ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition)Copyright © 2017 Magnolia Press Zootaxa 4305 (1): 001–079 http://www.mapress.com/j/zt/ Monograph https://doi.org/10.11646/zootaxa.4305.1.1 http://zoobank.org/urn:lsid:zoobank.org:pub:1192C3A0-5CCB-4A86-903C-A2B82906A5F9 ZOOTAXA Revision of the Recent species of Exechonella Canu & Bassler in Duvergier, 1924 and Actisecos Canu & Bassler, 1927 (Bryozoa, Cheilostomata): systematics, biogeography and evolutionary trends in skeletal morphology JULIA P. CÁCERES-CHAMIZO1, JOANN SANNER2, KEVIN J. TILBROOK3 & ANDREW N. OSTROVSKY4,5,6 1Departamento de Medio Ambiente, Instituto de Fomento Pesquero, Balmaceda 252, 5502276, Puerto Montt, Chile 2Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, P.O. Box, 37012, Washington, DC 20013–7012, USA 3Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PW, UK 4Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Universitetskaja nab. 7/9, 199034, Saint Petersburg, Russia 5 Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, Geozentrum, University of Vienna, Althanstrasse 14, A–1090, Vienna, Austria 6Corresponding author. E-mail: oan_univer@yahoo.com Magnolia Press Auckland, New Zealand 4305Accepted by K. Fehlauer-Ale: 22 May 2017; published: 14 Aug. 2017 JULIA P. CÁCERES-CHAMIZO, JOANN SANNER, KEVIN J. TILBROOK, ANDREW N. OSTROVSKY Revision of the Recent species of Exechonella Canu & Bassler in Duvergier, 1924 and Actisecos Canu & Bassler, 1927 (Bryozoa, Cheilostomata): systematics, biogeography and evolutionary trends in skeletal morphology (Zootaxa 4305) 79 pp.; 30 cm. 14 Aug. 2017 ISBN 978-1-77670-198-8 (paperback) ISBN 978-1-77670-199-5 (Online edition) FIRST PUBLISHED IN 2017 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: magnolia@mapress.com http://www.mapress.com/j/zt © 2017 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)CÁCERES-CHAMIZO ET AL.2 · Zootaxa 4305 (1) © 2017 Magnolia Press Table of contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Material and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Systematic account . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Family Exechonellidae Harmer, 1957 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Genus Exechonella Canu & Bassler in Duvergier, 1924. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Type species: Exechonella grandis (Duvergier, 1921) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Exechonella ampullacea species-complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Exechonella ampullacea Hayward & Ryland, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Exechonella erinacea (Canu & Bassler, 1929) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Exechonella reniporosa n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Exechonella variperforata n. sp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Exechonella safagaensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Exechonella maldiviensis n. sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Exechonella antillea species-complex. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Exechonella antillea (Osburn, 1927) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Exechonella pumicosa Canu & Bassler, 1928. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Exechonella californiensis n. sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Exechonella vieirai n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Exechonella floridiana n. sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Exechonella panamensis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Exechonella harmelini n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Exechonella brasiliensis species-complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Exechonella brasiliensis Canu & Bassler, 1928 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Exechonella azeezi n. sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Exechonella similis n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Exechonella claereboudti n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Exechonella catalinae n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Exechonella albilitus species-complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Exechonella elegantissima n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Exechonella nikitai n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Exechonella vavrai n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Exechonella verrucosa species-complex. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Exechonella verrucosa (Canu & Bassler, 1927) n. comb. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Exechonella spinosa Osburn, 1940 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Exechonella kleemanni n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Exechonella rimopora n. sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Family Actisecidae Harmer, 1957 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Genus Actisecos Canu & Bassler, 1927 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Actisecos regularis Canu & Bassler, 1927 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Actisecos discoidea (Canu & Bassler, 1929). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Abstract The present study describes species of Exechonella and Actisecos discovered through the examination of recent collec- tions from the Red Sea, coast of Oman and Maldive Islands (Indian Ocean) and the Lizard Island, Australia (Great Barrier Reef, Coral Sea) in comparison with historical collections. Eight species of Exechonella are redescribed: E. grandis (type species), E. ampullacea, E. antillea, E. brasiliensis, E. erinacea, E. pumicosa, E. spinosa and E. verrucosa. Eighteen new species of Exechonella are also described: E. azeezi n. sp., E. catalinae n. sp., E. californiensis n. sp., E. claereboudti n. sp., E. elegantissima n. sp., E. floridiana n. sp., E. harmelini n. sp., E. kleemanni n. sp., E. maldiviensis n. sp. E. nikitai n. sp., E. panamensis n. sp., E. reniporosa n. sp., E. rimopora n. sp., E. safagaensis n. sp., E. similis n. sp., E. variperfo- rata n. sp. E. vavrai n. sp. and E. vieirai n. sp. The species studied were grouped in five species complexes. Additionally, two species from the genus Actisecos—A. regularis and A. discoidea were redescribed. The current revision highlights a number of important taxonomical, biogeographical and morphological questions that are of the general biological interest. Among thеm is a polyphyletic nature of Cheilostomata possessing umbonuloid frontal shield. Key words: bryozoans, Exechonellidae, Actisecidae, new species, systematics, biogeography, evolution Zootaxa 4305 (1) © 2017 Magnolia Press · 3REVISION OF THE RECENT SPECIES OF EXECHONELLA Introduction The generic name Exechonella was used for the first time in Duvergier (1924) for Cyclicopora (?) grandis Duvergier, 1921 from the Early Miocene of Gironde, the Aquitanian region, France. This author pointed out that the name Exechonella itself was coined by Canu and Bassler who planned to publish it soon. Indeed, two papers by Canu appeared in 1925 (co-authored by Lecointre) and 1927 (co-authored by Bassler) containing the name Exechonella. In the first it was given merely as “Exechonella Canu et Bassler, mss”—a member of a particular family but with no included species cited, whereas in the second as “Exechonella, new genus” with diagnosis and Hiantopora magna McGillivray, 1895 from the Miocene of Victoria, Australia, as a ‘genotype’. In all above- mentioned papers Exechonella was included in the family Arachnopusiidae Jullien, 1888. Canu and Bassler (1929), Bassler (1935), and Harmer (1957) all treated Canu and Bassler (1927) as the authors of the genus, with H. magna as type species. In particular, Harmer (1957) gave the authorship as Exechonella (Canu & Bassler, MSS) Duvergier, 1924 nom. nud. “Nomenclator Zoologicus”, however, has Canu and Lecointre, 1925 as the authors of the genus Exechonella; this cannot be correct as the entry was not accompanied by any included species or a diagnosis. Also, since Duvergier’s (1924) paper contains a taxon description, it satisfies the criteria of availability according to the article 12 of the International Code of Zoological Nomenclature (ICZN), and should not be considered as a nomen nudum. In contrast to the above authors, Cheetham (1966, p. 62) stated that priority should belong to Duvergier, arguing that: “However irregular, Duvergier’s introduction of the genus has priority, with C.? grandis the type species by monotypy.” Cheetham has subsequently been followed in his opinion by most authors (for example, Hayward & Ryland 1995; Cook & Bock 2004; Tilbrook 2006). ICZN article 50.1.1 states, however, that “… if it is clear from the contents that some person other than an author of the work is alone responsible both for the name or act and for satisfying the criteria of availability other than actual publication, then that other person is the author of the name or act. If the identity of that other person is not explicit in the work itself, then the author is deemed to be the person who publishes the work.” Thus, Duvergier (1924, p. 159) was the first to publish the name Exechonella (Exechonella Canu et Bassler, mss) and description of its type species. It was additionally stressed in his text (p. 159), however, that the authors of the generic name are Ferdinand Canu and Ray S. Bassler: "MM. Canu et Bassier ont placé cette belle espèce dans le nouveau genre Exechonella qu'ils publieront prochainement"". The most accurate position is to accept authorship of Exechonella as Canu & Bassler in Duvergier, 1924, with Cyclicopora (?) grandis Duvergier, 1921 as type species, not Hiantopora magna McGillivray, 1895. Harmer (1957) established the family Exechonellidae for Exechonella alone when redescribing Exechonella tuberculata (MacGillivray, 1883) and E. magna (MacGillivray, 1895) from several Indo–West Pacific localities and southern Australia. Since this time several additional genera, both Recent and fossil, have been included in Exechonellidae: Anarthropora Smitt, 1868, Anexechona Osburn, 1950, Enantiosula Canu & Bassler, 1930, Oviexechonella Di Martino & Taylor, 2015, Stephanopora Kirkpatrick, 1888, Triporula Canu & Bassler, 1927, and Xynexecha Gordon & d´Hondt, 1997. Cook and Bock (2004) provide an extended discussion on the diagnostic characters of these genera. However, Enantiosula and Triporula are currently considered as synonymous, while a placement of Triporula and Anarthropora in Exechonellidae is uncertain (Bock 2016). Currently 19 fossil and Recent nominal species are considered as valid (Bock 2016) (two of them do not belong to Exechonella, see below) although more species should be included in this list. The earliest known fossil representatives of the Exechonella are E. chathamensis Gordon and Taylor, 2015 from the Ypresian, Early Eocene, Chatham Island, New Zealand, and ‘Cheilopora’ orbifera Canu & Bassler, 1920 from the Claibornian, Middle Eocene, USA. In addition, more than 10 fossil species (while the affinities of some are questionable) were described from western Europe (France, Italy, England), North America (Alabama, North and South Carolina, Florida), Africa (Nigeria), Asia (Taiwan, Kalimantan) and Australia (Victoria, South Australia) (Manzoni 1869; MacGillivray 1895; Canu 1918; Canu & Bassler 1920, 1929; Duvergier 1921; Brown 1956; Cheetham 1966; Lagaaij 1973; Hu 1987; Cook & Bock 2004; Gordon and Taylor 2015; Di Martino & and Taylor 2015; Di Martino et al. 2017). The data on them are very scant, however, and their descriptions require thorough revision. Recent species of Exechonella have a pantropical (from tropical to subtropical) distribution being described from the numerous localities in the Caribbean, Mediterranean and Red Seas, Indian Ocean (east Africa, Mauritius, Réunion, Madagaskar, Maldives, Sri Lanka), around Australia (Victoria, Queensland, Western Australia), the Pacific (Indonesia, Philippines, South China Sea, New Guinea, Solomon Islands, Vanuatu, Hawaii, New Zealand, CÁCERES-CHAMIZO ET AL.4 · Zootaxa 4305 (1) © 2017 Magnolia Press California), Atlantic Ocean (Brazil, west Africa) (for reviews and lists of both, Recent and fossil species see Canu and Bassler (1929), Harmer (1957), Cook (1985), Cook and Bock (2004), Tilbrook (2006), Gordon (2016), d’Hondt (2016a, b) and references therein). The superficial morphological similarity of Exechonella species has been the main reason for taxonomic confusion previously, with several ‘well-known’ species being ‘widely distributed’. In this connection Cook and Bock (2004) stressed the high morphological variability between localities and populations suggesting that each of such “species” may include more than one taxon. The current study is based on a new material obtained from the Mediterranean, Red and Coral Seas, Indian Ocean (Oman, the Maldive Islands), and Atlantic Ocean (Brazil) as well as the specimens stored in the Smithsonian Institution, Washington, and the Virginia Museum of Natural History, Martinsville, USA, and the Museum of Tropical Queensland, Townsville, Australia. In total 26 species of Exechonella were studied. Eighteen of them are considered as new, and eight species were redescribed together with the type species of the genus Exechonella, E. grandis. Additionally, we redescribed two species of the genus Actisecos, one of which was previously described as Exechonella. Material and methods The material from the north Red Sea, the Northern Bay of Safaga, was taken from the sediment samples collected by SCUBA during field work in 1984, 1986, 1987 and 1992 by the staff of the Department of Palaeontology, University of Vienna, Austria (Ostrovsky et al. 2011). The bryozoan colonies found were encrusting dead mollusc shells, live corals and coral rubble at 1–45m depth. Bryozoan colonies growing on corals from Jeddah, the east coast of the Red Sea, were collected by A. Antonius in the late 1970’s (collection date not specified). Material from the Maldive Islands was collected by SCUBA in 2008 (on mollusc shells and coral rubble) from one site (5–19 m depth) near Vabbinfaru Island, by A.N. Ostrovsky, A. Azeez A. Hakeem and R. Tomasetti, and in 2009 from one site (10 m depth) by N.A. Ostrovsky and M. Ali. The material from Oman was collected in 2009 at two sites near Salalah (8–9.5 m depth) by A.N. Ostrovsky and M. Claereboudt using SCUBA. The material from Brazil was collected in 2003 (1 m depth) by L.M. Vieira and M.D. Correia, and in 2012 by the staff of Laboratório de Porifera–Museu de Zoologia, Universidade Federal da Bahia (LABPOR-UFBA). The material from Lebanon, Mediterranean Sea, was collected by SCUBA at two sites (depth 5‒21 m) in 1999, 2000, 2002 and 2004 by J.-G. Harmelin, on coral, barnacles, bivalve shells, bryozoan, polychaete tubes and coralline algae. The material from Florida, Atlantic Ocean, was collected by SCUBA in 1999 by J.E. Winston, on shell-hash concretion. The material from Lizard Island, Great Barrier Reef, was collected by SCUBA (depth 6.5‒16 m) in 2012 by A.N. Ostrovsky and K.J. Tilbrook, on bivalve shells and coral rubble. Whilst most of the Australian material (except two paratypes of Exechonella similis n. sp.) is deposited in the Museum of Tropical Queensland (MTQ), Townsville, Australia, the specimens from the Northern Bay of Safaga and Jeddah, Red Sea, from Brazil, Lebanon, Oman and Maldive Islands are kept at the Department of Palaeontology, Geozentrum, University of Vienna (DPUV, former name Institut für Palaeontologie, Universität Wien, IPUW). The final destination of these collections will be the Senckenberg Museum, Frankfurt am Main, Germany. Scanning electron microscopy (SEM) was carried out on colonies cleaned with bleach, and scanned either sputter-coated with gold or uncoated. Images used are derived from the DPUV, National Museum of Natural History, Washington (USNM) and the Queensland Museum (QM), Brisbane, Australia. Additional specimens embedded in plastic were loaned from the Nationaal Natuurhistorisch Museum, Leiden (NNHML), the Netherlands, for the light microscopical investigation. Systematic account Family Exechonellidae Harmer, 1957 Genus Exechonella Canu & Bassler in Duvergier, 1924 Type species: Cyclicopora ? grandis Duvergier, 1921 Zootaxa 4305 (1) © 2017 Magnolia Press · 5REVISION OF THE RECENT SPECIES OF EXECHONELLA Diagnosis. Colonies encrusting, predominantly unilaminar, but becoming bi- and multilaminar or erect in some species. Zooids large (length 0.6–1.6 mm), convex, oval or hexagonal, separated by deep grooves. Peristome from low, collar-like, to long, cylindrical. Primary orifice rounded or oval, often with angular poster and with inner lamina underlaying the anter wall and typically ending with paired condyles—lateral or distolateral. Frontal shield umbunuloid with numerous foramina, opened or covered with an external cuticular layer. Marginal pores always present around zooidal periphery, though not always obvious. Vertical zooidal walls (lateral and transverse) wide or narrow, represented by multiporous mural septula with communication pores arranged in one or several rows. Adventitious avicularia generally present, being associated with lateralmost foramina, which are often larger than the rest of the foramina. Avicularia predominantly oval or round, with a small opening in the nipple or button-like central part but, occasionally, triangular in shape with a cross-bar. Some species have adventitious kenozooids, with a porous frontal wall, that are often associated with lateral avicularia. No ovicells, embryos are incubated in the internal brood sacs. Ancestrula is autozooidal in shape. Type species: Exechonella grandis (Duvergier, 1921) Cyclicopora? grandis: Duvergier 1921, p. 174–175, pl. 3, figs 2, 3. Hippexechonella grandis: Vigneaux 1949, p. 68. Material. Syntypes: C.B. (Collection de Bryozoaires) 125-1, C.B. 125-2, University of Bordeaux, collection of J. Duvergier. Villandraut (Gamachot), France. Aquitanian, Early Miocene. Two SEM-images of one zooidal fragment from a syntype deposited at ‘bryozoa.net’ by D.P. Gordon. Original description. Le zoarium encroûtant. Les zoécies sont distinctes, séparées par un sillon marqué, ovales, ventures et perforées de très gros pores. Ces trémopores sont très régulièrement placés en quinconces et entourés d’une large bordure en relief de forme hexagonale. La péristomie est essez saillante. L’apertura est elliptique, transverse, séparée entre le milieu et le tiers inférieur par deux cardelles minces et saillantes. Deux aviculaires bordés comme les trémopores et symétriquement placés de chaque côté vers le tiers supérieur ont une forme semi-elliptique, le bord courbe étant à l’intérieur et plus éleve que le bord rectiligne. … L’absence d’ovicelle ne permet pas une attribution générique certauine. Translation [with remarks]. Zoarium [colony] encrusting. Zooecia [zooids] distinct, separated by a distinct furrow, oval, swollen and perforated by very large pores. These tremopores [foramina] are positioned very regularly in quincunx being surrounded by a large rim giving [them] a hexagonal shape. The peristome is rather prominent. The aperture [orifice] is transversally elliptical, divided between the middle and the lower third by two thin and prominent cardelles [condyles].Two [small] avicularia bordered [by a rim] like tremopores [foramina] and symmetrically placed on each side [being directed] towards the distal third [of zooid] and having semi-elliptical shape; the curved [proximal] edge being inside [more centrally placed towards zooidal midline] and higher than the straight [distal] edge. … Absence of the ovicell does not enable generic attribution. Aperture [orifice] height 0.30 [mm], width 0.34 [mm]. Zooecia [autozooid] length 1.20 [mm], width 1‒1.20 [mm]. Comments. The circumstances surrounding publication of the type species description were regrettably a source of considerable confusion. Description of the type species was printed twice in 1921: in volume 72 (second fascicle published 30 December) of the Actes de la Société Linnéenne de Bordeaux (p. 174‒175) as well as separately, as a reprint or Extrait des Actes de la Société Linnéenne de Bordeaux (p. 34‒35) from the same volume 72. The illustrations were designated as Plate 3, fig. 2, 3 in both cases, however. Despite this, in his 1924 paper, Duvergier on p. 158 (volume 75 of the Actes) mentioned this species as Exechonella grandis Duvergier, 1920, presumably in error. It should be mentioned here that volume 75 of Actes was published during the two consecutive years 1923 and 1924 constituting a second source of confusion: the first fascicule was published 20 September 1923 (p. 1–68), whereas the second fascicle was published 30 June 1924 (p. 69–190) including Duvergier’s paper on p. 145–190. Unfortunately, this