over the operculum neatly. Sometimes the abaxial 2 or 3 marginals are much longer than the adaxial ones (Fig. 6e). The outer marginal surface has 2 or 3 longitudinal furrows down the length of the elongated distal point and granules cover the remaining scale area (Fig. 7e,g). The keel is channelled and the base of the keel is tuberculate. The submarginals have a pointed distal edge (Fig. 7h?k). They are wider than the marginals, with a width of 440?610 ?m (average 525 ?m), and a height of 520?600 ?m (average 560 ?m). They curve away from the polyp body (similar slant to marginals) and are thus visible from an anterior view (see Figs 6e, marked 1, and 6f). The body-wall scales are round to elliptical in shape (Fig. 7l?n), larger and wider towards polyp head (average of 400 ?m high, 485 ?m wide, H:W 0.9), smaller and round towards polyp base (average of 325 ?m high, 455 ?m wide, H:W 1.2). The distal edge of the sclerites in all the above categories is finely serrate; proximal edge is irregularly lobate. The outer layer of coenenchymal scales are elliptical (Fig. 7o,s,p), 190?320 ?m high (average 240 ?m), 590?750 ?m wide (average 680 ?m) with an average H:W of 0.35. The outer surface of these scales is covered in granules, the inner surface is tuberculate. The inner layer of scales are smaller, thin and roughly circular (Fig. 7q,r), with granules on the outer surface and a finely tuberculate inner surface. Coenenchymal scales generally have finely serrated proximal and distal edges. Distribution Circum-Antarctic, from 115 to 2100 m depth. Remarks Thouarella variabilis var. a (hereafter called T. variabilis typica) and T. variabilis var. gracilis Wright & Studer, 1889 have identical polyp shape and structure, and sclerite sizes and shapes. Thouarella variabilis var. gracilis is described as, what we interpret from Wright and Studer (1889), having more secondary and tertiary ramification than T. variabilis typica. However, there are varying degrees of ramification within a single colony and given the similar nature of all sclerites these two varieties are thus proposed to be synonymous with T. variabilis. TAYLOR ET AL.28 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 6. Thouarella variabilis var. a typical, syntype, NHM 89.5.27.56: a) syntype, 22 cm long; b) close up of several polyps; c) close up of brooding polyps; d) lateral view of two polyps; e) stereo opercular view, NB?1 indicates submarginal scale; f) abaxial polyp view. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 29REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 7. Thouarella variabilis, syntype, NHM 89.5.27.56: a,b) outer and c) inner surface of operculars; d,f) inner and e,g) outer surface of marginals; h,j) inner and i,k) outer surface of submarginals; l?n) outer surface of body-wall scales; o,p,s) inner and q,r) outer surface of coenenchymal scales. TAYLOR ET AL.30 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Within the material examined, we found the branching of T. variabilis to occur in up to four directions (rather than three directions as noted in Wright & Studer 1889). Some juvenile colonies can appear almost pinnate (e.g. SMF, EPOS 03, sta. 281), although on closer inspection branchlets depart in three directions. Also, although there is some regularity with spiral branchlet placement, it is not consistent. USNM 1130283 and SMF ?Am Twist? samples have smaller polyps than the holotype, their maximum length being 1.5 mm rather than 1.5?1.85 mm, but are otherwise identical. The complex bushy bottlebrush shape of T. variabilis specimens make them ideal habitat for associates and worms, brittlestars, and ascidians were found within their branches. True to its name, T. variabilis can have polyps that look dissimilar (Brito 1993); polyps with elongated claw- like marginals are shown in Fig. 6c (some of these polyps were brooding) and open, flared polyps (Fig. 6b) with elongated submarginals (Fig. 6b1) are also common. Comparisons Thouarella variabilis is unusual within the genus Thouarella in having elongated marginals that do not fold over the operculum neatly, and it is this character that makes this species distinct from all others. The species has a similar number of scales in the abaxial row as T. pendulina, T. hicksoni, T. brucei, and T. striata and comparisons to these species are made here: Polyps of T. pendulina are much smaller and more clustered (up to 70 per cm) than those of T. variabilis. Polyps of T. hicksoni are a similar size and have a comparable number of abaxial scales to those of T. variabilis, however, the isosceles triangle-shaped operculars in the latter differ from the operculars of the former which have a blunt, rounded distal edge (and operculars of T. variabilis which consequently form a tighter opercular cone). Also, T. hicksoni lacks elongated submarginals, although they can have a pointed distal edge. Polyps of T. brucei are a similar size to T. variabilis but have wider triangular operculars. Opercular, marginal, and submarginal sclerites of T. striata have densely arranged granules on their outer surface that could be confused with those on sclerites of T. variabilis. However, the inner surface of T. striata marginals have sharp striations running perpendicular to the distal edges; these are absent in T. variabilis. Although now transferred to Plumarella, the species originally described as Thouarella diadema has polyps with 3?5 body-wall scales in the abaxial row and polyps of a similar-size and shape to those of T. variabilis. The major difference between these two species is that marginals of the former species lack a keel (the defining difference between Plumarella and Thouarella). 3. Thouarella brevispinosa Wright and Studer, 1889, new rank Figs 8, 9 Thouarella variabilis var. brevispinosa Wright & Studer, 1889: 69; Thomson & Henderson 1906: 38 (list); Molander 1929: vol. 2, 74?5 Thouarella (Thouarella) var. brevispinosa Cairns & Bayer 2009: 27 (listed) Material examined: Holotype, NHM89.5.27.54, 12 cm, H.M.S. Challenger, sta. 145A, 46?41?S, 38?10?E, off Prince Edward Island, 566 m, 27 Dec 1873. Other material: ZMH, R/V W. Herwig, sta. 245, SW Atlantic, 36?49?S, 54?02?W, 550 m, 14 Jun 1966. Description The holotype consists of a single branch (Fig. 8a). The branchlets are mostly simple (some secondary, and even tertiary branching), the longest being 25 mm, arranged around the main stem in at least 4 directions, in a bottlebrush formation. The polyps are large, 2.5?3 mm high, and isolated on branches and branchlets at wide intervals of 7?11 per cm. They are inclined at 60? and distally flared with splayed marginals (Fig. 8b?d). Each polyp has 6?7 scales in the abaxial row (Fig. 8c) and 7 longitudinal rows reducing to 4 at the polyp base. Scales of 4 categories cover each polyp: 8 operculars, 8 marginals, pointed submarginals and a variable number of body-wall scales. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 31REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 8. Thouarella brevispinosa, holotype, NHM89.5.27.54: a) 12 cm colony; b) lateral polyp view; c) abaxial polyp view; d) stereo opercular view. TAYLOR ET AL.32 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 9. Thouarella brevispinosa, holotype, NHM89.5.27.54: a,d?f) inner and b,c,g) outer surface of opercular scales; h) inner and i,j) outer surface of marginal scales?the lateral and distal edges of j are eroded; k,l) inner and m,n) outer surface of submarginal scales; o?q) outer and r,s) inner surface of body-wall scales; t) coenenchymal scales?inner surface on top right and bottom three right scales, remainder show the outer surface. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 33REVISION OF OCTOCORAL GENUS THOUARELLA The tips of the operculars meet in an apex to form a cone. The operculars are lanceolate, or isosceles triangle- shape with a squared proximal edge (Fig. 9f,g), to arrowhead shape (Fig. 9a?e; although sometimes they have a rounded distal edge, Fig. 9f,g). They are 270?770 ?m high (average 540 ?m) and 200?410 ?m wide (average 310 ?m), with a H:W of 1.2?2.1 (average 1.7). They have a single, large simple keel on the inner surface that is sometimes channelled with small lateral striations running parallel (Fig. 9a). The proximal half to third of the inner surface is tuberculate; the outer surface is longitudinally concave towards the distal edge and there are sparse granules and occasional fine striations in a radial pattern from the proximal area. Marginals are 510?830 ?m high (average 730 ?m), 490?600 ?m wide (average 530 ?m), with a H:W of 1.0?1.6 (average 1.4). They have a broad angular base (Fig. 9i,j) and a central triangular distal projection (Fig. 9h). The inner scale surface is keeled, the keel having a single channel running longitudinally from the scale centre. There are 2?3 ridges parallel to the keel (more developed than in operculars) and tubercules cover the proximal area with a smooth band distally that has infrequent small ridges perpendicular to distal edge. The outer marginal surface has rows of granules radiating from the centre of the scale. Generally there are 2 circlets of abaxial and lateral submarginals; the submarginals have a pointed distal edge (Fig. 9l?n) and a reduced keel on the inner surface (Fig. 9k, l). The adaxial submarginals have a more rounded distal edge, more typical of body-wall scales (Fig. 9k). Submarginals are wider than marginals, 550?690 ?m (average 610 ?m), 450?620 ?m high (average 540 ?m), with a H:W of 0.8?1.0 (average 0.9). The inner surface is tuberculate and the outer surface has sparse granules sometimes spread radially towards distal edges (Fig. 9m). Body-wall scales are elliptical to circular (Fig. 9o?s) and similar in size to submarginal scales; their distal edge curves gently away from the polyp body. The inner surface is covered in tubercles and the outer surface with sparse granules; the proximal edge can also be covered in tubercles. The distal edges of all sclerites of this species are finely serrate; the proximal edges are irregularly lobate. Coenenchymal scales are oval to round or angular in shape (Fig. 9t), 100?200 ?m long or wide, with very sparse, irregular, granules on the outer surface; the inner surface is tuberculate. Distribution Known only from two locations: the type location off Prince Edward Island, and east of Buenos Aires, Argentina, approximately 7300 km away. Depth range is 550?566 m. Comparisons Colonies of T. variabilis var. brevispinosa have larger polyps with more scales in the abaxial row than those of T. variabilis. The former also has sparser branching and taller operculars with a more complete opercular cone than the latter. We thus propose this variety to be elevated to species rank, namely Thouarella brevispinosa. The polyps of T. brevispinosa are distally flared and a similar size to the polyps of T. antarctica (comparison is made previously), T. striata, and T. affinis which are thus compared below. The polyps of T. affinis have a similar number of scales in the abaxial row as those of T. brevispinosa, however, the majority of polyps in the latter have taller marginals that are more acutely elongate than the former, whose marginals are modestly pointed. The size and shape of the marginals of polyps of T. brevispinosa and T. striata are very similar, however the inner surface of the marginals of the latter have robust striations flanking the keel whereas the former have fine striations. Sclerites of T. striata are thick; those of T. brevispinosa are more delicate. Also, tubercles on the scales of T. striata are more densely arranged and the polyps tend to be smaller. The polyps of T. brevispinosa have fewer scales in the abaxial row than those of T. koellikeri and the abaxial marginals are taller and wider, creating a more flared polyp shape whereas the polyps of the latter are smaller and clavate. 4. Thouarella affinis Wright and Studer, 1889 Figs 10, 11 Thouarella affinis Wright & Studer, 1889: 66?68, pl.11, fig. 3; Thomson & Henderson 1906: 38 (list); K?kenthal 1912: 302 (listed) Thouarella (Epithouarella) affinis K?kenthal 1915: 151 (key); 1919: 435?436; 1924: 300 (key) Thouarella (Thouarella) affinis Cairns & Bayer 2009: 27 (listed) TAYLOR ET AL.34 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 10. Thouarella affinis, holotype, NHM 1889.5.27.44: a) 13 cm long colony, with polychaete along stem; b) lateral polyp view; c) close up of polyps; d) stereo opercular view. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 35REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 11. Thouarella affinis, holotype, NHM 1889.5.27.44: a?c,g) inner and d?f) outer surface of opercular scales; h,i) inner and j) outer surface of marginal scales; k?n) outer and o?q) inner surface of body-wall scales; r,w) outer and s?v) inner surface of coenenchymal scales. Some SEM images by ZGR. TAYLOR ET AL.36 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Material examined: Holotype, NHM1889.5.27.44, 65 mm fragment, H.M.S. Challenger, sta. 135D, off Inaccessible Island, Tristan de Cunha, 37?25?S, 12?22?30?W, 91?128 m, 15 Jul 1874. Other material: ZMH, R/V W. Herwig, sta. 232, east of Isla de los Estados, Tierra del Fuego, Argentina, SW Atlantic, 54?46?S, 62?30?W, 800 m, 1971. Description As only a small fragment was available, descriptions of axis and colony morphology were taken from the type description. The colony is bottlebrush, (Fig. 10a) but can appear bilateral. The axis is yellow, stiff, and brittle, although the branch apex is more flexible. The stem twists in a spiral from base to a quarter-length from the apex whereupon the next twist commences. The branching of this species is dense, with only 1.5?2 mm between branchlets; becoming denser towards the apex. The branchlets are mostly simple, with some forking (dividing usually in basal region of branchlet), upwardly inclined 60?90?, and up to 50 mm long. The branchlets are arranged in spirals from 3 sides of the main stem with 4 branchlets occurring within one spiral, but as the stem twists the spiral is difficult to follow. The polyps are isolated, 1.1?2.1 mm high, at a density of 7?9 per cm (with denser placement at branchlet apex, which generally has a polyp at the tip). The polyps can be modestly flared but generally have a wide, rounded head extending from a slender polyp body making them clavate (Fig. 10b,c; H:W of 1.3?2.1, average 1.7). The polyps are arranged in short spirals of 3?4 and angled distally at 45?60?. Each polyp has 8 longitudinal rows with 6?7 scales in each abaxial row and 5 adaxially. The tall rounded operculum rises above the marginal scales. The operculars are isosceles-triangle shaped (Fig. 11a,b), tongue-shaped (Fig. 11c?f), or lanceolate (Fig. 11g), 540?780 ?m high (average 610 ?m) and 220?350 ?m wide (average 280 ?m), with an average H:W of 2.2 (range from 1.8?2.5). The outer scale surface is longitudinally concave with granules across the proximal area and occasional low striations spreading radially from centre towards distal edge (Fig. 11d?f). The inner surface has a low, complex multi-keel (Fig. 11a,b), or a dense area of low striations (Fig. 11c); the proximal half of the scale is tuberculate. The marginals are somewhat diamond-shaped (Fig. 11h?j), 460?610 ?m high (average 525 ?m) and 460?640 ?m wide, with an average H:W of 1 (ranges from 0.8?1.3). The inner surface has a smooth band along the distal edge which is broken by a small, simple keel (Fig. 11h) with 2 or 3 adjacent striations whilst the remainder is tuberculate. The adaxial marginals frequently have no defined keel with just 4 or 5 short, sharp striations perpendicular to the distal edge (Fig. 11i). The outer surface is mostly smooth with some granules that often form radial striations (Fig. 11j). The body-wall scales occur in a range of shapes from circular and irregular to elliptical (Fig. 11k?q). They are generally broader than high, 350?490 ?m high (average 430 ?m), 380?780 ?m wide (average 540 ?m), with an average H:W of 0.8 (ranges from 0.6?1.1), and curved slightly away from the polyp body. Tubercles cover the inner scale surface. Granules occur sparsely on the outer surface and sometimes tubercles occur along the proximal edge. The distal edge of all sclerites of this species is finely serrate whilst the proximal edge is irregularly lobate. There is a single layer of roughly circular (Fig. 11r-u) or sometimes elongated coenenchymal scales (Fig. 11v, w) that are 190?280 ?m high (average 225 ?m), 230?430 ?m wide (average 300 ?m), with an average H:W of 0.8 (range from 0.4?1.1). There are large prominent granules on the outer surface of the scales and fine tubercles on the inner surface. Distribution This species is known only from the type location Tristan de Cunha, and also Inacessible Island, mid-South Atlantic. The depth of observed occurrence is 91?800 m. Remarks The holotype material examined is damaged so the number of polyps per cm may be an underestimate. Comparisons Wright and Studer (1889) considered T. affinis to be very similar to T. antarctica and the polyps of these species do have a similar number of scales in the abaxial rows (6?7 T. affinis, 5?7 T. antarctica). However, the latter has a Zootaxa 3602 (1) ? 2013 Magnolia Press ? 37REVISION OF OCTOCORAL GENUS THOUARELLA more complexly structured marginal keel with large lateral projections compared to the modest keel found on marginals of the former. The polyps of T. viridis are a similar shape and size to T. affinis and they also have similar shaped marginals, although those of T. viridis are slightly taller. However, the operculars of the polyps of T. viridis are pointed, while those of T. affinis are mostly tongue-shaped (with some triangular-shaped operculars with squared proximal edges). In addition, the body-wall scales of the former have more pronounced striations perpendicular to the distal edge (that are visible in lateral polyp view) than the latter. The polyps of T. affinis are more rounded than those of T. brucei. The polyps of the latter also have fewer scales in the abaxial row and marginals that are narrower with a higher H:W ratio. Polyps of T. koellikeri tend to be longer than those of T. affinis, with more scales in the abaxial row. Also, the former has pointed triangular operculars whereas those of the latter are mostly tongue-shaped. 5. Thouarella koellikeri Wright and Studer, 1889 Figs 12, 13 Thouarella K?llikeri Wright & Studer, 1889: 64?65, pl. 11 fig. 5; Thomson & Henderson 1906: 38 (list); Versluys 1906: 35 Thouarella (Parathouarella) k?llikeri K?kenthal 1915: 150 (key); 1919: 435; 1924: 299 Thouarella (Thouarella) koellikeri Cairns & Bayer 2009: 27 (list) Material examined: Holotype, NHM 1889.5.27.41 and USNM 1002247, which is a fragment of the holotype, H.M.S. Challenger, sta. 308, 50?08?30?S, 74?41?W, 320 m, 5 Jan 1876, 1 colony. Other material: USNM 1112997, sample 5, Puyuhapi, Chile, South Pacific Ocean, 30 m, 10 Jan 2000, 2 colonies, no location information; USNM 1002247, sample 174, Chile, South Pacific Ocean, no location information, 25 m, 12 Mar 2006, 2 colonies; NHM (no catalogue number), H.M.S. Challenger, 51?27?30?S, 74?3?W, 730 m, 10 Jan 1856, fragment; SMF, R/V W. Herwig, sta. 245, SW Atlantic, 36?49?S, 54?02?W, 550 m, 14 Jun 1966; SMF, R/V W. Herwig, sta. 376, SW Atlantic, 43?23?S, 60?19?W, 100 m, 16 Jul 1966; SMF, R/V W. Herwig, sta. 311, Patagonian Shelf, SW Atlantic, 46?54?S, 60?28?W, 480 m, 18 Feb 1971; SMF, R/V W. Herwig, sta. 293, North Falkland Islands, 49?36?S, 59?25?W, 350 m, 13 Feb 1971; USNM 97997, R/V Eltanin, cruise 7, sta. 499, south of Coronation Island, South Orkney Islands, sub-Antarctic, 62?06?S 45?08?W to 62?06?S 45?10?W, 485 m, 20 Feb 1963, 7 colonies; USNM 98169, R/V Eltanin, cruise 6, sta. 339, west of Beauchene Island, Falkland Islands, sub-Antarctic, 53?06?S, 59?27?W, 512?586 m, 3 Dec 1962; USNM 98019, R/V Eltanin, cruise 12, sta. 1089, NE of Clarence Island, South Shetland Islands, Antarctic Ocean, 60?47?S, 53?30?W, 641 m, 14 Apr 1964; USNM 79475, R/V Eltanin, cruise 9, sta. 740, east of Cape Horn, Drake Passage, South Atlantic Ocean, 56?06?S, 66?19?W, 384?494 m, 18 Sep 1963; USNM 1130298, R/V Hero, cruise 721, sta. 1075, 64?47?24?S, 64?07?36?W, south of Anverse Island, Palmer Basin, Antarctica, 91?110 m, 23 Feb 1972. Description The holotype has one main branch off the stem (Fig. 12a). The branchlets are mostly undivided, leaving the main stem primarily in 4 directions. Two of the 4 directions are consistently around 120? apart, roughly alternately pinnate, and between these 2 rows of branchlets there is often another row of branchlets. These 3 planes/rows of branchlets depart on one side and there are occasional branchlets directly opposite, which tend to be short or broken, especially towards the colony base (possibly because of the reduced protection these branchlets receive). The arrangement of branching can appear pinnate, however, the branchlets are on all sides of the main stem in 4 directions, and thus the colony is bottlebrush. The polyps are isolated and clavate with a rounded opercular cone (Fig. 12c,e). They emanate from branches and branchlets in a roughly alternating arrangement (Fig. 12b), 12?15 per cm (more clustered towards branchlet tip), upwardly inclined at 45?60? and are 1.6?2.5 mm high (average 2.2). The sclerites are in 8 longitudinal rows with 7?10 scales in abaxial rows (Fig. 12d) but reduced in number adaxially to only 5?7. The scales on each polyp fit into 4 categories: 8 operculars, 8 marginals, 8 submarginals and many body-wall scales. TAYLOR ET AL.38 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 12. Thouarella koellikeri, holotype, NHM 1889.5.27.41: a) 19 cm long colony; b) close up of branchlet; c) lateral polyp view; d) abaxial polyp view; e) stereo opercular view. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 39REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 13. Thouarella koellikeri, holotype, NHM 1889.5.27.41: a,d) inner and b) outer surface of opercular scales; c) side view of opercular keel; e) inner and f,g) outer surface of marginal scales; h?j) inner and k) outer surface of submarginal scales; l,o) inner, and m,n,p) outer surface of body-wall scales; q) top left, fourth and fifth from left on top row and fifth on bottom row are of the inner surface of coenenchymal scales, the remainder are outer surface images. Some SEM by ZGR. TAYLOR ET AL.40 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The operculars are isosceles triangle- (Fig. 13a,d) to arrowhead-shaped (Fig. 13b), 360?560 ?m high (average 480), 180?350 ?m wide (average 250), with an average H:W of 1.95. They have a large, single keel on their inner surface (side view of keel, Fig. 13c), with a corresponding deeply concave longitudinal outer surface (Fig. 13b). The proximal half of the inner surface is covered with small densely placed tubercles. The outer surface has granules that are often aligned to form striations arranged radially from the proximal third. As the distal circumference of a polyp is not wide enough to accommodate 8 marginal scales they are arranged in 2 alternating circles of 4 with their lateral edges overlapping (Fig. 12e). The marginals fold over the operculars, fitting into their concave outer surface. The marginals are mostly triangular distally (Fig. 13e?g), and rounded laterally with a flat proximal edge. They are 420?580 ?m high (average 480 ?m), wider than operculars (340?520 ?m, average 430), with an average H:W of 1.1. Abaxial marginals are more pointed than the adaxial. The inner surface bears a large keel usually with a single channel running its length and lateral projections (Fig. 13e). Tubercles are more widely spaced than on operculars but still cover the basal portion of the inner surface. The outer surface has granules in radial rows from the central proximal area that fade towards scale edges (Fig. 13g). The submarginals are shorter than the marginals (Fig. 13h?k), 320?590 ?m high (average 430 ?m), 230?490 ?m wide (average 430 ?m), with an average H:W of 1. Generally the submarginals have a more rounded distal edge than the marginals. The submarginals are more pointed on the abaxial side of the polyp (Fig. 13h,j) than the adaxial (Fig. 13k). The scales proximal to the submarginals also sometimes have a modest distal point and a small keel on their inner surface. The submarginals differ from the marginals as tubercles cover a larger proportion of inner surface. The body-wall scales arch slightly away from the polyp body and are of various shapes. They are often pentagonal with a rounded distal edge, or circular to elliptical (Fig. 13l?p), 280?520 ?m high (average 390 ?m), 220?600 ?m wide (average 380 ?m), with an average H:W of 1. The inner surface is tuberculate with a narrow smooth band distally that can bear a few small ridges (Fig. 13l,o) whilst the outer surface is covered in granules. The coenenchymal scales are small, circular (Fig. 13q), 120?180 ?m diameter (average 150 um), with an average H:W of 1. The outer surface has radial striations from centre to the scale edge whilst the inner surface is tuberculate. The distal edge of all sclerites are finely serrate and the proximal edge irregularly lobate. Distribution This species has been found along the southern coast of Chile, Argentina, and off the Antarctic Peninsula from 91?1920 m. Remarks Contrary to Wright and Studer (1889), who described dorsal branchlets as simple and short (10?25 mm), some colonies have dorsal branchlets up to 51 mm long with similar polyp orientation and stem flexibility as the ventral and lateral branchlets. Comparisons Thouarella koellikeri most closely resembles T. viridis, as both have clavate polyps and a bushy, bottlebrush to bilateral appearance. However, the marginal scales of the polyps of T. koellikeri are high with a single-channelled keel, whereas those of T. viridis are shorter and have 2?4, and sometimes five, longitudinal ridges instead of a keel. Distal inner surface ridges are found on submarginal scales of the polyps of T. viridis whereas the polyps of T. koellikeri specimens tend to have a small, single keel on the submarginals of the first row. The polyps of T. koellikeri also have more scales in the abaxial row than those of T. viridis. Versluys (1906) described the ramification of T. koellikeri as similar to that of T. moseleyi and the two species do have long, fine, flexible branchlets that could appear similar. However, the latter has pinnate, uniplanar colonies and the former has colonies that are bottlebrush to bilateral. Also, the polyps of T. koellikeri specimens are isolated while those of T. moseleyi occur in pairs. Although most are modestly flared, some polyps of T. antarctica have a similar clavate shape to those of T. koellikeri, but the polyps of the latter tend to have more scales in the abaxial row (7?10, rather than 5?7). Also the marginals of T. antarctica are larger and bear a more complex keel than those found on the polyps of T. koellikeri. Lastly, T. antarctica has a true bottlebrush colony form whereas the branchlets of T. koellikeri colonies leave the main stem in two or three directions giving it a bushy to bilateral appearance. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 41REVISION OF OCTOCORAL GENUS THOUARELLA The bushy appearance of colonies of T. koellikeri is similar to that of T. bipinnata however the former has polyps with a wider head and, when dried, the body-wall scales reflect away from the polyp body, something that is not seen in polyps of T. bipinnata. The polyps of T. koellikeri are also longer and narrower, with taller operculars, and marginals with a higher H:W ratio than those of T. bipinnata. Thouarella koellikeri has similar sclerite shapes to both T. brevispinosa and T. brucei, however, colonies of T. brucei have distally flared polyps, fewer scales in the abaxial row, longer marginals bearing a more acute distal point, and flatter keels than T. koellikeri. Thouarella brevispinosa, although having a similar number of abaxial scales as T. koellikeri, has taller marginals and more flared, open polyps (see Table 3). 6. Thouarella brucei Thomson and Ritchie, 1906 Figs 14, 15 Thouarella brucei Thomson & Ritchie, 1906: 852?854, pl. 1 fig. 1, pl. 2 fig. 1; K?kenthal 1919: 439; 1924: 301 Thouarella versluysi K?kenthal, 1907: 202?203 Thouarella (Thouarella) brucei Cairns & Bayer 2009: 27 (listed) Not Thouarella brucei Broch 1965: 27?28, pl. 4 (= Digitogorgia sp.) Material examined: Holotype, NHM 1933.3.13.130, Scotia (Scottish National Antarctic expedition of 1902?04), Burdwood Bank or Gough Island, 102?182 m, 1 Dec 1903 or 22 April 1904; fragment of holotype, ZMA COEL03574; Syntype of Thouarella versluysi, MNHWU, D.T.E. sta. 103, South Africa, 35?10?S, 23?2?W, 500 m, two 2.5 cm fragments. Other material: USNM 1130164, R/V Eltanin, cruise 22, sta. 1536, west tip of South Georgia, sub-Antarctic, 54?30?S, 39?20?W, 659?686 m, 8 Feb 1966, 6 colonies; USNM 98029, R/V Eltanin, cruise 22, sta. 1536, west tip of South Georgia, Antarctica, 54?29?S, 39?22?W, 659?686 m, 8 Feb 1966, 2 colonies (30 cm, 12 cm); USNM 98337, R/V Eltanin, cruise 21, sta. 290, west mouth of Strait of Magellan, Antarctica, 52?41?S 74?35?W to 52?45?S 74?28?W, 188?247 m, 6 Jan 1966, 3 colonies; USNM 98195, R/V Islas Orcadas, cruise 575, sta. 93, South Georgia Island, Antarctic Ocean, 54?38?48?S, 38?51?18?W, 261?270 m, 9 Jun 1975, 1 colony. Description The holotype is a rigid and sparsely branched colony (not shown). The main stem is robust and stiff although the smaller branchlets are more flexible. The axis is circular in cross-section and light yellow, with side branchlets an even lighter shade. Branching occurs in up to 4 directions all around the main stem at irregular intervals. The branchlets emanate at 60?, and are upwardly inclined. Overall colony structure appears more bilateral than bottlebrush as the close-set branchlets curve into one plane. Secondary and tertiary branching of the branchlets is common. The polyps are isolated, 1.5?2.3 mm high, with some occurring on the main stem, and arising in all directions on branchlets. There are 9?12 polyps per cm, modestly flared distally (Fig. 14a,c) and upwardly inclined at 40?45?. Each polyp has 7 longitudinal rows, with 4?5 scales in the abaxial row and 2?3 in the adaxial. Two rings, the lower consisting of 4 smaller operculars, the upper of 4 larger operculars, form the operculum. Upper operculars align with the outer ring of marginals whilst the lower operculars align with the inner ring of marginals. The operculars range in size from 390?680 ?m high (average of 510 ?m), 170?330 ?m wide (average of 250 ?m), with a H:W of 1.5?2 (average 2). The operculars are arrowhead shaped with a rounded apex (Fig. 15a?e). The outer surface of operculars is longitudinally concave with sparse granules (Fig. 15a,b). Every opercular has a simple keel on its inner surface and is tuberculate proximally. The marginals also occur in 2 rings, upper and lower. They are diamond-shaped (Fig. 15f?h), 490?760 ?m high (average of 635 ?m), 350?570 ?m wide (average of 470 ?m), with a H:W of 1.1?1.7 (average 1.4) in the holotype (smaller sizes in voucher specimens). The inner surface of the marginal scales has a complex multi-keel (Fig. 15f) sometimes with a flat central area. The inner marginal surface is tuberculate below the keel base whilst the outer surface has granules at the centre and is smooth towards scale edge. The submarginals are diamond to oval-shaped, with an arched distal edge (Fig. 15j,i), 230?670 ?m high (average 440 ?m), 230?615 ?m wide (average 380 ?m) with a smaller H:W than the marginal scales (average of 1.14). The inner surface is tuberculate with a narrow smooth band along the distal edge whilst the outer surface has sparsely placed granules. TAYLOR ET AL.42 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 14. Thouarella brucei, holotype, ZMA. COEL03574: a) abaxial view of polyp; b) 6.5 cm long fragment of holotype; c) lateral view of polyp; d) stereo opercular view Zootaxa 3602 (1) ? 2013 Magnolia Press ? 43REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 15. Thouarella brucei, holotype, ZMA. COEL03574: a,b) outer surface and c?e) inner surface of opercular scales; f) inner and g,h) outer surface of marginal scales; i) inner and j) outer surface of submarginal scales; k,m) inner and l) outer surface of body-wall scales; n) coenenchymal scales, top row outer surface, bottom row inner surface. Photo and some SEM by ZGR. TAYLOR ET AL.44 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The body-wall scales are large (Fig. 15k?l), 160?560 ?m high (average 320 ?m), 160?590 ?m wide (average 350 ?m), and generally circular to elliptical in shape (average H:W 0.9). The outer surface has granules and small striations at the distal edge and the inner surface is tuberculate. The proximal edge of all the scales above is coarsely lobate; the distal edge is finely serrate. The coenenchymal scales are circular (Fig. 15n) with a diameter of 50?150 ?m. The outer surface is covered with sharp-peaked granules and small radial striations and the inner surface is tuberculate. Distribution Mid- to southwest Atlantic, off the southern coast of Chile and the Antarctic Peninsula, at depths from 100?686 m. Remarks Thouarella versluysi was described by Kukenthal (1907) one year after T. brucei. K?kenthal mentioned that T. versluysi was very similar to T. brucei but offered no explanation. K?kenthal also went as far as listing T. brucei as species dubiae atque incertae sedis in his 1924 key. Thouarella versluysi and T. brucei both have a bottlebrush colony morphology (although T. brucei can appear bilateral it is technically bottlebrush). There was not enough material to determine the colony shape of the T. versluysi syntype, however the original description and colony picture depict a bottlebrush colony (K?kenthal 1907). Both species have isolated polyps that are upwardly inclined at between 40?60? and 4?6 scales in the abaxial row of polyps. Thouarella versluysi has slightly smaller polyps than T. brucei, a slightly lower opercular scale H:W (average of 1.8 versus 2), a higher marginal scale H:W ratio (average of 1.7 versus 1.4), and the abaxial surface of sclerites of T. brucei have more peaked granules. These are very minor differences and not enough, in our opinion, to separate these specimens as individual species; Thouarella versluysi is thus synonymised with T. brucei. Specimens examined in this study have slightly smaller polyp lengths and, as a consequence, smaller sclerite sizes than the holotype. Comparisons The polyps of Thouarella brucei and T. brevispinosa have marginal and opercular scales of an almost identical shape. Thouarella brevispinosa has larger polyps with more scales in the abaxial row than T. brucei (6?8 rather than 4?5) and the branchlets of the former are more tightly placed. More material is required of both species to confirm the differences and similarities listed here. Thouarella brucei shares a similar bilateral?bottlebrush branching morphology with T. koellikeri, T. bipinnata and T. andeep. However, the polyps of T. brucei are distally flared, similar to those of T. andeep, whereas polyps of T. koellikeri and T. bipinnata are clavate and arranged in an irregular alternate manner. The operculars of the polyps of T. andeep have a smooth inner surface whereas those of T. brucei, whose polyps are also smaller, have a simple keel (see Table 3). Lastly, the polyps of T. brucei have fewer scales in the abaxial row than the polyps of T. koellikeri. The polyps of T. brucei examined in this study have a similar size and number of abaxial scales as T. hicksoni, although those of T. brucei are larger. Thouarella brucei, however, has polyps with operculars that form a full cone, whereas the operculars of the polyps of T. hicksoni are narrower and do not form an opercular cone. The polyps of the T. hicksoni are also far more clustered. 7. Thouarella striata K?kenthal, 1907 Figs 16, 17 Thouarella striata K?kenthal, 1907: 204?205; 1915: 150 (key); 1919: 426?428, text figs 197?201; Broch 1965: 31?32, pl. 7, figs 20?21 (sample not seen) Not Thouarella striata Nutting, 1912: 69, pl. 10 figs 2, 2a (sample not seen) Thouarella stricta Molander 1929: 75 (incorrect subsequent spelling) Thouarella (Parathouarella) striata Thomson & Rennet 1931: 27 Thouarella (Thouarella) striata Cairns & Bayer 2009: 27 (listed) Material examined: Holotype, MNHWU, Nr. 57, Bouvet Island, 54?26?S, 3?24?E, 457 m. Other material: ZMH, R/V W. Herwig, sta. 285, Patagonian Shelf, SW Atlantic, 42?19?S, 58?01?W, 825 m, 21 Jun 1966, 2.5 cm fragment; ZMH, R/V W. Herwig, sta. 244, SW Atlantic, 36?51?S, 54?01?W, 800 m, 14 Jun 1966. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 45REVISION OF OCTOCORAL GENUS THOUARELLA Description As only a 2.5 cm fragment of the holotype was examined, the general morphology is taken from the original description (K?kenthal 1907) and the new specimens listed above. The colonies are branched once or twice and flabellate, with branchlets in a bottlebrush arrangement. The branchlets are mostly simple (rare secondary branching), 25 mm in length, emerging from the main stem at almost 90?; some branchlets are arranged in one plane. The polyps are isolated, weakly inclined towards the branchlets at 45?80? (Fig. 16b) and closely spaced, 14?20 per cm (more densely arranged at branchlet base). They are variable in shape, some clavate, some modestly flared distally (the holotype has distally flared polyps, Fig. 16c,d), 1.5?2.2 mm high (average 1.85 mm). There are 4?6 scales in abaxial rows (Fig. 16d) and 3?4 in the adaxial row. The operculars are triangle to lanceolate-shaped and acutely pointed (Fig. 17 a?c), 520?780 ?m high (average 660 ?m), 230?350 ?m wide (average 295 ?m), with an average H:W of 2.3. The inner opercular surface is keeled with the keel often having multiple longitudinal striations (Fig. 17b,c) that spread radially from proximal keel area towards lateral edges of the scale. The proximal third of the inner surface is tuberculate. The outer surface is concave longitudinally with low striations radiating from a proximal centre (Fig. 17a). The marginals are arranged in 2 alternate circles of 4, one inner and one outer (Fig. 16e), (although this is not consistent), and they are wider than the operculars, 530?680 ?m (average 600 ?m), and slightly shorter, 520?680 ?m (average of 600 ?m), with an average H:W of 1. They have a triangular distal area and are more squared proximally than the operculars (Fig. 17d?f) and they have a strong, multi-channelled keel with striations perpendicular to the distal edge. The proximal half of the inner surface is heavily tuberculate whilst the outer surface is densely covered with granules, with some scales having shallow radial striations towards the distal edge of the scale (Fig. 17f). The submarginals are shorter than the marginals, 530?540 ?m high, 520?700 ?m (average 610 ?m) wide, with an average H:W of 0.88, and have a modest distal point (Fig. 17g,h). The inner surface is tuberculate across the basal four-fifths of the scale, with a band of striations running perpendicular to the distal edge. The outer surface is covered with densely placed granules. The body-wall scales are generally rounded (average H:W 1; Fig. 17 j?m) with a pointed arch-shaped distal edge (Fig. 17k,m). Some abaxial body-wall scales have a sculpted distal edge (Fig. 17i). Body-wall scales are 270?580 ?m high (average 428 ?m), 240?650 ?m wide (average 448 ?m), progressively reducing in size from the polyp head to base. The body-wall scales have a heavily tuberculate inner surface, with a smooth band bearing a few ridges perpendicular to the distal edge and the outer surface is covered in granules (Fig. 17k). Some scales have deep radial striations running from the central proximal area (Fig. 17i). All the sclerites have an irregular distal edge and the proximal edge is coarsely lobate. The coenenchymal scales are elliptical to circular-shaped (Fig. 17n?q) with serrated edges and are 100?500 ?m long. The outer surface is covered in granules or is heavily sculpted (Fig. 17q) whilst the inner surface is densely tuberculate. Distribution This species has been recorded from the South Atlantic, including Bouvet Island to Burdwood Bank (Broch 1965) and the Patagonian Shelf at depths from 457?800 m. Broch?s unconfirmed identification (1965) was from 110 m depth. Remarks Thouarella striata has a variable polyp form. The surfaces of scales of the polyps from the holotype, both inner and outer, are deeply striated. Other specimens have finer striations on the outer surface but similar deep striations on the inner. The specimen from station 244 from ZMH (June 1966) was brooding. Comparisons With the number of abaxial scales on the polyps ranging from 4?6, T. striata is comparable to several species, namely T. variabilis, T. brucei, T. pendulina, T. hicksoni, T. bipinnata and T. andeep (see Table 3). TAYLOR ET AL.46 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 16. Thouarella striata, SMF 1966, sta. 285: a) 14 cm long colony. Holotype, MNHWU: b) 2.5 cm long fragment; c) lateral polyp view; d) abaxial polyp view; e) stereo opercular view. Photo b) by ZGR. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 47REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 17. Thouarella striata, holotype, MNHWU: a) outer and b,c) inner surface of operculars; d,f) outer and e) inner surface of marginal scales; g,h) inner surface of submarginal scales; i) abaxial body-wall scale with sculpted distal edge, j,l) inner surface of circular body-wall scales, k) inner and m) outer surface of body-wall scales; n?p) outer and q) inner surface of coenenchymal scales. TAYLOR ET AL.48 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Thouarella variabilis generally has fewer scales in the abaxial row than T. striata and lacks wide triangular marginals and striations on the distal edge of the inner surface of marginal and opercular scales. This lack of striations is the primary difference between T. striata and the other species listed above. In addition, the operculars of the polyps of T. andeep have a smooth inner surface and a rounded distal edge whereas operculars of the polyps of T. striata are triangular with a strong keel. The polyps of T. andeep also have fewer scales in the abaxial row and have accessory operculars, which have so far not been found in specimens of T. striata. When compared to the polyps of T. striata, those of T. pendulina are smaller and more tightly placed, and the outer surface of the sclerites lack striations. In addition, the colonies of T. pendulina have a true bottlebrush colony shape. The polyps of T. hicksoni are smaller and more densely arranged than those of T. striata. Colonies of T. bipinnata are uniplanar whereas those of T. striata have a bushy, bottlebrush shape. The polyps of the former are also clavate. 8. Thouarella crenelata K?kenthal, 1907 Figs 18, 19 Thouarella crenelata K?kenthal, 1907: 205; 1912: 302 Thouarella (Epithouarella) crenelata K?kenthal 1915: 151 (key); 1919: 436?438, text figs 216?219, pl. 43, fig. 70; 1924: 300?301; Cairns & Bayer 2009: 28 (listed), fig. 7i?m Material unavailable: The holotype is held in ZMB however material was too fragile to send from ZMB or MNHWU (where fragments are held). The type locality is eastern Bouvet Island, southern Atlantic Ocean, 457 m depth. Material examined: USNM 98086 (SEM stubs T53 & T68, stored at NMNH), R/V Hero, cruise 824, sta. 26?1, Lecointe Island, Brabant Island, Palmer Archipelago, Antarctic Peninsula, 64?14?03?S, 61?57?57?W, 238?285 m, 24 Mar 1982; USNM 99148, R/V Marion Dufresne, cruise 42, sta. 22, Mac Robertson Land, Lars Christensen Coast, north of Cape Darnley, Antarctica, 66?58?S, 72?52?E, 525 m, 26 Jan 1958; USNM 98160, R/V Hero, cruise 731, sta. 1947, Flandres Bay, Danco Coast, Antarctic Peninsula, 65?00?31?S, 63?28?06?W, 204?250 m, 11 Mar 1973; USNM 1128900, R/V Hero, cruise 731, sta. 1939, Wednesday Island, Butler Passage, Palmer Archipelago, Antarctic Peninsula, 64?58?39?S, 63?45?46?W, 75?120 m, 9 Mar 1973; USNM 1071563, R/V Hero, cruise 731, sta. 1812, Bismarck Strait, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?51?54?S, 63?39?45?W, 280?300 m, 19 Feb 1973; USNM 80154, R/V Professor Siedlecki, cruise 601, sta. 29, South Georgia Island, sub-Antarctic, 54?32?S, 39?05?W, 201?210 m, 3 Dec 1986; USNM 98028, R/V Eltanin, cruise 22, sta. 1536, west tip of South Georgia Island, sub-Antarctic, 54?29?S, 39?22?W, 659?686 m, 8 Feb 1966; USNM 97996, R/V Eltanin, cruise 7, sta. 499, south of Coronation Island, South Orkney Islands, sub-Antarctic, 62?06?S 45?08?W to 62?06?S 45?10?W, 485 m, 20 Feb 1963; USNM 58162, R/V Eastwind, sta. 006C, west of Brabant Island, South Shetland Islands, Antarctic Pensinsula, 64?50?S, 63?12?W, 283.5 m, 29 Jan 1966; USNM 76900, R/V Edisto, Deep Freeze IV, sta. 31, Nansen Island, Biscoe Islands, Antarctic Peninsula, 66?20?S, 67?47?W, 25 Mar 1959; USNM 98030, R/V Eltanin, cruise 22, sta. 1536, 54?30?S, 39?20?W, west tip of South Georgia Island, sub-Antarctic, 659?686 m, 8 Feb 1966; USNM 84342, R/V Eltanin, cruise 9, sta. 732, South Georgia Island, sub-Antarctic, 53?36?S, 36?51?W, 220?265 m, 12 Sep 1963; USNM 84343, R/V Professor Siedlecki, cruise 86?01, sta. 2, Shag Rocks, South Georgia Island, sub-Antarctic, 53?20?S, 42?42?W, 417?514 m, 29 Nov 1986; USNM 98102, R/V Professor Siedlecki, cruise 86?01, sta. 3, Shag Rocks, South Georgia Island, sub-Antarctic Ocean, 53?26?S, 42?29?W, 294?329 m, 29 Nov 1986; USNM 98099, R/V Hero, cruise 702, sta. 510, Antarctic, 64?48?S, 63?31?18?W, 219 m, 18 Mar 1970; USNM 1129152, R/V Hero, cruise 721, sta. 1143, Wauwermans Island, Bismarck Strait, Palmer Archipelago, Antarctic Peninsula, 64?57?11?S, 63?43?W, 230?260 m, 14 Mar 1972; USNM 1129153, R/V Eastwind, cruise 66, sta. 006C, haul 3, 64?50?24?S, 63?12?54?W, 283 m, 29 Jan 1966; USNM 1129151, R/V Hero, cruise 731, sta. 1945, Paradise Harbor, Gerlache Strait, Palmer Archipelago, Antarctic Peninsula, 64?48?27?S, 63?05?24?W, 260 m, 11 Mar 1973; SMF, EPO5, 3, sta. 291, GSN 14, 19 Feb 1989. Although no material was located in the Smithsonian collection, or elsewhere from the type locality, many specimens that match descriptions of T. crenelata and a photograph of the holotype (Fig. 18d) were located, all from the sub-Antarctic. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 49REVISION OF OCTOCORAL GENUS THOUARELLA Description The colonies are sparsely branched with the longest specimen (USNM 98086) measuring 35 cm (Fig. 18a). The branchlets are in a bottlebrush arrangement on branches although some colonies appear uniplanar where the branchlets curve in 2 directions. The branchlets are mostly simple with some secondary branching and branchlets are up to 30 mm long, arising in all directions (although most are only in 3?4 directions) at an angle of between 60?90?. Colonies tend to be dark to light yellow. The polyps are isolated, clavate (Fig. 18b?d), 2.3?3.0 mm high (average 2.1 mm), upwardly inclined at 60?90?, at a density of 5?11 per cm at the branchlet base, reaching 8?19 at tip. Each polyp has 8 longitudinal rows of scales, 6?10 (average 8) in the abaxial row (Fig. 18c) reducing to 6?7 per row adaxially. Sclerites get shorter and wider from polyp tip to base. The operculars are lanceolate (Fig. 19c) to arrow-head shaped (Fig. 19a,b,d), 530?710 ?m high (average 610 ?m), 270?380 ?m wide (average 325 ?m), with a H:W of 1.7?2.4 (average 1.9). The inner surface has a single large keel (keel side view Fig. 19e) and there are many lateral projections adjacent to the keel. These multiple sharp lateral ridges lead to an irregular distal edge. Lateral areas above the tuberculate base on the inner surface are relatively smooth with a finely serrate edge. The outer surface has many sharp radial ridges or striations from the central proximal area extending towards the distal edge. However, the centre of the scale is smooth with a deep longitudinal valley (Fig. 19d), and there are granules proximally and some tubercles showing at the proximal edge. The marginals are fan-shaped with a curved to pointed, dentate distal edge (Fig. 19f,g). They are 380?510 ?m high (average 438 ?m), 340?480 ?m wide (average 420 ?m), with a H:W of 1 (average 0.9?1.2). They bear a large keel on the inner surface with multiple dentate projections (Fig. 19f) whilst there are smooth areas adjacent to the keel and sparse tubercules across the proximal half. The outer surface has sparse, large granules, some stretching into radial ridges from the central proximal area and tubercles are also visible at the proximal edge (Fig. 19g). The marginals have a serrate lateral edge. The adaxial marginals have a reduced keel with tubercles covering the majority of the inner surface of the scales. The submarginals are elliptical in shape (Fig. 19h?l), 410?450 ?m high (average 430 ?m), 600?610 ?m wide (average 600 ?m), with a H:W of 0.7?0.75 (average 0.7). The proximal two-thirds of the inner surface is tuberculate with a smooth band across the distal third. There are 3 or 4 small keels and ridges perpendicular to the distal edge (Fig. 19j?l). From a side view the keel and ridges have large serrations. The outer surface is smooth with sparse granules centrally (Fig. 19h,i) and rare radial ridges and tubercles proximally. The distal edge has wide serrations and the proximal edge is coarsely lobate. The body-wall scales are relatively wide, short and elliptical (Fig. 19m?o), 600?620 ?m (average 610 ?m) wide, 290?400 ?m high (average 345 ?m), with a H:W of 0.5?0.7 (average 0.6). The inner surface is tuberculate with a smooth band along the distal edge (Fig. 19m). Radial striations along the distal edge of the outer surface result in a serrated distal edge whilst the lateral areas are relatively smooth. There are granules across the proximal area with some tubercles visible at the proximal edge (Fig. 19n,o). The coenenchymal scales are smaller than the body-wall scales, with a circular to irregular shape (Fig. 19p), 150 ?m diameter, with an irregularly serrate distal edge. The outer surface has granules and radial striations whilst the inner surface is tuberculate. Distribution This species has a circum sub-Antarctic distribution, found from depths of 75?686 m. Remarks Some branches appear uniplanar, as in the holotype (K?kenthal, 1907), as the branchlets curve in 2 directions. K?kenthal (1912) referred to this structure as ?biradial?. It is likely that this is the result of a commensal annelid inducing the branchlets to form around its body. Comparisons For a number of characters, Thouarella crenelata, T. chilensis, and T. parachilensis are morphologically similar and are probably closely related (see Table 3). The polyp shapes of these species are similar, although those of T. parachilensis are more bulbous distally than the more modestly clavate polyps of T. crenelata and the polyps of T. chilensis are more flared. Although there are differences in the number of abaxial scales the range of abaxial scale counts in all 3 species overlap making this a poor defining character: T. crenelata 6?11, TAYLOR ET AL.50 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 18. Thouarella crenelata. USNM 98086: a) colony, 35 cm; b) polyps; c) abaxial polyp view, e) stereo opercular view of polyp. Holotype, ZMB: d) close up of polyps. Photo d) by Carsten Lueter, ZMB. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 51REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 19. Thouarella crenelata, USNM 98086: a?c) inner, d) outer and e) lateral view of operculars; f) inner and g) outer surface of marginal scales; h,i) outer and j?l) inner surface of submarginal scales; m) inner and n,o) outer surface of body-wall scales; p) outer surface of coenenchymal scale. TAYLOR ET AL.52 ? Zootaxa 3602 (1) ? 2013 Magnolia Press T. parachilensis 8?15 and T. chilensis 6?8. As well as the varying sclerite shapes and sizes, the most prominent difference among these species is the density of polyp placement at the tip of a branchlet: Thouarella crenelata has 9?19 polyps per cm (average 11), T. parachilensis 18?48 (average 32) and T. chilensis 21?28 (average 22). Although there is moderate overlap in these ranges the branchlet tip of T. parachilensis specimens are ?barrel-shaped? with tight polyp placement and thus is distinguishable from T. crenelata. The marginal scales of T. crenelata also have a more pronounced dentate distal edge and the opercular scale surface is much more deeply and distinctly ridged than that found on the polyps of T. chilensis or T. parachilensis. Thouarella crenelata and T. viridis are very similar species. They were described as different species based on the number of scales in the abaxial row and the surface ornamentation of the mariginal scales (Zapata-Guardiola & L?pez-Gonz?lez 2010a). Our study reports an expansion in the range of the number of scales in the abaxial row of the polyps of T. crenelata from the 9?10 of K?kenthal (1915; 1924) to 6?11 (average of 8), which overlaps that of T. viridis (6?7). The scales of polyps of T. crenelata have a dentate distal edge whereas those of polyps of T. viridis lack this character. The colony form of Thouarella crenelata was originally described as similar to that of T. koellikeri (K?kenthal 1907), which has nearly pinnate branching, leaving one side of the stem without branchlets (described as ?biradial? by K?kenthal 1919). Specimens identified here as T. crenelata are bottlebrush but can have a bilateral appearance when the branchlets curve in two directions. There are a similar number of scales in the abaxial row of the polyps of both T. crenelata and T. koellikeri and both have polyps that are clavate, however those of the latter have operculars with a simpler keel. Polyps of T. crenelata have a comparable number of scales in the abaxial row, and a similar number of polyps per cm as colonies of T. clavata. But the former has more densely placed polyps at the tip of the branchlets, longer polyps, and polyps with marginals with larger serrations on the distal edge in comparison to the smooth to finely serrate edge of the latter. 9. Thouarella clavata K?kenthal, 1908 Figs 20, 21 Thouarella aff. antarctica K?kenthal 1907: 203?4 Thouarella clavata K?kenthal, 1908: 11 Thouarella (Parathouarella) clavata K?kenthal 1919: 430?433, text figs 209?212, pl.43, fig. 69 Thouarella (Thouarella) clavata Cairns & Bayer 2009: 27 (listed) Material examined: Holotype, ZMB Cni 6080, D.T.E Agulhasstrom, sta. 103, SW of Port Elizabeth, South Africa, 35?10.5?S, 23?2.0?E, 500 m; Syntype, MNHWU, 2 cm dried fragment; USNM 1140264, University of Cape Town Ecological Surveys, LBT 75 G, 32?03.3' S 16?02' E, 680?800 m, 25 Sep 1971. As so little material was available for study the colony description is based on K?kenthal?s 1908 study and his more detailed 1919 record of this species. There is some confusion surrounding this species as the specimen from ZMB has clavate polyps, very unlike those seen in K?kenthal (1919) and they in fact look similar to T. crenelata. As the MNHWU syntype more closely resembles images within K?kenthal (1919) we have based descriptions on this specimen. Unfortunately, it was not possible to take adequate SEM images of sclerites and polyps of the syntype as the specimen is in a very poor condition and disintegrated in SEM preparations. Using microscopy it was possible to identify a second T. clavata specimen: USNM 1140264. We thus illustrate specimen USNM 1140264, whose polyps and sclerites are identical to the few poor SEM images obtained from the syntype. Description The holotype stem base is slightly curved, the main stem is straighter (no holdfast), and branching is dense and in all directions (Fig. 20a), although the branchlets curve to create ventral and dorsal colony planes. The branchlets are mostly 30 mm long (some 35 mm), often forked at the branchlet base, and orientated at almost 90? to the main stem or branch. The dorsal plane branchlets of USNM 1140264 are greatly shortened and the proximal branchlets are also reduced in length (Fig. 20d). We believe that USNM 1140264 is conspecific to the MNHWU syntype. The following descriptions are of USNM 1140264 (unless stated) as this is the only known whole colony of T. clavata from which it was possible to take clear SEM images. Isolated polyps are sparsely placed on branchlets (Fig. 20d), 7?8 per cm. They are distally Zootaxa 3602 (1) ? 2013 Magnolia Press ? 53REVISION OF OCTOCORAL GENUS THOUARELLA flared (Fig. 20e, 21c) with a low a conical operculum, 1.4?1.7 mm high (average 1.5), and mostly in a single plane. Each polyp has 6?7 scales in one abaxial row (Fig. 21a) and 4 scales in each adaxial row. The operculars are arranged in 2 rings, an inner ring made up of smaller operculars and an outer ring of large operculars. The inner operculars are a tall?triangular shape (Fig. 21d,h), 350?390 ?m high (average 370 ?m), 150?230 ?m wide (average 180 ?m), with a H:W of 1.6?2.5 (average 2.1). Most of the outer operculars are larger with a wider lanceolate shape (Fig. 21e?g), 590?770 ?m high (average 680), 340?420 ?m wide (average 390), with a H:W of 1.5?1.9 (average 1.7). The operculars have a simple keel on the inner surface (Fig. 21e), are tuberculate proximally, and the outer surface is deeply concave and smooth (Fig. 21g). The proximal edge is coarsely lobate whilst the distal edge is serrate. The distal edge of the marginals are triangular with an angular proximal edge and are tuberculate across most of the inner surface, 790?900 ?m high (average 860 ?m), 480?650 ?m wide (average 600 ?m), with a H:W of 1.4?1.6 (average 1.5). The keel is simple and flat faced (Fig. 21j) and the outer surface is covered in granules with a smooth distal border (Fig. 21i). The submarginals are diamond-shaped, 690?750 ?m high (average 720 ?m), 650?730 ?m wide (690 average ?m), with a H:W of 1. There is a small keel on the inner surface corresponding to the peak on the distal edge (Fig. 21k). The remainder of the inner surface is tuberculate whilst the outer surface is covered in granules (Fig. 21l). The body-wall scales have a circular distal edge, are often irregular in shape (Fig. 21m, n), 220?340 ?m high (average 260 ?m), 250?490 ?m wide (average 330 ?m), with a H:W of 0.4?1.5 (average 0.9). The proximal edge is coarsely lobate. The inner surface is tuberculate, with a narrow smooth band along the distal margin whilst the outer surface is relatively smooth but has sparsely distributed granules. The coenenchymal scales are smaller than the body-wall scales, 120?220 ?m high (average 160 ?m), 140?250 ?m wide (average 190 ?m), with a H:W of 0.5?1.2 (average 0.9). They are circular to widely elliptical in shape (Fig. 21o?s) with a very smooth outer surface that bears a few small granules and a tuberculate inner surface. Distribution This species is only known from the type locality, southwest of Port Elizabeth, South Africa, at 500 m depth. Remarks The hand-drawn images in K?kenthal?s 1919 publication (text figs 209, 210) show modestly flared polyps like those on his plate XLIII. However, he described these polyps as clavate. We use the word ?clavate? to describe a polyp with a rounded distal head region, and K?kenthal appears to use the word to describe any polyp with a wider head than base. The syntype from MHWU is in bad condition, the sclerites are brittle and they partially disintegrated when they were cleaned in an attempt to carry out SEM observations?however, the polyps are distally flared, as in K?kenthal?s (1919) illustrations. The ZMB sample afforded clearer SEM images but the polyps are clavate and not like those illustrated by K?kenthal (1919), and also the opercular keel is strong, whereas it was described by K?kenthal (1907) as weak. The illustration of T. clavata (K?kenthal 1919: text figs 209, 210) shows a distally flared polyp with pointed marginals and the holotype description mentions clustered polyps. The MHWU sample most closely resembles this description and we are thus inclined to believe this is the true T. clavata, although this makes the name T. clavata a contradiction to our current use of this descriptive term. More samples of this species are required from the type locality to complete a full description and improve comparisons (below). Two polyp morphs were illustrated by K?kenthal (1919, Fig. 210), one of which may have been brooding. Comparisons The number of polyps per cm, number of pairs of abaxial scales (5?6), and flared polyp shape makes this species comparable to T. antarctica, T. brucei, and T. andeep (Table 3). Thouarella antarctica has a bottlebrush colony shape and shorter, more rigid branchlets than colonies of T. clavata. The remaining species have a bottlebrush to bilateral appearance similar to T. clavata, although colonies of T. andeep have shorter more rigid branchlets and marginals that are more acutely pointed than those of T. clavata. The polyps of T. clavata and T. brucei look almost identical, but branchlets of colonies of T. brucei are more sparsely placed than those of T. clavata (Fig. 20a). However, these differences in growth form are very minor. Thouarella brucei was originally described from Burdwood Bank and is found around Antarctica whereas T. clavata has been found only off the south coast of South Africa so there could be a separation in geographical distribution. More material of T. clavata is required to confirm that these two species are distinct. TAYLOR ET AL.54 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 20. Thouarella clavata, holotype ZMB Cni 6080: a) image of 11 cm colony, fig. 69 from K?kenthal 1919. Syntype, MNHWU: b) fragment of branchlet; c) close up of two polyps. USNM 1140264: d) colony; e) close up of polyps. Photos by SJ. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 55REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 21. Thouarella clavata, USNM 1140264: a) abaxial view of polyp; b) stereo opercular view of polyp; c) lateral polyp view; d,e,f) inner and g,h) outer surface of operculars; i) outer and j) inner surface of marginals; k) inner and l) outer surface of submarginals; m) inner and n) outer surface of body-wall scales; o,p,q) outer and r,s) inner surface of coenenchymal scales. TAYLOR ET AL.56 ? Zootaxa 3602 (1) ? 2013 Magnolia Press 10. Thouarella pendulina (Roule, 1908) Figs 22, 23 Rhopalonella pendulina Roule, 1908: 4, pl.1, fig. 5?8; Gravier 1914: 70?77, text figs 86?98, pl. 5, figs 21?15; K?kenthal 1912: 290 Thouarella pendulina K?kenthal 1915: 151; 1919: 440; 1924: 302 Thouarella (Thouarella) pendulina Cairns & Bayer 2009: 27 (listed); Zapata-Guardiola & L?pez-Gonz?lez 2010a: 179 Thouarella antarctica Broch 1965: 24?26, pl. 2, figs 5?7 Material examined: Holotype, MNHN?Octo.0000?0232 and paratype, MNHN?Octo.0000?0211, Expedition Antarctique Francaise (1903?1905), no. 640 collected, Booth (Wandel) Island. Other material: USNM 98341, R/V Islas Orcadas, cruise 876, sta. 111, Coronation Island, South Orkney Islands, sub-Antarctic, 60?25?36?S, 46?25?18?W, 97?128 m, 16 Feb 1976, 2 colonies; USNM 98359, R/V Hero, cruise 721, sta. 1075, Arthur Harbour, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?24?S, 64?7?36?W, 91?104 m, 23 Feb 1972, 3 colonies; USNM 1130339, R/V Eltanin, cruise 27, sta. 1896, Franklin Island, Victoria Land, Antarctica, 76?10?S, 168?17?E, 70?81 m, 18 Jan 1967; USNM 1130348, south end of Balleny Islands, Buckle Island, Antarctica, 66?53?S, 163?19?E, 55?164 m, 10 Feb 1974, 15 colonies; USNM 1130344, R/V Hero, cruise 731, sta. 1756, Arthur Harbour, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?14?S, 64?06?43?W, 91 m, 17 Feb 1973; USNM 85314, R/V Hero, cruise 721, sta. 1073, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?30?S, 64?07?36?W, 64?100 m, 23 Feb 1972; USNM 98149, R/V Hero, cruise 691, sta. 33, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 63?46?30?S, 61?47?51?W, 73?91 m, 13 Feb 1969; USNM 98150, R/V Hero, cruise 702, sta. 507, Port Lockroy, Wiencke Island, Palmer Archipelago, Antarctic Peninsula, 64?49?18?S, 63?31?21?W, 64?128 m, 17 Mar 1970; USNM 98158, R/V Hero, cruise 731, sta. 1944, Neumayer Channel, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?46?40?S, 63?25?33?W, 100?150 m, 11 Mar 1973; USNM 98170, R/V Eltanin, cruise 6, sta. 435, Astrolabe Island, Bransfield Strait, Antarctic Peninsula, 63?14?S, 58?42?W, 73 m, 8 Jan 1963; USNM 98171, R/V Eltanin, cruise 6, sta. 436, Astrolabe Island, Bransfield Strait, Antarctic Peninsula, 63?13?S, 58?47?W, 73 m, 8 Jan 1963; USNM 98228, R/V Islas Orcadas, cruise 876, sta. 107, Coronation Island, South Orkney Islands, sub- Antarctic, 60?26?30?S, 46?22?48?W, 102?108 m, 16 Feb 1976; USNM 98335, off south end of Buckle Island, Balleny Islands, Antarctic, 66?53?S, 163?19?E, 55?164 m, 10 Feb 1974; USNM 98343, USAP, SOSC?L46, Antarctic, 63?17?S, 62?09?W, 12 Jan 1973; USNM 98360, R/V Hero, cruise 721, sta. 5438, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?27?S, 64?07?W, 32?90 m, 27 Mar 1972; USNM 98363 and 98390 (same location), R/V Islas Orcadas, cruise 876, sta. 112, Coronation Island, South Orkney Islands, sub- Antarctic, 60?27?48?S, 46?23?06?W, 93?102 m, 16 Feb 1976; USNM 1120943, R/V Hero, cruise 691, sta. 28, south of Low Island, South Shetland Islands, sub-Antarctic, 63?25?30?S, 62?09?30?W, 91 m, 10 Feb 1969; USNM 1129159, R/V Eltanin, cruise 32, sta. 2059, south of Pennall Bank, Ross Sea, Antarctica, 77?58?30?S, 178?4?58?E, 655 m, 25 Jan 1968; USNM 1130330, R/V Hero, cruise 691, sta. 33, Hoseason Island, Bransfield Strait, Antarctic Peninsula, 63?36?30?S, 61?47?51?W, 73?91 m, 13 Feb 1969; USNM 1130342, R/V Eltanin, cruise 27, sta. 1896, Victoria Land, Franklin Island, Ross Sea, Antarctic, 76?10?01?S, 168?16?58?E, 70?81 m, 18 Jan 1967; USNM 1130344, R/V Hero, cruise 731, sta. 1756, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?13?S, 64?6?42?W, 91 m, 17 Feb 1973; USNM 1130345, R/V Eltanin, cruise 51, sta. 5762, Moubray Pennell Bank, Victoria Land, Ross Sea, Antarctic, 76?2?6?S, 179?57?W, 347?358 m, 9 Feb 1972; USNM 1130347, R/V Hero, cruise 731, sta. 1915, west of Bonaparte Point, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?S, 64?4?32?W, 35?60 m, 6 Mar 1973; USNM 1130349, R/V Hero, cruise 731, sta. 1823, Arthur Harbor, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?47?20?S, 64?6?58?W, 90?110 m, 20 Feb 1973; SMF, EPOS 03, sta. 212, GSN 2, Weddell Sea, 60?50?S, 55?38.9?W, 414 m, 15 Jan 1989; SMF, Terre Ad?lie, Antarctica, D114, Patrick Arnaud leg, no precise location or depth information; SMF, R/V Hero, sta. 90, South Janus Island, Palmer Archipelago, Antarctica, 73?100 m, 23 Mar 1972, no precise location information; SMF, R/V Hero, sta. 90, South Janus Island, Palmer Archipelago, Antarctica, 62?90 m, 23 Mar 1972, no precise location information. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 57REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 22. Thouarella pendulina: a,d,e) Paratype, MNHN, Oct.0000-0211: a) broken colony; d) abaxial and lateral view of polyps on branchlet; e) stereo opercular view of polyps. USNM 98359: b) colony, 22 cm; c) close up of polyps. TAYLOR ET AL.58 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 23. Thouarella pendulina, paratype, MNHN, Oct.0000-0211: a,c,d) inner and b,e) outer surface of opercular scales; f,g,h) inner and h,i) outer surface of marginal scales; k) inner surface of submarginal; l) outer and m?o) inner surface of body- wall scales; p?r) outer and s,t) inner surface of coenenchymal scales. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 59REVISION OF OCTOCORAL GENUS THOUARELLA Description The description of the holotype is of a 34.5 cm long colony, 60 mm at its widest point. Colonies of this species are generally of an unbranched bottlebrush arrangement (Fig. 22a,b), although a few have been seen to have limited branching with 2 or more stems. The branchlets leave the main stem in at least 4 directions, extend horizontally, then droop, most having secondary and tertiary branching which can appear simple as divisions are very close to the stem. The branchlets are 1?3 mm apart, and up to 40?42 mm long. The axis is woody with fine longitudinal striations, flexible (except at colony base which is thickened into a calcified holdfast) and is 5?6 mm diameter base. The polyps are crowded (Fig. 22c,d), with a density of 27?41 per cm (average 34). They are 0.9?1.2 mm high (average of 1 mm), appressed against the branchlets, 2?3 times longer than their diameter, and irregularly arranged. There are fewer polyps at the branchlet base, and they are more clustered at the centre and tip of the branchlets whilst there are no polyps on the main stem. The polyps are cylindrical at their base, thicker towards the operculum, with a slightly rounded shape and pointed summit. There are 4?5 scales in the abaxial row (Fig. 22d) but fewer in the adaxial row. Eight operculars create a tall cone rising above the marginals with the 2 adaxial operculars being reduced in size. The operculars are in 2 alternate circles, one inner, one outer, however this is not strict as the adaxial operculars are often inside the inner opercular circle. There are 6?7 isosceles triangle to lanceolate-shaped operculars, each having an acutely pointed distal edge (Fig. 23b?e). Opercular scale sizes range from 260?490 ?m high (average 357 ?m), 150?320 ?m wide (average 240 ?m), with an average H:W of 1.5. There are 1 or 2 adaxially placed, smaller, diamond-shaped operculars (Fig. 23a). The outer opercular surface is moderately concave longitudinally and there are granules sparsely covering the proximal area, sometimes these are aligned radially. The inner surface has a simple keel, which may be half the opercular length (Fig. 23c,d), and is sometimes channelled and flat-faced whilst the proximal half of the inner surface is tuberculate. The marginals are in inner and outer alternate circles of 4, although the adaxial marginals are reduced and do not conform to this pattern (Fig. 22e). Six of the 8 marginals are diamond to triangular shaped (Fig. 23f?j), higher, wider, and rounder than the operculars, 330?650 ?m high (average 460 ?m), 250?430 ?m wide (average 330 ?m), with an average H:W of 1.4. Generally the inner lateral marginals have a pointed distal edge that is angled to the right or left (Fig. 23g,h). The remaining 2 adaxial marginals are reduced in size and more circular. This reduction can be extreme such that these scales are sometimes not visible from an anterior view. The outer surface of marginals has granules sparsely covering the proximal area and some tubercles at the proximal margin. The inner surface has a modest simple keel and is tuberculate proximally with a narrow smooth band along the distal edge. Some abaxial submarginals have a pointed distal edge (Fig. 23k). Large angular, circular and elliptical body-wall scales (Fig. 23l?o) of variable number cover the polyp in rows. These scales are 210?600 ?m high (average 350 ?m), 230?510 ?m wide (average 340 ?m), with an average H:W of 1, and are larger towards the polyp anterior. The outer surface is smooth with a few granules at the base whilst the inner surface is tuberculate. All the sclerites of this species have a finely serrate distal edge and roughly lobate proximal edge. The coenenchymal scales are small, 150?280 ?m high (average 220 ?m), 120?200 ?m wide (average 165 ?m), and irregularly circular (Fig. 23p?t), with an average H:W of 1.34. The inner surface is tuberculate and granules sparsely placed across the outer surface. Distribution This species has a circum-Antarctic distribution and is found from 32?655 m depth. Remarks Thouarella pendulina was originally described within Rhopalonella Roule, 1908, a genus purportedly differentiated from Thouarella in having densely arranged polyps (Roule 1908). This tight clustering remains one of the distinguishing characteristics of this species although it is now considered to be within the range of variation of Thouarella. The polyps of this species have two alternating rings of marginals, however the adaxial marginals are usually not synchronised with the alternating pattern and are reduced and thus not visible from the anterior (Fig. 22e). The polyps of Thouarella pendulina can in fact be compressed against the stem, reducing the number of adaxial body- TAYLOR ET AL.60 ? Zootaxa 3602 (1) ? 