division was not reflected either on the title page (which shows just 1923) or inside volume 75. Consequently, the Zoological Record does not cite the 1921 paper until volume 59, 1922 (published in 1924), giving the date for E. grandis Duvergier as 1920. The 1924 Duvergier paper was included in the Zoological Record for the year 1924, giving the date as 1923, however.CÁCERES-CHAMIZO ET AL.6 · Zootaxa 4305 (1) © 2017 Magnolia Press Remarks on the genus Exechonella. An inner lamina as understood here is an upper margin of the distal vertical cystid wall surrounded by the peristome (Fig. 1F). In frontal view it is seen as a narrow calcified semi-ring distally appressed to the internal surface of the peristome. Thus, the internal lamina forms an inner edge of the anter upon which the operculum presumably rests when closed. It ends laterally or distolaterally with paired condyles that are in fact the most raised parts of the cystid distal wall. In the species with a long peristome the inner lamina is seen only in oblique view, and the condyles are often not seen at all. Adventitous kenozooids of various shapes (from oval to triangular and irregular) are relatively small, being budded laterally or proximally from autozooids. Kenozooidal cystids never reach the basal surface of the colony. As noted previously, Exechonella has an umbonuloid frontal shield, smooth or pustulose in texture, perforated by numerous foramina of variable size and shape. The underside of the frontal shield is represented by the external wall whereas its frontal surface has a hypostegal coelom and cuticular wall (both lined by epithelia) above. Thus, the foraminal luminae (holes) are perforations of the calcified shield open from its lower side, and either open or covered with a cuticular wall from above (see below). The foramina may be placed on a top of the conical tube (E. albilitus Tilbrook, 2006) (see Tilbrook 2006, p. 121, pl. 20, f), or have a raised or flat rim (E. papillata Cook & Bock, 2004) (see Cook & Bock 2004, p. 268, fig.1b, c). A peristome may be present; either a long or moderate- sized tube (E. tuberculata (MacGillivray, 1883)) (see Cook & Bock 2004, p. 272, fig. 3c, d) or low collar (E. brasiliensis Canu & Bassler, 1928) (see Canu & Bassler 1928a, p. 15, pl. III, fig. 5), surrounding a rounded or oval primary orifice. Whilst avicularia are lacking in some species, in most one or, normally, two unusual, small adventitious avicularia with a nipple-like central structure (the kenozooids of Cook & Bock 2004), develop on the outer rim of the two lateralmost foramina (see E. papillata in Cook and Bock 2004, fig.1c, d). In E. magna and related species, single or paired conventional avicularia with a cross-bar develop laterally in some zooids (Cook & Bock 2004, p. 273, fig. 2a, b, d) (see also Discussion). Based on these characters Cook and Bock (2004) distinguished four groups of Exechonella species that we discuss elsewhere. The first group includes the type species, E. grandis and some fossil species from Europe and North America, together with the E. antillea-complex, E brasiliensis and E. papillata and is characterized by a short collar–like peristome, numerous round foramina (with a cuticle that covers the foraminal openings), and avicularia with the central nipple-like structure. The second group corresponds to their Exechonella magna species- complex, which have lateral triangular avicularia with a cross-bar, and open, uncovered foramina. The third group includes E. tuberculata and E. ampullacea Hayward & Ryland, 1995 and includes species with a long tubular peristome and a cuticular layer covering the foraminal openings, and without avicularia. The last ‘group’ exclusively consists of the fossil Exechonella marginata (MacGillivray, 1895 with erect and branching colonies, zooids with raised (often trumpet-like) foraminal rims, and without avicularia. While the division proposed by the above authors is rather provisional, some species from our material fall in two of these groups (first and third) that we additionally split into E. antillea-, E. brasiliensis- and E. ampullacea- species complexes using most ‘typical’ species for their designation. The rest were additionally grouped to E. albilitus and E. verrucosa-species complexes. Species belonging to E. ampullacea-complex all possess the bottle-like zooids with long tubular peristomes, ‘pocket’-like structure near condyles, numerous mid-sized foramina and have no avicularia. A tube-like (but shorter than in the E. ampullacea-complex) peristome is characteristic for the species of E. albilitus-complex. In our material all attributed species possess a ‘shelf’ (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) and widely scattered tube-like or conical foramina. Avicularia-like structures were seen only in one species. E. antillea- and E. brasiliensis-complexes consist of similar species with avicularia and a low collar-like peristome having a central fold-like projection proximally. The main difference between these species groups is the size of the foramina (larger in E. brasiliensis-complex) and pattern of the foraminal placement (with less free space between foraminal rims that tend to fuse in E. antillea-complex). The foraminal gymnocystal rim is more prominent in the species of the E. brasiliensis-complex and flattened in E. antillea-complex. E. verrucosa species-complex is characterized by the special shape and structure of the hollow frontal projections (spikes) formed by the fusion of the gymnocystal rims of 2‒4 foramina. In addition to the generally similar zooidal shape—oval or pentagonal—and low peristome, these species also have foramina with small round or slit-like openings. Avicularia are present in some species. Zootaxa 4305 (1) © 2017 Magnolia Press · 7REVISION OF THE RECENT SPECIES OF EXECHONELLA Exechonella ampullacea species-complex Exechonella ampullacea Hayward & Ryland, 1995 (Fig. 1, Table 1) Exechonella ampullacea: Hayward & Ryland 1995, p. 547, fig. 7e. Exechonella ampullacea: Tilbrook & Gordon 2016, p. 597, fig. 3d. ? Exechonella tuberculata: Harmer 1957, p. 653–654 (in part), pl. 54, fig. 14. ? Exechonella tuberculata: Gordon 1984, p. 70, pl. 23, fig. d. Material examined. Holotype: QM G304975. Coral Sea, Great Barrier Reef, Heron Island, about 20 feet depth along the reef edge, 21 April, 1972. Paratype: QM G304977. Coral Sea, Great Barrier Reef, Heron Island, about 20 feet depth along the reef edge, 21 April, 1972. Description. Colonies encrusting, unilaminar, multiserial. Autozooids “bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long, anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral condyles seen as narrow elongated plates with rounded distal part. Condyles are associated with a small opening (‘pocket’) of unknown function. Long tubular peristome is pustulose externally and with longitudinal grooves on its internal surface (in upper half), the rim is flared. Frontal shield pustulose, with 16‒41 rounded or oval foramina. The lumen of each foramen has smooth gymnocystal walls, whereas an area around it (often seen as a slightly elevated wide ring) has an inner wall surface. The proximal part of the frontal shield is ‘reduced’ in some zooids making a sort of ‘gaps’ in the ‘corners’ between zooids. Marginal pores small and rounded, with centrally perforated cuticular plate, predominantly seen in zooids on the periphery of the colony. The distalmost part of zooid below peristome can bear up to two rows of such pores. No avicularia. Adventitious kenozooids with a few pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in two rows. Ancestrula unknown. TABLE 1. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella ampullacea Hayward & Ryland, 1995. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. All species of Exechonella ampullacea-complex are characterized by very similar zooidal morphology having the bottle-like cystids, with long tubular peristomes that often prevent an observation of the inner lamina and the condyles. The main differences between the species are explained by the size, shape and, sometimes, number of the frontal foramina as well as presence and shape of projections associated with them (see below). E. ampullacea differs from the other species of this complex by the absence of any kind of frontal projections. In contrast, E. tuberculata and E. erinacea have massive conical (spike-like) projections developed in association with all foramina. The rest of the species have less developed processes in association with some foramina. Harmer (1957) described under the name E. tuberculata two specimens from New Guinea that clearly represent two different species, as was noted by Tilbrook (2006) who earlier had the opportunity to examine most of Harmer’s material. Whereas the first, depicted on pl. 54, fig. 13, has numerous pointed processes associated with frontal foramina and thus might belong to E. erinacea, another, shown on pl. 54, fig. 14, is similar to E. ampullacea Heron Island, Great Barrier Reef m±sd r n AzL 785±64 667–889 15 AzW 441±65 354–606 15 FoN 31±6.5 16–41 16 FoD 61±5.3 51–71 29 OD 30±7.6 20–40 29CÁCERES-CHAMIZO ET AL.8 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 1. Exechonella ampullacea Hayward & Ryland, 1995. Great Barrier Reef, Heron Island (A, C, E: holotype QM G304975; B, D, F: paratype QM G304977). A, B, general view of the colony from above. C, cleaned frontal shield showing the shape of foramina. D, condyle with a ‘pocket’; E, lateral view of the holotype specimen showing mural septula and kenozooid (arrow); F, broken autozooid showing distal transverse wall with communication pores, right condyle with a ‘pocket’ (arrowhead), distal, proximal and lateral walls of peristome and underside of broken frontal shield. Marginal pores with centrally perforated cuticular plate are seen together with more distal communication pores (their cuticular plate is completely or partially destroyed), and cross-sectioned foramen of the frontal shield (seen above). Scale bars: A, B = 1 mm; C, F = 100 μm; D = 30 μm; E = 500 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 9REVISION OF THE RECENT SPECIES OF EXECHONELLA although its foramina look slightly smaller and not as numerous as in the holotype. Also, an elevated foraminal rim was not shown in the Harmer’s depiction. While both these specimens clearly belong to the species of the E. ampullacea species-complex, their restudy is required. Gordon (1984) described E. tuberculata from Kermadec Ridge, New Zealand, that fairly corresponds to E. ampullacea by its general zooidal morphology and, in particular, by the absence of the frontal processes associated with foramina. It should also be noticed that Cook and Bock (2004), when illustrating E. tuberculata, used a specimen from the Bass Strait. Earlier Cook (1967) made sketches of zooids from the colonies (as E. tuberculata) collected in the type locality (Port Phillip Heads, Victoria), but they are too schematic for any definite conclusion. Six type specimens in two wooden slides with glass covers are kept in the Museum Victoria, Melbourne. Both slides contain three specimens of various sizes each, first labeled Lagenipora tuberculata McG, P.P.H., 65927, H627, F45627, and the second slide labeled F45627 which was mentioned as a number of the holotype by Cook and Bock (2004). Photos of the slides with the specimens seen through the glass covers were kindly provided by the Invertebrate Palaeontology collection manager Dr R. Schmidt. Re-examination of this material that is presumably very fragile (P.E. Bock, pers. comm., 2016) as well as other specimens attributed to E. tuberculata is necessary to make further progress. Another species belonging to the “group [that] includes …E. tuberculata and E. ampullacea was described by Cook and Bock (2004, p. 267) as Exechonella sp. cf. discoidea Canu & Bassler, 1929. While it undoubtedly belongs to E. ampullacea species-complex, it is clearly not Actisecos discoidea (Canu & Bassler, 1929) as will be shown later, and more similar to E. anuhaensis Tilbrook, 2006. Distribution. Exechonella ampullacea has been found at the Heron Island, Great Barrier Reef, Coral Sea, south Pacific Ocean, and Pulau Jong, Jurong Island, Singapore. Exechonella erinacea (Canu & Bassler, 1929) (Fig. 2, Table 2) Coleopora erinacea: Canu & Bassler 1929, p. 268–269, pl. 19, figs 5–8. Material examined. Lectotype: USNM 7967, encrusting on shell. Philippines, Jolo Island, Jolo Light, 6o 4´25´´N, 120o 58´30´´E, Albatross Station D.5137, depth 20 fathoms, 14 Febuary 1908. Description. Colonies encrusting, unilaminar, multiserial. Autozooids convex, oval, separated by grooves. Very narrow gymnocystal rim is seen between some zooids. Primary orifice oval, wider than long, anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral triangular condyles with their tips directed to the orifice midline. Long and tubular peristome is pustulose externally. Frontal shield pustulose, with 32–46 rounded or oval foramina. Lumen of each foramen has vertical, wide gymnocystal walls, whereas an area around is a slightly elevated, wide ring with an inner wall surface. In old zooids foramina distally or distolaterally bear a large thick spike-like process. Marginal pores small and rounded, predominantly visible in the distal part of zooid. No avicularia. Adventitious kenozooids of various shapes are seen between autozooids; with 2‒6 pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in two rows. Ancestrula is unknown. Remarks. Although E. erinacea was described by Canu and Bassler (1929) as Coleopora, it was suggested later that this species belongs to Exechonella (Cook & Bock 2004). It is characterized by the presence of its large thick spike-like process associated with foramina, and its closest relative is E. tuberculata (MacGillivray, 1883) whose holotype and additional specimens were examined and figured by Cook and Bock (2004) (see above). Although both species show similar foramina structures and large zooids (approximately 1 mm in length), there are a number of differences between them as follows: (1) E. erinacea has a bigger range of the foramina number, 32– 46, whereas it is 16–27 in E. tuberculata; (2) frontal shield is less prominent and swollen in E. erinacea which makes marginal pores visible, the condition that is absent in E. tuberculata; (3) there is very narrow gymnocystal rim between zooids in E. erinacea, and it is absent in E. tuberculata; (4) foraminal processes are pointed in the former species and blunt in the latter; (5) finally, a presence of kenozooids with 2–6 pores is recorded in E. erinacea and not in E. tuberculata.CÁCERES-CHAMIZO ET AL.10 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 2. Exechonella erinacea (Canu & Bassler, 1929). Philippines, Jolo Island (A‒D: lectotype USNM 7967). A, B, general view of the colony from above. C, three autozooids showing opercula and a shape of the primary orifice. Kenozooids with pores pointed by arrows. D, close-up of two zooids showing the shape of foraminal luminae and a condyle (arrowhead). Scale bars: A, B = 500 μm; C, D = 200 μm. TABLE 2. Measurements (in µm, except number of foramina) of the lectotype specimen of Exechonella erinacea (Canu & Bassler, 1929). Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Specimen USNM 7967 was mentioned among two cotypes of E. erinacea (as Coleopora) by Canu and Bassler (1929). We selected it as lectotype. Our check of the second specimen (USNM 7968) showed it does not belong to Exechonella. Harmer (1957, pl. 54, figs 13, 14) figured two specimens from the New Guinea as E. tuberculata (see also Philippines m±sd r n AzL 938.4±60.8 861–1055 7 AzW 754.1±100.3 639–917 7 OrL 190±7.8 181–195 3 OrW 245.3±16.7 236–264 3 FoN 41±4.8 32–46 8 FoD 48.6±7.28 42–61 21 OD 94.19±7.4 79–109 21 Zootaxa 4305 (1) © 2017 Magnolia Press · 11REVISION OF THE RECENT SPECIES OF EXECHONELLA above). One of them is more similar to E. erinacea because the foramina number exceeds 30 and the frontal processes are pointed. Its restudy is required before more definite conclusion can be made. Distribution. The present species is found near the Philippines. Exechonella reniporosa n. sp. (Fig. 3, Table 3) Material examined. Holotype: MTQ G100215, on coral (mounted on SEM stub and coated with gold). Coral Sea, Great Barrier Reef, Lizard Island, Watson’s Bay, depth 6.5 m, 4 October 2012. Etymology. The name reflects the kidney-like shape of the frontal foramina that is commonly met in younger zooids in this species. Derived from the Latin word “ren” (kidney). Description. Colonies encrusting, unilaminar, multiserial. Autozooids bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long, with the proximal edge straight or slightly concave. Anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral condyles seen as narrow, flat or roundish elongated plates. Condyles are often associated with a small opening (‘pocket’) on the internal surface of the peristome. Long tubular peristome is pustulose externally and with shallow longitudinal grooves on its internal surface, the rim is slightly flared. Frontal shield pustulose, with 13‒45 foramina (also counted in ancestrula and early generations of zooids). The lumen of each foramen has vertical gymnocystal walls, whereas an area around is a slightly elevated wide ring with an inner wall surface. In older zooids foramina are predominantly oval and sometimes round. In younger peripherical zooids they are predominantly kidney-shaped because of a short blunt projection developing asymmetrically on the foraminal ring and, thus, changing the originally oval/round shape of the foramen. In younger zooids the oval/round foramina are predominantly placed along the mid-line of the zooid whereas kidney-shaped ones are curved towards their closest lateral side of zooid or proximally. The proximal part of the frontal shield is ‘reduced’ in some zooids making a sort of ‘gap’ in the ‘corner’ between zooids. Marginal pores small and rounded, well seen in peripherical zooids, but hidden in those of the center of the colony. No avicularia. Adventitious kenozooids with 3‒6 pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in two rows. Ancestrula autozooidal, smaller than the rest of zooids, with less frontal foramina. TABLE 3. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella reniporosa n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Lizard Island, Great Barrier Reef m±sd r n AzL 770±104 531–891 14 AzW 469±81 406–641 14 OrL 141±11.1 131–153 3 OrW 170±7.2 165–178 3 FoN 28±8 13–45 15 FoD 78±7.6 63–94 24 OD 25±6.3 16–31 24 PeL 256±23.6 219–281 5 PeW 241±17.9 219–266 5 AncL 593 ‒ 1 AncW 422 ‒ 1CÁCERES-CHAMIZO ET AL.12 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 3. Exechonella reniporosa n. sp. Great Barrier Reef, Lizard Island (A‒F: holotype MTQ G100215). A, general view of the colony from above. B, central part of the colony showing multiporous mural septulum in left autozooid. C, proximal part of the colony with ancestrula. D, peripheral autozooid showing typical foraminal shape. E, primary orifice with condyles shown by arrows (lower part of the ‘pocket’ seen above the right condyle). F, close-up of adventitious kenozooid (k) with five pores, three of them having a tiny central pore. Scale bars: A = 1 mm; B‒E = 100 μm; F = 10 μm. Remarks. Exechonella reniporosa n. sp. is characterized by the kidney-like shape of its foramina in younger, peripherical zooids. The specific shape of the foramina is explained by the development of the associated blunt projection that changes the original oval or round shape of the foramen. For instance, similar blunt projections are sometimes met in the E. variperforata n. sp. (see below), but their development does not affect the foraminal shape. Tilbrook (2006, p. 116) mentioned a specimen NHM 1964.3.20.15 from Zanzibar (assigned to E. discoidea) in which “the numerous reniform frontal foramina radiating in concentric arcs from the proximal of the peristome. This specimen should be further restudied to compare it with our material that also has these characters. Zootaxa 4305 (1) © 2017 Magnolia Press · 13REVISION OF THE RECENT SPECIES OF EXECHONELLA Distribution. Exechonella reniporosa n. sp. has been found only at the Lizard Island, Great Barrier Reef, Coral Sea, south Pacific Ocean. Exechonella variperforata n. sp. (Fig. 4, Table 4) ? Exechonella tuberculata: Scholz & Cusi 1991, p. 412, 428, pl. 4, fig. 1. Material examined. Holotype: MTQ G100217 (mounted on SEM stub and coated with gold), on coral. Coral Sea, Great Barrier Reef, Lizard Island, Pigeon Point, depth 8–10 m, 9 October 2012. Paratype: MTQ G100218, two fragments (mounted on SEM stub and coated with gold). Coral Sea, Great Barrier Reef, Lizard Island, Pigeon Point, depth 8–10 m, 9 October 2012. Other material studied: MTQ G100220 (mounted on SEM stub and coated with gold). CReefs Heron Island 2010. Coral Sea, Great Barrier Reef, Heron Island, Site HI10-051, 23° 27’ 37.764’’ S, 151° 55’ 45.444’’ E, depth 16 m, 24 November 2010, collected by K.J. Tilbrook, G. Cranitch. Etymology. The name was given because of the variations in shape and size of the frontal foramina in comparison with the other species of this complex. Derived from the Latin word “variis” (various). Description. Colonies encrusting, unilaminar, multiserial. Autozooids bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long, anter wall underlain by an inner lamina (only visible in oblique view) ending in small rounded distolateral condyles. Long tubular peristome is pustulose externally and with longitudinal grooves on its internal surface, the rim is flared often with short pointed spikes. Frontal shield pustulose, with 8‒20 foramina of various shapes: from round and oval to irregular. In some zooids from one to six foramina bear the short triangular, blunt or pointed, process. Each process has mostly gymnocystal surface connected with vertical gymnocystal walls of its foramen. The area around a foramen is a slightly elevated narrow ring with an internal wall surface. Gymnocystal walls of neighbour lateralmost foramina often confluent with each other thus making the edge of frontal shield zigzag-like in outline. In this case the areas between foraminal luminae are closely apposed to the frontal shield of the neighbour zooid. The proximal part of the frontal shield is ‘reduced’ in some zooids making a sort of ‘gap’ in the ‘corner’ between zooids. 