2013 Magnolia Press wall scales per row to one or two. This is an oddity within Thouarella whose polyps generally depart the branchlets at 45?60? and have at least 3?4 adaxial body-wall scales per row. Thouarella pendulina has a variable gross morphology. Some colonies have tightly packed simple branchlets, which are densely covered in polyps. Other colonies have sparser branching (1?2 per cm) with fewer polyps per cm on branchlets. Some colonies have branching between these extremes. Comparisons There are several species that have a similar number of abaxial scales (4?5) as T. pendulina and should thus be compared (Table 3). Thouarella pendulina could most easily be mistaken for T. hicksoni, whose colony form is bottlebrush and polyps similar in size (with 4?5 scales in the abaxial row), shape, and are also clustered (although in T. pendulina they are more clustered). However, the operculars of the polyps of T. hicksoni are tongue-shaped, whereas those of T. pendulina are lanceolate with a pointed distal edge. Also, the inner surfaces of the operculars of T. hicksoni do not have a well-defined keel, instead tending to have an area of longitudinal striations. Although the polyps of T. brucei have a similar number of abaxial body-wall scales as those of T. pendulina, the latter has an almost bilateral colony appearance (although it is technically bottlebrush), polyps that are larger and more flared, and larger operculars than the former. Thouarella andeep also has 4?5 scales in the abaxial rows, however its polyps are flared and larger, making the operculars and marginals larger than those in the polyps of T. pendulina. The polyps of T. andeep are also less clustered, and more splayed than those of T. pendulina. The gross morphology of some ramified colonies of T. pendulina is very similar to that of T. variabilis. However, colonies of T. variabilis have longer polyps that are less clustered and elongated marginals that are absent in the former. Thouarella striata has larger polyps than those found on T. pendulina and distinctive striations on the inner surface of sclerites (lateral to the keel on the marginals and perpendicular to the distal edge on other sclerites) that are absent in T. pendulina. Thouarella pendulina has a similar shaped polyp to T. longispinosa (=Dasystenella acanthina). However, the former has eight marginals (not five as in Dasystenella) and polyps of T. pendulina do not occur in whorls. 11. Thouarella chilensis K?kenthal, 1908 Figs 24, 25 Thouarella chilensis K?kenthal, 1908: 11; 1912: 302?304 (incorrectly described as new), text figs 4?8, pl.11, fig. 5; 1915: 150 (key) Thouarella (Epithouarella) chilensis K?kenthal 1919: 436, text fig. 215; 1924: 300; Cairns & Bayer 2009: 28 (listed) Material examined: Holotype, C1780, ZMH, Iquique, Chile, no depth, 14 cm colony. Other material: NHM 89.5.27.43, H.M.S. Challenger, sta. 148A, off Crozet Island, sub-Antarctic, 46?5?S, 51?52?E, 1005 m, 3 Jan 1874, 1 fragment; USNM 1129149, R/V Islas Orcadas, cruise 575, sta. 65, Candlemas Island, South Sandwich Islands, Scotia Sea, 56?44?17?S, 26?58?36?W, 302?375 m, 31 May 1975; USNM 97967, R/V Hero, cruise 715, sta. 873, Thetis Bay, Tierra del Fuego, Argentina, 54?34?S, 65?50?W, 118 m, 26 Oct 1971; USNM 97966, R/V Hero, cruise 715, sta. 873, Thetis Bay, Tierra del Fuego, Argentina, 54?34?S, 65?50?W, 119 m, 26 Oct 1971, 2 colonies (8.5 cm, 9 cm); USNM 1099387, R/V Lawrence M. Gould, cruise LMG06?05, sta. 2, off Isla Grande de Tierra del Fuego, Argentina, South Atlantic Ocean, 53?47?S, 64?53?W, 120 m, 15 May 2006, 3 small fragments; USNM 98283, R/V Eltanin, cruise 11, sta. 974, north of Cape San Diego, Tierra del Fuego, Argentina, South Atlantic Ocean, 53?33?S, 64?56?W, 119?124 m, 12 Feb 1964, 7 colonies; USNM 97965, R/V Hero, cruise 715, sta. 870, north of Islas de los Estados, Argentina, 54?34?S, 64?00?W, 84 m, 24 Oct 1971; MNHN, MD 42, sta. 5, CP 30, Williams Bank, SE Indian Ocean, 53?18?S, 73?19?E, 250 m, 15 Jan 1983; SMF, EPOS 3, sta. 290, AT 24, Cape Norvegia, Weddell Sea, Antarctica, 71?05.9?S, 12?34?W, 522?531 m, 19 Feb 1985; ZMH, R/V W. Herwig, sta. 278, Patagonian Shelf, SW Atlantic, 40?57?S, 56?52?W, 200 m, 21 Jun 1966; ZMH, R/V W. Herwig, sta. 142, Patagonian Shelf, SW Atlantic, 42?06?S, 57?55?W, 788?765 m, 04 Jan 1971; ZMH, R/V W. Herwig, sta. 590, Burdwood Bank, SW Atlantic, 54?39.1?S, 61?44.6?W, 940?960 m, 1978; MNHN, MD 24, sta. 42, CM 59, L?na Bank, sub-Antarctic, 52?59?S, 44?22.7?E, 295?325 m, 4 Sep 1980; SMF, R/V W. Herwig 1971, sta. 277, 52?S, 55?20?W, 1200 m; SMF, MD 42, sta. 22, 1968, no location information. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 61REVISION OF OCTOCORAL GENUS THOUARELLA Description The holotype is a single bottlebrush branch (Fig. 24a), with short, 15 mm long, rigid branchlets that depart the main stem in at least 4 directions. The polyps are isolated, upwardly inclined at 45?80?, 2.5?2.75 mm high, with a density of 11?23 per cm on branchlets, and densely placed at the branchlet tip, at 21?28 per cm (Fig. 24b). The polyps are modestly distally flared, stout, and have 8 longitudinal rows of body-wall scales and 6?8 scales in each abaxial row (Fig. 24c). The operculars are triangular to arrow-head shaped (Fig. 25e?g), 415?510 ?m high (average 460 ?m), 200?300 ?m wide (average 250 ?m), with a H:W of 1.65?2.00 (average 1.8). The outer surface has granules arranged radially from the proximal central area (Fig. 25e,f) that develop into striations towards the distal edge whilst the inner surface bears a complex, multi-keel (Fig. 25g). Accessory operculars are occasionally present (Fig. 25a?d), approximately 225?150 ?m high, 100?115 ?m wide, with an average H:W of 1.7 (1.5?1.95). The marginals are a wide triangle to lanceolate shape (Fig. 25h?l), 520?565 ?m high (average 535 ?m), 460?560 ?m wide (average 510 ?m), with a H:W of 0.9?1.2 (average 1).The outer surface, similar to the operculars, has granules arranged radially from the proximal central area that develop into striations towards the distal edge (Fig. 25h,i,l). The inner surface has a channelled multi-keel with rough edges (Fig. 25j,k). Sometimes the keel has lateral extensions that are visible from the outer surface. The proximal inner surface is covered with tubercles and areas lateral to the keel are often ridged/striated. Submarginals are wider (with rounded lateral edges), and shorter than the marginals, having a modest distal point (Fig. 25m?o), a height around 350 ?m, width around 400 ?m and a H:W of 0.8,. The inner surface is tuberculate, with occasional ridges perpendicular to the distal edge. The outer surface has granules in a radial pattern that develop into striations towards the distal edge, which is similar to the marginals and the operculars. The body-wall scales are roughly elliptical (Fig. 25p?t), 290?400 ?m high (average 350 ?m), 445?700 ?m wide (average 560 ?m), with a H:W of 0.4?0.8 (average 0.6). Generally, the outer surface bears peaked granules towards the central proximal area, while the rest is covered in pronounced striations that extend radially to the distal edge (Fig. 25p,t). Tubercles are visible at the proximal edge. The inner surface is tuberculate, with a relatively smooth band along the distal edge that often has small ridges. The proximal edge of all the above sclerites is coarsely lobate with a distal edge that is irregular to serrate (unless otherwise stated). The coenenchymal scales are similarly shaped to body-wall scales except more circular and slightly smaller, down to 250 ?m diameter (Fig. 25u?w). Distribution This species is found on the Patagonian Shelf, southern Atlantic Ocean, around the Antarctic Peninsula, and in the southern Indian Ocean, at depths between 84?960 m. Remarks The holotype of T. chilensis was located in the ZMH, however, it was not marked as the holotype. The location and date of the inscription by K?kenthal (1908) match the data in the original type description as does the morphology and we therefore believe C1780 to be the holotype. This specimen was originally listed by the collector Schnehagen (possibly Capt. J. Schnehagen, although his collections were primarily from the South China Seas) as T. antarctica and was described by K?kenthal as T. chilenisis in 1908. Some colonies are sparsely branched, similar to T. parachilensis (Fig. 28a). The colonies are generally a light yellow to white shade of colour. The dense cylindrical clusters of polyps of T. chilensis were used by K?kenthal to distinguish this species from T. affinis and T. crenelata (K?kenthal 1915; 1924). As the original diagrams and descriptions did not quantify the density of clustering there have been several specimens identified as T. chilensis in museums that have denser clusters of polyps at the branchlet tip than the holotype of T. chilensis. These are in fact a new species, T. parachilensis (described below). A sample of T. chilensis (USNM 97966) was also incorrectly considered to be a voucher of T. antarctica by Cairns & Bayer (2009, Fig. 6g?l). TAYLOR ET AL.62 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 24. Thouarella chilensis, holotype, ZMH C1780: a) colony, 14 cm; b) close up of polyps; c) abaxial and lateral views of polyps; d) stereo opercular view of polyp. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 63REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 25. Thouarella chilensis, holotype, ZMH C1780: a?c) inner and d) outer surface of accessory operculars; e,f) outer and g) inner surface of opercular scales; h,i,l) outer and j,k) inner surface of marginal scales; m) inner and n,o) outer surface of submarginal scales; p,r,t) outer and q,s) inner surface of body-wall scales; u) inner and v,w) outer surface of coenenchymal scales. TAYLOR ET AL.64 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Comparisons The dense polyp arrangement of T. chilensis makes it easily mistaken for both T. antarctica and T. parachilensis. Marginals, submarginals and body-wall scales of T. chilensis have an ornamented distal edge with several ridges/ striations adjacent to the keel. The marginals of T. antarctica have a smoother edge that is more acutely pointed than on the marginals of T. chilensis. The polyps of the latter species also have, on average, more scales in the abaxial rows than the former. The operculars of the polyps of T. antarctica also tend to be thinner and more delicate than those of T. chilensis. The polyps of T. parachilensis are rounded and bulbous with 8?15 scales in the abaxial row whilst in contrast, polyps of T. chilensis are more squat and stout with just 6?8 abaxial scales. The polyps of T. chilensis are very similar to those of T. crenelata, both species having similar polyp and sclerite sizes and shapes. The polyps of T. chilensis are, however, more clustered on the branchlets than those of T. crenelata, whose polyps are more evenly spaced. The polyps of T. chilensis generally have fewer scales in the abaxial row than T. crenelata and the outer surfaces of sclerites of the latter are smoother than the striated surfaces found on the scales of T. chilensis. The specimens identified in museums and the literature seen within this study suggest that polyps of T. crenelata are more rounded than those of T. chilensis, however, without having viewed the holotype of T. crenelata it is difficult to be certain. Polyps of Thouarella chilensis have a similar number of abaxial body-wall scales (6?8) to those of T. viridis (6?7) and T. affinis (6?7). Both of the latter have a sparser polyp placement, and taller body-wall scales with a higher H:W than T. chilensis. Thouarella affinis also has flared rather than clavate polyps. Polyps of Thouarella koellikeri have a similar number of scales in the abaxial row as those of T. chilensis. The sclerites of the former are more delicate, the polyps having thinner body-wall scales, marginals that curve away from the polyp body and have a simple keel, whereas sclerites of the latter are thicker with more ornamented marginals that have a wide, complex keel (the lateral extensions of which can sometimes be seen from an abaxial view). 12. Thouarella hicksoni Thomson, 1911 Figs 26, 27 Thouarella hicksoni Thomson, 1911: 886?887, pl. 44, figs 3, 3a, pl. 45, fig. 1; K?kenthal 1919: 439?40; 1924: 301?2; Stiansy 1940: 32, text fig. G, pl. 4, fig. 21; Williams 1992: 277?280, fig. 1H, 66?68; Cairns & Bayer 2009: 27 (listed) Thouarella Hicksoni Tixier-Durivault 1954: 625 Material examined: Holotype, NHM 1962.7.20.36, off Cape St. Francis, South Africa, 135 m, rocky substratum, 19 Feb 1902, 8.5 cm and 4.5 cm fragments seen. Other material: USNM 53911, south of Port Elizabeth, South Africa, 34?15?S, 25?05?E, 11 m, SCD 8?J, collected by J. Day, 1958, 2 colonies; USNM 53912 + USNM 53813 (same location), SCD 3?D, South Africa, 34?30?S, 24?40?E, collected by J. Day, 102 m, 18 Apr 1958. Description The holotype is bottlebrush in shape, tapering at the tip (Fig. 26a). The branchlets emanate in 4 directions approximately perpendicular to the main stem, and are tightly placed at 1 mm intervals (Fig. 26b,e). Secondary and tertiary ramification is common and occurs close to the branchlet base. The axis is yellow, iridescent, and has fine longitudinal striations. The polyps rarely occur on the stem but are usually isolated on branchlets and can be placed in a spiral in 3 directions, but this is inconsistent. The polyps are modestly flared (Fig. 26c,d), angled at 30? to being appressed against the branchlet, and are 1?1.25 mm high, with a H:W of 1.79?1.95, with a clustered arrangement (Fig. 26e) of 16?22 per cm, less towards the branchlet base. Each polyp has 7 longitudinal rows of body-wall scales reducing to 4 rows at the base. There are 4?5 scales in the abaxial rows (Fig. 26c), 3?4 in the outer and inner lateral rows, and 2?3 scales in the adaxial rows. There are 8 operculars, measuring 300?360 ?m high (average 330 ?m), 170?210 ?m wide (average 190 ?m), with an average H:W of 1.7. Two to three of the largest operculars are lanceolate with a pointed distal edge (Fig. 27e) whilst the remainder are tongue-shaped (Fig. 27d). The operculars have a longitudinally concave outer surface, which is smooth, with tubercles sparsely arranged across the proximal area. The inner surface of the operculars have longitudinal median striations or a small simple keel, and the proximal third is tuberculate. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 65REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 26. Thouarella hicksoni, holotype, NHM 1962.7.20.36: a) 4.5 cm colony; b) close up of branchlet; c) abaxial polyp view; d) lateral polyp view; e) branchlet; f) stereo opercular view of polyp. TAYLOR ET AL.66 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 27. Thouarella hicksoni, holotype, NHM 1962.7.20.36: a) inner and (,c) outer surface of accessory opercular scales; d,e) inner surface of opercular scales; f,g) inner and h) outer surface of marginal scales; i,j) inner surface of submarginal scales; k,n) inner and l,m,o) outer surface of body-wall scales; p) outer surface of a coenenchymal scales. Photos by SJ. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 67REVISION OF OCTOCORAL GENUS THOUARELLA Beneath the 8 operculars are 2?4 (perhaps more in other colonies) accessory operculars (Fig. 27a?c) that are 200?210 ?m high (average 200 ?m), 110 ?m wide, a fraction the size of regular operculars, with a H:W of 1.75?1.9 (average 1.8). They have a relatively smooth outer surface with tubercles visible at the proximal edge and small median longitudinal striations or a small keel (Fig. 27a) on the inner surface, as is present on the larger operculars. The marginals form 2 alternate circles of 4 inner and 4 outer scales, although the pattern is not strict. They have a wide circular to oval body and are pointed distally (Fig. 27f?h) with a channelled keel on the inner surface (lateral keel projections can sometimes be visible from an abaxial view). Their dimensions are 350?480 ?m high (average 400 ?m), 220?320 ?m wide (average 280 ?m), with an average H:W of 1.4 (range of 1.1?2). The adaxial marginals are often shorter with a reduced or absent distal point (probably because these sclerites are compressed against the polyp and thus reduced in size). The inner surface of all marginals is tuberculate with smooth lateral areas adjacent to the keel. The outer surface is covered with granules which are placed more densely in the proximal central area, gradually diminishing in number towards the distal edge. The submarginals are elliptical with those of the abaxial side often having a moderately pointed distal edge (Fig. 27i,j). They are 250?270 ?m high (average 260 ?m), 260?280 ?m wide (average 270 ?m), with an average H:W of 0.9. The inner surface has small, simple single or double (and rarely treble) keels. The central area is tuberculate with a smooth band along the distal edge lateral to the keels. The outer surface is identical to that of the body-wall scales, as described below. Body-wall scales are semi-circular (Fig. 27k), fan-shaped (Fig. 27o), circular (Fig. 27l) or irregular in shape (Fig. 27n,m), often with an irregularly lobate proximal edge. Body-wall scales are 190?270 ?m high (average 220 ?m), 140?310 ?m wide (average 240 ?m), average H:W of 0.9 (range of 0.7?1.4). The outer surface is covered with granules proximally, with some tubercles at the proximal edge; the inner surface is tuberculate with a smooth band along the distal edge. The coenenchymal scales are circular (Fig. 27p), 110?150 ?m high (average 130 ?m), 100?180 ?m wide (average 140 ?m), with an average H:W of 1, with a smooth outer surface and tuberculate inner surface. Distribution This species is only known from the Port Elizabeth region, South Africa, at depths of 11?135 m. Remarks Contrary to Thomson?s description (1911), the branchlets at the colony base tend to be shorter; likely as a result of damage when collected. A small, circular, pebble-encrusted casing (perhaps an egg case) was found within the branchlets of the holotype. Comparisons Thouarella hicksoni and T. pendulina are very similar, sharing a similar number of abaxial body-wall scales, polyp length, and a clustered polyp arrangement (see Table 3). However, T. hicksoni has fewer polyps per cm and some operculars that have a tongue-shaped distal edge (Table 3). The polyps of T. striata, T. variabilis, and T. andeep have a similar number of scales in the abaxial row as the polyps of T. hicksoni, however, these three species have large, distally flared polyps that are arranged less densely on the branchlets than is found on specimens of T. hicksoni. The polyps of T. hicksoni have a similar number of scales in the abaxial rows, and similar marginal shapes as found in the polyps of T. brucei, however, the former species generally has smaller (noting that some additional specimens of T. brucei have smaller polyps than the holotype), more pointed polyps, and more clustered, finer, flexible branchlets. 13. Thouarella bipinnata Cairns, 2006 Thouarella bipinnata Cairns, 2006: 176?181, figs 8, 9; Cairns & Bayer 2009: 28 (listed) Material examined: Holotype, USNM 53015, Gerda 177, Straits of Florida, off northwest corner of Little Bahamas Bank, 27?17?N, 79?34?W, 686 m depth, 30 Jun 1963. Other material: all other specimens are from the original description (Cairns 2006). TAYLOR ET AL.68 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Description Description modified from the original (Cairns 2006). Colonies are uniplanar, delicate, and irregularly pinnate to bipinnate (occasionally 2 branchlets occur contiguously on the same side of the stem). The largest specimen (the holotype) is 9 cm long and 10 cm wide with a basal axis diameter of 1.6 mm. The holotype has 4 larger diameter branchlets near the colony base, each with a series of smaller branchlets, up to 30 mm long, that are placed roughly alternately at intervals of 5?15 mm. The axis is golden-yellow colour with a white calcareous discoidal holdfast. The polyps occur on the main stem and branchlets in a roughly alternating arrangement. Occasionally 2 polyps are arranged opposite to each other but there is no consistent tendency towards pairing or whorls. The polyps of the holotype are orientated toward one face of the colony, with a density of 11?14 per cm, they stand perpendicular to the branchlet, are modestly clavate, and up to 2.4 mm high with a H:W of 1.8?2.2. Each polyp has 6?8 longitudinal rows of scales with 3?5 in the abaxial row. The scales increase in size proximally as the polyp diameter decreases such that at the polyp base there are no adaxial scales and the inner-laterals are either reduced or absent. The operculars are lanceolate to arrowhead-shaped, up to 900 ?m high, with a H:W of 2.1?2.9, and form a well-defined operculum. The outer surface has radial striations from the proximal centre and a deep depression, corresponding to a large simple keel on the inner surface, the keel having many adjacent striations. Tubercules cover the proximal third of the inner surface of the opercular scales. The marginals are arranged in inner and outer rings of 4 scales each with their distal edges overlapping. The marginal scales are the same size as the operculars but more rounded proximally and have a pointed distal edge and a lower H:W of 1.3?2.1. The inner surface bears a complex keel with wide lateral projections whilst the remaining inner surface area is tuberculate with a narrow smooth distal band along the lateral edges. The outer surface has low radial striations from the proximal centre and some granular markings. The submarginals are elliptical, with a short, pointed distal edge, and are 500?600 ?m high with a H:W of 0.9?0.95. The inner surface is tuberculate with a wide smooth edge distally and some ridges perpendicular to the edge whilst the outer surface is mostly smooth with rare granules arranged radially from the proximal centre. The body-wall scales are roughly rectangular, sometimes rounded, usually broader than wide (H:W of 0.85?0.9), and can be 800 ?m wide towards the polyp base. The proximal outer surface is covered in granules and sometimes striations. The inner surface is tuberculate, often with ridges perpendicular to the distal edge. As with all polyp sclerites of this species, the distal edge is finely serrate and the proximal edge coarsely lobate. The coenenchymal scales are irregular shaped, up to 600 ?m in diameter, and have a highly concave outer surface. For images see Cairns (2006). Distribution Blake Plateau, off northern Florida, and Straits of Florida, off Little Bahamas Bank, to Guyana, from depths of 507?1000 m. Comparisons Thouarella bipinnata is the only species within Group 1 that is truly uniplanar with bipinnate to pinnate branching. There are several species that can appear bilateral e.g. T. koellikeri, the colonies of which also have roughly alternating polyps of a similar size to T. bipinnata. However, the polyps of T. koellikeri are more rounded, there are double the number of scales in the abaxial rows (7?10, rather than 3?5 in T. bipinnata), and polyps of T. koellikeri have a lower opercular cone than those of T. bipinnata. Thouarella affinis and T. viridis have colonies that can both appear bilateral, however, the polyps of both have more scales in the abaxial rows (6?7) than T. bipinnata. Thouarella brucei and T. andeep can have a bilateral colony shape and both have 4?5 scales in the abaxial rows of polyps, comparable to T. bipinnata. However, T. bipinnata has modestly clavate polyps, very different from the distally flared polyps of T. andeep and T. brucei. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 69REVISION OF OCTOCORAL GENUS THOUARELLA 14. Thouarella viridis Zapata-Guardiola and L?pez-Gonz?lez, 2010a Thouarella viridis Zapata-Guardiola & L?pez-Gonz?lez, 2010a: 169?180, figs 7?10. Holotype (not examined): ZMH C11744, ANT XIX/5, sta. PS61/164?01, west of South Georgia, Antarctica, 53?23.8?S, 42?42.03?W, 312.5?321.6 m, 9 Apr 2002. Material examined: Paratype, USNM 1128949, Antarktis XIX/5, R/V Polarstern, sta. PS61/167?01, west of South Georgia Island, sub-Antarctic, 53?23.68?S, 42?42.23?W, 306?342.7 m, 9 Apr 2002, 1 colony, 1 fragment. Other material: USNM 1130303 and USNM 98027 (same location), R/V Eltanin, cruise 22, sta. 1536, west tip of South Georgia Island, sub-Antarctic, 54?30?S, 39?20?W, 659?686 m, 8 Feb 1966; USNM 78401, R/V Eltanin, cruise 5, sta. 217, Le Maire Strait, Tierra del Fuego, Argentina, 54?22?S, 64?42?W, 106?110 m, 23 Sep 1962; ZMH, R/V W. Herwig, sta. 328, Patagonian Shelf, SW Atlantic, 42?52?S, 58?38?W, 1200 m, 22 Feb 1971; ZMH, R/V W. Herwig, sta. 285, Patagonian Shelf, SW Atlantic, 42?19?S, 58?01?W, 825 m, 21 Jun 1966; ZMH, R/V W. Herwig, sta. 311, Patagonian Shelf, SW Atlantic, 46?54?S, 60?28?W, 480 m, 18 Feb 1971; ZMH, R/V W. Herwig, sta. 243, Burdwood Bank, SW Atlantic, 54?57?S, 56?54?W, 500 m, 04 Feb 1971; ZMH, R/V W. Herwig, sta. 271, south Falkland Islands, sub-Antarctic, 52?40?S, 60?39?W, 405 m, 09 Feb 1971. Description Description modified from Zapata-Guardiola and L?pez-Gonz?lez (2010a). The holotype consists of a fragment of one colony. Branching is in at least 3 directions, and thus bottlebrush, however branches can be curved, giving the colony a bilateral appearance. The branchlets are up to 30 mm long, at a density of 7?8 per cm, and usually simple with occasional secondary branching. Fresh specimens are a shade of green, fading to white after preservation. The axis is ochre coloured, stiff and thick, with a basal axis diameter of 4 mm. The polyps are clavate with a conical operculum, 1.5?2.5 mm high, isolated (occasionally opposite) but emanating from branchlets in irregular spirals. The polyps are more clustered towards the branchlet tip and sparser at the base, with an average density of 14?15 per cm. The polyps have 8 longitudinal rows of body-wall scales, 6?7 scales in each abaxial row. The operculars are lanceolate to arrow-head shaped, some with a wide bilobate base, and are 620?780 ?m high and 470?640 ?m wide. The inner surface bears a prominent simple keel that often has lateral projections and adjacent longitudinal ridges; tubercles densely cover the proximal third of the scale. The outer surface is deeply longitudinally concave, corresponding to the keel on the inner surface whilst the proximal region has radial striations extending from a proximal centre, and granules distally. The marginal scales are pentagonal to widely trianglular in shape, 450?630 ?m high and 470?640 ?m wide. The inner surface has a wide, multiple keel with ridges adjacent and tubercles cover the proximal two-thirds to three-quarters of the inner surface. The outer marginal surface is covered with low relief granules that are more concentrated proximally. The body-wall scales and submarginals cannot be differentiated. Both are fan-shaped with a rounded distal edge, wider than they are high, 270?510 ?m high, 340?740 ?m wide, decreasing in size towards the polyp base. The inner surface is tuberculate, with a smooth distal band broken by several ridges perpendicular to the distal scale edge with the occurrence of ridging decreasing from polyp tip to its base. The outer scale surface is similar to that of the marginals. All polyp sclerites of this species have a coarsely lobate proximal edge. The coenenchymal scales are round to elliptical in shape and up to 130?360 ?m high. The inner surface is tuberculate and the outer surface has closely spaced granules that stretch into striations. The scale edges are irregular with warts proximally whilst the distal edge is finely serrate. For images see the original description (Zapata-Guardiola and L?pez-Gonz?lez 2010a). Distribution Our specimens extend the range of this species from the Falkland Islands and South Georgia Island, west to the Patagonian Shelf at depths from 106?825 m. TAYLOR ET AL.70 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Remarks The green shading makes this species easily recognisable. Comparisons The opercular scales of the polyps of Thouarella viridis have a deep longitudinal groove on the outer surface, and a complex keel, with many longitudinal adjacent ridges, on the inner surface. Conversely, those of T. antarctica has a relatively shallow groove on the outer surface and the keel is more simple, with multiple projections extending from a central point. The polyps of T. antarctica are also more flared than those of T. viridis, the latter having clavate polyps. The polyps of Thouarella koellikeri have more scales in the abaxial rows than T. viridis (7?10 in the former, 6?7 the latter), so although the polyps are of a comparable size, the scales of T. koellikeri are generally smaller. The keels on the marginal scales of the former are simple whereas those of the latter have adjacent ridges. The abaxial body-wall scales of the polyps of T. koellikeri also lack the distinctive teeth/ridges found on those of T. viridis. The polyps of Thouarella parachilensis are densely clustered at a branchlet tip. This clustering is absent on the branchlets of T. viridis, and the flat operculum of the former differs markedly from the tall, rounded operculum of the latter. The polyps of Thouarella affinis have a similar number of scales in the abaxial rows as the polyps of T. viridis however the marginals of the former have simpler keels. The submarginal scales of T. viridis also have multiple ridges on their inner distal edge and on some of the body-wall scales, which are absent in the former. The polyps of Thouarella crenelata are clavate, similar to those of T. viridis however, the latter has a tall operculum whereas the former has an operculum not visible in lateral view. The polyps of T. crenelata also tend to have more scales in the abaxial rows than is found on the polyps of T. viridis. 15. Thouarella minuta Zapata-Guardiola and L?pez-Gonz?lez, 2010a Thouarella minuta Zapata-Guardiola & L?pez-Gonz?lez, 2010a: 169?180, figs 11?13. Material unavailable: Holotype, ZIZMH C11742, ANT XXI?2, sta. PS65?166?01, Austasen, Antarctica, 70?56.83?S, 10?32.61?W, 253.2?338 m, 15 Dec 2003. Material examined: Paratype, USNM 1128948, ANT XXI/2, sta. PS65/166?01, Austanen, Cape Norvegia, Antarctica, 70?56.83?S, 10?32.61?W, 253.2?338 m, 15 Dec 2003. Other material: USNM 82873, Deep Freeze II, sta. 17, Staten Island, Tierra del Fuego, Argentina, 71?18?S, 13?32?W, 238 m, 27 Dec 1956; SMF, EPOS 3, sta. 257, AT19, Weddell Sea, Cape Norvegia, Antarctica, 71?39.5?S, 12?34.7?W, 301?330 m, 15 Feb 1989. Description Description modified from the original (Zapata-Guardiola and L?pez-Gonz?lez 2010a): The holotype is a single branch which is 66 cm long, 5.5 cm wide, with branchlets emerging from all sides in a bottlebrush arrangement although the basal 9 cm of the main branch lacks branchlets. The branchlets are up to 45 mm long, simple at the base, then dividing into 2, sometimes 3, branchlets with the terminal branchlets being up to 35 mm long. The axis is woody, light brown in colour, with a diameter of 3 mm. The holotype is fixed to a rock by a greyish discoidal holdfast, which is 13 mm in diameter. The polyps are isolated, arranged alternately or in loose spirals, 11?18 per cm, and are very small, 0.71?0.96 mm high, 0.3?0.44 mm wide, cone-shaped, and appressed against both the branchlets and the main stem. There is a quick reduction from 8 marginals at the polyp tip as the polyp scales are arranged in 5 longitudinal rows. The polyps have 3?4 scales in the abaxial rows. The tall, conical operculum gives the polyp a tapered distal shape. The operculum is composed of isosceles triangle or spoon-shaped operculars 250?450 ?m high, 70?160 ?m wide, which are reduced in size on the adaxial side of the polyp. The inner opercular surface has a simple, sometimes flat surfaced keel, with tubercules across the keel base and a smooth band along the lateral edges of the scale. The outer opercular surface is smooth with a few, small granules towards the proximal edge. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 71REVISION OF OCTOCORAL GENUS THOUARELLA The marginals are round to diamond-shaped, 210?280 ?m high, 160?230 ?m wide, and reduced in size on the adaxial side of the polyp. The proximal two-thirds of the inner surface is tuberculate with a smooth band along the distal edge broken by a small, simple keel whilst the outer surface is smooth. The submarginals are indistinguishable from body-wall scales; both are roughly circular, 220?280 ?m diameter, with adaxial scales being reduced in size. The inner scale surface is tuberculate and the outer surface is smooth. All polyp sclerites have a finely serrate distal edge and coarsely lobate proximal edge. The coenenchymal scales are round to elliptical, 120?220 ?m maximum diameter/width. The inner surface is sparsely tuberculate whilst the outer surface is smooth to slightly sculpted with sparse ridges and granules sometimes arranged radially. The images of the colony and sclerites are in the original description by Zapata-Guardiola and L?pez-Gonz?lez (2010a). Distribution Our specimens extend the range of T. minuta from Austasen, eastern Weddell Sea, Antarctica, to circum-Antarctic, at depths of 226?610 m. Remarks Thouarella minuta has the smallest polyps of any described Thouarella species. Comparisons With only three or four scales in the longitudinal abaxial rows, Thouarella minuta is comparable to T. variabilis, T. striata, T. pendulina, T. hicksoni and T. andeep (Table 3). However, all these species generally have polyps of 1 mm or greater length. The smallest polyps are found on colonies of T. pendulina and T. hicksoni, which sometimes have polyps of 1 mm (polyps of T. minuta are 0.71?0.96 mm high). The operculars of the polyps of T. hicksoni are blunt- tipped and those of T. pendulina are more triangular than the spoon-shaped operculars of T. minuta. 16. Thouarella andeep Zapata-Guardiola and L?pez-Gonz?lez, 2010b Fig. 40c,d Thouarella andeep Zapata-Guardiola & L?pez-Gonz?lez, 2010b: 142?145, fig. 8c,d, 11?13 Material unavailable: Holotype, ZMH C11744, R/V Polarstern, Antarktis XXIV/2, sample no. PS7/048?01, off Atka Bay, Antarctica, 70?24?S, 8?19?43?W, 601.8 m, 17 Jan 2008, 2 fragments. Material examined: Paratype, USNM 1123418, details same as holotype. Other material: USNM 98298, R/V Eltanin, sta. 1089, Clarence Island, NE of South Shetland Islands, sub- Antarctic, 60?47?S, 53?30?W, 641 m, 17 Apr 1964; USNM 1130294, R/V Hero, cruise 721, sta. 1144, Bismarck Strait, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?52?09?S, 63?50?09?W, 440?480 m, 14 Mar 1972; USNM 1130291, R/V Hero, cruise 824, sta. 35?B, 64?50?33?S, 63?51?00?W, 312?330 m, 26 Mar 1982, 1 fragment; USNM 1130289, R/V Eltanin, cruise 12, sta. 1081, east of South Orkney Islands, Scotia Ridge, Antarctica, 60?34?S, 40?44?W, 345?350 m, 13 Apr 1964; USNM 98276, R/V Eltanin, cruise 27, sta. 1870, Cape Adare, Victoria Land, Ross Sea, Antarctica, 71?16?S, 171?31?E, 659?714 m, 14 Jan 1967; USNM 85296, R/V Eltanin, cruise 11, sta. 970, SW coast of Staten Island, Tierra del Fuego, Argentina, 54?59?S, 64?53?W, 586?641 m, 11 Feb 1964, 1 fragment; USNM 1130287, R/V Eltanin, cruise 12, sta. 1089, NE of Clarence Island, South Shetland Islands, Antarctic Ocean, 60?47?S, 53?30?W, 641 m, 14 Apr 1964; SMF, EPOS 3, sta. 293, GSN 15, 20 Feb 1989, 1 colony, no location information. Description Description modified from Zapata-Guardiola and L?pez-Gonz?lez (2010b): The colonies appear alternately pinnate although branching is in 3 directions with 2 pinnate rows creating a plane and one row of branching between these 2 rows. The colonies are light pink or white with a bronze axis. The largest colony is 8 cm long (USNM 98276) with a very rigid stem and branchlets, the latter being 21?22 mm long. The polyps of the paratype are isolated, with a density of 10?11 per cm (more clustered at branchlet tip) and upwardly inclined 80?90? from branchlets and main stem. They are 1.9?3.4 mm high, very wide at 0.7?0.95 mm TAYLOR ET AL.72 ? Zootaxa 3602 (1) ? 2013 Magnolia Press and distally flared in shape, with a tall conical operculum. The polyps have 7 longitudinal rows of body-wall scales, quickly reducing to 4 at the base with 4?5 scales in each abaxial row. There are 5 to 6 tongue-shaped accessory operculars, 240?420 ?m high, 70?300 ?m wide, which lie underneath the operculars. The inner surface is tuberculate across the proximal half, smooth distally, and has no keel whilst the outer surface is smooth sometimes with low striations proximally. The operculars are arranged in 2 alternate circles of 4, they are tongue-shaped, sometimes constricted distally, 510?1100 ?m high, 340?520 ?m wide. The outer circle of operculars is larger than the inner circle. The inner surface of the larger scales have striations perpendicular to the distal edge, no distinct keel, and densely arranged tubercles proximally. Smaller operculars have a smooth inner surface and no striations. The outer surface has striations radiating from a central proximal area. The marginals have a wide triangle-shape with a pointed distal edge, which can be acutely elongated. The scales are 950?1320 ?m high and 740?990 ?m wide. The inner surface can have a complex multi-keel (Fig. 40c,d) or an area of striations. The area adjacent to the keel is smooth, and there are tubercules densely arranged below this. The outer surface is densely covered in granules. The submarginals are not differentiated from body-wall scales and both are irregularly fan-shaped, elliptical, and oval, with a maximum height of 540?840 ?m. The inner surface has a dense covering of tubercules, sometimes with a very narrow smooth band along the distal edge whilst the outer surface has densely arranged granules. As with all body-wall sclerites, the distal edge is finely serrate and the proximal edge coarsely lobate. The coenenchymal scales have a diverse range of shapes from circular to oval to lobate. These scales have a densely tuberculate inner surface and an outer surface with densely arranged granules, that is also often heavily striated. The scale has a maximum length of 60?93 ?m. The images of this species are found in the original description by Zapata-Guardiola and L?pez-Gonz?lez (2010b). Distribution The specimens described here extend the range of T. andeep to include the southwest Atlantic Ocean, off the tip of South America, and circum-Antarctic areas, at depths from 312?714 m. Remarks Thouarella andeep was originally described as having a bottlebrush colony. This is true in the strictest sense of the word, however, as in many Thouarella species, branching is not in all directions (usually just in 3), the overall appearance of which can look alternately pinnate. We also add that the marginals do have a keel (see Fig. 40c,d, from paratype). Comparisons With four to five scales in each longitudinal abaxial row, a bottlebrush branching arrangement, and distally flared polyps, Thouarella andeep is comparable to: T. minuta, T. pendulina, T. hicksoni, T. variabilis, T. striata, and T. brucei (Table 3). Thouarella minuta, T. pendulina, T. hicksoni, and T. variabilis all have polyps smaller than those of T. andeep. Of the remainder, T. striata often has distinct striations on the outer surface of the body-wall sclerites, whereas T. andeep has fine granules, and the latter also lacks the striations common on the inner surface of T. striata sclerites. Furthermore, T. brucei has a keel on the operculars that is lacking in T. andeep. Thouarella brucei also usually has smaller polyps than T. andeep. 17. Thouarella parachilensis sp. nov. Figs 28, 29 Material examined: Holotype, USNM 98338, R/V Islas Orcadas, cruise 575, sta. 90, South Georgia Island, sub- Antarctic, 54?50?36?S, 37?23?48?W, 223?227 m, 7 Jun 1975, 1 colony; Paratype: USNM 98190 (SEM images), R/V Professor Siedlecki, cruise 86?01, sta. 121, 53?57?S, 38?10?W, South Georgia Island, sub-Antarctic, 90?100 m, 6 Dec 1986, 1 colony; Paratype, ZSL SG09, Ev. 35, 53?44.07?S, 37?14.58?W, NW of South Georgia Island, sub-Antarctic, 125 m, 18 Jan 2009. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 73REVISION OF OCTOCORAL GENUS THOUARELLA Other material: USNM 84341, R/V Professor Siedlecki, cruise 86?01, sta. 122, 53?55?S, 38?03?W, South Georgia Island, sub-Antarctic, 119?130 m, 16 Dec 1986; USNM 97951, R/V Islas Orcadas, cruise 575, sta. 12, 53?38?12?S, 37?54?42?W, South Georgia Island, sub-Antarctic, 130?137 m, 13 May 1975; USNM 98087, R/V Professor Siedlecki, cruise 86?01, sta. 19, 54?02?S, 39?06?W, South Georgia Island, sub-Antarctic, 212?224 m, 2 Dec 1986; USNM 98387, R/V Hero, cruise 721, sta. 1144, Bismarck Strait, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?52?09?S, 63?50?09?W, 440?480 m, 14 Mar 1972; USNM 98361, R/V Hero, cruise 731, sta. 1884, Quintana Island, Wilhelm Archipelago, Antarctic Peninsula, 65?06?12?S, 64?59?51?W, 100?180 m, 3 Mar 1973; USNM 98104, R/V Professor Siedlecki, cruise 86?01, sta. 9 and 10, Shag Rocks, South Georgia Island, sub-Antarctic, 53?3?S, 41?57?W, 133?165 m, 30 Nov 1986; USNM 98173, R/V Eltanin, cruise 22, sta. 1536, west tip South Georgia Island, sub-Antarctic, 54?30?S, 39?20?W, 659?686 m, 8 Feb 1966; USNM 98085, R/V Eltanin, cruise 12, sta. 993, west of Aspland Island, South Shetland Islands, Antarctic Ocean, 61?25?01?S, 56?31?01?W, 300 m, 13 March 1963; USNM 98159, R/V Hero, cruise 731, sta. 1944, Neumayer Channel, Anvers Island, Palmer Archipelago, Antarctic Peninsula, 64?46?40?S, 63?25?33?W, 100?150 m, 11 Mar 1973. Etymology The name refers to Thouarella chilensis, for which this species was often mistaken. Description The colonies are flabellate (Fig. 28a), sparsely branched, and usually brown-red in coloration. The largest specimen (the holotype) is 290 mm long and 200 mm wide. The branches are feather-shaped with shorter branchlets at the apex and towards the base. The branchlets are sturdy, departing perpendicular to the branch on all sides, in a bottlebrush arrangement. There are 3?5 branchlets per cm, they are usually a maximum of 30 mm long, shorter towards colony base, mostly simple with some secondary branching, and ramification usually occurs close to the branchlet base. The polyps of the holotype are clavate and bulbous (Fig. 28b,c), sometimes with a flat adaxial surface (being compressed against neighbouring inner polyps; Fig. 28e). The polyps are 2.5?2.8 mm high, placed at an almost right-angle to the branchlets at the branchlet base but upwardly inclined towards the branchlet tip (up to 45?). They are spaced at 9?30 per cm at branchlet base and in a dense cluster at branchlet tip, where they form an almost solid cylinder of polyps (?barrel-shaped?, Fig. 28c) with 18?48 per cm. Each polyp has 8 longitudinal rows of scales, 8?15 scales in the abaxial rows (average 11, Fig. 28d), and a reduced number adaxially. The scales are progressively wider and shorter from polyp head to base. The operculum is flat. The operculars are arrowhead or lanceolate in shape (Fig. 29a?f) but can be wider and pentagonal, up to 420?510 ?m high (average 460 ?m), 230?410 ?m wide (average 340 ?m), with an average H:W of 1.4 (1.2?1.8). The inner opercular surface has a large, multi-keel (Fig. 29a,f) and many adjacent ridges resulting in a serrate distal edge whilst the proximal half is tuberculate. The outer scale surface has a deep longitudinal indentation (Fig. 29b?e), large granules extend into ridges that run perpendicular to the distal edge, and there can be tubercles along the proximal edge. The marginals are wider than the operculars, 340?510 ?m (average 440 ?m), 380?470 ?m high (average 430 ?m), with an average H:W of 1 (range from 0.7?1.2). The marginals are elliptical in shape with a pointed distal edge (Fig. 29g,h). The inner surface has a small, simple keel with smaller adjacent keels leading to a serrated distal edge. The proximal two-thirds is tuberculate and distal third smooth lateral to the keel and ridges. The outer surface has a longitudinal groove with sparse, large granules occurring towards the proximal edge, where tubercles are also visible. The submarginals are clearly visible from an anterior polyp view (Fig. 28e) as the distal edges curve slightly away from the polyp body. They are elliptical (Fig. 29i?k), wider than the marginals, 540?890 ?m (average 700 ?m), and about the same height, 350?550 ?m (average 430 ?m), with an average H:W of 0.6 (range from 0.4?0.9). The ridges are infrequent on the inner surface perpendicular to distal edge, the edge being serrate whilst the remainder of the inner surface is tuberculate. The outer surface has sparse granules proximally. TAYLOR ET AL.74 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 28. Thouarella parachilensis sp. nov, holotype, USNM 98338: a) colony, 29 cm long, 20 cm wide; b,c) close up of ?barrel-shaped? clusters of polyps; d) abaxial polyp view; e) stereo opercular view. Photo by SJ. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 75REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 29. Thouarella parachilensis sp. nov, holotype, USNM 98338: a,f) inner and b?e) outer surface of opercular sclerites; g) outer and h) inner surface of marginal scales; i,k) outer and j) inner surface of submarginal scales; l,n,p,q) outer and m,o) inner surface of body-wall scales; r) coenenchymal scales?top row right, middle row right, bottom row left show the outer surface, remainder inner surface. TAYLOR ET AL.76 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The body-wall scales are elliptical, very broad (Fig. 29l?q), curved around the polyp circumference, average height 380 ?m (270?520 ?m), width 790 ?m (620?1000 ?m), with an average H:W of 0.5 (range from 0.4?0.6). The inner surface is tuberculate with a narrow smooth band along the distal edge. The outer surface has large, sparse, peaked granules concentrated in the centre of the scale and sporadic tubercles proximally with the remainder being smooth whilst the distal edge has large serrations. All of the above sclerites of this species have a coarsely lobate proximal edge. The coenenchymal scales are circular to elliptical (Fig. 29r), 240?320 ?m diameter, with similar dimensions to the small body-wall scales, but flatter, with less curvature, and a strongly jagged distal edge. Distribution Thouarella parachilensis has been found 1000 km west of, and around, the waters of South Georgia Island and south to the Antarctic Peninsula, 90?480 m. Remarks The specimens of this species have long been incorrectly identified as Thouarella chilensis because of the densely clustered polyps at the branchlet tip that were mistaken for the densely arranged polyps found on that species, as described by K?kenthal (1908; 1915; 1924). Comparisons It is the cylindrical arrangement of the clustered, bulbous polyps at the branchlet tip that make T. parachilensis noticeably different from other Thouarella species, except for T. chilensis. Thouarella parachilensis has 8?15 abaxial body-wall scales per row (average of 11), a comparable number to T. koellikeri, T. chilensis, T. crenelata and T. brevispinosa. The polyps of T. koellikeri have 7?10 scales in the abaxial rows and a tall operculum of large operculars with a simple keel. This is distinct from T. parachilensis, which has a flat operculum with much smaller operculars bearing a complex keel. Thouarella brevispinosa has 6?8 scales in the abaxial rows, which are distally flared, and colonies have more evenly spaced polyps than the clavate, clustered polyps of T. parachilensis (Table 3). The polyps of T. parachilensis are bulbous and more rounded, usually with a higher number of scales in the abaxial rows than those of T. crenelata or T. chilensis. The polyps of T. crenelata have a more open operculum in anterior view than those of T. parachilensis and polyps of T. chilensis are more stout and stocky in shape. Species Group 2?polyps in pairs or whorls 18. Thouarella hilgendorfi (Studer, 1878) Plumarella hilgendorfi Studer, 1878: 648?649, pl. 2, figs 15a?e Thouarella hilgendorfi Wright & Studer 1889: 62, figs 18?25; Versluys 1906: 24?29, pl. 2, fig. 7, text figs; Thomson & Henderson 1906:38 (list); Roule 1908: 1; Kinoshita 1908a: 21?22, pl. 5, fig. 42; Nutting 1912: 66?67; Aurivillius 1931: 248?252, pl. 5, fig. 8, text fig. 48; Chave & Malahoff 1998: Table 1 (listed) Not Thouarella hilgendorfi Thomson 1927: 33?34, pl. 1, fig. 23, pl. 4, fig. 4, 5; Carpine & Grasshoff 1985: 32 (=T. grasshoffi) Thouarella typica Kinoshita, 1907: 230; 1908a: 23?24, pl. 2, fig. 9, pl. 5, fig. 43; Nutting 1912: 68 Thouarella hilgendorfi forma plumatilis Aurivillius, 1931: 252?256, pl. 5, fig. 9 Thouarella (Euthouarella) hilgendorfi K?kenthal 1915: 150; 1919: 415?416; Cairns 2006: 188 (discussion); Cairns & Bayer 2009: 28, figs 6m?s (listed); Cairns 2010: 415?422 Thouarella sp. cf. T. typica Grigg & Bayer 1976: 171 (listed); Parrish & Baco 2007: 192 (listed) Material examined: Holotype, ZMB Cni 2070 (see Versluys, 1906). ?Jeddobay? (=Tokyo Bay), Japan, 548 m, 60 mm fragment. Other material: USNM 56812, Star II (station unknown), Kaiwi Channel between Oahu and Molokai, 21?18?N, 157?32?W, 366 m, 1977, 1 large dried colony, SEM C1393-1397. Description Modified from description in Cairns (2010): Zootaxa 3602 (1) ? 2013 Magnolia Press ? 77REVISION OF OCTOCORAL GENUS THOUARELLA The colonies are flabellate, consisting of several main branches that are irregularly dichotomous. Each main branch is covered by numerous closely spaced, undivided, 20?25 mm length branchlets originating from all sides of the main branches in a bottlebrush arrangement. The largest specimen (USNM 56812) is 48 cm tall, 34 cm wide, with a broken basal stem, the diameter of which is 9.5 mm. The axis of the holotype is pale yellow to bronze in colour, and covered by white coenenchyme and polyps. The polyps of the holotype are 1?1.4 mm high, flared distally, slightly inclined upward, in whorls of 3 on branchlets and placed randomly on larger-diameter branches, with 6?7 whorls per cm. Approximately 1 in 20 polyps are highly modified by a pair of parasitic copepods, with each modified polyp being much larger, up to 1.6 mm high and 1.2 mm in diameter and thus 2?3 times the volume of a typical polyp. The parasite-modified polyps lack operculars, and their body-wall scales flare outward, having a ridged inner face, and a coarsely serrate distal margin. Generally the polyps have 8 longitudinal rows of body-wall scales, usually 6 or 7 abaxial pairs, 5 or 6 outer-lateral pairs, 3 or 4 inner-lateral pairs, and only 1 or 2 adaxial pairs. The operculars are triangular, often arranged in 2 quartets, alternating in size, with the larger operculars reaching 350?450 ?m high (H:W of 1.4?2.1) but the smaller operculars only reaching 180?230 ?m high (H:W of 1.6?2.2) and are highly curved. The opercular outer surface is smooth with a serrate distal edge. The longitudinally concave outer surface corresponds to the smooth, convex (not ridged or keeled) inner surface. The marginals also occur in 2 quartets, as do submarginals, the innermost 4 aligned with inner marginals, and outer 4 submarginals with outer marginals. The marginal scales have a broad elliptical base, a prominently spinose distal projection, and are up to 500?600 ?m high and 300?400 ?m wide (H:W of 1.2?1.8). The distal 60?65% of the scale is occupied by a projecting spine. The outer distal surface is smooth and the proximal area is covered with granules. The inner surface bears 3?4 prominent spines, and finely serrate ridges that form a complex keel that fits into the longitudinal furrow on the corresponding opercular outer surface. The submarginal scales are similar to the marginals but with a much shorter distal spine (35% length of scale) and a correspondingly lower H:W of 1.2 with a small simple keel on their inner surface. The body-wall scales are crescent-shaped with a finely serrate distal edge, a smooth outer surface, and are usually wider than high (H:W of 0.6?0.8). The adaxial side of the polyps are covered with particularly wide adaxial and inner lateral body-wall scales. The coenenchymal scales are similar to body-wall scales, mostly elliptical in shape with a smooth, flat outer surface, approximately 250 ?m wide and 150 ?m high, and a finely serrate distal edge. For images see Cairns (2010). Distribution Hawaii, Japan, Indonesia, and Indian Ocean at depths from 164?750 m. Remarks Thouarella typica is identical to T. hilgendorfi and were synonymised in Cairns (2010). Comparisons Within Group 2 only three species have a bottlebrush branching arrangement: T. grasshoffi Cairns, 2006, T. hilgendorfi, and T. laxa. Thouarella grasshoffi and T. hilgendorfi have true bottlebrush branching arrangements whereas branchlets of T. laxa are found mostly in one plane, although the length and flexibility of branchlets means the latter can appear bottlebrush. The colonies of T. grasshoffi tend to be taller than they are wide, with rare branching, whereas colonies of T. hilgendorfi are wider than tall, and flabellate. The polyps of T. grasshoffi and T. hilgendorfi have a very similar size, those of the former being pointed and conical, with slightly shorter marginals, compared with the distally flared polyps of the latter. 19. Thouarella moseleyi Wright and Studer, 1889 Figs 30, 31 Thouarella moseleyi Wright & Studer, 1889: 61?62, pl. 14, fig. 1, 1a, pl. 21, fig. 2; Versluys 1906: 29?30, figs 26, 27 (in text) Thouarella (Euthouarella) moseleyi K?kenthal 1915: 150; 1919: 417?418; 1924: 292, 294; Cairns & Bayer 2009: 28 (listed) Thouarella moseleyi var. spicata Thomson & Henderson, 1906: 38, 42?43, pl. 3, figs 2, 4 (sample not seen) Material examined: Holotype, NHM 1889.5.27.39, H.M.S. Challenger, sta. 171, Kermadec Islands, NE of New Zealand, 28?33?S, 177?50?E, 1097 m, 15 Jul 1874, 6 cm colony. TAYLOR ET AL.78 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Description The holotype was originally approximately 160 mm long (from Wright & Studer 1889: pl. 14, fig. 1) but only a 60 mm fragment now remains. The branchlets are pinnate, possibly alternately pinnate (Fig. 30a,b), although the colony can appear bottlebrush as branchlets are flexible and curve in all directions. The branchlets are mostly simple, some with secondary branching and they are 15?20 mm long. The axis is thin, calcareous, flexible, and ?somewhat flattened? (Wright & Studer 1889). The polyps are clavate with a tall, conical operculum (Fig. 30c), 1.5 mm high, paired, standing perpendicular to the branchlet, with some on the main stem. Each polyp has 6 longitudinal rows of body-wall scales and that number reduces rapidly adaxially from the marginal. There are 4?5 scales in the longitudinal abaxial row, and 3?4 in the adaxial rows. The thin, lanceolate operculars (can be wider with rounded distal edge, Fig. 31b) measure 450?640 ?m high (average 510 ?m), 140?270 ?m wide (average 200 ?m), with a H:W of 2.2?3.1 (average 2.6). The inner surface is smooth with a simple keel running longitudinally from the tip for three-quarters of the scale length (Fig. 31c) whilst the proximal quarter is tuberculate. Wider operculars have a wider, ridged area on the inner surface rather than a distinct keel (Fig. 31b). The outer scale surface is longitudinally concave and smooth, with granules arranged radially from the proximal centre and tubercles are visible at the proximal edge. The opercular edge appears smooth, but may be worn and thus not representative. The marginals are twice as wide as the operculars, 400?410 ?m (average 406 ?m), 455?510 ?m high (average 480 ?m), with a H:W of 1.1?1.3 (average 1.2), and are diamond-shaped (Fig. 31d?f). The inner surface has 4 or 5 tall, thin keels (Fig. 31d,f) with smooth areas lateral to the keels whilst the remainder is tuberculate. The outer surface is longitudinally concave and smooth, with granules distributed radially from the proximal centre with some tubercles being visible at the proximal edge (Fig. 31e). The distal edge is irregular, possibly worn, and the proximal edge is coarsely lobate. The submarginals are fan-shaped to elliptical (Fig. 31g,h), 320?420 ?m high (average 383 ?m), 470?480 ?m wide (average 475 ?m), with a H:W of 0.7?0.9 (average 0.8). The inner surface is tuberculate, the distal edge having a wide area of perpendicular ridges rather than a keel. The outer surface and scale edges are as the body- wall scales, below. The body-wall scales are circular to fan-shaped (Fig. 31i?l), 300?400 ?m high (average 340 ?m), 300?475 ?m wide (average 370 ?m), with a H:W of 0.7?1.2 (average 0.9). The inner surface is tuberculate with a narrow smooth band along the distal edge, and occasionally, small teeth perpendicular to the distal edge. The outer scale surface is smooth with sparse granules across the proximal area whilst the distal edge is smooth and the proximal edge is coarsely lobate. There are 2 layers of coenenchymal scales (Fig. 31m): sclerites from the inner layer are circular in shape and sclerites from the outside layer are elliptical. The inner surface of the coenenchymal scales is tuberculate with a smooth band running along the distal edge whilst the outer surface is smooth, sometimes with sparsely placed granules. The distal edge is smooth and the proximal edge is coarsely lobate. Distribution This species is known from 2 locations (excluding var. spicata), northwest of the Kermadec Islands in the South Pacific and north of Sumbawa Island in Indonesia, 6600 km away. It has been recorded from depths of 794?1097 m. Remarks The number of polyps per cm was impossible to tell from the small holotype fragment that remains. More material of this species from the type locality is required to confirm the differences between it and T. laxa, which has a very similar polyp morphology and pinnate branching. A variety of T. moseleyi (var. spicata) was described in Thomson and Henderson (1906). The differences between the polyps of the holotype and those of the variant are mainly that the latter has a taller conical operculum and marginal scales with a more elongated, pointed spine (which may be bifid). The tall conical operculum is similar to that of the polyps of T. grasshoffi. However, colonies of T. grasshoffi have a true bottlebrush branching arrangement. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 79REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 30. Thouarella moseleyi, holotype, NHM 1889.5.27.39: a) 6 cm colony; b) close up of the few remaining polyps; c) lateral view of polyp; d) stereo opercular view. TAYLOR ET AL.80 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 31. Thouarella moseleyi, holotype, NHM 1889.5.27.39: a) outer and b,c) inner surface of opercular scales; d,f) inner and e) outer surface of marginal scales; g,h) inner surface of submarginal scales; i,l) inner and j,k) outer surface of body-wall scales; m) coenenchymal scales?outer surface shown on top left and bottom right scales, remainder show the inner surface. Some SEM by ZGR. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 81REVISION OF OCTOCORAL GENUS THOUARELLA Comparisons Within Group 2 only two other species, T. laxa and T. tydemani, have pinnate colonies or colonies that appear pinnate. The ridges running perpendicular to the distal edge of the body-wall scales on the polyps of T. moseleyi are similar to those reported on the body-wall scales in a recent description of T. tydemani (Zapata-Guardiola and L?pez-Gonz?lez 2010a). The polyps of T. tydemani, however, have long spinose marginals and are distally flared, whereas polyps of T. moseleyi are clavate with shorter marginals. The polyps of T. moseleyi are more robust than those of T. laxa, with wider marginals that are not as spinose, and a fitted opercular cone. There are also several ridges running perpendicular to the distal edge of the submarginals, which are absent in the polyps of T. laxa. 20. Thouarella laxa Versluys, 1906 Figs 32, 33 Thouarella laxa Versluys, 1906: 30?32, pl. 1, fig. 5; pl. 3, fig. 8; text figs 28?33; Aurivillius 1931: 255?256 Not Thouarella laxa K?kenthal & Grozawsky 1908: 36?37, pl. 2, fig. 13 Thouarella (Euthouarella) laxa K?kenthal 1915: 150; 1919: 417; 1924: 293?294, text fig. 164; Cairns & Bayer 2009: 28 (in list) 4; Zapata-Guardiola and L?pez-Gonz?lez 2010a: 72?78 Thouarella flabellata K?kenthal, 1907: 207 Thouarella (Euthouarella) flabellata K?kenthal 1915: 150 (key); 1919: 408 (key), 418?420, pl. 42, fig. 64, figs 182?186 in text; 1924: 294?295; Cairns & Bayer 2009: 28 (listed) Thouarella regularis K?kenthal, 1907: 206?207 Thouarella tenuisquamis K?kenthal, 1908: 11; 1915: 150 (key), 151 Thouarella (Euthouarella) tenuisquamis K?kenthal 1919: 408 (key), 421, pl. 42, fig. 65, figs 187?190 (in text); 1924: 295; Cairns & Bayer 2009: 28 (listed) Thouarella carinata K?kenthal, 1908: 11?12; 1915: 150 (key) Thouarella (Euthouarella) carinata K?kenthal 1915: 150 (key); 1919: 408 (key), 423?425, pl. 42, fig. 66; 1924: 296; Cairns & Bayer 2009: 28 (listed) Material examined: Holotype of T. laxa, ZMA, COEL03576, Siboga expedition, sta. 88, Strait of Makassar, Sulawesi, Indonesia, 0?34?06?N, 119?08?05?E, 1301 m, 20 June 1899, 2 branchlets (80 mm, 90 mm); Holotype of Thouarella flabellata, sta. 257, east coast of Somalia, 1?48?02?N, 45?42?05?E, 1644 m, 3 fragments of 75 mm, 45 mm and 40 mm; Syntype of Thouarella tenuisquamis, MNHWU, northwest of Sumatra, Malaysia, south of Nicobar, 4?53?01?N, 93?33?05?E, 752 m; Syntype of Thouarella carinata, USNM 50127, Golden Hind, sta. 38, Okinawa and ?Urugakanal?, Japan, 731 m, 85 mm fragment. Description The colonies are sparsely branched (Fig. 32a). The branches generally have alternate pinnate branchlets with infrequent branching between these 2 planes and sometimes on the dorsal face. This forms a rudimentary bottlebrush arrangement (Fig. 32b) that can form a feather-shape. Branchlets are flexible, upwardly inclined at 45?, generally simple, with the longest being approximately 40 mm. Polyps of the holotype are rarely on the main stem, usually in pairs or whorls of 3 on branchlets, with a density of 5?7 pairs per cm, distally flared (Fig. 32c,d), upwardly inclined at 45?60?, and 1.2?1.5 mm high. Each polyp has 7 longitudinal rows, 5?6 scales in each abaxial row. The operculars are arranged in roughly 2 alternate rings of 4 (Fig. 32e). In the inner ring the scales are smaller (Fig. 33a?c), 280?300 ?m high (average 292 ?m), 140?210 ?m wide (average 166 ?m), with a H:W of 1.8 (range from 1.4?2.1). In the outer ring the scales are larger 370?630 ?m high (average 500 ?m), 120?370 ?m wide (average 292 ?m), with a H:W of 1.9 (ranges from 1.3?3.1). The larger operculars are triangular (Fig. 33e) although, if broken, they have a rounded, blunt apex, usually tapering slightly to a narrow distal edge (Fig. 33f), making them tongue-shaped. The outer opercular surface is smooth and concave longitudinally, having small granules proximally and tubercles at the base. The inner surface has fine tubercles covering the proximal third to half of the scale, the remainder is smooth with longitudinal central ridges (no distinct keel). The smaller operculars are lanceolate with a smooth outer surface that has a small number of granules at the base and is slightly concave; the inner surface is smooth with fine tubercles over the proximal quarter to third. TAYLOR ET AL.82 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 32. Thouarella laxa, holotype, ZMA COEL03576: a?c,e) original images of holotype from Versluys, 1906, a) 20 cm colony; b) close up of small branch; c) pair of polyps; e) stereo opercular view of polyps. Thouarella carinata (now synonymised with T. laxa), syntype, USNM 50127: d) polyp. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 83REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 33. Thouarella laxa, holotype, ZMA COEL03576: a,b,d) inner and c,e) outer surface of opercular scales; f) outer and g,h) inner surface of marginal scales; i,j) inner surface of submarginal scales; k,n) inner and l,m) outer surface of body-wall scales; o) coenenchymal scales?outer surface bottom right, remainder are the inner surface. TAYLOR ET AL.84 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The marginals are 570?800 ?m high (average 705 ?m), 370?550 ?m broad (wider than largest opercular), with an average H:W of 1.5 (range from 1.3?1.7). They have a circular to diamond-shaped base and a triangular, acutely pointed distal edge (Fig. 33f?h). The outer surface is smooth with low relief granules proximally whilst the inner surface has 2 or 3 ridges longitudinally placed along the keel (which is sometimes flattened) and tubercles covering the proximal half in a semi-circle leaving smooth wings lateral to the keel and along the distal edge. The submarginals are as described below for body-wall scales but slightly wider, 410?490 ?m (average 470 ?m), and taller, 500?610 ?m (average 570 ?m), with a H:W of 1.2. They have a pointed distal edge and a small keel on the inner surface (Fig. 33i,j), which has adjacent ridges perpendicular to the distal edge. The body-wall scales are usually circular (Fig. 33k?n), 250?590 ?m high (average 320 ?m), 280?390 ?m wide (average 310 ?m), with an average H:W of 1 (range from 0.6?1.7). The outer surface is mostly smooth with some granules proximally whilst the inner surface is tuberculate with a smooth band along the distal edge. The coenenchymal scales are circular to elliptical (Fig. 33o), 100?310 ?m high (average 200 ?m), 130?290 ?m wide (average 200 ?m), with a H:W of 0.4?1.5 (average 1). All the sclerites of this species have a finely serrate distal edge and roughly lobate proximal edge. Distribution This species occurs from the east coast of Africa (Somalia) to eastern Asia (Sumatra, Philippines, Japan) at depths of 400?1644 m. Remarks Thouarella laxa was recently redescribed by Zapata-Guardiola and L?pez-Gonz?lez (2010a). However, the polyp illustrated was incongruent with the holotype in that it showed the polyp head turning at an angle rather than a regular distally flared shape (Fig. 32c,d). Although T. laxa, T. carinata, T. flabellata, and T. tenuisquamis have been described from disparate locations such as Somalia and Japan, at a polyp and sclerite level these specimens are identical. Thouarella flabellata has fewer pairs/whorls of polyps per cm (5?6) than T. tenuisquamis (7?8), T. laxa (5?7), and T. carinata (7?8). Thouarella carinata is more likely to have 3 polyps in a whorl whereas the remaining species tend towards pairs. However, the number of polyps per whorl may increase with colony age and is variable in other Thouarella species (e.g. T. grasshoffi), so this small discrepancy should not be considered in defining species. The T. carinata and T. tenuisquamis holotypes are single branches and may even be one branch of a flabellate colony (see Fig. 32a,b of T. laxa). Thouarella carinata also has a more extended distal edge on its marginals, and the holotypes of the remaining species are in a relatively poor condition with few intact polyps, many having marginals reduced in length through wear. However, the marginals that were intact looked identical to those of T. laxa. In all these specimens the inner surface of the small operculars tended to be smooth and larger operculars had a longitudinally ridged area distally. The outer surface of all sclerites is smooth with sparsely placed granules. The differences described above are minor and despite the long distances between type localities, the minor differences in branching, polyp and sclerite shapes are not sufficient to delineate unique species. Therefore, T. carinata, T. flabellata, and T. tenuisquamis are thus proposed for synonymisation with T. laxa, this name having priority. Comparisons Polyps of T. laxa have a similar distal flare as those of T. hilgendorfi and T. tydemani and the sclerites of these species are all nearly identical in shape. Colonies of T. laxa however have long, flexible branchlets emanating from the stem in at least three directions whilst branching on T. tydemani is alternately pinnate. The branchlets of T. hilgendorfi are bottlebrush but branching is denser, with sturdier, less flexible branchlets, and there are more whorls and pairs per cm than found on T. laxa. These characters could be affected by environmental factors and, at a polyp level, these species are similar. Sampling of fresh material from type locations and perhaps genetic studies could shed light on the relationship between these two species and T. grasshoffi, which also has a similar polyp structure. The polyps of T. moseleyi are more rounded than those of T. laxa and consequently the former have shorter, narrower marginals. Additionally, the operculars of the former make a better-formed cone than those in the polyps of the latter and there are several ridges running perpendicular to the distal edge of the submarginals, a character not present in the polyps of T. laxa. Only a minute piece of T. moseleyi was examined, so more material is required Zootaxa 3602 (1) ? 