1‒2 rows of small, rounded marginal pores are seen mainly in the peripheral zooids. The distalmost part of zooid below peristome can be bear up to three rows of such pores. In the central part of the colony zooids are closely appressed and the marginal pores are not seen. No avicularia. Adventitious kenozooids with 2‒4 pores, each having cuticular plate. Vertical zooidal walls narrow or wide, represented by multiporous mural septula with communication pores arranged in two or several rows. Ancestrula unknown. TABLE 4. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella variperforata n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Lizard Island, Great Barrier Reef m±sd r n AzL 794±100 600–1000 26 AzW 536±53.3 433–650 26 OrL 154 143–164 2 OrW 226 210–233 2 FoN 15±2.5 8–20 27 FoD 80±13.2 50–109 45 OD 50±11.1 31–78 45 PeL 325±25 313–375 6 PeW 285±18.3 260–313 6CÁCERES-CHAMIZO ET AL.14 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 4. Exechonella variperforata n. sp. Great Barrier Reef, Lizard Island (A, B: holotype MTQ G100217; C‒F: paratype MTQ G100218). A, general view of the colony from above. Ancestrular zone is overgrown by calcareous algae. B, autozooid showing various foraminal shapes. C, general view of the colony fragment from above (‘gaps’ between zooids are clearly seen; peristome of left zooid bears two spikes). D, lateral view of the same fragment showing marginal pores arranged in 2‒3 rows and multiporous septula. E, primary orifice with condyles (arrows) visible. F, distolateral view of the frontal shield with foramina, two of which bear short pointed process. Scale bars: A = 1 mm; B‒ F = 100 μm. Remarks. Exechonella variperforata n. sp. is characterized by its comparatively fewer foramina with narrow rim, by the irregular shape of some of them and by small rounded condyles. Most of the species of this complex are characterized by relatively high number of frontal foramina (16–41 in E. ampullacea, 13–45 in E. reniporosa n. sp., 23–46 (Safaga) and 30–58 (Jeddah) in E. safagaensis n. sp., and 13– 37 in E. maldiviensis n. sp.) (see below). E. variperforata n. sp. is the only species with 8–20 foramina per zooid. The variability of the foraminal shape is rather prominent character of this species that is also met (though in lesser degree) in E. maldiviensis n. sp. Zootaxa 4305 (1) © 2017 Magnolia Press · 15REVISION OF THE RECENT SPECIES OF EXECHONELLA Apart of our material from the Lizard Island, north part of the Great Barrier Reef, an additional colony of E. variperforata n. sp. has been collected at the Heron Island, south part of the Great Barrier Reef. Scholz and Cusi (1991), described and illustrated a colony from Leyte, Philippines, identified as E. tuberculata, but it shows all the major characters of E. variperforata n. sp., including shape of the peristome margin, and reduced number of foramina and their shape. Distribution. Despite of the above suspicions, the current distribution of E. variperforata n. sp. is restricted to the Great Barrier Reef. Exechonella safagaensis n. sp. (Fig. 5, Table 5) ? Lagenipora tuberculata: Waters 1909, p. 172–173. ? Exechonella tuberculata: Balavoine 1959, p. 271, pl. 3, fig. 4. ? Exechonella tuberculata: Powell 1969, p. 358. ? Exechonella tuberculata: Dumont 1981, p. 635. ? Lagenipora tuberculata: Thornely 1905, p. 113. ? Lagenipora tuberculata: Thornely 1907, p. 188. ? Lagenipora tuberculata: Thornely 1912, p. 146. Material examined. Holotype: DPUV 2013-0001-0001, on dead coral Coscinaraea sp. Red Sea, the Northern Bay of Safaga, transect B 9, depth 38 m, 16 July 1987. Paratypes: DPUV 2013-0001-0002, on coral rubble, Porites sp. Red Sea, the Northern Bay of Safaga, transect B 7, depth 45 m, 15 November 1986; DPUV 2013-0001-0003¸ on coral Echinopora sp. Red Sea, the Northern Bay of Safaga, transect B 11, depth 40 m, 14 July 1987; DPUV 2013- 0001-0004, on coral Coscinaraea sp. Red Sea, the Northern Bay of Safaga, transect B 9, depth 38 m, 16 July 1987; DPUV 2013-0001-0005, on coral Echinopora sp. Red Sea, the Northern Bay of Safaga, transect B 11, depth 40 m, 14 July 1987; DPUV 2013-0001-0006, on coral rubble. Red Sea, the Northern Bay of Safaga, west the Northern Bay of Safaga Island, transect A 5, depth 1–2 m, September 1992; DPUV 2013-0001-0007, on coral rubble. Red Sea, the Northern Bay of Safaga, depth 14 m, 17 February 1992; DPUV 2013-0001-0008, on coral rubble. Red Sea, the Northern Bay of Safaga, 24 February 1987. Mounted on SEM stubs and coated with gold: DPUV 2013-0001- 0009, on coral rubble. Red Sea, the Northern Bay of Safaga, depth 25 m, 10 July 1987; DPUV 2013-0001-0010, on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Other material examined: IPUW 7020, seven colony fragments on the pieces of coral Porites sp. Red Sea, the Northern Bay of Safaga, transect B 9, depth 38 m, 16 July 1987; IPUW 7021, on coral Echinopora sp. Red Sea, the Northern Bay of Safaga, transect B 11, depth 40 m, 14 July 1987; IPUW 7022, on bivalve shell. Red Sea, the Northern Bay of Safaga, Ras Abu Soma, 2 October 1992; IPUW 7023 (mounted on SEM stub and coated with gold), IPUW 7024, two colonies on coral rubble. Red Sea, Jeddah, coll. by Dr. A. Antonius in the late 1970’s (collection date not specified). DPUV collection (non-numbered specimens mounted on SEM stubs and coated with gold): two small colonies, Red Sea, the Northern Bay of Safaga (further collecting data not specified); 3-zooid colony on bivalve shell, Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1‒20 m, September 1992; small colony, Red Sea, the Northern Bay of Safaga, station B 3/2, depth 4 m, sand between coral patches, 16 July 1987; ancestrula, on coral Alveopora viridis, Red Sea, the Northern Bay of Safaga, transect B 7, depth 45 m, 15 November 1986. Etymology. Named after the Northern Bay of Safaga, Red Sea, from where the holotype specimen was collected. Description. Colonies encrusting, unilaminar, multiserial. Autozooids bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long. Anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral condyles seen as narrow elongated plates slightly widening distally. ‘Pocket’ associated with a condyle has been detected in some zooids. Long tubular peristome is pustulose externally and with longitudinal grooves on its internal surface. Peristome rim is slightly flared, in some colonies with a variable number of small projections. Frontal shield pustulose, with 23– 46 (Safaga) and 30–58 (Jeddah) rounded or oval foramina. Lumen of each foramen has vertical, wide gymnocystal walls, often wrinkled, whereas an area around is a slightly elevated wide ring with an inner wall surface. In some zooids from one to ten foramina bear long conical and sharp frontal processes (spikes). Each process has mostly a CÁCERES-CHAMIZO ET AL.16 · Zootaxa 4305 (1) © 2017 Magnolia Press gymnocystal surface with its edges merging on the back side of the spike (sometimes forming a conical ‘tube’), connected with corresponding gymnocystal walls of its foramen. Marginal pores small and rounded, with centrally perforated cuticular plate. The distalmost part of zooid below peristome can bear up to two rows of such pores. No avicularia. Adventitious kenozooids with 2‒5 pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in 1–2 rows. Ancestrula autozooidal, with foramina sometimes as numerous as in regular autozooids. TABLE 5. Measurements (in µm, except number of foramina) of specimens of Exechonella safagaensis n. sp. from Safaga and Jeddah, Red Sea. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Our material from the Red Sea is strongly reminiscent of Exechonella ampullacea from Heron Island. The examination of its holotype allowed recognition of the following major similarities and differences, namely: (1) in both species autozooids of oval shape with tall and tubular peristome and a range of frontal foramina of 23–46 (Safaga), 30–58 (Jeddah) and 16–41 (Heron Island) (original description of E. ampullacea mentions 30– 44 foramina, but re-examination of the holotype showed autozooids with as few as 16 foramina); (2) presence of narrow elongated condyles in distolateral position; (3) similar zooidal size with length to width ranges of 667– 889×354–606 µm (Heron Island), 607–1160×351–733 µm (Safaga) and 560–900×480–600 µm (Jeddah). The difference is the total absence of the frontal pointed processes in the Heron Island material. In contrast, such processes are always found in the colonies from the Red Sea. Our Red Sea specimens are superficially similar to E. tuberculata (MacGillivray, 1883) that has been often mentioned in the Red Sea (Waters 1909; Balavoine 1959; Powell 1969; Dumont 1981; Winston 1986 [based on Dumont’s paper]), Indian Ocean near Madagascar, Réunion and India (Thornely 1905, 1907, 1912; Robertson 1921; d’Hondt 2016a, b) and from different localities in Indonesia, Philippines, Sri Lanka, New Guinea, Australia (Canu & Bassler 1929; Harmer 1957; Scholz & Cusi 1991) and New Zealand (Gordon 1984). E. tuberculata was described (as Lagenipora) by MacGillivray in 1883 from Port Phillips Heads, Australia. Cook and Bock (2004) examined the holotype of this species and additionally described and illustrated a small colony from the Bass Strait (figs 3b–d) (see above). The species is characterized by zooids with long tubular peristome and 16–27 foramina (Cook and Bock mentioned not more than 20 foramina in the description). Each foramen bears large thick blunt process only one side of which (faced to foraminal opening) is gymnocystal. Such processes are not so numerous in E. safagaensis n. sp., being also pointed and more slender. After examining a considerable amount of material from the Northern Bay of Safaga and Jeddah, however, we are certain that the local species of Exechonella, could be easily assigned to E. tuberculata by previous authors due to the presence of these spinous processes. Northern Bay of Safaga, Red Sea Jeddah, Red Sea m±sd r n m±sd r n AzL 797±132 607–1160 31 715±100 560–900 11 AzW 495±78.5 351–733 31 520±35 480–600 11 OrL 133±17.1 110–159 9 ‒ ‒ ‒ OrW 170.4±16.4 147–200 9 ‒ ‒ ‒ FoN 37±6.3 23–46 24 47±7.9 30–58 10 FoD 68±7.6 47–83 47 70±11 60–80 10 OD 29±5.5 17–43 47 26±7 20–40 10 PeL 245±95.4 140–450 13 280 ‒ 1 PeW 255±46.5 200–350 14 240 ‒ 1 AncL 750±68 700–850 4 ‒ ‒ ‒ AncW 450±41 400–500 4 ‒ ‒ ‒ Zootaxa 4305 (1) © 2017 Magnolia Press · 17REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 5. Exechonella safagaensis n. sp. Red Sea (A‒C: paratype DPUV 2013-0001-0009, the Northern Bay of Safaga; D‒F: paratype DPUV 2013-0001-0010, the Northern Bay of Safaga; E, IPUW 7023, Jeddah). A, general view of the colony from above. Ancestrular zone is broken. B, central part of the same colony. C, lateral view of the peripheral part of the same colony showing non-damaged peristomes with flared edge and frontal processes associated with foramina. D, lateral view of the peripheral part of the colony showing non-damaged peristomes with rounded edge without spikes and lateral multiporous septula. E, primary orifice with condyles hardly visible (arrows). F, close-up of the frontal shield with foramina two of which bear pointed process. Scale bars: A = 1 mm; B‒E = 100 μm; F = 10 μm. When Waters (1909, p. 172) reported E. tuberculata (as Lagenipora) from the Sudanese Red Sea, he noted the presence of these projections and wrote that they “do not occur on all the pores and are not so large as in those from Australia.” This note spports our suggestions. Also, optical photo of the two-zooid specimen of ‘E. tuberculata’ published by Balavoine (1959, pl. 3, fig. 4) shows a resemblance with our material. The remaining authors dealing with the Red Sea bryozoans only mentioned E. tuberculata in the species lists.CÁCERES-CHAMIZO ET AL.18 · Zootaxa 4305 (1) © 2017 Magnolia Press Distribution. Exechonella safagaensis n. sp. is only found in the Red Sea; in the Northern Bay of Safaga (western coast) and Jeddah (eastern coast). Exechonella maldiviensis n. sp. (Fig. 6, Table 6) Material examined. Holotype: DPUV 2013-0002-0001, on coral rubble (mounted on SEM stub and coated with gold). Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, House Reef, depth 5–19 m, 12–13 January 2008. Paratypes: DPUV 2013-0002-0002, DPUV 2013-0002-0003, on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, depth 10 m, 3 August 2009; DPUV 2013-0002-0004, DPUV 2013-0002-0005, DPUV 2013-0002-0006, DPUV 2013-0002-0007 (mounted on SEM stub and coated with gold), on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Angsana Ihuru Island, House Reef, depth 8 m, 28 July 2009; DPUV 2013-0002-0008 (mounted on SEM stub and coated with gold), on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, House Reef, depth 5–19 m, 12–13 January 2008. Other material examined: IPUW 7025, on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, depth 10 m, 3 August 2009. Etymology. Named after the Maldive Islands, where the species has been found. Description. Colonies encrusting, unilaminar, multiserial, patch-like or dichotomously branching. Autozooids bottle-like: convex, oval-elongated, separated by deep grooves and pits in the ‘corners’ between zooids. Primary orifice oval, wider than long, anter wall underlain by an inner lamina (only visible in oblique view) ending in distolateral condyles seen as narrow elongated plates slightly widening distally. Condyles are associated with a ‘pocket’ of unknown function in some zooids. Long tubular peristome is pustulose externally and with longitudinal grooves on its internal surface, the rim is slightly flared. Frontal shield pustulose, with 13–37 foramina of various shapes, mostly round and oval, but often irregular in some colonies. The lumen of each foramen has vertical gymnocystal walls, whereas an area around is a slightly elevated wide ring with an inner wall surface. In some zooids from one to four foramina bear high flattened pointed process (sometimes ‘curved’ around a half of the foraminal opening). Each process has a gymnocystal surface faced to the foraminal lumen and connected with its gymnocystal walls. The process ‘back-side’ has an inner wall surface. Marginal pores small and rounded, with centrally perforated cuticular plate, only seen in the marginal zooids. No avicularia. Adventitious kenozooids with 2–4 pores, each having centrally perforated cuticular plate. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in 1–2 rows. Ancestrula unknown. TABLE 6. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella maldiviensis n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Maldive Islands, Indian Ocean m±sd r n AzL 786±140 513–1132 37 AzW 503±89 359–737 37 OrL 149±15.8 116–165 9 OrW 195±17 165–213 9 FoN 23±6.3 13–37 31 FoD 72±15.4 46–109 88 OD 35±7.6 20–54 88 PeL 266±30.2 220–310 9 PeW 305±28.8 240–330 9 Zootaxa 4305 (1) © 2017 Magnolia Press · 19REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 6. Exechonella maldiviensis n. sp. Indian Ocean, Maldive Islands (A‒D: holotype DPUV 2013-0002-0001; E: paratype DPUV 2013-0002-0008; F: paratype DPUV 2013-0002-0007). A, general view of holotype from above. Ancestrular zone is broken. B, central part of the same colony. C, peripheral part of the same colony showing typical frontal processes, some ‘curved’ around foramina. D, primary orifice with condyles (right condyle with a ‘pocket’ shown by arrow). E, general view of the dichotomously branching paratype colony from above (one zooid shows partially broken peristome with flared edge, intrazooidal budding is seen in another zooid (arrow)). Ancestrular zone is overgrown by calcareous algae. F, lateral view of the peripheral part of the colony showing zooidal frontal shields with pointed processes associated with foramina, marginal pores and lateral multiporous septulum. Scale bars: A, E = 1 mm; B‒D, F = 100 μm. Remarks. Exechonella maldiviensis n. sp. is characterized by its flattened and pointed frontal processes that sometimes ‘curved’ around the foramen in some zooids.CÁCERES-CHAMIZO ET AL.20 · Zootaxa 4305 (1) © 2017 Magnolia Press E. maldiviensis n. sp. in several respects reminiscent of E. variperfotara n. sp. In both species zooids are often characterized by the frontal shield with foramina of various shapes. The differences between these species are the wide (E. maldiviensis n. sp.) and narrow (E. variperfotara n. sp.) rim around the foraminal lumen, and the shape and size of the foramen-associated projections that are rather long, flattened and pointed in E. maldiviensis n. sp., sometimes ‘curved’ around a half of the foraminal opening, and short, pointed or blunt in E. variperforata n. sp. (although tips were all broken in them). Distribution. Exechonella maldiviensis n. sp. is known at present only from Vabbinfaru Island and Angsana Ihuru Island, North Male Atoll, Maldive Islands, Indian Ocean. Exechonella antillea species-complex Exechonella antillea (Osburn, 1927) (Figs 7–8, Table 7) Lepralia antillea: Osburn 1927, p. 128–129, figs 6–7. Exechonella antillea: Fransen 1986, p. 87–90, fig. 29a–g. ? Exechonella antillea: Shier 1964, p. 616; Hayward 1988, p. 293; Di Martino, Taylor & Portell 2017, p. 140, fig. 34. Not Phylactella labrosa: Osburn 1914, p. 213. Not Exechonella antillea: Osburn 1940, p. 366–367; Osburn 1950, p.95–96, pl.10, figs 9–10; Cook 1967, p. 337–339, pl.1, fig. e; Hayward 1974, p. 377, fig. 4c; Dumont 1981, p. 635; Cook 1985, 129–131, fig. 38, pl. 15, figs a, b; Winston 1986, p. 19, fig. 40; Vieira 2008, p. 82–83, pl. 19, figs a–c; Vieira et al. 2008, p. 24. Not Exechonella antillea var spinosa: Osburn 1940, p. 367–368, pl. 4, fig. 35. Material examined. Lectotype: USNM 11960, on a pottery shard. Caribbean Sea, Curaçao, Spanishwater, 19 April 1920, coll. by Dr C.J. van der Horst. Paralectotype: USNM 545920, Caribbean Sea, Curaçao, Spanishwater, 18 April 1920, coll. by Dr C.J. van der Horst. Other material examined: NNHML Coll. N° 2997, two slides, eight colony fragments embedded in Canada balsam, Sta. Cur82.093, Netherlands Antilles, Curaçao, St. Joris Bay, inner bay, eastern part, 4 October 1982, coll. by C.H.J.M. Fransen. Description. Colony encrusting, unilaminar, multiserial. Autozooids pentagonal, hexagonal or oval in shape, separated by narrow grooves. Primary orifice wide pear-shaped, slightly longer than wide, poster (one-third) tending to be more quadrate (angular) than the anter (two-thirds) which has a rounded outline; anter wall underlain by an inner lamina which ends at well-defined triangular condyles, their tips directed to the orifice midline, extending beyond the edge a step-like curved area below. Operculum dark brown in non-cleaned material. Peristome low, collar-like, with relatively thin wall having 1–2 lateral blunt projections in some zooids. Peristome is often parallel-sided laterally or sometimes oval, its wall proximally lower and more narrow than distally with small medial blunt projection, areas either side of this projection wrinkled. Frontal shield smooth or slightly pustulose, perforated by 34–52 well-separated rounded or oval foramina, each with a wide smooth (often wrinkled) gymnocystal rim, raised slightly above the frontal shield and sloping towards the small central opening; fusions between the rims of 2–3, up to 5, foramina are not rare, sometimes common. Small marginal pores are predominantly oval. Lateral areas in some zooids are