2013 Magnolia Press ? 85REVISION OF OCTOCORAL GENUS THOUARELLA to confirm the difference between these species as sclerite measurements, sclerite arrangement, and polyp arrangement are very similar. 21. Thouarella tydemani Versluys, 1906 Thouarella tydemani Versluys, 1906: 34?35, pl. 1, fig. 2, figs 34?37 (in text) Thouarella tydemany Brito 1993: 220?221 ?Hookerella pulchella Gray, 1870: 45 Thouarella (Euthouarella) tydemani Cairns & Bayer 2009: 28 (listed) Material unavailable: Holotype, COEL09256, ZMA, Siboga expedition, sta. 297, Lesser Sunda Islands, Indonesia, 10?39?S, 123?40?E, 520 m, 27 Jan 1900, 200 mm colony. Only 3 mounted slides remain of this species, images of which were seen. They contain 2 branchlets, polyps and coenenchymal scales. The original colony is presumed lost as the holotype was not present at ZMA (Zapata-Guardiola & L?pez-Gonz?lez 2010a) or any of the other museums contacted within this study. As no material was available the type description was used for species comparisons. Description The colony is flat with infrequent uniplanar branching. The branchlets are simple, 15?20 mm long, rarely 30 mm, alternately pinnate with a few ventral branchlets. The polyps are distally flared, approximately 1.5 mm high, standing at 80?90? inclination from branchlets, paired, rarely in whorls, 3?6 per cm with some polyps on the main branch. The operculars are in a modest cone of 4 larger, outer, longitudinally concave operculars and 4 smaller, inner, distally blunt operculars. The marginals are 450?500 ?m high, almost spinose with a keel visible on the inner surface. Body-wall scales appear circular, some bearing ridges perpendicular to the distal edge. Recently published additional description and images are in Zapata-Guardiola and L?pez-Gonz?lez (2010a). Distribution Known only from the type location off the Lesser Sunda Islands, Indonesia, at 520 m depth. Remarks Versluys (1906) separated Thouarella laxa and T. tydemani, the latter having wider and larger polyps. Zapata- Guardiola and L?pez-Gonz?lez (2010a) illustrated that the variation in nearly all characters (size of polyps, number of whorls per cm, number of polyps per whorl etc) in T. laxa was broad enough to encompass the dimensions seen in T. tydemani. The only difference found between T. laxa and T. tydemani was that the body-wall scales of the latter have short ridges perpendicular to the distal edge, which are absent in T. laxa. Versluys (1906) also considered Hookerella pulchella Gray, 1870 very similar to T. tydemani in colony form but he did not mention the number of polyps per cm or the sclerite shape. Without a reliable illustration or accurate description from Gray (1870), Versluys described T. tydemani, ignoring H. pulchella (the holotype or a specimen of which cannot be located). Comparisons Thouarella tydemani was compared to T. laxa by Versluys (1906) and rightly so as the polyps of these species are nearly identical in every respect. Body-wall scales of T. tydemani may bend away from the polyp body, have ridges perpendicular to their distal edge, and have slightly shorter marginals than are found on T. laxa (this is in contrast to Zapata-Guardiola & L?pez-Gonz?lez, 2010a, who found polyps of T. laxa had marginals that were on average 370 ?m and thus shorter than those of T. tydemani). However it is the branching pattern that makes these species truly distinct. Colonies of T. laxa have long, flexible branchlets, departing the stem in at least 3 directions, whereas colonies of T. tydemani are mostly pinnate with more rigid branchlets. Additionally, the polyps of T. laxa have a flat operculum and branchlets inclined at a 45?60?, rather than 90? as in T. tydemani. More material of T. tydemani would help to assess further differences between these two species. Polyps of T. tydemani are distally flared and look very similar to those of T. hilgendorfi. However, the pinnate branching structure of T. tydemani differentiates this species from the bottlebrush branches of T. hilgendorfi. TAYLOR ET AL.86 ? Zootaxa 3602 (1) ? 2013 Magnolia Press 22. Thouarella coronata Kinoshita, 1908 Figs 34, 35 Thouarella (Diplocalyptra) coronata Kinoshita, 1908c: 519?520, fig. 2; 1908b: 56?59, figs 4?6 (in text); Cairns & Bayer 2009: 28 (list), 35, figs 7a?g Thouarella coronata Aurivillius 1931: 255 (listed) Thouarella (Euthouarella) coronata K?kenthal 1915: 150 (key); 1924: 296 (key) Material examined: USNM 50118, fragment of holotype, UMUT, Uji Island, Kyushu Island, 146 m, May 1908, 13 cm colony of which we viewed 20 mm. A small fragment of the holotype was available for study, however, the colony shape and branchlet arrangement narrative below relies heavily on the original description. Description The colony is mostly sympodially branched with dichotomous branching in one upper portion of the colony (top left of Fig. 34a). Basal branchlets are up to 50 mm long, 5?12 mm apart, and on rare occasions 20 mm apart. The axis is brown with a yellowish metallic lustre. The polyps are distally flared with a slender polyp body (Fig. 34d,e) 1.9?2.1 mm high, standing perpendicular to the branchlet in pairs and sometimes whorls of 3 (Fig. 34c), with 5?7 pairs or whorls per cm. There are 8 marginals, but only 7 longitudinal rows of body-wall scales with 5?6 scales in the abaxial rows. The operculars are lanceolate to triangular in shape (Fig. 35d?h), 260?455 ?m high (average 290 ?m), 120?240 ?m wide (average 180 ?m), with an average H:W of 1.6 (range from 1.3?2). The outer surface is smooth whilst the inner surface has a small elliptical tuberclulate area proximally and a smooth distal area. Beneath the operculars are 3?4 (perhaps more in other samples) small accessory operculars (Fig. 35a?c) which are irregular or tear-shaped, 80?200 ?m high (average 150 ?m), 70?140 ?m wide (average 100 ?m), with an average H:W of 1.1. The outer surface is smooth, the inner surface is also smooth with a small patch of tubercles proximally. The scale edges are relatively smooth (not serrated). The marginals are equilateral triangle-shaped with a rounded proximal edge (Fig. 35i?k), 430?560 ?m high (average 490 ?m), 270?330 ?m wide (average 310 ?m), with an average H:W of 1.6 (range from 1.3?2.1). The outer scale surface is smooth distally with granules proximally. The inner surface has a multi-channelled keel with smooth areas lateral to the keel and tubercles covering the proximal half below the keel base. A marginal scale?s proximal edge is roughly lobate, and may be angular. Some submarginals have small keels or ridges on the distal edge of the inner surface and are a wide tear-shape and pointed distally (Fig. 35l,m). They have a tuberculate inner surface with a narrow smooth band along the distal edge whilst the outer surface is smooth with some granules proximally. Body-wall scales are circular (Fig. 35n?p), 190?340 ?m high (average 250 ?m), 200?310 ?m wide (average 240 ?m), with an average H:W of 1.1 (range from 0.9?1.2). The outer surface is smooth, sometimes with granules proximally whilst the inner surface is tuberculate with a smooth band along the distal edge and infrequent small ridges running perpendicular to the edge. The distal edge of all polyp sclerites of this species is finely serrate (unless otherwise stated) whilst the proximal edge is coarsely lobate. The coenenchymal scales are circular (Fig. 35q), around 130 ?m diameter and much smaller than the body- wall scales. The outer scale surface is smooth and slightly concave with edges raised from the axis whilst the inner surface is tuberculate. Several hundred cylindrical rodlets were found in each tentacle. Distribution Known only from type locality, Kyushu Island, Japan, 146 m depth. Remarks This is the only Thouarella species known to contain tentacular rodlets, a form of sclerite often found in Plumarella. It is also the only Thouarella species known to have a sympodial branching pattern. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 87REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 34. Thouarella coronata, holotype, UMUT: a) 13 cm colony; b) close up of polyps; c) whorl of three polyps; d) abaxial polyp view; e) lateral polyp view; f) stereo opercular view. SEM by RZG. TAYLOR ET AL.88 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 35. Thouarella coronata, holotype, UMUT: a,b) outer and c) inner surface of accessory operculars; d,g,h) outer and e,f) inner surface of opercular scales; i,j) outer and k) inner surface of marginal scales; l,m) inner surface of submarginal scales; n) inner and o,p) outer surface of body-wall scales; q) coenenchymal scales?inner surface top row left, bottom row right and middle; remainder are the outer surface. Some SEM by ZGR. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 89REVISION OF OCTOCORAL GENUS THOUARELLA Comparisons Although the majority of the T. coronata colony is sympodially branched a portion is dichotomously branched (more examples of this species are required to confirm the branching pattern). Apart from T. coronata, only two other species within Group 2 have dichotomous, uniplanar branching: T. parva, also from Japan, and T. biserialis (Nutting, 1908), from Hawai?i. Kinoshita?s drawings (1908d, figs 1, 2) indicate that T. parva differs from T. coronata in having shorter, more rounded marginals and polyps diverging from branchlets at approximately 45? rather than 90?. The sclerites of polyps of T. biserialis and T. coronata are very similar. The marginals of polyps of T. biserialis appear to curve over the operculum creating a cylindrical, rounded polyp, whereas those of T. coronata are flared outward. The polyps of the former are inclined at 45? and of the latter are perpendicular to branchlets. The importance of these characters remains unclear, so for now these species are considered to be distinct. 23. Thouarella parva Kinoshita, 1908 Fig. 40 a,b Thouarella (Diplocalyptra) parva Kinoshita, 1908d: 53?56, figs 1?3; Cairns & Bayer 2009: 28 (list) Thouarella (Amphilaphis) parva K?kenthal 1915: 149 (key); 1919: 410; 1924: 290 (key) Material unavailable: Holotype, Kodzu Island, Japan, depth unknown. Unfortunately the holotype was not present within the University of Tokyo Museum collection (Dr Ueshima, pers. comm.), and so Kinoshita?s original description of a 73 mm fragment (1908d) is summarised below. Description The colony is uniplanar with dichotomous branching. The branchlets diverge from the main stem at around 50?, 5?13 mm between branchlets. The colony colour is white to light yellow. The polyps are 1 mm high and upwardly inclined to the branchlets at around 45?, the widest point being around the marginals. They are slender toward the base (Fig. 40a), arranged in pairs, with a density of about 6 per cm, and each has 8 longitudinal rows of body-wall scales. There are 5?6 scales in the abaxial rows, and 5 in the outer and inner lateral rows, reducing to 4 adaxially. From a lateral view the operculars are completely concealed by the marginals. Very small accessory operculars are present (Fig. 40bI). The operculars are lanceolate (Fig. 40bII), 160?360 ?m high and 90?160 ?m wide. The distal half of the outer opercular surface is slightly concave and both the inner and outer surfaces have granules arranged radially in the proximal area. The inner surface is likely to be tuberculate proximally, as is typical for the genus. The marginals are an irregular triangle-shape (Fig. 40bIII) and approximately the same size as the largest opercular (400 ?m), although wider proximally. The body-wall scales are not as tall as the marginals (350?380 ?m) and are broader (Fig. 40bV, bVI). The outer surface of the body-wall scales has radially arranged granules from the central proximal area whilst the inner scale surface is tuberculate with a smooth band along the distal edge, occasionally with several ridges perpendicular to the distal edge. The coenenchymal scales are smaller than body-wall scales, and circular to elliptical in shape. The outer surface is sculpted and folded with sparse tubercles on the inner surface. The distal and lateral edges of all sclerites are finely serrate with a coarsely lobate proximal edge. Distribution This species is only known from Kodzu Island and Sagami Bay, Japan. The depth from which the sample was taken is unknown. Remarks Kinoshita was the first to note accessory operculars in Thouarella (1908d, Fig. 2, shown here in Fig. 40b) and T. parva remains one of the few Thouarella species with this kind of sclerite. The marginals of the polyps of T. parva (Fig. 40bIII) appear to have a small keel on their inner surface, and the specimen is thus considered to be Thouarella. However, this is far from clear and the rounded distal edge of what appear to be marginals in Fig. 40b, and lack of a clear keel could indicate that this is actually a species of TAYLOR ET AL.90 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Plumarella. More material is required to confirm the placement of T. parva within Thouarella. Comparisons Dichotomous branching precludes this species from being T. hilgendorfi, T. moseleyi, T. laxa, T. tydemani, or T. grasshoffi from within Group 2. Additionally, these species all have tall, triangular marginals that are absent in T. parva. Only two other Thouarella species have dichotomous branching: T. coronata and T. biserialis. The polyps of T. coronata diverge at 90? to the branch, whereas those of T. parva depart at 45?. This seems to be a very small difference, however, without more material of T. parva it is impossible to determine the extent of the character differences between these species. There are believed to be specimens of T. parva in Japan (Cairns, pers. comm.), but until this material is examined these species are considered to be distinct. Polyps of both T. parva and T. biserialis depart from branchlets at approximately 45? and all their sclerites appear to be very similar shapes and sizes. The polyps of T. biserialis have marginals with a distinct keel, which may be present on T. parva, but the polyps of T. biserialis are clavate whereas those of T. parva are modestly flared with a relatively tall operculum. 24. Thouarella biserialis (Nutting, 1908) Amphilaphis biserialis Nutting, 1908: 573, pl. 43, fig. 4, pl. 47, fig. 4; Cairns & Bayer 2009: 28 (listed) Thouarella biserialis Kinoshita 1908c: 519?520, 2 text figs; K?kenthal 1915: 151 (listed); 1919: 438?9; 1924: 301; Parrish & Baco 2007: 192 (listed) Thouarella (Diplocalyptra) biserialis Cairns, 2010: 417, figs 2?3 Material examined: Holotype, USNM 22583, USFWS Albatross 398210, Mawiliwili, Kaua?i Island, Hawaii, North Pacific Ocean, 21?56?25?N, 159?21?40?W, 73?426 m, June 1902, 2 short branches. Description Modified from description in Cairns (2010): The holotype, now in 2 fragments of 4 cm and 3 cm length, appears to be from a dichotomously branched, uniplanar colony. The polyps are cylindrical to clavate, 1.2?1.5 mm high, curved upward at 45?, and arranged in pairs standing on opposite sides of the branchlets with the plane of the colony. The polyps are rarely in whorls of 3. There are 6?7 scales in 8 longitudinal rows, 5?6 in the outer lateral rows, 2?3 in the inner lateral rows and 1?2 adaxially. Adaxial rows are short, revealing a largely naked adaxial face. The operculars are lanceolate to widely-triangular, small (up to 280 ?m high), and bluntly tipped, with a H:W of 1.6?2.0. The outer opercular surface is flat and has granules proximally whilst the distal inner surface is smooth (unkeeled), bearing rounded longitudinal bulges. The marginal scales are triangular, up to 400 ?m high, with a H:W of 1.5?1.8, with a wide multi-keel area on the inner surface and granules sparsely covering the outer surface. The marginal scales fold over the smaller operculars, shielding them from view. The body-wall scales are often wider than high, up to 290 ?m high with a H:W of 0.67?1.1. Those in the upper part of the polyp have a series of longitudinal ridges on the distal inner surface, resulting in a serrated distal edge. The coenenchymal scales are elliptical, up to 300 ?m in diameter and their outer surface is concave and smooth with some granules. For images see Cairns (2010). Distribution Known only from type locality southeast of Kaua?i, Hawaii, at depths of 73?426 m. Comparisons Being dichotomously branched with polyps in pairs, T. biserialis is comparable to T. parva and T. coronata. Thouarella parva is most similar to T. biserialis as both have polyps that depart branchlets at 45? and more rounded marginals than those found on polyps of T. coronata. However, the polyps of T. biserialis have a distinct keel on the inner surface of marginals, something not clearly illustrated for T. parva. Additionally, polyps of T. biserialis appear more clavate than those of T. parva and T. coronata. The polyps of T. coronata are a similar size to those of Zootaxa 3602 (1) ? 2013 Magnolia Press ? 91REVISION OF OCTOCORAL GENUS THOUARELLA T. biserialis, however, they diverge from branchlets at 90? rather than 45?. Additionally, the polyps of T. biserialis are clavate rather than being distally flared, as in T. coronata, which also has polyps with taller, more pointed marginals than found on T. parva. 25. Thouarella grasshoffi Cairns, 2006 Thouarella (Euthouarella) grasshoffi Cairns, 2006: 184?188, figs 1a, 12, 13; Cairns & Bayer 2009: 28 (listed) Material examined: Holotype, USNM 1078188, Manning Seamount, North Atlantic Ocean, 38?08.74?N, 61?05.473?W, 1458 m, 16 May 2004. Other material: all lots from Cairns (2006). Description Description modified from Cairns (2006): The colonies consist of 1?3 main branches from which numerous closely spaced (usually less than 2 mm apart) branchlets originate on all sides of the main branch, in a bottlebrush arrangement. The branchlets are undivided, up to 4 cm long and flexible in tension. The holotype is a single main stem 35 cm long and 8?9 cm wide that has been broken from its base. The axis is 2.4 mm in diameter and is a brownish colour. The polyps of the holotype occur randomly on the main stem and in regular pairs (10?20% of polyp projections are whorls of 3) every 1.5?1.9 mm on branchlets. They are modestly distally flared, curved upward toward branchlet tip, and are rarely greater than 1.3 mm in length and 0.7 mm in diameter. The sclerites are in 6?8 longitudinal rows with 5?7 scales in the longitudinal abaxial rows. The operculars form a tall cone and are isosceles triangle-shaped with a pointed apex, 260?620 ?m high but most are 450?550 ?m, with a H:W of 2.1?3.2. The proximal quarter of the inner surface is tuberculate, the distal half bearing a multi-keel. The outer surface has granules radiating from the central proximal area. The marginal scales are not arranged in 2 defined rings, as in most Thouarella species, but as 2 sets of 3 with both lateral edges overlapping those of the adjacent marginal and the 2 remaining marginals with one lateral edge above and the other below their adjacent marginal. The marginals have an acutely pointed tip with a broad base, with a H:W of 0.93?2.1 and are up to 540 ?m long. The proximal half of the inner surface is tuberculate, the distal half bears 1?3 modest longitudinal keels, sometimes bearing lateral projections. The outer surface is covered in granules. The submarginal scales are rounded, up to 340 ?m high, almost elliptical, and broader than high (H:W of 0.65?0.89). The adaxial scales are rarely larger than 220 ?m. Some of the submarginals have a small point at the distal edge and a corresponding small ridge perpendicular to the distal edge on the inner surface. The inner surface of both these and the body-wall scales has a smooth band along the distal edge and tubercules occur across the proximal three-quarters of the scales. The outer surface of the sclerites is smooth with a few granules proximally. The distal edge of all polyp sclerites of this species is finely serrate with a coarsely lobate proximal edge. The coenenchymal scales are elliptical to elongate in shape, rarely more than 320 ?m high with a H:W of 1.3?1.8. These scales have a tuberculate inner surface and a slightly concave, smooth outer surface, sometimes with rare granules. For images see Cairns (2006). Distribution This species is found in the western Atlantic, on the New England Seamount Chain; at depths from 814?1458 m. It also occurs in the eastern Atlantic including off the Cape Verde Archipelago, the Great Meteor Seamount, the Azores Archipelago and the Celtic Sea, at depths from 720?1760 m. Comparisons Thouarella grasshoffi is unique within Group 2 in having a true bottlebrush colony shape (T. hilgendorfi does have bottlebrush branches but has a wider, flabellate colony shape, see Table 3). The placement of the branchlets of T. laxa is pinnate but can appear bottlebrush because its flexible branchlets can be curved. The polyps of T. laxa are a similar size with similar spacing as those of T. grasshoffi, however, the former has a low opercular cone and shorter TAYLOR ET AL.92 ? Zootaxa 3602 (1) ? 2013 Magnolia Press operculars with a blunt distal edge, whereas T. grasshoffi has a tall opercular cone, reflected in tall, triangular operculars. There is also a geographical separation between the two species with T. grasshoffi being found in the North Atlantic and T. laxa in the Indo-West Pacific. Most species within Group 2 have polyps that are distally flared whilst Thouarella grasshoffi and T. moseleyi have more rounded, clavate polyps. The latter species differs from the former in having polyps with shorter marginals and a colony with a pinnate branching arrangement (so the colony can appear bilateral), whereas T. grasshoffi has a bottlebrush colony form. Recent and new species combinations Plumarella diadema (Cairns, 2006) Fig. 36 Thouarella (Thouarella) diadema Cairns, 2006: 181?184, figs 10?11; Cairns & Bayer 2009: 28 (listed) Thouarella sardana Zapata-Guardiola & L?pez-Gonz?lez, 2010b: 136?139, figs 2c,d, 5, 7 Plumarella diadema Cairns 2011: 8 Material examined: Holotype, USNM 1078187, R/V Calypso, sta. 1776, 241 km SE of Sao Paulo, Brazil, 24?54?04?S, 44?26?00?W, 1000 m; Paratype of Thouarella sardana USNM 1123420, Antarktis XIX/5, R/V Polarstern, sample no. PS61/164?01, west of South Georgia Island, sub-Antarctic, 53?23?48?S, 42?42?02?W, 312?321 m, 9 Apr 2002; Paratype of T. sardana, USNM 1123420; USNM 1130273, USNM 1129185 and USNM 1130274 (from same location), R/V Eltanin, cruise 22, sta. 1536, west tip of South Georgia Island, sub-Antarctic, 54?30?S, 39?20?W, 659?686 m, 8 Feb 1966. Other material: USNM 98090, R/V Eltanin, cruise 6, sta. 339, west of Beauchene Island, south of Falkland Islands, sub-Antarctic, 53?06?S, 59?27?W, 512?586 m, 3 Dec 1962, 2 colonies; USNM 98095 and USNM 98094 (same location), R/V Eltanin, cruise 9, sta. 740, east of Cape Horn, Drake Passage, Tierra del Fuego, Argentina, 56?06?S, 66?24?W, 384?494 m, 18 Sep 1963; USNM 98098 and USNM 77396 (from same location), R/V Eltanin, cruise 22, sta. 1592, Burdwood Bank, Scotia Sea, 54?44?S, 55?33?W, 1647?2044 m, 14 Mar 1966; USNM 98089, R/V Eltanin, cruise 5, sta. 283, west of Adelaide Island, Antarctic Peninsula, 66?26?S, 74?46?W, 3350?3693 m, 25 Oct 1962; USNM 77396, ZMH, R/V W. Herwig, sta. 226, SW Atlantic, 33?53?S, 51?52?W, 460 m, 11 Jun 1966; ZMH, R/V W. Herwig, sta. 191, SW Atlantic, 46?13?S, 59?49?W, 805 m, 17 Jan 1971; USNM 98101, R/V Professor Siedlecki, cruise 86?01, sta. 2, Shag Rocks, South Georgia Island, Sub-Antarctic, 53?20?S, 42?42?W, 417?514 m, 29 Nov 1986. Description See the holotypic publication for full taxonomic description (Cairns 2006). We add that that the specimens reported herein, including the holotype of T. diadema (now Plumarella diadema), usually reveal 2?8 small accessory operculars beneath the operculars. The polyp arrangement was originally described as ?roughly alternating? (Cairns 2006, p.181), however, with the wider body of material examined here, we conclude that this is not strictly true as usually the polyps originate from all sides of the branchlet. Also, P. diadema can have a pinnate colony structure (USNM 98089, Fig. 36b,c) and most colonies appear bilateral, although they have branching in 3 directions and are thus technically bottlebrush. The marginals of some polyps of USNM 98030 have double spines and operculars that are bifurcate, likely a variation in a single colony (Fig. 36d,e). Distribution Additional specimens expand the range of P. diadema from S?o Paulo, Brazil, south to the tip of Argentina and east to South Georgia Island, sub-Antarctic. The depth of occurrence ranges from 278?3693 m. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 93REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 36. Plumarella diadema. Holotype, USNM 1078187: a) 6 cm colony; d) inner and e) outer surface of bifurcate marginal. USNM 98089: b) close up of polyps; c) pinnate colony form, 10 cm; c) 10 cm pinnate colony form. Photos by SJ. TAYLOR ET AL.94 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Remarks Thouarella sardana was differentiated from T. diadema because it has accessory operculars (Zapata-Guardiola & L?pez-Gonz?lez 2010b). However, the holotype of T. diadema also has accessory operculars (although they do not occur in every polyp), which were not mentioned specifically in the original description (Cairns 2006), and thus these species are considered to be conspecific, as was suggested in Cairns (2011). Thouarella diadema has no keel on the inner surface of its marginals and it is thus considered to be a Plumarella, in agreement with Cairns (2011). A deep-living specimen of P. diadema (USNM 98098, 1647?2044 m), did not have accessory operculars in any of the polyps studied but was identical in every other respect to this species. The deepest specimen, USNM 98089 (3350?3693 m), is pinnate but the polyps and sclerites are identical to those of P. diadema. One specimen from SMF (WH 1971, sta. 191) has much smaller polyps, a maximum height of 2 mm (half the size of other specimens) and a very bushy, ramified branching structure. Some marginal scales of this specimen have a wider, winged base and a smoother inner surface. However, in all other respects, this specimen was identical to P. diadema and is thus included here; it may be a juvenile specimen. Comparisons Plumarella diadema differs from Plumarella (formerly Thouarella) bayeri Zapata-Guardiola & L?pez-Gonz?lez 2010b in having more acutely triangular/arrowhead-shaped operculars, and colonies with bushy/bottlebrush rather than dichotomous branching. Thouarella variabilis is very similar to P. diadema except polyps on colonies of T. variabilis are smaller and the spines of the marginals are keeled, rather than being channelled and circular in cross-section, as in P. diadema. The difference between these two forms of spines, one keeled, one not, differentiate Thouarella and Plumarella. Additionally, operculars on the polyps of T. variabilis tend to be narrower, leaving visible gaps into the sub- opercular region when viwed from the anterior, whereas the operculars of polyps of P. diadema are wider, and form a more complete covering. The long spines of the marginals on polyps P. diadema can be mistaken for those of Dasystenella acanthina, but the polyps of the latter occur in whorls, and that genus is defined by having five, rather than eight, marginal scales. Plumarella recta (Nutting, 1912) Figs 37c,d, 38 Thouarella recta Nutting, 1912: 67?68, pl. 7, figs 1, 1a, pl. 19, fig. 2; K?kenthal 1919: 440?1; 1924: 302; Aurivillius 1931: 255?256 Thouarella (Thouarella) recta Cairns & Bayer 2009: 28 (listed) Plumarella recta Cairns 2011:8 Material examined: Holotype, USNM 30040, R/V Albatross, sta. 5079, south of Omae Zaki, Honshu Island, Japan, 34?15?N, 138?E, 475?505 m, 19 Oct 1906, 5 cm fragment. Description The colony appears uniplanar, however, branchlets depart the main stem in 3 directions (2 rows at 160? creating an almost flat surface, with a third row placed sporadically along the dorsal spine at 260?), thus it is technically bottlebrush (Fig. 37c). The ventral branchlets (in 2 rows) depart alternately from the stem. The branchlets are usually simple, sometimes forked, upwardly inclined at 60?, and the longest branchlet is 24 mm. The polyps stand at 90? to the branchlets (Fig. 37d), 1.2?1.4 mm high, generally isolated in one plane along the branchlet, with a density of 7?9 polyps per cm, and are modestly distally flared (Fig. 38m). The operculum is a raised cone of 8 acute triangle-shaped operculars (Fig. 38n,c?e), 260?320 ?m high (average 290 ?m), 120?230 ?m wide (average 165 ?m), with a H:W of 1.4?2.3 (average 1.8). The distal and lateral scale edges are serrate although the lateral edges of some are pectinate whilst the proximal edges are roughly lobate. The inner surface is smooth (unkeeled) with a small patch of tubercles in the centre proximally. The outer surface is smooth with several small granules in the central proximal area. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 95REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 37. Plumarella alternata, holotype, USNM 30097: a) colony, approx. 16 cm long; b) close up of polyps. Plumarella recta, holotype, USNM 30040: c) colony 5.5 cm long; d) close up of polyps. Photos by RZG. TAYLOR ET AL.96 ? Zootaxa 3602 (1) ? 2013 Magnolia Press FIGURE 38. Plumarella recta, holotype, USNM 30040, identical sclerites to those of P. alternata: a) inner and b) outer surface of accessory operculars; c,d) inner and e) outer surface of opercular scales; f,g) inner and h) outer surface of marginal scales; i) outer and j,k) inner surface of body-wall scales; l) coenenchymal scales?first column of scales show the inner surface, remainder are the outer surface; m) lateral view of polyp; n) stereo opercular view of polyp. SEM taken by ZGR. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 97REVISION OF OCTOCORAL GENUS THOUARELLA Between 2 and 4 accessory operculars are found underneath the operculars (Fig. 38a,b), which are identical to those of P. alternata. They are generally less than 200 ?m high and 100 ?m wide, round-tipped, tongue-shaped with a small patch of tubercles at the base of the inner surface and a smooth outer surface. The marginal scales have a circular base with an elongated smooth distal spine. The circular base has a pectinate edge which can continue up the edges of the spine (Fig. 38f?h). These scales, 320?840 ?m high (average 530 ?m), 165?350 ?m wide (average 220 ?m), with a H:W of 1.4?3.3 (average 2.5), are too long to fold over the operculars. The adaxial marginals are smaller than those found abaxially. The inner surface is smooth with a sparsely tuberculate central circle at the base. The outer surface is smooth with few small granules towards the proximal area of the basal circle. The body-wall scales are mostly elliptical to fan-shaped (Fig. 38i?k), although the shape is obscured by the large pectinate lateral and distal edges. Some are smaller and placed irregularly, disrupting row placement. The body-wall scales are 190?290 ?m high (average 230 ?m), 255?365 ?m wide (average 290 ?m) with a H:W of 0.7?1 (average 0.8). The outer surface is smooth with few granules whilst the inner surface has sparse tubercules and a tuberculate proximal edge. The coenenchymal scales are numerous, small, and circular to elliptical in shape with finely serrate edges (Fig. 38l), 100?120 ?m high (average 110 ?m), 80?160 ?m wide (average 125 ?m), with a H:W of 0.7?1.4 (average 0.9). The inner surface has only several sparse tubercles whilst the outer surface is smooth with just a few granules. Distribution This species is only known from the south coast of Honshu Island, Japan, at depths of 475?505 m. Remarks All species of Thouarella have polyps with keeled marginals, however T. recta does not, and was thus transferred to Plumarella (Cairns 2011). The mostly smooth, unkeeled inner surface of the operculars and the marginals, the elongated marginals unable to fold over the operculum, and the smooth outer surface of the body-wall scales are characters found in P. recta and common to Plumarella. Unlike Cairns (2011), we keep P. recta and P. alternata as separate species. The holotype is mostly denuded of polyps making the estimation of the density of polyps per cm tentative. The longitudinal rows of scales along the polyp body are disrupted with smaller, circular body-wall scales (see Fig. 38m), which makes counting the number of scales in the two abaxial rows difficult. Nutting (1912) counted 8?9 scales in a longitudinal row. Within this study we count 4?6 large scales in the abaxial rows, discounting smaller proximal circular scales. Comparisons Plumarella recta is most similar to P. alternata (see below) except that its polyps stand at 90? to the branchlet whereas those of the latter are at 45?, and roughly alternating. Without being certain of the importance of this morphological feature, and despite the identical appearance of these polyps, these species are kept distinct. Plumarella alternata (Nutting, 1912) Fig. 37 a,b Thouarella alternata Nutting, 1912: 69?70, pl. 9, figs 1, 1a, pl. 19, fig. 3; Aurivillius 1931: 255?256 Thouarella attenuata K?kenthal 1919: 438 (spelled incorrectly); 1924: 301 Thouarella (Thouarella) alternata Cairns & Bayer 2009: 27 (listed) Plumarella alternata Cairns 2011:8 Material examined: Holotype, USNM 30053, R/V Albatross, Northwestern Pacific Expedition, sta. 5080, west of Izu Islands, Honshu Island, Japan, 34?10?30?N, 138?40?E, 924 m, 19 Oct 1906; Paratype, USNM 30054, R/V Albatross, Northwestern Pacific Expedition, sta. 5079, south of Omae Zaki, Honshu Island, Japan, 34?15?N, 138?E, 869?924 m, 19 Oct 1906. TAYLOR ET AL.98 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Diagnosis Identical to P. recta (identical sclerites to Fig. 38), except the polyps are upwardly facing at 45? and roughly alternating in arrangement. Distribution This species is currently only known from Honshu Island, Japan, at depths of 869?924 m. Remarks The alternating polyps and a lack of keels on the marginal scales suggest that this species be placed within Plumarella, as suggested in Cairns (2011). Comparisons Without further material or knowing the importance of polyp orientation, we are hesitant to synonymise P. alternata and P. recta despite their identical sclerite and polyp sizes and shapes. This is in contrast to Cairns (2011), where these species are synonymised. Plumarella superba (Nutting, 1912) Primnodendron superbum Nutting, 1912: 71?72, pl. 9, fig. 2, 2a; pl. 19, fig. 4 Thouarella (Amphilaphis) superba K?kenthal 1919: 412; 1924: 291 Thouarella superba Dautova 2007: 299 (sample not seen) Thouarella (Thouarella) superba Cairns & Bayer 2009: 28 (listed); Heifetz et al. 2005: 133 (listed) Plumarella superba Cairns 2011: 13?14, figs 2C, 9a?l Material examined: Holotype, USNM 50150, R/V Albatross, Northwestern Pacific Expedition, sta. 4778, Semisopochini Island, western Aleutian Islands, North Pacific, 78?133 m, 5 Jun 1906. Description See full description in Cairns (2011). Distribution This species occurs in the Aleutian Islands, possibly to the western boreal Pacific, Sakhalin Island (Dautova 2007) at depths from 29?133 m. Remarks The gross morphology of the colony is dichotomously uniplanar, with clear dorsal and ventral faces. The branches have branchlets on all sides in a bottlebrush arrangement, however, ventral and dorsal branchlets are much shorter than lateral branchlets. The lack of a keel on the inner surface of the marginals suggests that this species is a Plumarella, as the genus description of Plumarella is now known to include bottlebrush colonies and specifically species with a smooth inner marginal surface, i.e. unkeeled (Cairns, 2010). Plumarella bayeri (Zapata-Guardiola and L?pez-Gonz?lez, 2010b), new combination Thouarella bayeri Zapata-Guardiola & L?pez-Gonz?lez, 2010b: 133?135, figs 2a,b, 3, 4. Material examined: Paratype, USNM 1123419, details same as holotype, R/V Polarstern, ANT XIX/5, sta. PS61/ 164?01, west South Georgia Island, sub-Antarctic, 53?23.80?S, 42?42.03?W, 312.5?321.6 m, 9 Apr 2002. Description Fully described in Zapata-Guardiola and L?pez-Gonz?lez (2010b). Zootaxa 3602 (1) ? 2013 Magnolia Press ? 99REVISION OF OCTOCORAL GENUS THOUARELLA Distribution This species is currently known only from the west coast of South Georgia Island, at depths from 306?342 m. Remarks The marginals of the polyps of Thouarella bayeri are unkeeled (they have a long spine that is circular in cross section, and have longitudinal grooves on the inner surface), which suggests that the species should not be considered a Thouarella but a Plumarella. The diagnosis of Plumarella has expanded to include colonies with bottlebrush branches, such as P. superba (Cairns, 2011), making T. bayeri more suitably classified as Plumarella. Apart from the colony shape, P. bayeri is identical to P. diadema, which is bottlebrush (although it can appear bilateral). Plumarella undulata (Zapata-Guardiola and L?pez-Gonz?lez, 2010b), new combination Thouarella undulata Zapata-Guardiola & L?pez-Gonz?lez, 2010b: 133?135, figs 2a,b, 3, 4 Material unavailable: Holotype, ZIZMH C11742, ANT XIX/5, sta. PS61/167?01, west of South Georgia, Antarctica, 53?23.68?S, 42?42.23?W, 306?342.7 m, 9 Apr 2002. Material examined: Paratype, USNM 1123421, sample PS61/167?01, Antarktis XIX/5, R/V Polarstern, west of South Georgia Island, sub-Antarctic, 53?23?41?S, 42?42?14?W, 306?342.7 m, 9 Apr 2002. Other material: USNM 98291, R/V Eltanin, sta. 305, west of Sars Bank, Drake Passage, Chile, Antarctic, 59?59?S/ 70?43?W to 59?58?S/ 70?32?W, 2782?2827 m, 1 Nov 1962, 2 colonies; USNM 99150, R/V Polarstern, EPOS3, sta. 295, AGT 26, Queen Maud Land, Coats Land, Off Cape Norvegia, Antarctic, 71?08?48?S, 13?48?06?W, 2037 m, 21 Feb 1989; USNM 1129186 and USNM 1130315 (same location), R/V Eltanin, cruise 22, sta. 1536, 54?30?S, 39?20?31?W, 659?686 m, 8 Feb 1966. Description Fully described in Zapata-Guardiola and L?pez-Gonz?lez (2010b). In addition to the original description, we would like to emphasize the radially arranged granules and striations on the outer surface of the operculars. Distribution Specimens from this study extend the known range of P. undulata across the southwest Atlantic Ocean and south to Cape Norvegia, Antarctica, 306?2827 m depth. Remarks Because the marginals of the polyps are long, spinose, and unkeeled, this species is considered to be a Plumarella (see Cairns, 2010). The only character that differentiates P. diadema from P. undulata is the extreme longitudinal curving and outer surface striations of operculars on the polyps of the latter. The operculars of the polyps of P. diadema can be curved and the two largest tend to have some abaxial striations, however, less so than are found on P. undulata, and the majority of operculars are generally smooth. Dasystenella acanthina (Wright and Studer, 1889) Fig. 39 Stenella acanthina Wright & Studer, 1889: 59, pl. 14, fig. 3, pl. 20, fig. 10 Stenella (Dasystenella) acanthina Versluys 1906: 39,48 Thouarella longispinosa K?kenthal, 1912: 299, figs 1?3 Thouarella (Euthouarella) longispinosa K?kenthal 1915: 151 (in part); 1919: 441 (in part); 1924: 302 (in part); Broch 1965: 26?27, pl. 3 figs 8?10 Thouarella longispinosa Gravier 1914: 61?63, pl. 7, figs 35?36, pl. 10, figs 52?55; Thomson & Rennet 1931: 24?26; Utinomi 1964: 11?12, fig. 6, pl. 2 Thouarella acanthina Brito 1993: 242?243 TAYLOR ET AL.100 ? Zootaxa 3602 (1) ? 2013 Magnolia Press Dasystenella acanthina Bayer 1981: 934, 937, 946 (key to genus); Bayer & Stefani 1989: 454 (key to genus); Cairns 2006: 188?189; Cairns & Bayer 2009: 32 (listed), 47?49, fig. 18 i?p Material examined: Syntype of Stenella acanthina, NHM 89.5.27.48a, Deutsch Subpolar Expedition 1901?1903, Gauss?Station, off Argentina, 385 m, 12 Jan 1903; Syntype of Thouarella longispinosa, MNHWU and SMF; USNM 84325, R/V Eltanin, cruise 12, sta. 1083, east of South Orkney Islands, Scotia Ridge, Antarctic, 60?51?S, 42?57?W, 284 m, 14 Apr 1964. The MNHWU syntype of T. longispinosa is in poor condition with few intact polyps. The SMF sample is in a good condition. Examination of all the polyps confirmed the proposed synonymy. The colony description was taken from K?kenthal (1912). Description of Thouarella longispinosa syntype (MNHWU) The colony is bottlebrush in branching, with branchlets up to 22 mm long. The polyps are 1.5?2.0 mm long, distally flared (Fig. 39c), and upwardly inclined, in whorls of 3 or 4, rarely in pairs, with 5 whorls per cm. The polyps are covered with a small number of scales in 5 longitudinal rows, reducing to 4 at the polyp base. Each polyp has 4 scales in an abaxial row (Fig. 39c), 2 lateral rows, each with 3 scales, and 2 reduced rows of 3 small scales adaxially. The operculum is tall and conical, composed of 8 elongated isosceles triangle-shaped operculars. The operculars are not evenly spread around the circumference, the 2 reduced inner adaxial operculars being smaller (Fig. 39h) than the abaxial operculars (Fig. 39k), the latter of which have a proximally diagonal basal edge, depending on their opercular position. The inner surface of all operculars bears a simple, flattened keel. The operculars are 100?430 ?m wide (average 260 ?m), and 555?970 ?m long (average 770 ?m). Tubercles cover the proximal half of the inner surface and smaller operculars have fewer tubercles. The outer surface has a slightly concave median longitudinal groove and is usually smooth. Infrequent striations radiate from the central proximal area. Each polyp has 5 marginals. Three are very long abaxial marginals (Fig. 39n, similar in shape to large operculars), 530?1340 ?m high (average 840 ?m), 300?570 ?m wide (average 440 ?m), with a H:W of 1.3?2.6 (average 1.9). Two of these 3 are outer laterals (Fig. 39m) with the remaining 2 small, square to circular-shaped marginals placed adaxially (Fig. 39b1) and of a similar size to smaller body-wall scales (Fig. 39f,g). Large marginals do not fold over the operculum but are upwardly inclined and lean slightly adaxially giving the 2 laterals a diagonal proximal edge (Fig. 39m, n). The proximal half of the inner surface is covered in tubercles to the base of the keel, which is channelled. The outer surface is smooth with sparse granules and a modest longitudinal groove. The body-wall scales can be large (same size as largest operculars) and circular (Fig. 39e), 220?500 ?m high (average 350 ?m), 200?570 ?m wide (average 420 ?m), with a H:W of 0.8?1.1 (average 0.9). Tubercles cover the inner surface whilst the outer surface is smooth with some granules across the central proximal area of larger scales. Body-wall scales have a finely serrated distal edge. The coenenchymal scales are small and circular to elliptical in shape (Fig. 39l), 150?200 ?m wide and high. All sclerites of this species have a coarsely lobate proximal edge. Distribution This species is found off Tierra del Fuego, the South Shetland Islands and the South Scotia Ridge between the South Orkney and South Sandwich Islands, from 110?5087 m depth. Remarks When K?kenthal (1912) transferred Stenella acanthina to Thouarella he mentioned that it was very similar to T. longispinosa K?kenthal, 1915. Thomson and Rennet (1931) described T. longispinosa as having 4?5 marginals. Thouarella longispinosa does have five marginals and is thus Dasystenella. Brito (1993) does not explain clearly the inclusion of D. acanthina in Thouarella and we believe this is incorrect based on the lower number of marginals found in D. acanthina. Zootaxa 3602 (1) ? 2013 Magnolia Press ? 101REVISION OF OCTOCORAL GENUS THOUARELLA FIGURE 39. Dasystenella acanthina, images from syntype of Thouarella longispinosa (synonymised here with D. acanthina), MNHWU: a) 4.8 cm and 2 cm colony fragments; b) adaxial polyp view; c) abaxial polyp view; d) stereo opercular view; e) outer and f,g) inner body-wall scales; h?k) inner surface opercular scales; l) coenenchymal scales, upper scale outer surface, lower scale inner surface; m) inner and n) outer surface of marginal scales. NB?some operculars are missing. ?1? indicates small adaxial marginal scale. Image a) by ZGR. TAYLOR ET AL.102 ? Zootaxa 3602 (1) ? 2013 Magnolia Press The specimens of Thouarella longispinosa from MNHWU and SMF differ from the holotype of D. acanthina in having polyps with operculars and marginals more similar in size to each other, although, marginals of the specimens of T. longispinosa are generally longer and have a higher H:W of 2.7, compared to 2.1 in D. acanthina (Cairns 2006). However, Cairns (2006) lists some specimens of D. acanthina from southerly latitudes with polyps that are smaller and more upwardly inclined with marginals that have a much higher H:W of 3.5. Given this wide variation and the limited differences between specimens of T. longispinosa and the description of D. acanthina, we propose that T. longispinosa be synonymised with D. acanthina, noting that a revision of Dasystenella is required. FIGURE 40. Thouarella parva, holotype: a) lateral polyp view, modified from Fig. 1 Kinoshita, 1908d; b) sclerites from Kinoshita, 1908d?I. accessory operculars, II. operculars, III. marginals, IV. submarginals, V,VI. body-wall scales. Thouarella andeep, USNM 1123418: c,d) inner surface of marginal scales. Acknowledgements This work was sponsored by a Smithsonian Fellowship and NERC CASE Studentship, NE/F00785X/1, in partnership with the Marine Resources Assessment Group (MRAG) Ltd, London. Many useful discussions were had by the first author with Dr Manfred Grasshoff and Rebeca Zapata-Guardiola, for which we are grateful. We would also like to thank the support of individuals at several museums and institutes without whose help in providing holotypes this paper would have been impossible: Andrew Cabrinovic, NHM; Aude Andouche, MNHMP; Elly Beglinger, ZUMA; Rei Ueshima, UMUT; Yukimitsu Imahara, Biological Institute on Kuroshio; Beata M. Pokryszko, MNHWU; Carsten Lueter, ZMB; Dr. Andreas Schmidt-Rhaesa, Zoological Museum, University of Hamburg. At the Smithsonian Institution, where the majority of this work was undertaken, we are indebted to Tim Coffer, Jennifer Hammock, Paul Greenhall and Scott Whittaker. Special thanks are again due to Rebeca Zapata-Guardiola for kindly allowing us to use some of her SEM images and photos; James Soda for Zootaxa 3602 (1) ? 2013 Magnolia Press ? 103REVISION OF OCTOCORAL GENUS THOUARELLA preparing stubs and taking some SEM images; Diane Wyse for sclerite measurements and species identifications; and Jon Schleyer for specimen photographs. We reserve special mention and thanks for the late, great Dr F. M. Bayer, whose beautiful SEM images also grace these pages. And, of course, we appreciated the three anonymous reviewers? very useful comments which ultimately improved the manuscript. References Alderslade, P. 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