separated by a poorly developed narrow gymnocystal rim. Avicularia, when present, are placed on the outer raised wall of the two lateralmost foramina which are larger than the rest of the foramina and sometimes have a ‘double’ opening as a result of fusion of the opposite sides of foraminal gymnocystal rim. Each avicularium has a central nipple-like skeletal structure with a central pore through which the tendons of two muscles are passing towards a membranous mandible with a ring sclerite laying above the nipple-like structure. Mandible is thin, semi-round or semi-oval, closes the lumen of the foramen. Internal chamber of avicularium from where the muscles arise is filled with trilobate (?) granular tissue of unknown nature. There is also a central round body (presumed vestigial polypide with a ganglion) from which at least two bundles (presumably reduced retractor-muscles) go towards the bottom of the avicularian chamber. Adventitious kenozooids with 3–8 pores sometimes seen near autozooidal margins, these are often associated with the avicularia or may be alone. Vertical zooidal walls represented by multiporous mural septula with 1–2 rows of communication pores. Ancestrula not observed. Zootaxa 4305 (1) © 2017 Magnolia Press · 21REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 7. Exechonella antillea (Osburn, 1927). Caribbean Sea, Curaçao (A‒G: lectotype USNM 11960, non-cleaned colony). A, C, D, general view of lectotype from above. Some lateralmost foramina shown by arrows in D. B, close-up of autozooid with an operculum removed. E, close-up of autozooid with two lateralmost foramina bearing avicularia, each associated with kenozooid (k). Two more kenozooids (k) are seen proximally. F, avicularium with a mandible closing a foraminal lumen (arrowhead points to mandible edge). G, primary orifice with a peristome and condyles. Kenozooid (k) is seen in the upper left corner. Scale bars: A, B, F, G = 100 μm; C = 500 μm; D, E = 200 μm.CÁCERES-CHAMIZO ET AL.22 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 8. Exechonella antillea (Osburn, 1927). Caribbean Sea, Curaçao (A‒H: NNHML Coll. N° 2997, total mounts). A, autozooid with forming polypide and ovary (ov). B, autozooid containing polypide and 2-blastomers embryo (e) inside the internal brood sac (its wall shown by arrows). C‒D, autozooids with their frontal shield showing radiating sutures connecting foramina. Large lateralmost foramina bearing avicularia (not-recognizable in this magnification) are associated with kenozoidal (k) chamber. E, autozooid with polypide and lateral avicularium (arrowhead). F, avicularium showing semi-circular mandible (outline shown by arrowheads), rounded sclerite (s) and nipple-like structure with central opening (arrow). Granular tissue is visible. G, part of the frontal shield showing avicularium with semi-circular mandible (outline shown by arrowheads), rounded sclerite (s) and tendons of two muscles (arrow). Several foramina occluded by diatomeans are seen too. H, avicularian internal chamber with granular tissue and central body—presumed rudimentary polypide with retractor muscles below (arrows). Scale bars: A‒E = 100 μm; F = 50 μm; G, H = 20 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 23REVISION OF THE RECENT SPECIES OF EXECHONELLA TABLE 7. Measurements (in µm, except number of foramina) of the lectotype specimen of Exechonella antillea (Osburn, 1927). Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Exechonella antillea (Osburn, 1927) was originally described as Lepralia antillea from Curaçao, in the Caribbean Sea. It has subsequently been recorded by many authors from many tropical and subtropical areas: the Caribbean Sea and western Atlantic—Puerto Rico (Osburn 1940), Florida (Shier 1964; Winston 1982), Jamaica (Winston 1986), Curaçao (Fransen 1986), Coast of Alagoas, Bahia and São Paulo, Brazil (Vieira 2008; Vieira et al. 2008), eastern Atlantic—Senegal and Ghana (Cook 1967, 1985), Mediterranean Sea (Hayward 1974), Red Sea (Cook 1967; Dumont 1981; Winston 1986 [based on Dumont’s paper]), and the Pacific Ocean—California (Osburn 1950). In his 1927 paper Osburn mentioned nine colonies of what he described as E. antillea (“April 19, one colony on an oyster shell, and May 18, 1920, eight colonies on a broken piece of pottery”, p. 128), but only two specimens were found in the USNM collection that were received by the USNM in 1968 after Osburn’s death. The information on his hand written labels differs, however, from what is in the 1927 paper. The USNM 11960 was indicated as ‘type specimen’ on the label by Osburn, and we select it as a lectotype. The collecting date was written by him as Apr-19-21 that we interpret as between 19th and 21th of April since all the species described in the Osburn’s (1927) paper were collected during spring, 1920 (by C.J. van der Horst). This specimen, despite the date of collecting, grows on the pottery shard, not on oyster. The second existing colony USNM 545920 judging from the label was collected on 18 April, 1920. Osburn detached it from its substrate and glued it to a glass slide with Canada balsam. We selected it as paralectotype. The above description is based on the lectotype, whereas the paralectotype has no avicularia, and some zooids have a peristome with flat pointed lateral processes. This specimen also shows the early developmental stages of the frontal shield with foramina being round elevated projections. In older zooids foraminal rims become wider and sometimes fuse. Later Osburn (1940) reported without illustration as E. antillea a specimen from Puerto Rico. In addition, in this and also in 1927 paper he mentioned that the specimen that he briefly described as Phylactella labrosa (Busk, 1854) from the Dry Tortugas, off Florida, in 1914 belongs to this species too. Examination of these two specimens showed that USNM 545921 (Puerto Rico) belongs to E. vieirai n. sp., whereas USNM 545922 (Dry Tortugas) belongs to E. pumicosa (see also below). Comparison of the specimen USNM 10741, described as Exechonella antillea by Osburn (1950) from the Gulf of California, with the holotype from Curaçao, showed several important differences and resulted in the description of the new species E. californiensis n. sp. (see below). Shier (1964) also reported E. antillea from northwest Florida. The description of his specimen is reminiscent of that of the holotype, but unfortunately there are no illustrations in the paper to make a more precise comparison possible. Fransen (1986) redescribed Exechonella antillea based on specimens from the type locality (Curaçao), and his description fits well to our observations. However, comparing his material (colony fragments mounted on slides embedded in Canadian balsam) with that described by Osburn (1927) we detected some differences that may reflect the variation mentioned by Fransen (1986). These differences are: (1) primary orifice shape was described Curaçao, Caribbean Sea m±sd r n AzL 793±82.3 650–927 14 AzW 580±42.4 530–650 15 OrL 210±12.1 190–238 19 OrW 198±13.7 169–220 19 FoN 43±5.5 34–52 15 FoD 52±6.8 36–60 33 OD 17±3.7 19–37 33CÁCERES-CHAMIZO ET AL.24 · Zootaxa 4305 (1) © 2017 Magnolia Press as wide as long by Fransen, but it is slightly longer than wider in the holotype; (2) the frontal shield bears 40–86 foramina in the Fransen’s material, while the maximal number in the holotype is 52. Unfortunately, due to the preservation method there are no specimens for the SEM study among the Fransen’s material available. On the other hand, the semitransparent fragments in whole mounts make the investigation of internal structures possible; the internal brooding sacs containing an embryo each are clearly visible, as are the muscle ascending from the avicularium chamber and passing through the opening of the nipple structure (see below). Fransen also described and illustrated the tubular “attachment organs” situated on the basal side of zooids (see also Shier 1964). Fossil specimens were recently described (as E. antillea) from the early Miocene of Florida (Di Martino et al. 2017). While general morphology and zooidal size are similar, the primary orifice is distinctly smaller in the fossil material that also shows no medial blunt process of the peristome as well as no lateral foramina with avicularia. Cook (1967, 1968) reported as Exechonella antillea several specimens from Senegal, Ghana, Guinea, Red Sea and Caribbean, mentioning the wide range of variation in many characters. Later on she admitted, however, that the east Atlantic material significantly differs from the specimens of Fransen from the Caribbean (pers. comm. in Fransen 1986). Also, the optical photo published by Cook (1967, pl. 1E) is of very poor quality. We believe that the specimens above mentioned (stored at the Natural History Museum, London, and Zoological Museum, University of Copenhagen) belong to different species and require careful re-examination. Later Cook (1985) again reported E. antillea from Ghana, two specimens of which she illustrated using SEM. These both differ significantly from the holotype of E. antillea, in fact we believe that there are two different species included in her paper. The first specimen seen (Cook 1985, pl. 15, fig. a) shows (in contrast with a holotype) the orifice wider proximally than distally and with fewer frontal foramina merged in short ‘chains’ (similar to E. pumicosa from the Caribbean, see below). The Figure 38 also demonstrates the spine-like processes on the peristome of the “typical” form that are reminiscent those in E. vierai from Brazil (see below). The second specimen shown, the so-called “cribrimorph form” (Cook 1985, pl. 15, fig. b), has a characteristic radial series of foramina with fused rims (see Tilbrook 2006). Whilst neither of these specimens can be attributed to E. antillea sensu stricto both should be restudied and compared with those described by Cook (1967) from Ghana earlier. Cook (1967), Dumont (1981) and Winston (1986) [based on Dumont’s paper] mentioned E. antillea in the Red Sea, but the analysis of the literature, illustrations and available specimens can not confirm this distribution (see discussions elsewhere in this paper). Hayward (1988) noted this species from Mauritian waters, but again this record devoid of the description and illustration, similar to the specimens described by Cook (1967, 1985), requires critical re-examination. Finally, Exechonella ‘antillea’ was recorded by Vieira (2008) and Vieira et al. (2008) in Brazilian waters; we attribute this material to a new species (see below). Distribution. Exechonella antillea has been attributed a wide distribution previously. However, our analyses have determined the presence of several morphologically distinct species, with geographically-limited distributions, within material formerly assigned to Osburn’s (1927) species. This species complex has been noted previously (Cook & Bock 2004), and is similar to that found in other genera with supposedly “well-known, widely- distributed” species (e.g. Tilbrook 1999; Harmelin 2006; Harmelin et al. 2012). Therefore, E. antillea s. s. is restricted in its distribution to the Caribbean. Exechonella pumicosa Canu & Bassler, 1928 (Fig. 9, Table 8) Exechonella pumicosa: Canu & Bassler 1928, p.70–71, pl. 14, fig 1, text fig. 11a. Phylactella labrosa: Osburn 1914, p. 213. ? Exechonella antillea: Winston 1982, p. 136, fig. 60. Material examined. Holotype: USNM 7838, encrusting on worm tube. Atlantic Ocean, Florida, Fowey Light, 15 miles south of Miami, depth 40 fathoms, November 1914, coll. by J.B. Henderson. Additional material examined: USNM 10127, Atlantic Ocean, Florida, Fowey Light, 15 miles south of Miami, depth 40 fathoms, November 1914, coll. by J. B. Henderson; USNM 545922, [Dry] Tortugas, depth 22 fathoms. Description. Colony encrusting, unilaminar, multiserial. Autozooids pentagonal in shape, longer than wide, separated by narrow grooves. Zooidal periphery surrounded by a narrow gymnocystal rim that is seen in most Zootaxa 4305 (1) © 2017 Magnolia Press · 25REVISION OF THE RECENT SPECIES OF EXECHONELLA zooids. Primary orifice wide, pear-shaped, almost as long as wide. Poster (one-third) narrower than anter (two- thirds), mostly of rounded outline, but tending to be more quadrate (angular) in some zooids. The anter wall is underlain by an inner lamina, the ends of which form well-defined mostly triangular condyles, with their points directed to the midline and extending beyond the edge of the step-like curve below. The collar-like peristome is thick-walled, oval or parallel-sided laterally, having the various width proximally, sometimes with low blunt processes. In most zooids the collar proximal edge is wide and flat, with a smooth medial area, but slightly wrinkled either side. In some zooids a tiny central (blunt or pointed) projection occurs on it. Frontal shield with 40– 62 well-separated, rounded or oval foramina, each with a wide, smooth gymnocystal rim, the walls raised slightly above the frontal shield and sloping towards the small lumen. Rims of most foramina fuse into ‘chains’ of 2–8, sometimes forming radiating pore rows known in cribrimorph cheilostomes. With age the foraminal rims occupy most of the frontal surface, leaving only narrow furrows between each other. Small marginal pores are predominantly oval and elongated. Avicularia not observed. Kenozooids with 3–5 pores were sometimes met on autozooidal margins. Vertical zooidal walls wide, represented by multiporous mural septula with 1–2 rows of communication pores. Ancestrula not observed. TABLE 8. Measurements (in µm, except number of foramina) of two specimens of Exechonella pumicosa Canu & Bassler, 1928. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. While being very similar, Exechonella pumicosa differs from E. antillea by thicker peristomes many of which have wide and flat proximal edge normally without a blunt projection. Also foraminal rims occupy most of the frontal surface in the former species, leaving only narrow furrows between each other. Many of them fuse forming ‘chains’ (linear or branching) of 3–7 foramina. In the latter species the frontal surface between foraminal rims is well seen and ‘fused’ foramina are not so numerous and ‘chains’ much shorter (2–3 foramina). In the studied specimens the number of frontal foramina ranges from 40 to 62 in E. pumicosa and from 34 to 52 in E. antillea. In addition, avicularia are not seen in the studied specimens of E. pumicosa (while a presence of these polymorphs is not a stable character). On the other hand, most of zooids are surrounded by a narrow raised ‘gymnocystal’ rim in this species whereas it is only rarely seen in E. antillea. It should be noted that different specimens from the Fowey Light show a varying degree of foraminal rim fusion, with most zooids predominantly having short chains of 2–3 zooids that are similar to E. antillea. Exechonella pumicosa was originally described by Canu and Bassler (1928b) from Miami, Florida, but subsequently it has been synonymized under E. antillea (e.g. Osburn 1940, 1950; Shier 1964; Winston 1982 and Fransen 1986). However, examination of the holotype of E. pumicosa using the SEM allows for the distinction between these two closely related species. Examination of the specimen USNM 545922 described as Phylactella labrosa by Osburn (1914) from Dry Tortugas, Florida, (and later synonymized by him with E. antillea, see above) showed numerous chains of the fused foramina in its zooids that points to E. pumicosa. The maximal number of foramina was 68 that also correspond more to this species than to E. antillea. Also, while kenozooids are present in this specimen, avicularia are missing. This specimen also shows the early developmental stages of the frontal shield with foramina being round elevated projections without a rim. In older zooids foraminal rims were aquired. With time becoming wider they eventually fuse. Florida, Atlantic Ocean m±sd r n AzL 798±61 714–900 8 AzW 639±73 529–757 8 OrL 194±18 171–214 8 OrW 192±14 171–214 8 FoN 47±7 40–62 8 FoD 49±8.4 25–65 34 OD 9±2.5 5–14 34CÁCERES-CHAMIZO ET AL.26 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 9. Exechonella pumicosa Canu & Bassler, 1928. Florida (A‒D: holotype USNM 7838, Atlantic Ocean, non-cleaned colony; E: USNM 10127, Atlantic Ocean; F‒G: USNM 545922, Caribbean Sea, non-cleaned colony). A‒B, general view of holotype from above. C‒D, close-up of autozooids showing shape of primary orifice. E, general view of old abraded colony from above. F, peripheral part of non-cleaned colony with young zooid forming frontal shield (in the centre) and kenozooid (arrow). G, zooidal orifice with partially broken operculum. Kenozooid (k) is seen in the right upper corner. Scale bars: A, B, E, F = 500 μm; C, G = 200 μm; D = 100 μm. Winston (1982), in her study of the Indian River area, Florida, described and illustrated a specimen (as Exechonella antillea) that in our opinion belongs to E. pumicosa although the foraminal luminae are larger than those in the holotype. The original description of E. pumicosa made by Canu and Bassler (1928b) mentions the presence of avicularia, but we did not observe them in the holotype. Winston’s (1982) figure 60 does not show avicularia either, although these polymorphs were mentioned in her description. In addition to three specimens from Florida we checked a non-numbered specimen from Bocas del Toro, Zootaxa 4305 (1) © 2017 Magnolia Press · 27REVISION OF THE RECENT SPECIES OF EXECHONELLA Panama (collected by K.J. Tilbrook and J.E. Winston in 2004, and currently kept in the Virginia Museum of Natural History, USA; authors possess four SEM-images) that strongly reminiscent a holotype of E. pumicosa. However, in comparison with the holotype it has a smaller zooidal size and larger foramina. It also possesses avicularia on the wall of two lateralmost foramina, which are larger than the rest of the foramina. It should be noticed that avicularia were predominantly seen in the peripheral zooids in this specimen that might explain their absence in the holotype of E. pumicosa. More material from Panama is required to make a definite conclusion if this specimen could belong to the new species or not. Distribution. Exechonella pumicosa is currently known only from Dry Tortugas, Gulf of Mexico, and Atlantic side of Florida, USA. Exechonella californiensis n. sp. (Fig. 10, Table 9) Exechonella antillea: Osburn 1950, p. 95–96, pl. 10, figs 9–10. Material examined. USNM 10741. Pacific Ocean, Gulf of California, 24° 22’ 15” N, 110° 19’ 15” W. Albatross Station D.2825, depth 7 fathoms, 30 April 1888. Etymology. Named after the Gulf of California, where the species has been found. Description. Colony encrusting, unilaminar, multiserial. Autozooids pentagonal or hexagonal in shape, often with a narrow gymnocystal rim, separated by grooves. Prominent slits are also seen between some zooids. Primary orifice wide pear-shaped, almost as long as wide, poster (one-third) tending to be quadrate (angular), anter (two- thirds) with a rounded outline. The anter has an inner lamina which ends at well-defined, usually ‘boot’-shaped (triangular) condyles with rounded tip directed to the orifice midline, and normally not extending beyond the edge a step-like curved area below. Collar-like peristome low, thin-walled, pustulose externally with short blunt processes in some zooids. It is normally oval, but often parallel-sided laterally, low, flat and rather narrow proximally. Proximal edge of the orifice straight or slightly concave. Frontal shield smooth or slightly pustulose, perforated by 28–35 well-separated rounded or oval foramina, each with a wide smooth (often wrinkled) gymnocystal rim, raised slightly above the frontal shield and sloping towards the small central opening; fusions between the rims of two foramina occasionally seen in some zooids. Small marginal pores are predominantly oval. Avicularia not observed. Kenozooids of various shapes and sizes and with 3–8 pores are often met near lateral and/ or proximal autozooidal margins. Ancestrula not observed. TABLE 9. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella californiensis n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Originally this species was described by Osburn (1950) from the Gulf of California, Pacific Ocean, as E. antillea (see above). The differences between the holotypes of these two species are the following: (1) primary orifice in the Californian material is almost as wide as long (224×222 µm), but it is longer than wide (210×198 µm) in the Atlantic material; (2) in the Gulf of California specimen the proximal orificial edge is straight California, Pacific Ocean m±sd r n AzL 894±78.7 729–1000 9 WzL 639±33.5 571–683 10 OrL 224±24.2 190–260 9 OrW 222±12.3 200–240 9 FoN 31±2.02 28–35 12 FoD 63.12±7.24 42–73 25 OD 26.52±4.45 20–35 25CÁCERES-CHAMIZO ET AL.28 · Zootaxa 4305 (1) © 2017 Magnolia Press or slightly concave, but in the Curaçao material it has a small knob-like central projection; (3) the peristomial rim bears blunt projections in some zooids in the Californian material, whereas it is smooth in E. antillea; (4) zooids in the Californian specimen have 28–35 frontal shield foramina and fusions of the foraminal rims are infrequent, however in the holotype of E. antillea some 34–52 frontal shield foramina were seen, and fusions of the foraminal rims are common; (5) ‘gaps’ or slits between the frontal shields of the neighbouring zooids are common in E. californiensis n. sp. specimen whereas they are absent in the Caribbean one (these slits are reminiscent of the ‘pits’—in fact, not fully-formed parts of the frontal shield—observed in the species of E. ampullacea-complex); (6) no avicularia have been seen in the material from California thought they are present in the E. antillea holotype specimen. Instead, kenozooids are very abundant in the E. californiensis n. sp. holotype specimen. Considering all these differences an existence of two separate species seems obvious. Distribution. The present species is currently known from the Gulf of California only. FIGURE 10. Exechonella californiensis n. sp. Pacific Ocean, California (A‒D: holotype USNM 10741, non-cleaned colony). A, general view of holotype from above. B‒C, close-up of autozooids showing shape of primary orifice and kenozooids (k). D, zooidal orifice with removed operculum. Scale bars: A = 500 μm; B‒D = 200 μm. Exechonella vieirai n. sp. (Fig. 11,Table 10) Exechonella antillea: Osburn 1940, p. 366–367; Souza 1989, p. 498; ? Rocha 1995, p. 75; Vieira 2008, p. 82–83, pl. 19, figs a– c; Vieira et al. 2008, p. 24; Almeida et al. 2015, p. 4. Zootaxa 4305 (1) © 2017 Magnolia Press · 29REVISION OF THE RECENT SPECIES OF EXECHONELLA Exechonella sp.: Winston et al. 2014, p. 191, fig. 32. Material examined. Holotype: DPUV 2016-0001-0001, eight fragments of the same colony (three fragments mounted on the SEM stub uncoated, five fragments in 70% alcohol). Atlantic Ocean, Brazil, Alagoas, Francês, depth 1 m, 19 March 2003. Other material studied: USNM 545921, Caribbean Sea, ‘Porto Rico’=St. 2385, off Point Brea, near the mouth of Guanicha Harbor, depth 8 fathoms, 1915. UFBA 366, one fragment. Atlantic Ocean, Brazil, Bahia, Salvador, Itapu, 12° 57´ S, 38° 21´ W, intertidal, on rocks, March 2012 (image provided by A.C.S. Almeida). Etymology. Named after Dr. Leandro Manzoni Vieira, who was the first to recognize this species as new. Description. Colonies encrusting, unilaminar, multiserial. Autozooids hexagonal to oval in shape, with distinct gymnocystal rim, separated by narrow grooves. Primary orifice subcircular. Poster with rounded (sometimes, more angular) outline, slightly smaller, almost as wide as the anter. Anter wall underlain by an inner lamina which ends form well-defined triangular condyles, with their blunt points directed to the orifice midline and slightly extending beyond the edge of step-like curve below. The collar-like peristome wide, subcircular, sometimes with parallel lateral sides. Its lowest proximal part with a small blunt projection and wrinkled lateral sides. In some colonies zooidal peristomes can bear 4–7 flat pointed processes. Frontal shield flat to slightly convex, perforated by 28–52 foramina (that occupy most of the frontal shield), each with wide and flat gymnocystal rim (often with wrinkles), raised slightly above the frontal shield which is smooth. Fusions between 2–3 foraminal rims are frequent. Marginal pores rounded or elongated, 1–2 most proximal ones are the largest. Avicularia are present on the outer raised wall of the 1–2 larger lateralmost foramina in some zooids. Each avicularium has a central nipple-like structure with a central pore. Kenozooids are very small, having 3–4 pores with centrally perforated cuticular plate. Vertical zooidal walls wide, represented by multiporous mural septula with 1–2 rows of communication pores. Ancestrula autozooidal, with foramina less closely spaced than in ordinary zooids. TABLE 10. Measurements (in µm, except number of foramina) of the holotype of Exechonella vieirai n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Vieira (2008) and Winston et al. (2014) described and illustrated E. vieirai n. sp. (as E. antillea and Exechonella sp. correspondingly) from the coastal waters of Brazil (with zooids having 40–53 and 45–60 foramina correspondingly). Other mentions of this species (also as E. antillea) were found in Souza (1989), Rocha (1995), Vieira et al. (2008) and Almeida et al. (2015), and Dr Vieira kindly informed us about the identity of these records (pers. com. 2016). Comparison shows that the orifice shape in this species is sub-circular with anter and poster of about the same size and with round outline (although the poster outline can be more angular in some zooids). Instead the poster (one-third) has angular outline and it is narrower than the anter (two-thirds) in E. antillea. The peristome is mainly subcircular in E. vieirai n. sp. although some zooids have its lateral sides parallel as in E. antillea. In E. vieirai n. sp. frontal foramina are closely spaced with wide and flattened gymnocystal rim, whereas Alagoas, Atlantic Ocean m±sd r n AzL 856±110 634–1096 14 AzW 695±55.34 609–789 14 OrL 222±24.4 166–262 14 OrW 211±19 176–237 14 FoN 41±6.2 28–52 12 FoD 75±15 49–105 60 OD 30±8.3 20–48 60 AncL 795 – 1 AncW 393 – 1CÁCERES-CHAMIZO ET AL.30 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 11. Exechonella vieirai n. sp. (A‒F: DPUV 2016-0001-0001, Atlantic Ocean, Brazil; G, H, USNM 545921, Caribbean Sea, Puerto Rico). A, B, general view of two holotype fragments from above. Some lateral foramina with avicularia shown by arrows. C, D, primary orifices of different shape. E, close-up of two zooids on fragment periphery. Lateral foramen with avicularium shown by arrow. F, close-up of the above foramen with avicularium (foraminal lumen obstructed by a dust particle). G, general view of the colony from above. H, close-up of zooid showing details of primary orifice and peristome. Scale bars: A = 1 mm; B, G = 500 μm; C, D, H, = 200 μm; E = 400 μm; F = 50 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 31REVISION OF THE RECENT SPECIES OF EXECHONELLA it is more narrow and sloping towards the opening in E. antillea. Also gymnocystal rim around zooidal periphery is poorly developed in the latter species whereas it is distinct in the former. Noteworthy, closely spaced foramina in E. vieirai n. sp. are similar to those in E. pumicosa, however, they do not form chains as in the latter species. Morphological plasticity between the colonies Exechonella vieirai n. sp. is seen when observing peristomes. In some colonies only few zooids have pointed processes on them, whereas in others all zooids have these processes, including ancestrula. There are also colonies having no processes on the peristomes at all or they could very low (Vieira, pers. comm. 2016). Examination of the specimen USNM 545921, described by Osburn (1940) as E. antillea from ‘Porto Rico’ (and also mentioned in his 1927 paper) revealed that it belongs to E. vieirai n. sp. Distribution. Colonies encrusting stones. Exechonella vieirai n. sp. is currently known from Brazil, south- west Atlantic Ocean, and from Puerto Rico, Caribbean Sea. Exechonella floridiana n. sp. (Fig. 12, Table 11) Material examined. Holotype: USNM 545918, encrusting a shell-hash concretion. Atlantic Ocean, Walton Rocks, South Hutchison Island, St. Lucie County, Florida, coll. 99–11, 1999, by Dr. J.E. Winston. Etymology. Named after the Florida Peninsula, where the species has been found. Description. Colony encrusting, unilaminar, multiserial. Autozooids pentagonal, hexagonal or oval in shape, separated by narrow grooves. Narrow marginal gymnocystal rim is seen in some zooids. Primary orifice sub- circular, almost as long as wide, poster (one-third) smaller than the anter (two-thirds), both of rounded/oval outline. Anter wall underlain by an inner lamina which ends form triangular condyles, with their blunt points slightly extending beyond the edge of step-like curve and directed to the orifice midline. A low thick-walled peristome is slightly longer than wide when seen from above. Its proximal part wide and flat, with a smooth central area and wrinkled lateral sides. Frontal shield smooth, perforated by 29–40 rather closely spaced foramina, each with wide and smooth gymnocystal rim raised slightly above the frontal shield, towards a small central opening. Fusions between the rims of 2–4 foraminal rims are frequent. Marginal pores are mostly oval and elongated. Avicularia are present on the outer raised rim of two larger lateralmost foramina that frequently have two openings. Each avicularium has a thin round mandible and the central nipple-like structure underneath. Kenozooids with 2–3 pores closed by cuticular plate. Vertical zooidal walls narrow or wide, represented by multiporous mural septula with 1– 2 rows of communication pores. Ancestrula is unknown. TABLE 11. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella floridiana n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Exechonella floridiana n. sp. is characterized by its primary orifice subcircular, with the poster (one-third) slightly smaller than the anter (two-thirds), both of rounded outline. Peristome is low and thick-walled with its proximal part wide and flat. Avicularia frequently have two openings. Also the general proportion between South Hutchison Island, Florida, Atlantic Ocean m±sd r n AzL 774±68 712–879 10 AzW 580±53 515–682 11 OrL 223±7.6 205–227 11 OrW 217±10 197–227 11 FoN 40±3.6 29–40 11 FoD 56±7 40–70 40 OD 19±4.2 10–30 40CÁCERES-CHAMIZO ET AL.32 · Zootaxa 4305 (1) © 2017 Magnolia Press the length of the orifice and that of the frontal shield shows a relation of 1:1–1.5 in E. floridiana n. sp. and 1:2 in the rest of the species from the E. antillea-complex. FIGURE 12. Exechonella floridiana n. sp. Atlantic Ocean, Florida (A‒D: holotype USNM 545918, non-cleaned colony). A, general view of holotype from above. B, close-up of autozooid with two avicularia (arrowheads) associated with lateralmost foramina. Details of primary orifice are visible (operculum removed). C, close-up of autozooid with two avicularia (arrowheads) associated with lateralmost foramina. Each lateral foramen has two openings. D, lateralmost foramen with avicularium and two openings. Scale bars: A = 500 μm; B = 200 μm; C = 100 μm; D = 50 μm. Dr. Winston kindly sent us the colony from her collection made in Florida that was originally identified and labeled as E. antillea. The comparison of this specimen with the holotype of E. antillea showed that it is a new species. Its orifice poster is of almost the same width as the anter, while poster is clearly narrower in E. antillea. The proximal edge of the peristome in the latter species is rather narrow with a small knob-like projection, and it is wide and flat in E. floridiana n. sp. It also shows a peculiar ‘avicularian’ foramina that often possess two openings that are not covered with a mandible. In contrast, avicularia-bearing foramina in E. antillea possess only one opening that is often covered by the rounded mandible. Exechonella floridiana n. sp. is also strongly reminiscent E. pumicosa by its peristome shape. Comparison with the holotype showed that the former species has less foramina (29–40) per zooid with larger openings of 19 µm in average whereas there are 40–62 foramina of just 9 µm in the latter species. Also, the foraminal rims seem to fuse more often, making longer ‘chains’ of foramina in E. pumicosa. Distribution. Exechonella floridiana n. sp. was found in the Atlantic Ocean, off the Walton Rocks, South Hutchison Island, St. Lucie County, eastern coast of Florida. Zootaxa 4305 (1) © 2017 Magnolia Press · 33REVISION OF THE RECENT SPECIES OF EXECHONELLA Exechonella panamensis n. sp. (Fig. 13, Table 12) Exechonella antillea: Hughes & Jackson 1992, p. 453. Exechonella antillea: Winston 1986, p. 19, fig. 40. Material examined. Holotype: USNM 545919, on a piece of coral. Caribbean Sea, San Blas Archipelago, Holandes Cays, depth 15–20 m, collected between July 1987 and May 1988 (Hughes & Jackson 1992). FIGURE 13. Exechonella panamensis n. sp. Caribbean Sea, San Blas Archipelago (A‒F: holotype USNM 545919). A‒D, general view of holotype from above. In B and D some avicularia associated with lateralmost foramina shown by arrows. E, F, close-up of autozooids showing shape of primary orifice. Avicularia shown by arrowheads. Scale bars: A, C = 1 mm; B, D, = 500 μm; E, F = 200 μm.CÁCERES-CHAMIZO ET AL.34 · Zootaxa 4305 (1) © 2017 Magnolia Press Etymology. Named after the Isthmus of Panama, near which coast this species has been found. Description. Colony encrusting, unilaminar, multiserial. Autozooids hexagonal or sometimes oval in shape, separated by well-defined narrow grooves. Zooidal periphery surrounded by a narrow gymnocystal rim. Primary orifice suboval, wider than long, poster (one-third) predominantly with angular outline, slightly narrowing proximally. Anter (two-thirds) with rounded outline, its wall underlain by an inner lamina which ends form tiny condyles, rounded or triangular. Step-like curved area below condyles ill-defined. A low peristome, narrow-walled, with 5–7 long, thin hollow spikes, proximally forming smooth and flat band. Typically there six spikes in a peristome, three distal, slender, and two lateral and one mid-proximal that are more robust. Lateral and proximal spikes bifurcate in some zooids. Frontal shield smooth, perforated by 56–67 closely spaced foramina, each with wide and smooth gymnocystal rim with walls slightly above the frontal shield and slightly sloping towards a central opening. Fusions between foraminal rims of 2–4 (up to 5) are frequent. Ten to 23 long, thin and hollow spikes, mostly straight, but some slightly curved, arise from foraminal rims, often where they fuse with each other. Marginal pores are mostly oval and elongated. Small nipple-like conic avicularia are present on the outer raised rim of two lateralmost foramina. Gymnocystal rim of such foramina bears a thin spike. Kenozooids were not seen. Vertical zooidal walls wide, represented by multiporous mural septula with 2–3 rows of communication pores. Ancestrula is unknown. TABLE 12. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella panamensis n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. For the first time this species was illustrated by Winston (1986) (as E. antillea). Exechonella panamensis n. sp differs from the other species of E. antillea-complex by its hollow spikes (projections) that arise from the foraminal rims on the frontal wall and also around the peristome, as well as by its small condyles. Distribution. At present, the species has been recorded in Caribbean Sea, San Blas Archipelago, near Panamanian coast, and Río Bueno, Jamaica. Exechonella harmelini n. sp. (Fig. 14, Table 13) Exechonella antillea: Hayward 1974, p. 377, fig. 4c. Exechonella cf. antillea: Harmelin et al. 2016, pp. 422, 424, fig. 4c. Exechonella antillea: Sokolover et al. 2016, p. 448, fig. 8. Material examined. Holotype: DPUV 2016-0002-0001, Mediterranean Sea, Lebanon, Selaata, depth 21 m, cave, 14 September 2002 (mounted on SEM stub, uncoated). Paratypes: DPUV 2016-0002-0002, Mediterranean Sea, Lebanon, Selaata, depth 21 m, cave, 14 September 2002 (mounted on SEM stub, uncoated). Three fragments on the same SEM stub: DPUV 2016-0002-0003 (two fragments of the same colony, on coral with barnacle), DPUV 2016- 0002-0004, Mediterranean Sea, Lebanon, Tripoli, Ramkine Island, depth 13 m, 22 October 1999; DPUV 2016- 0002-0005, Mediterranean Sea, Lebanon, Tripoli, Ramkine Island, cave, depth 5–7 m, 31 May 2000 (mounted on SEM stub, uncoated). Other material examined: IPUW 7537, four colonies, on polychaete tubes and coralline San Blas Archipelago, Caribbean Sea m±sd r n AzL 1202±123.4 955–1499 15 AzW 1009.2±110.7 706–1156 15 OrL 270±17 242–302 20 OrW 368±21.1 305–397 20 FoN 61±4.0 56–67 10 FoD 110±10.4 85–139 36 OD 39±6.15 28–54 36 Zootaxa 4305 (1) © 2017 Magnolia Press · 35REVISION OF THE RECENT SPECIES OF EXECHONELLA algae. Mediterranean Sea, Lebanon, Selaata, depth 32–35 m, overhang-drop off, 24 September 2002; IPUW 7538, eight fragments, on coralline algae. Mediterranean Sea, Lebanon. Turkey Kas, Canyon Cave, depth 18 m, 27 September 2004; IPUW 7539, two fragments (one growing on bryozoan colony). Mediterranean Sea, Lebanon, Tripoli, Ramkine Island, depth 13 m, 22 October 1999; IPUW 7540, one colony (on barnacle) and three fragments. Mediterranean Sea, Lebanon, Tripoli, Ramkine Island, cave, depth 13 m, 31 May 2000: IPUW 7541, seven fragments, detached and on polychaete tubes. Mediterranean Sea, Lebanon, Selaata, depth 21 m, cave, 14 September 2002; IPUW 7542, two colonies, on bivalve shell. Mediterranean Sea, Lebanon, Selaata, depth 21 m, cave, 14 September 2002. Etymology. Named after Dr. Jean-Georges Harmelin who collected this species. Description. Colony encrusting, unilaminar, multiserial. Those living on small substrata can form whorls (both, clock- and anticlockwise) resulting in 2–3-layered colonies. Autozooids hexagonal or oval in shape, flat, separated by well-defined narrow grooves. Narrow marginal rim is seen between zooids. Primary orifice wide, pear-shaped, longer than wide, poster (one-third) smaller than the anter (two-thirds), rounded or, occasionally, tending to be more quadrate. Anter of rounded outline with an inner lamina which ends at well-defined triangular condyles, their tips directed to the orifice midline, usually extending beyond the edge a step-like curved area beneath. In some zooids the condyles flattened or swollen. A low, smooth, thick-walled peristome, most prominent laterally, slightly longer than wide, oval or with parallel lateral sides. Proximal part is wider than its distal part or has about the same width, but it is narrower in some zooids. Its medial area smooth, but wrinkled either side. Small central blunt projection was observed in many instances. Frontal shield smooth, perforated by 44–67 well- separated rounded or oval foramina, each with a wide smooth (often wrinkled) gymnocystal rim, raised slightly above the frontal shield and sloping towards the small central opening; fusions between the rims of 2–5 foramina are common. Small marginal pores are predominantly oval and well-seen around the zooid. Lateral avicularia are present on the outer raised rim of the two lateralmost foramina. Each avicularium has a central nipple-like structure with a central pore. A thin round mandible closes the lumen of the foramen. Adventitious kenozooids with 2–5 pores, each with centrally perforated cuticular plate. At least some kenozooids associated with avicularia. Vertical zooidal walls wide, represented by multiporous mural septula with 2–3 rows of communication pores. Ancestrula autozooidal. TABLE 13. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella harmelini n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Hayward (1974) described and illustrated this species (as Exechonella antillea) from Chios, Aegean Sea. His figure 4c shows a specimen, having a wide peristome and more rounded orifice. Recently, Harmelin et al. (2016, fig. 4c) published the SEM photo of Exechonella specimen (as E. cf. antillea) from the Lebanese coast that is strongly reminiscent the specimen from Chios. Finally, we obtained several SEM photos of two colonies of the same appearance from the Israeli coast (courtesy of Dr. N. Sokolover, Tel Aviv University). One of these colonies having ancestrula was recently illustrated (as E. antillea) (Sokolover et al. 2016, fig. 8). It should be also noticed that foraminal ridges cover almost entire frontal surface in three left zooids (as if they would fuse, while tiny furrows still separate them) in the illustrated colony from Israel thus making an appearance of the frontal shield quite unusual. Most zooids have typical appearance, however. Lebanon, Mediterranean Sea m±sd r n AzL 980±99.2 872–1246 17 AzW 682±70 593–845 17 OrL 273±19.7 247–308 15 OrW 261±12.0 240–285 15 FoN 55±8.3 44–67 17 FoD 60±12 41–84 36 OD 16±4 8–27 36CÁCERES-CHAMIZO ET AL.36 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 14. Exechonella harmelini n. sp. Mediterranean Sea, Lebanon (A, C, D, F: holotype DPUV 2016-0002-0001, non- cleaned; B, paratype DPUV 2016-0002-0002, non-cleaned; E, G, H, paratype DPUV 2016-0002-0005). A, B, general view of holotype and paratype from above. ‘Spiral’ pattern of zooidal budding is clearly visible. C, general view of the central part of non-cleaned holotype from above. D, E, close-up of autozooids with avicularia associated with lateralmost foramina (some shown by arrows). F, H, close-up of autozooid showing details of primary orifice and variability of its shape. Kenozooids (k) with pores having centrally perforated cuticular plate are visible in H. G, details of the frontal shields of two neighbour zooids showing lateralmost foramina (one with two openings) with avicularia (arrowheads). Scale bars: A, B = 2 mm; C = 1 mm; D, E = 500 μm; F, G = 200 μm; H = 300 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 37REVISION OF THE RECENT SPECIES OF EXECHONELLA Mediterranean E. harmelini n. sp. belongs to E. antillea species-complex and its closest relative is E. pumicosa from the Caribbean Sea. Both species have similar number of foramina in a frontal shield, but in E. pumicosa rims of most foramina fuse forming ‘chains’ of 2–8, while in E. harmelini n. sp. the fusion of 2–3, in some case 5 rims were recorded. Mediterranean specimens have bigger zooidal size (980×682 µm) than colonies from Florida (798×635 µm). Also in six colonies of E. harmelini n. sp. the characteristic astogenetic pattern has been recorded resulting in the formation of “whorls” on the surface resulting in multilayered colonies. Finally, in three studied colonies of E. pumicosa no avicularia were found. While this character can not be used as a reliable (see above), and all other species of E. antillea species-complex have these polymorphs, we decided to mention it. Noteworthy, Hayward (1974) described and figured small rounded avicularia with a central cross-bar in this species. The latter is a misinterpretation of the presence of two closely situated openings, one of the nipple-like structure and the other of the avicularium-bearing foramen. Distribution. The present species is known from Chios, Aegean Sea, and coasts of Lebanon and Israel, east Mediterranean. Exechonella brasiliensis species-complex Exechonella brasiliensis Canu & Bassler, 1928 (Fig. 15, Table 14) Exechonella brasiliensis: Canu & Bassler 1928a, p. 72, pl. 3, fig. 5; Vieira et al. 2008, p. 24. Not Exechonella brasiliensis: Winston & Heimberg 1986, p. 15, figs 26–27; Winston 1986, p. 19; Tilbrook et al. 2001, p. 65, fig. 8g. Material examined. Holotype: USNM 8547, encrusting on rock. Atlantic Ocean, Brazil, Bay of Bahia, Norseman St. 320, 1876, coll. by Rathbun. Other material examined: USNM 8580, encrusting on rock. Atlantic Ocean, Brazil, Bay of Bahia, Norseman St. 343, Plataforma, 1876, coll. by Rathbun; USNM 8581, encrusting on rock. Atlantic Ocean, Brazil, Bay of Bahia, Periperi, Norseman St. 335, 1876, coll. by Rathbun; USMN 8582. Atlantic Ocean, Brazil, Bay of Bahia, Norseman St. 326, 1876, coll. by Rathbun. Description. Colonies encrusting, unilaminar, multiserial. Zooids pentagonal, hexagonal or oval, some with a narrow gymnocystal rim, separated by a narrow groove. Primary orifice pear-shaped or subcircular, longer than wide, poster (one-third) narrower and more angular than the anter (two-thirds) of a more rounded outline; anter wall underlain by an inner lamina the ends of which proximally form well-defined, usually ‘boot’-shaped (triangular) condyles with pointed or rounded tip, extending slightly beyond the edge of the step-like curved area below. Operculum light brown in dry non-cleaned material. A low, smooth, collar-like peristome, most prominent laterally, sometimes slightly flared, oval or with parallel lateral sides; peristome edge even or sometimes waved, its proximal edge low and flat or, incidentally, with low, central, blunt projection. Frontal shield convex, smooth, evenly covered with 12–33 round or oval, sometimes angular, well-separated foramina with very large lumen, each with a relatively narrow raised rim of smooth or wrinkled gymnocyst. Foraminal rims widen during ontogeny, but fusions between them are rare. Incidentally, a short spike is formed on the gymnocystal rim in some foramina. Rims of lateral foramina often fused with the marginal gymnocystal rim thus making the zooidal outline zigzag- like. Marginal pores are small, and often overshadowed by the wide rims of neighbouring frontal foramina. One or two lateral avicularia seen in many zooids, situated on the outer edge (often raised, reminiscent an ear) of lateralmost foramina; these foramina are comparable in size with the other foramina. Each avicularium is represented by a shallow depression with a central nipple-like elevation (thin-walled conical or cylindrical) with a central pore, pointing frontally or tilted. In non-cleaned specimens the nipple is covered with a thin cuticular mandible, oval in shape, frequently shrinking in dried material. Vertical zooidal walls wide, represented by multiporous mural septula with one row of communication pores. Kenozooids and ancestrula are unknown. Remarks. Exechonella brasiliensis is characterized by its low, smooth, collar-like peristome and frontal shield evenly covered with very large, round or oval, well-separated foramina. Originally described from the Atlantic coast of Brazil, Exechonella brasiliensis has since been mentioned from the Indian Ocean, Indonesia, Komodo Island (Winston & Heimberg 1986; Winston 1986), the Pacific Ocean, Vanuatu Archipelago (Tilbrook et al. 2001) and Atlantic Ocean, Brazil, Bay of Bahia (Almeida et al. 2015). WhileCÁCERES-CHAMIZO ET AL.38 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 15. Exechonella brasiliensis Canu & Bassler, 1928. Atlantic Ocean, Brazil (A‒E: holotype USNM 8547; F‒H: USMN 8582). A, C, D, general view of holotype from above. B, close-up of autozooid, showing shape of primary orifice; E, close-up of frontal shields with two foramina bearing avicularia (arrowheads). F, view of central part of colony from above (some lateralmost foramina with avicularia shown by arrows). G, close-up of autozooid showing shape of primary orifice and lateralmost foramina with avicularium (arrowhead). H, close-up of lateralmost foramina with avicularium. Scale bars: A, B, E = 100 μm; C, D, G = 200 μm; F = 500 μm; H = 50 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 39REVISION OF THE RECENT SPECIES OF EXECHONELLA we consider the specimen from Vanuatu to be E. similis n. sp. (see below), specimens from Komodo and Bay of Bahia should be checked to establish the species identity. TABLE 14. Measurements (in µm, except number of foramina) of Exechonella brasiliensis Canu & Bassler, 1928. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Comparison of published illustrations and recently collected material from Lizard Island (described below as E. similis n. sp.) with the material of Canu and Bassler (USNM) revealed several differences between specimens from different localities: (1) the primary orifice in E. brasiliensis is almost as long as wide, whilst on average it is wider than long in the specimens from Komodo, Vanuatu and Lizard Island; (2) while the poster is angular and narrower than the anter in most zooids of E. brasiliensis, it has the same width with a rounded outline in colonies from Komodo and Pacific; (3) the condyles are less prominent in the Indo–Pacific specimens; (4) in some zooids of E. brasiliensis the proximal border of the peristome bears a small blunt projection, but it is far more common and more prominent in the Indo–Pacific material; (5) whilst the range in foramina number is similar between the localities (12–33 in Brazil, 14–19 in Komodo, 16–23 in Vanuatu and 21–36 in Lizard Island), the average diameter of the lumen differs—almost 2.4 times larger in the holotype than in the specimen from Komodo (63 µm vs 26 µm), 1.6 times that of the specimen from Vanuatu (63 µm vs 39 µm) and 1.7 times of the specimens from Lizard Island; (5) the foramina with avicularia are normally larger than those without them in the Indo–Pacific material, and they are easily distinguished, but they are of a similar size in E. brasiliensis; (6) in E. brasiliensis the kenozooids are not seen in the frontal view, whereas they are easily recognizable in the specimens from the Indo– Pacific; (7) finally, the marginal pores are obvious in the Indo–Pacific species, but in the Brazilian material they are frequently hidden by the rims of the nearest frontal foramina. These rims also often fused with the marginal gymnocystal rim of the zooid giving it the zigzag-like outline. Distribution. Exechonella brasiliensis was originally described from the Bay of Bahia, Brazil, south-west Atlantic Ocean. It has not been found in the Brazilian waters since its original description (Dr L. Vieira, pers. comm. 2016). Exechonella azeezi n. sp. (Fig. 16, Table 15) ? Exechonella brasiliensis: Winston & Heimberg 1986, p. 15, figs 26–27. Material examined. Holotype: DPUV 2012-0001-0001, on coral rubble. Red Sea, the Northern Bay of Safaga, south to Ras Abu Soma, depth 1–20 m, September 1992. Paratypes: DPUV 2012-0001-0002, DPUV 2012-0001- 0003, DPUV 2012-0001-0004, DPUV 2012-0001-0005, DPUV 2012-0001-0006, DPUV 2012-0001-0007, DPUV 2012-0001-0008 (two last specimens mounted on the SEM stubs and coated with gold), on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Other material examined: IPUW 7010, on coral, Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992; IPUW 7011, on living coral. Red Sea, the Northern Bay of Safaga, Sandy Island, 1 November 1984; IPUW Bay of Bahia, Atlantic Ocean m±sd r n AzL 874±123.5 654–1121 28 AzW 607.6±98.2 467–836 29 OrL 217±28.3 154–275 31 OrW 210±25 185–266 32 FoN 19±4.7 12–33 32 FoD 108±13.6 85–138.5 51 OD 63±10.9 34.6–88.5 145CÁCERES-CHAMIZO ET AL.40 · Zootaxa 4305 (1) © 2017 Magnolia Press 7012, five colony fragments. Red Sea, the Northern Bay of Safaga, 2 August 1987; IPUW 7013, on coral rubble (mounted on the SEM stub and coated with gold). Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, depth 10 m, 3 August 2009; IPUW 7543, on coral (mounted on the SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, west part of Safaga Island, transect A 5, depth 1–2 m, September 1992; IPUW 7544, IPUW 7545, on coral (mounted on the SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992; IPUW 7546, on bivalve shell (mounted on the SEM stub, uncoated). Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, House Reef, depth 5– 19 m, 12–13 January 2008. Etymology. Named after Mr. Abdul Azeez Abdul Hakeem, a prominent local environmentalist and educator, who has generously provided help to many scientists visiting the Maldives. Description. Colonies encrusting, unilaminar, multiserial. Zooids pentagonal, sometimes hexagonal or oval, separated by a narrow groove. Primary orifice subcircular, wider than long, poster narrower (one-third) than the anter (two-thirds), predominantly of rounded outline, but angular in some zooids. Anter wall underlain by an inner lamina the ends of which form triangular or oval elongated condyles, with pointed or rounded tips pointing medially and typically extending beyond a step-like curved area below. Peristome is low, collar-like, slightly flared, with a pustulose external surface, sometimes bearing low, pointed projections (seen in one colony), rounded or oval in outline, more often narrowing proximally or can be with parallel lateral sides; the proximal edge normally with a prominent central fold-like projection, with a blunt tip, frontally-directed. Frontal shield convex, predominantly pustulose, evenly covered with 13–35 circular or oval, well separated foramina, with a relatively narrow raised rim with a peripheral inner wall surface and smooth or slightly wrinkled gymnocystal sloping walls, surrounding a central lumen. Fusions between foraminal rims not common. Small round or oval marginal pores are obvious. Lateral avicularia are frequent, developing in either or both lateralmost foramina, which are larger than the rest of the foramina; each avicularium is situated on the outer (often raised) edge of a foramen obvious as a shallow depression (sometimes surrounded by a low rim) with a central button-like elevation with thick walls (sometimes cylindrical with thinner walls) and a central pore. In non-cleaned specimens the entire structure is covered with a thin oval operculum. Oval or triangular kenozooids are frequent (even budding from the ancestrula), often associated with avicularia, with a frontal surface bearing 6–8 small pores with centrally perforated cuticular plate. Ancestrula autozooidal, smaller than subsequent autozooids. Vertical zooidal walls wide, with multiporous mural septula with 1–3 rows of communication pores. TABLE 15. Measurements (in µm, except number of foramina) of specimens of Exechonella azeezi n. sp. from the Red Sea and the Maldives. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. It is worth noting that the colonies of Exechonella azeezi n. sp. from Safaga and Maldives differ slightly in the size of the orifice; it is larger in the Red Sea specimens (average 204×220 µm) than those from the Maldives (178×188 µm); also, although the frontal foramina have the same shape and distribution in both sets of material they are larger, on average, in the Red Sea than in Maldives (77 versus 50 µm). Northern Bay of Safaga, Red Sea Maldive Islands, Indian Ocean m±sd r n m±sd r n AzL 774±64.4 610–910 41 784±90.2 620–900 22 AzW 596±87.9 410– 850 41 581±81 400–670 22 OrL 204±24.6 160–300 41 178±15.7 150–200 22 OrW 220±20.5 180–260 41 188±15.7 160–210 22 FoN 24±4.4 18–31 29 28±8.6 13–35 13 FoD 78±9.1 55.1–100 92 50.4±4.8 42–58 14 OD 29.2±7.8 11.1– 57.1 214 20±5.2 11–32 20 AncL 556±50 500–596 3 657.2 579–735.3 2 AncW 379±82 318–472 3 459 432–485.3 2 Zootaxa 4305 (1) © 2017 Magnolia Press · 41REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 16. Exechonella azeezi n. sp. (A‒G: A, IPUW 7544; B, G, paratype DPUV 2012-0001-0008; C, IPUW 7543; D, IPUW 7545, non-cleaned; E, F, paratype DPUV 2012-0001-0007 (all from Red Sea). H, I: D, IPUW 7546; I, D, IPUW 7013 (both from Maldive Islands)). A, general view of the part of colony from above. B, close-up of three zooids. Some lateralmost foramina with avicularia shown by arrows. C, lateral view of the peripheral part of the colony, showing peristome shape and multiporous mural septula. D, lateralmost foramen with avicularium. Arrowhead shows an edge of mandible. E, close-up of lateralmost foramen with avicularium associated with kenozooid (below). Pores of kenozooid have centrally perforated cuticular plates, larger marginal pores are seen laterally. F, G, close-up of two autozooids showing details of primary orifice and peristome. In F kenozooid (k) associated with avicularium (arrowhead) is visible to the left. H, general view of six peripheral autozooids from above. Some lateralmost foramina with avicularium shown by arrows. I, young colony of three autozooids and kenozooid (below). Supposed ancestrula is to the left. Scale bars: A = 1 mm; B, C, F, G, I = 100 μm; D, E = 10 μm; H = 500 μm.CÁCERES-CHAMIZO ET AL.42 · Zootaxa 4305 (1) © 2017 Magnolia Press Exechonella azeezi n. sp. is very reminiscent the specimens described as E. brasiliensis by Winston and Heimberg (1986) from Indonesia, Komodo Island, by Tilbrook et al. (2001) from Vanuatu, and E. similis n. sp. from the Lizard Island, Great Barrier Reef (see below), in several major characters. These are pustulose texture of the frontal shield bearing similar number of foramina of the same shape and distribution pattern, as well as the shape of avicularia and their close association with kenozooids. The differences are (1) primary orifice is subcircular with poster of the same width as anter and rounded outline in all specimens above mentioned, except E. azeezi n. sp. where the poster is narrower than the anter and angular in some zooids; (2) the number of frontal foramina that are less numerous on average in the Indonesian (17) and Vanuatu (19) material in comparison with the Red Sea (24), Maldives (28) and Lizard Island specimens (27); (3) the average size of the foraminal lumen is more similar in the Red Sea (29 µm), Maldives (24 µm) and Komodo (26 µm) material in comparison with the material from Vanuatu (39 µm) and Lizard (34 µm). To note the autozooidal length is quite variable in all localities, from 610–910 µm (Red Sea), 620–900 µm (Maldives) and 620–760 µm (Komodo), 790–1010 (Vanuatu) to 667– 877 µm (Lizard Island). Tilbrook (2006, p. 115) mentioned two specimens—one from the Red Sea and another from the Seychelles, in the collection of the Natural History Museum, London, as “appears to be E. brasiliensis”. Whether they belong to E. azeezi n. sp. should be checked. Distribution. Being found encrusting both dead and living corals, Exechonella azeezi n. sp. has a distribution in the Red Sea (The Northern Bay of Safaga), and in the Indian Ocean (Maldives). Exechonella similis n. sp. (Fig. 17, Table 16) Exechonella brasiliensis: Tilbrook et al. 2001, p. 65, fig. 8g. ? Exechonella brasiliensis: Winston & Heimberg 1986, p. 15, figs 26–27. Material examined. Holotype: MTQ G100216, on coral rubble (mounted on SEM stub and coated with gold). Coral Sea, Great Barrier Reef, Lizard Island, Cobey Hole, depth 16 m, 8 October 2012. Paratypes: DPUV 2016- 0001-0002, DPUV 2016-0001-0003 (on bivalve shells, non-cleaned, mounted on SEM-stubs, uncoated). Coral Sea, Great Barrier Reef, Lizard Island, Watson Bay, depth 6.5 m, 4 October 2012. Etymology. The name given because of very close similarity of this species to E. azeezii n. sp. Derived from the Latin word “similis” (similar). Description. Colonies encrusting, unilaminar, multiserial. Zooids pentagonal or hexagonal separated by a narrow deep groove. Primary orifice almost subcircular, wider than long, poster as wide as the anter but slightly smaller in size, both predominantly of rounded outline. Anter wall underlain by an inner lamina that ends in the mid-lateral side, to form triangular or oval elongate condyles, with pointed or rounded tips extending medially and beyond the edge of the step-like curve below. Peristome is low, collar-like, slightly flared, with a pustulose external surface. The proximal edge of the peristome normally with a prominent or soft central fold-like projection. In the ancestrular area peristome could have up to four such projections, distal, proximal and two lateral. Frontal shield convex, pustulose, evenly covered with 21–36 circular or oval, well-separated foramina, with a relatively narrow raised rim with a peripheral inner wall surface and smooth or slightly wrinkled gymnocystal sloping walls, surrounding a central lumen. Fusions between foraminal rims are not common in most zooids. Small round or oval marginal pores are obvious. Vertical zooidal walls with multiporous mural septula with one row of communication pores. Lateral avicularia are frequent, developing in either or both lateralmost foramina, which are larger than of the other foramina; each avicularium is situated on the outer (often raised) edge of a foramen obvious as a shallower or deeper depression (sometimes surrounded by a low rim) with a central button-like elevation with thick walls (sometimes cylindrical with thin walls) and a central pore. Oval or triangular kenozooids are frequent, often associated with avicularia, with a frontal surface having 4–7 small pores each with centrally perforated cuticular plate. Ancestrula autozooid-like, smaller or the same size. Remarks. Exechonella similis n. sp. is reminiscent of E. azeezi n. sp. in most characters. The main difference between these two species is the shape of the primary orifice typically subcircular with the anter and poster having the same width in the former species, and the poster typically more angular and narrow in the latter species. Both E. similis n. sp and E. azeezi n. sp. differ from E. brasiliensis by the primary orifice that is wider than long, pustulose Zootaxa 4305 (1) © 2017 Magnolia Press · 43REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 17. Exechonella similis n. sp. Great Barrier Reef, Lizard Island (A: paratype DPUV 2016-0001-0002; F, G: paratype 2016-0001-0003; B‒E, H: holotype MTQ G100216). A, general view of non-cleaned colony from above. Peripheral zooidal buds with membranous frontal wall are well seen. Peristomes with processes are seen in some zooids in the central colony part. B, E, F, close-up of autozooids. Some lateralmost foramina with avicularia shown by arrows in B. C, peripheral part of the colony, showing peristome shape and multiporous mural septula. D, close-up of autozooid showing details of primary orifice and peristome. G, non-cleaned lateralmost foramen with avicularium. Arrowhead shows an edge of mandible. H, close-up of lateralmost foramen with avicularium associated with kenozooid in cleaned colony. Pores of kenozooid have centrally perforated cuticular plates. Scale bars: A = 1 mm; B‒E = 100 μm; F = 500 μm; G = 50 μm; H = 10 μm.CÁCERES-CHAMIZO ET AL.44 · Zootaxa 4305 (1) © 2017 Magnolia Press surface of the peristome and the smaller foramina, button-like shape of the central element of avicularium, and the larger size of the lateralmost foramina (with avicularium) in comparison with the rest of the frontal foramina. The specimen from Komodo described by Winston and Heimberg (1986) should be additionally studied for comparative purposes. Distribution. Exechonella similis n. sp. has a west Pacific distribution including the areas of Vanuatu and Lizard Island, Great Barrier Reef. TABLE 16. Measurements (in µm, except number of foramina) of holotype specimen of Exechonella similis n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Exechonella claereboudti n. sp. (Fig. 18, Table 17) Material examined. Holotype: DPUV 2012-0003-0001, on bivalve shell (mounted on SEM stub and coated with gold). Indian Ocean, Oman, Salalah, near Mirbat, maximal depth 8.3 m, 18 January 2009. Paratype: DPUV 2012- 0003-0002, on bivalve shell (mounted on SEM stub, uncoated). Oman, Salalah, near Mirbat (right side of the “Kelp Bay”), maximal depth 9.4 m, 16 January 2009. Etymology. Named after the marine biologist Dr. Michel Claereboudt who organized and led the dive works in Oman during which this species was collected. Description. Colonies encrusting, unilaminar, multiserial. Autozooids pentagonal, hexagonal or oval in shape, slightly convex, separated by narrow grooves. Orifice oval, wider than long. Larger anter rounded whereas smaller poster typically angular (quadrate-like with rounded 'corners') or shallow rounded in some zooids. Anter wall underlain by an inner lamina which ends form prominent triangular condyles, with pointed or, sometimes, rounded tip extending beyond the edge of the step-like curve below. Peristome low, collar-like, flared, with pustulose external surface. When seen from above it has oval outline, often wider proximally, and sometimes with parallel lateral sides. Peristome edge bears 3–5, long fold-like projections/spikes, 0–2 distal, two lateral and one proximal. Frontal shield smooth, evenly covered with 34–50 rounded and oval, closely spaced foramina bordered by a relatively wide raised rim with a peripheral inner wall surface and smooth or slightly wrinkled gymnocystal sloping walls, surrounding a central lumen. Fusions of foraminal rims are frequent, forming chains of 2–3 foramina. Marginal pores are easily observed all around zooidal periphery. Vertical zooidal walls wide, represented by multiporous mural septula with 1–3 rows of communication pores. Avicularia present in one or both larger lateralmost foramina of most zooids. They are represented by a depression surrounded by a low rim with a button- like central structure with a central pore. Kenozooids are frequent, associated with avicularia, having 6–11 pores with a centrally perforated cuticular plate. Ancestrula autozooidal, smaller than zooids of the first generation. Lizard Island, Great Barrier Reef m±sd r n AzL 778±52.8 667–877 17 AzW 618±70 526–825 17 OrL 189±10.8 168–200 7 OrW 201±5.8 195–210 7 FoN 27±6.3 21–36 9 FoD 78±6.1 64–86 20 OD 34±5 29–47 20 AncL 683 656–710 2 AncW 472 417–526 2 Zootaxa 4305 (1) © 2017 Magnolia Press · 45REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 18. Exechonella claereboudti n. sp. Indian Ocean, Oman (A‒H: holotype DPUV 2012-0003-0001). A, general view of holotype from above. B, peripheral part of holotype (frontal view): primary orifices have either quadrate or shallow rounded poster. C, lateral view of peripheral part of holotype showing shape of peristomes and multiporous mural septula. D, close-up of several peripheral autozooids. Some lateralmost foramina with avicularium shown by arrows. E, ancestrular zone of holotype with ancestrula in the centre. F, H, details of primary orifice with shallow rounded poster and peristome. G, close-up of lateralmost foramen with avicularium associated with kenozooid in cleaned colony. Pores of kenozooid have centrally perforated cuticular plates. Marginal pores are visible in this and neighbour zooids. Scale bars: A, B = 1 mm; C‒H = 100 μm.CÁCERES-CHAMIZO ET AL.46 · Zootaxa 4305 (1) © 2017 Magnolia Press TABLE 17. Measurements (in µm, except number of foramina) of Exechonella claereboudti n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Exechonella claereboudti n. sp. is reminiscent both E. azeezi n. sp. and E. similis n. sp. differing from them by (1) peristome, normally wider proximally than distally when seen from above, with long spike-like projections (distal, lateral and proximal) on its rim, whereas in E. azeezi n. sp. and E. similis n. sp. the peristome is often narrower proximally, usually having only one proximal central projection; (2) orifice shape with typically quadrate (less often shallow rounded) poster as wide as anter (in E. claereboudti n. sp.), typically rounded poster as wide as anter (in E. similis n. sp.) and typically angular poster narrower than the anter (in E. azeezi n. sp.) (some variation between angular and rounded outline of the poster present in all species); (3) number of frontal foramina 30–50 in E. claereboudti n. sp. (even in a young colony studied, the first zooidal generation, including ancestrula, has over 40 foramina), compared with 18–31 of E. azeezi n. sp. (Red Sea) and 13–35 (Maldives) and 21–36 in E. similis n. sp. The high number of the foramina also results in common fusion of their rims in the former species, but this was not common it two latter species. Distribution. Exechonella claereboudti n. sp. was only found in the Indian Ocean, Oman, Salalah, near Mirbat. Exechonella catalinae n. sp. (Fig. 19, Table 18) Material examined. Holotype: DPUV 2012-0002-0001, on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Paratypes: DPUV 2012-0002-0002, DPUV 2012-0002- 0003, DPUV 2012-0002-0004, on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Mounted on the SEM stubs and coated with gold: DPUV 2012-0002-0005, DPUV 2012-0002-0006, DPUV 2012-0002-0007, on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Other material examined: IPUW 7014 (zooidal fragments mounted on SEM stub, coated with gold). Red Sea, the Northern Bay of Safaga, station B 3/2, depth 4 m, sand between coral patches, 16 July 1987; IPUW 7015, on coral rubble. Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1– 20 m, September 1992; IPUW 7016, on coral (mounted on SEM stub, uncoated). Red Sea, Jeddah. Etymology. Named after the first author’s daughter Catalina López–Cáceres. Description. Colonies encrusting, unilaminar, multiserial. Autozooids pentagonal, hexagonal or oval in shape, separated by a narrow groove. Primary orifice oval, wider than long, with both anter (two-thirds) and poster (one- third) rounded. Poster sometimes bears tiny central elevation. Anter wall underlain by an inner lamina that is hardly seen in a frontal view. Lamina ends in the proximal one third of the orifice with a pair of small, predominantly triangular condyles, pointed to the midline of the orifice (or slightly proximally). Proximal part of primary orifice is Oman, Indian Ocean m±sd r n AzL 852±77.7 700–1030 36 AzW 633±54.7 550–770 29 OrL 206±10 190–220 29 OrW 234±13.3 215–265 29 FoN 42±3.8 34–50 21 FoD 63.3±6.2 45.5–76.4 86 OD 24.3±3.7 17.6–32.5 124 AncL 724 698–750 2 AncW 489 477–500 2 Zootaxa 4305 (1) © 2017 Magnolia Press · 47REVISION OF THE RECENT SPECIES OF EXECHONELLA limited by a flat calcified shelf that is a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome. Shelf is smooth centrally and with fine wrinkles laterally in most zooids. Peristome tubular, low, with pustulose surface and smooth, sometimes swelled, rim. Frontal shield smooth or pustulose, evenly perforated by 37–59 (Safaga) and 61–83 (Jeddah) closely-spaced, circular to subcircular foramina, each with wide and smooth gymnocystal rim; fusions of the rims of 2–6 foramina are frequent. Marginal pores small and rounded, easily observed around the autozooidal periphery. Vertical zooidal walls wide, represented by multiporous mural septula with 1–3 rows of communication pores. Two (sometimes one, rarely none) lateral avicularia are present in each zooid, being situated on the external edge of the rim of larger lateralmost foramina (sometimes also occuring in the proximal part of zooid). This part of the rim is often raised having a shape of pointed or blunt projection, and these foramina are the largest in a zooid. Avicularium consists of a shallow depression, sometimes surrounded by a low denticulate rim, with a central nipple-like (low cylindrical or conical) structure with a central pore. Oval or triangular adventitious kenozooids are frequently developed, being recognized by a 3–6 small pores with a centrally perforated cuticular plate. These are often associated with avicularia, but also present in the colonies when the avicularia are absent, and sometimes bud from the ancestrula. Ancestrula autozooidal, having the same size as the rest of autozooids. TABLE 18. Measurements (in µm, except number of foramina) of Exechonella catalinae n. sp. from the Northern Bay of Safaga and Jeddah. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. E. catalinae n. sp. differs from all other species described in this paper as having the largest zooidal size with the average zooidal length 1.05 mm (Safaga) and 1.20 (Jeddah), and reaching maximal length up to 1.23 mm in some zooids. Except E. elegantissima n. sp., E. nikitai n. sp. and E. kleemanni n. sp. (see below), all other species have the average zooidal length less than 1 mm, although some of them have maximal zooidal size 1 mm or more. To note, the species of Exechonella with the largest zooidal size are E. gigantea Cook, 1967 and E. loslosensis Tilbrook, 2006 having zooidal length 1.2‒1.6 mm and 1.4‒1.7 mm correspondingly. E. catalinae n. sp. has tubular peristome, primary orifice with flat shelf proximally surrounded by a wall of the peristome, small, predominantly triangular condyles and no step-like curved area below a condyle in the outline of the primary orifice. Together with large zooidal size all these characters are in common with the E. albilitus- complex (see below). However, the appearance of the foramina in E. catalinae n. sp. is more like some species of E. brasiliensis and E. antillea species-complexes. Other distinctive characters of E. catalinae n. sp. are a dentate (uneven) rim surrounding the nipple-like central structure and raised lateral rim with a blunt or pointed projection in avicularia-bearing foramina, seen in the most of autozooids. Similar projections we observed only in one colony of E. azeezi n. sp. (E. brasiliensis-complex) that otherwise have simple rim with raised lateralmost part. Northern Bay of Safaga, Red Sea Jeddah, Red Sea m±sd r n m±sd r n AzL 1057±54 1010–1200 12 1205±17.3 1190–230 4 AzW 831±104 540–960 15 865±97 740–970 4 OrL 244±34 200–310 13 253±15.3 240–270 3 OrW 293±34 240–340 13 333±40 290–370 3 FoN 47±7.7 37–59 18 69±6.48 61–83 12 FoD 90.6±9.6 71.4–114.3 76 74±0.01 55–95 43 OD 28.6±4.7 14.3–43 74 37±0.01 21–51 43 PeL 218±67.2 130–350 7 380 360–400 2 PeW 413±15 400–440 7 435 410–460 2 AncL 1114 ‒ 1 1102 ‒ 1 AncW 857 ‒ 1 551 ‒ 1CÁCERES-CHAMIZO ET AL.48 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 19. Exechonella catalinae n. sp. Red Sea (A, C, F: paratype DPUV 2012-0002-0006, Northern Bay of Safaga; B, D: E, paratype DPUV 2012-0002-0007, Northern Bay of Safaga; G, H: IPUW 7016, Jeddah). A, G, general colony view from above. B, close-up of two zooids showing details of primary orifice and peristomes. Three lateralmost foramina shown by arrows. C, D, lateral view of peripheral colony part showing shape of peristomes and multiporous mural septula. E, close-up of lateralmost foramen with avicularium associated with kenozooid in cleaned colony. Central nipple-like structure is surrounded by denticulate rim. Pores of kenozooid have centrally perforated cuticular plates. F, H, details of primary orifice and peristome. Scale bars: A, C = 1 mm; B, D‒F = 100 μm; G = 2 mm; H = 400 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 49REVISION OF THE RECENT SPECIES OF EXECHONELLA We suggest that some numerical differences between colonies from Safaga and Jeddah observed should be attributed to the ecophenotypic variability. Additional material from Jeddah is needed for making this suggestion more precise. Distribution. Colonies of E. catalinae n. sp. is found in the Red Sea, in Northern Bay of Safaga (western coast) and Jeddah (eastern coast). Exechonella albilitus species-complex Exechonella elegantissima n. sp. (Fig. 20, Table 19) Material examined. Holotype: DPUV 2012-0006-0001, on coral rubble (mounted on SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, west part of Safaga Island, transect A 5, depth 1–2 m, September 1992. Paratypes: DPUV 2012-0006-0002, DPUV 2012-0006-0003 (mounted on SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, station B 3/2, depth 4 m, 16 July 1987. Other material examined: DPUV collection, non-numbered small fragment (mounted on SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. MTQ G100214, on coral (mounted on SEM stub, uncoated). Coral Sea, Great Barrier Reef, Lizard Island, Pigeon Point, depth 8–10 m, 9 October 2012. Etymology. The species is named because of its delicate structure with specific elegant peristome and small and scattered foramina. Derived from the Latin word “elegans” (elegant). Description. Colonies encrusting, unilaminar, multiserial. Autozooids oval, separated by narrow deep grooves. Primary orifice oval, wider than long, with proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) with a tiny smooth central projection (sometimes missing in proximal zooids) and wrinkled lateral areas. Anter (distal half of primary orifice) is underlain by an inner lamina that is not visible in frontal view, and which ends form thick and rounded condyles pointed downwards or directed to the orifice midline. Peristome tubular, slightly pustulose externally. Its proximal edge forms a deep and wide U- shaped sinus. Frontal wall convex, gently pustulose, with 9–21 small and widely dispersed foramina. Each foramen is a small and short, cylindrical or conical tube with rounded or slit-like opening. Base of some tubes is surrounded by a ring-like elevated area. Marginal pores small and rounded. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in one row. Adventitious kenozooids with 3–5 pores having centrally perforated cuticular plate. Ancestrula and avicularia are unknown. TABLE 19. Measurements (in µm, except number of foramina) of specimens of E. elegantissima n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Northern Bay of Safaga, Red Sea Lizard Island, Great Barrier Reef m±sd r n m±sd r n AzL 1006±115.5 870–1210 7 1002±98.2 850–1125 14 AzW 744.3±123.7 600–970 8 741±114 480–938 14 OrL 199±34.1 160–240 7 183±11.3 167–194 4 OrW 228.6±38.9 180–290 8 254±9.5 244–264 4 FoN 14±3.2 9–18 6 15±2.6 10–21 13 OD 18±6 7–31 51 23±7.6 10–40 23 PeL 275±28.1 240–300 7 ‒ ‒ ‒ PeW 367±15.1 350–380 7 ‒ ‒ ‒CÁCERES-CHAMIZO ET AL.50 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 20. Exechonella elegantissima n. sp. (A‒E: MTQ G100214, Great Barrier Reef, Lizard Island; F, G, holotype: DPUV 2012-0006-0001, Northern Bay of Safaga). A, general colony view from above. B, C, group of autozooids showing details of peristomes and frontal shields. Two kenozooids shown by arrows in C. D, E, details of primary orifice and peristome. Condyle shown by arrow F, G, lateral view of peripheral colony part showing shape of peristomes and narrow multiporous mural septula. Scale bars: A = 1 mm; B‒G = 100 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 51REVISION OF THE RECENT SPECIES OF EXECHONELLA Remarks. E. elegantissima n. sp. is characterized by its primary orifice with a central projection on the proximal edge, tubular peristome with a deep and wide U-shaped sinus and foramina with a small and short, cylindrical or conical tube. E. elegantissima n. sp. is reminiscent E. albilitus Tilbrook, 2006. The main difference is the shape of the peristome that is cylindrical with flared edge in E. albilitus (also having a length 400 µm), and with a proximal sinus (275 µm in length) in E. elegantissima n. sp. The number of frontal foramina (which base is conical and opening 34 µm) ranges between 20 and 30 in the former species, whereas there are of 9–21 foramina developed in the latter, in which most foramina of 18 µm are tube-like without elevated basal area. The specimens from the Red Sea and Australia totally correspond to each other by both morphology and size. Distribution. Exechonella elegantissima n. sp. was found in the Red Sea, the Northern Bay of Safaga and in the Coral Sea, northeast Australia, Great Barrier Reef, Lizard Island. Exechonella nikitai n. sp. (Fig. 21, Table 20) Material examined. Five colonies on one piece of dead coral—Holotype: DPUV 2012-0007-0001. Indian Ocean, Maldive Islands, North Male Atoll, Kuda Haa, 04° 20' 914'' N, 073° 40' 778'' E, depth 8–35 m, 16 January 2008. Paratypes: DPUV 2012-0007-0002, DPUV 2012-0007-0003. Indian Ocean, Maldive Islands, North Male Atoll, Kuda Haa, 04° 20' 914'' N, 073° 40' 778'' E, depth 8–35 m, 16 January 2008. IPUW 7017, IPUW 7018, Indian Ocean, Maldive Islands, North Male Atoll, Kuda Haa, 04° 20' 914'' N, 073° 40' 778'' E, depth 8–35 m, 16 January 2008. Paratypes: DPUV 2012-0007-0004, on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, depth 10 m, 3 August 2009, DPUV 2012-0007-0005, on coral rubble. Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, House Reef, depth 5–19 m, 12–13 January 2008. Additional material examined: DPUV 2012-0007-0006, DPUV 2012-0007-0007, DPUV 2012-0007-0008, on coral rubble (mounted on SEM stubs and coated with gold). Indian Ocean, Maldive Islands, North Male Atoll, Vabbinfaru Island, House Reef, depth 5–19 m, 12–13 January 2008. IPUW 7019, Indian Ocean, Maldive Islands, North Male Atoll, Angsana Ihuru Island, House Reef, depth 8 m, one colony, 28 July 2009. DPUV collection, three non-numbered fragments (one on coral), mounted on SEM stubs and coated with gold. Etymology. Named after the author’s son Nikita Ostrovskiy who collected this species. Description. Colony encrusting, unilaminar, multiserial, sometimes producing uniserial offshoots. Autozooids convex, oval, separated by deep grooves. Primary orifice oval, wider than long, with smooth proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome). Anter (distal half or more of primary orifice) is underlaid by an inner lamina, which ends form thick and rounded condyles directed downwards. Peristome tubular, with pustulose surface and flared rim visible in non-damaged zooids. In zooids of one colony the proximal edge of peristome had a wide U-shaped sinus. Frontal wall smooth, gently pustulose with 9–16 widely scattered foramina. Each foramen is a short tube with a rounded opening, and with its base often surrounded by a low ring-like elevation. Marginal pores small and rounded, observed around all zooidal periphery. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in one row. Avicularia unknown. Kenozooids are recognizable by a 5–12 small pores with centrally perforated cuticular plate. Ancestrula autozooidal, smaller than succeeding autozooids. Remarks. Exechonella nikitai n. sp. is characterized by its tubular peristome, primary orifice oval with smooth proximal shelf and thick and rounded condyles directed downwards, frontal wall with scattered foramina as a short tube with a rounded opening, and also uniserial offshoots/branches (seen in some colonies). Exechonella nikitai n. sp. is reminiscent to E. albilitus Tilbrook, 2006 (Solomon Islands) and E. elegantissima n. sp. (Red Sea). The comparison between these three species shows the following differences: E. albilitus has 20– 30 prominent conical foramina with rounded opening (34 µm in diameter in average), whereas there are 9–18 small and short, conical or tube-like foramina with rounded or slit-like openings (18 µm) in E. elegantissima n. sp., and 9–16 tube-like foramina with rounded opening (40 µm) and often with a ring-like elevation around its base in E. nikitai n. sp., sometimes also seen in E. elegantissima n. sp. The former species also has the largest zooidal size. In one colony of E. nikitai n. sp. zooids had peristomes with a sinus similar to that in E. elegantissima n. sp., but it was much wider in the former species.CÁCERES-CHAMIZO ET AL.52 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 21. Exechonella nikitai n. sp. Indian Ocean, Maldive Islands (A‒C, E, G, H: paratype DPUV 2012-0007-0006; D: paratype DPUV 2012-0007-0007; F: DPUV 2012-0007-0008). A, B, general colony view from above (in B peristomes have a sinus). C, D, lateral view of colony showing shape of peristomes and multiporous mural septulum. Kenozooids shown by arrows (in C). E, lateral view of autozooid showing shape of foramina, peristome, marginal pores and multiporous mural septulum. Kenozooid shown by arrow. F, close-up of autozooids (view from above). G, ancestrula (to the right) and two distal zooids. H, details of primary orifice and peristome. Condyle shown by arrow. Scale bars: A, B, D = 1 mm; C, E‒H = 100 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 53REVISION OF THE RECENT SPECIES OF EXECHONELLA TABLE 20. Measurements (in µm, except number of foramina) of specimens of Exechonella nikitai n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Tilbrook (2006, p. 115) mentioned that a specimen from the Maldives (kept at the Natural History Museum, London) “appears to be” E. albilitus, and its further comparison with other species having ‘elevated’ frontal foramina is required to make a more precise conclusion. Distribution. E. nikitai n. sp is only known from Maldive Islands (North Male Atoll, Vabbinfaru Island, Angsana Ihuru Island and Kuda Haa), Indian Ocean. Exechonella vavrai n. sp. (Fig. 22, Table 21) Material examined. Holotype: DPUV 2012-0005-0001, on mollusc shell (mounted on the SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, south of Ras Abu Soma, depth 1–20 m, September 1992. Paratype: DPUV 2012-0005-0002, ancestrula on coral rubble. Red Sea, the Northern Bay of Safaga, 31 July, 1987. Etymology. Named after palaeontologist Dr. Norbert Vávra for his life-long contribution to the study of bryozoans. TABLE 21. Measurements (in µm, except number of foramina) of the type specimens of Exechonella vavrai n. sp. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Maldive Islands, Indian Ocean m±sd r n AzL 1109±185.6 760–1570 47 AzW 752.5±149.5 420–1050 47 OrL 171.1±13.3 150–191.3 9 OrW 228.1±19.4 197–252 9 FoN 11±2.3 9–16 41 OD 40±9.1 17–61 80 PeL 281.1±52.8 180–360 10 PeW 316.7±27.4 260–350 10 AncL 822±69.3 767–900 3 AncW 545±118 417–650 3 Northern Bay of Safaga, Red Sea m±sd r n AzL 880±24.5 850–910 6 AzW 598±35.6 550–630 6 OrL 154±17.2 130–180 8 OrW 225.7±11.3 210–240 8 FoN 13±1.7 10–14 4 PeL 136±25.1 100–160 6 PeW 334±25.1 310–360 6 AncL 720 – 1 AncW 560 – 1CÁCERES-CHAMIZO ET AL.54 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 22. Exechonella vavrai n. sp. Red Sea (A‒F: holotype DPUV 2012-0005-0001). A, general view of holotype (overgrown by a colony of Puellina sp.) from above. B, close-up of five autozooids (lateral cylindrical foramina shown by arrows). C, D, lateral view of autozooids on colony periphery showing shape of peristomes, conical foramina, marginal pores and multiporous mural septulum (lateralmost cylindrical foramen with kenozooid shown in D by arrow). E, close-up of lateralmost cylindrical foramen (arrowhead) with kenozooid (k). F, details of primary orifice (condyles shown by arrows). Scale bars: A‒F = 100 μm. Description. Colony encrusting, unilaminar, multiserial. Autozooids pentagonal, hexagonal or oval in shape, separated by deep grooves. Primary orifice oval, wider than long, with proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome), smooth centrally and with wrinkled lateral areas. Anter wall (one-third of primary orifice) underlain by an inner lamina, which ends form thick and rounded condyles pointed downwards. A tubular thick-walled peristome, externally pustulose, with characteristic proximal lip separated from the distal part of the peristomial edge by a shallow ‘incision’. Frontal shield softly pustulose, with 10–14 conical foramina with wide round basal part and narrow distal tip (mostly destroyed in our Zootaxa 4305 (1) © 2017 Magnolia Press · 55REVISION OF THE RECENT SPECIES OF EXECHONELLA material) terminated by a circular opening. Foramina distributed predominantly in the central part of the frontal shield. In contrast with the others, two lateralmost foramina are ‘isolated’ and have cylindrical shape. Their opening is occluded presumably by the avicularian mandible, but preservation of the material was not sufficient to give more details. These foramina are associated with adventitious kenozooids, recognized by 3–5 small pores. Round marginal pores small and distinct. Vertical zooidal walls narrow, represented by multiporous mural septula with communication pores arranged in one, sometimes two rows. Ancestrula autozooidal, smaller than the rest of autozooids. Remarks. E. vavrai n. sp. is characterized by its thick peristome with a prominent proximal lip and incisions that are not known in any other species. The conical frontal foramina that are present in E. vavrai n. sp. are only comparable with those found in E. albilitus Tilbrook, 2006, although calcification in the former species is stronger. Distribution. E. vavrai n. sp. is only known in the Red Sea, Northern Bay of Safaga. Exechonella verrucosa species-complex Exechonella verrucosa (Canu & Bassler, 1927) n. comb. (Fig. 23, Table 22) Coleopora verrucosa: Canu & Bassler 1927, p. 6, 42, pl. 1, fig. 7; 1929, p. 267–268, pl. 20, fig. 4, pl. 26, fig. 9. Not Teuchopora verrucosa: Harmer 1957, p. 898, pl. 54, figs 11–12. Not Coleopora verrucosa: Winston & Heimberg 1986, p. 15–16, figs 33–34. Material examined. Holotype: USNM 8465, encrusting on erect cheilostome fragment. Philippines, Jolo Island, Jolo Light, 6o 4´25´´N, 120o 58´30´´E, Albatross Station D.5137, depth 20 fathoms, 5 March 1908. Other material examined: USNM 545930. Philippines, Jolo Island, Jolo Light, 6o 4´2´´N, 120o 58´3´´E, Albatross Station D.5137, depth 20 fathoms, 5 March 1908. Description. Colony encrusting, unilaminar, multiserial. Autozooids convex, pentagonal in shape, separated by deep grooves. Zooidal periphery surrounded by a narrow gymnocystal rim in some zooids. Primary orifice subcircular, slightly wider than long, poster (one-third) slightly wider than the anter (two-thirds). Anter wall underlain by an inner lamina, which ends in small triangular condyles pointed to the orifice midline. Orifice with proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) that has a smooth area in its central part with its left and right areas wrinkled. Peristome short, tubular, thick-walled with pustulose external surface. Peristomes of a smaller colony show bases of 5–6 long tubular processes two of which are preserved. Frontal shield slightly pustulose being perforated by 36–50 small, circular to subcircular foramina with a gymnocystal rim raised slightly above the frontal shield and sloping towards very small central opening. In a smaller specimen the gymnocystal rim is very narrow. In a larger specimen fusions between the rims of 2–3 foramina are common. In addition, frontal shield of most autozooids bears 4–6 thick-walled hollow processes (long, spire-like, sometimes with two peaks in the better preserved specimen) which formation involves the fusion of the gymnocystal rims of 2–5 foramina, whose openings are distinguished near the process base. Processes randomly distributed across the frontal shield with some having lateral position. Numerous oval marginal pores of various sizes well seen around zooidal periphery. Vertical zooidal walls narrow and represented by multiporous mural septula with one row of communication pores. Avicularia are present on the outer raised rim of the two largest lateralmost (sometimes proximal) foramina, which external border produces a long tubular projection. In some cases gymnocystal rim of this foramen fuses with rim of 2–3 neighbour foramina. Each avicularium has a central nipple-like structure with a central pore. A thin oval mandible closes the lumen of the foramen. In some zooids luminae are slit-like or seem occluded. Oval adventitious kenozooids are recognized by 3–6 small pores. These are often associated with avicularia. Ancestrula is unknown. Remarks. Canu and Bassler (1927, p. 6) introduced genus Coleopora with the type species C. verrucosa Canu & Bassler, 1927 mentioning hyperstomial ovicell in its description. Globular ovicell has been mentioned in this species in their next work too (Canu & Bassler 1929, p. 267) although it was not figured in both papers. Restudy of the type specimens showed that they belong to Exechonella, thus genus Coleopora requires a new type species. It differs from Exechonella by the pseudoporous structure of its lepralioid frontal shield and requires a revision.CÁCERES-CHAMIZO ET AL.56 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 23. Exechonella verrucosa (Canu & Bassler, 1927) n. comb. Philippines (A, B, G: holotype USNM 8465; C‒F, H, USNM 545930, non-cleaned colony). A, general colony view from above. Kenozooid is shown by arrow in A. B, E, close-up of autozooid. Lateralmost foramina with avicularia shown by arrows in B. C, three non-cleaned peripheral autozooids with their orificies closed by opercula. D, details of primary orifice and peristome. Condyle shown by arrow. F, close-up of partial frontal shield showing fused foraminal rims and their broken hollow processes. G, close-up of autozooidal frontal shield showing lateralmost foramina with avicularium, foramina, frontal processes and marginal pores. H, lateralmost foramina with avicularium. Mandible edge shown by arrowhead. Scale bars: A, C = 500 μm; B, E = 200 μm; D, F, G = 100 μm; H = 50 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 57REVISION OF THE RECENT SPECIES OF EXECHONELLA TABLE 22. Measurements (in µm, except number of foramina) of Exechonella verrucosa (Canu & Bassler, 1927) n. comb. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Thus, Exechonella verrucosa (Canu & Bassler, 1927) should be considered as a new combination. This species is characterized by its frontal shield with numerous small foramina with small lumen, and spire-like, thick-walled hollow processes on the frontal wall and peristome. Pointed process also develops on the lateral foramen. Harmer (1957) removed Coleopora verrucosa Canu and Bassler, 1927 to the genus Teuchopora during his study of the several specimens from the Indo–Pacific kept at the Natural History Museum, London. Later on, those from New Guinea, Philippines and Singapore (together with colonies from the Solomon Islands) were attributed to the new species E. loslosensis by Tilbrook (2006). This species also has spike-like projections on the peristome rim. Further similarities with E. verrucosa are the well-defined zooidal boundaries with chains of numerous, small and evenly spaced marginal pores, appearance of the frontal foramina and spire-like processes, and presence of one or two larger lateralmost foramina with avicularia inside (which nipple-like structures are visible on the Plate 20, A from Tilbrook 2006). The main differences between these two species are the shape of the orifice, number of frontal foramina, (about 40 in E. verrucosa and between 60–90 in E. loslosensis) and zooidal size reaching 1.4–1.7 mm in the latter species and less than 1 mm in the former. Winston and Heimberg (1986) described and illustrated a species of Exechonella (as Coleopora verrucosa) with long conical processes on the frontal shield from Komodo Island, Indonesia (see also below). The authors placed it in Exechonellidae, however, due to the frontal wall and orifice characters and not in Teuchoporidae as did Harmer (1957). The major differences between this specimen from Indonesia and the studied specimens of E. verrucosa are: (1) the shape of the foramina that are slit-like in the former and round or oval in the latter, and (2) the shape of the peristome that is slightly flared with a proximal projection on its rim in the species from Komodo, and tubular with several projections in E. verrucosa. Distribution. Exechonella verrucosa was found near Jolo Island, Philippines. Exechonella spinosa Osburn, 1940 (Fig. 24, Table 23) Exechonella spinosa new. var.: Osburn 1940, p. 367‒368 (part), pl. 4, fig. 35. Material examined: Lectotype: USNM 11849, three small fragments. Atlantic Ocean, Bermuda, May 1936. Description. Colony encrusting, unilaminar, multiserial. Autozooids convex, oval in shape. Primary orifice oval, wider than long. Peristome short and thick with 5–7 long and tubular projections around, which may stay simple or bifurcated at the end. Frontal shield slightly pustulose being perforated by about 40 spaced, circular to subcircular foramina, each with gymnocystal rim. Fusions between foraminal rims were not seen. Autozooids have Philippines m±sd r n AzL 988±124 785–1264 13 AzW 783±106 619–945 13 OrL 246±22 221–282 5 OrW 251±20 220–266 5 FoN 42±5.3 36–50 9 FoD 61.3±14.7 39–105 33 OD 9.2±1.6 7–13 26 PeL 420±44 348–469 6 PeW 399±34 358–451 6CÁCERES-CHAMIZO ET AL.58 · Zootaxa 4305 (1) © 2017 Magnolia Press long, spire-like hollow processes on the frontal shield. Their formation involves the fusion of the gymnocystal rims of several foramina, whose openings are distinguished near the process base. Vertical zooidal walls narrow and obviously represented by multiporous mural septula. Lateral avicularia and adventitious kenozooids were not seen in the studied fragments. TABLE 23. Measurements (in µm, except number of foramina) of the fragments of lectotype specimen of Exechonella spinosa Osburn, 1940. Abbreviations: autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), primary orifice length (OrL), primary orifice width (OrW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Despite the above redescription requires improvement based on the better preserved material from the type locality, E. spinosa is a ‘good species’ characterized by its frontal shield with numerous rounded foramina, spire-like, thinner hollow processes associated with foramina of the frontal shield and thicker, often branching processes on the peristome. Osburn in 1940, together with the description of E. antillea, described and figured, E. antillea new var. spinosa (p. 367–368, pl. 4, fig. 35) mentioning the only difference between them the presence of “tall unjointed spines” on the frontal shield and peristome. In fact, Osburn noticed that had two specimens, one from Bermuda and another from Jamaica, that he initially considered as different species because of the absence of the frontal spines in the second specimen. Finally this author decided that they belong to one species, because of the similarity in size. Comparison of the Osburn’s material from Bermuda (USNM 11849, selected here as lectotype consisting of three tiny fragments of presumably one colony) and the material from Port Antonio, Jamaica (USNM 9911, labeled as E. pumicosa, also represented by two small specimens loaned from Dr. Bassler) showed that the published illustration (Osburn 1940, p. 4, fig. 35) corresponds more to the Bermuda's fragments because of the presence of the frontal spines. Such spines were broken, however, in the specimens from Jamaica one of which also shows broken peristomial spines. The foraminal luminae are not round, but slit-like and their number (about 50) is higher in comparison to the specimen depicted by Osburn. We suggest that these specimens belong to a separate (while very similar) species. Examination of four SEM-images of the colony fragment from Bocas del Toro, Panama (currently non- numbered, kept in the collection of the Virginia Museum of Natural History, USA), also showed its close similarity to the fragments from Bermuda. We suggest it could belong to E. spinosa although better preserved material from the Bermuda, Jamaica and Bocas del Toro is required for better comparison. Describing material (as Lagenipora tuberculata MacGillivray) from Indian waters Thornely (1905, p. 113) included a comment as “there are also among [the studied colonies] some that have the hollow tubercles very much lengthened, ending in points” and “simple or branched spines round the margin of the much raised peristome”. While no illustrations were given, this description clearly shows a similarity of the Thornely’s material (kept at the Natural History Museum, London) with E. spinosa, and should be compared in the future. No branching spines were seen on the peristomes in the studied specimens in E. verrucosa and E. kleemanni n. sp. (see below), although better preserved material should be obtained to make more precise comparison between the species. Distribution. Until more specimens will be obtained, distribution of Exechonella spinosa should be restricted to Bermuda. Bermuda, Atlantic Ocean m±sd r n AzL 750 700‒800 2 AzW 663 625‒700 2 OrL 246 ‒ 1 OrW 300 ‒ 1 FoN 38 ‒ 1 FoD 57±2.1 53–60 10 OD 24±3.0 19–28 10 Zootaxa 4305 (1) © 2017 Magnolia Press · 59REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 24. Exechonella spinosa Osburn, 1940. Bermuda (A‒E: lectotype USNM 11849, A‒D, first fragment, E, second fragment). A, D, E, general view of fragments. B, primary orifice and peristome of first fragment. C, close-up of frontal shield showing foramina and broken processes. Scale bars: A = 1 mm; B‒E = 100 μm. Exechonella kleemanni n. sp. (Fig. 25, Table 24) Material examined. Holotype: DPUV 2012-0004-0001, on coral rubble (mounted on the SEM stub and coated with gold). Red Sea, the Northern Bay of Safaga, 23 July 1987. Etymology. Named after marine biologist Dr. Karl Kleemann who collected this species, and who kindly donated to us various bryozoan colonies that he found on corals. Description. Colony encrusting, unilaminar, multiserial. Autozooids convex, oval or pentagonal in shape, separated by deep grooves. Primary orifice oval, wider than long, poster (one-third) slightly narrower than the anter (two-thirds). Anter wall underlain by an inner lamina, which ends in drop-like condyles pointed to the orifice midline or downward. Orifice with proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) that has slight convex area or very low triangular projection in its central part. Areas to the left and to the right from this convex area/projection are wrinkled. Peristome tubular, slightly flared, with longitudinal grooves on its internal surface and pustulose externally. Frontal shield slightly pustulose being perforated by 31–56 foramina having a shape of short cylindrical or flattened tubes with gymnocystal internal wall surrounding its lumen and small, predominantly slit-like opening. Base of many or sometimes most of CÁCERES-CHAMIZO ET AL.60 · Zootaxa 4305 (1) © 2017 Magnolia Press these tubes is surrounded by a low conical elevation while some are situated in a small depression. Most autozooids have 4–8 long, spire-like, thick-walled hollow processes which formation involves the fusion of two, three or, rarely, four foraminal tubes, whose openings are distinguished near the process base. Processes randomly distributed across the frontal shield with some having lateral position. Small oval marginal pores well seen around zooidal periphery. Vertical zooidal walls narrow, represented by multiporous mural septula with 1–2 rows of communication pores. Avicularia are not recognizable during external examination, but they might be present underneath of 1–2 lateralmost processes formed close to adventitious kenozooids with 5–6 pores. Ancestrula is unknown. TABLE 24. Measurements (in µm, except number of foramina) of the holotype specimen of Exechonella kleemanni n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), number of frontal foramina (FoN), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Exechonella kleemanni n. sp., is characterized by its frontal shield with numerous foramina as short, mostly flattened tubes with small slit-like openings and spire-like, thick-walled hollow processes. The primary orifice oval with proximal shelf that is slightly convex or having a low triangular projection in its central part. Condyles are drop-like. While having a number of similarities, the studied colony of E. kleemanni n. sp. differs from E. verrucosa by the (1) primary orifice shape that is subcircular in the latter species and oval with slightly convex proximal edge or small projection in the former, (2) condyles that are triangular and directed towards the centre of the orifice, being situated almost in middle of the orifice lateral sides in E. verrucosa, and drop-like, directed proximally, and being situated in the proximal third of the orifice lateral side in E. kleemanni n. sp., (3) peristome that is short, flared and with long spike-like projections on its rim in the former species, and longer, cylindrical and just slightly flared, without projections in the latter (though all peristomes are damaged in our material). Further differences include (4) shape of frontal foramina, with a small opening in a depression surrounded by a wide flat rim in E. verrucosa and with a slit-like opening on the top of flattened cylindrical tube in E. kleemanni n. sp., (5) shape of zooids that are rather flat with a clear outline of the marginal pores in E. verrucosa, and convex with marginal pores hardly seen in E. kleemanni n. sp. Finally, (6) avicularia with a characteristic nipple area are present in 1–2 larger lateralmost foramina in the former species whereas they were not detected during external examination, but they might be present underneath of 1–2 lateralmost projections in the latter. Winston and Heimberg (1986) described and illustrated a similar species (as Coleopora verrucosa Canu & Bassler, 1927) with long conical processes associated with foramina from Komodo Island, Indonesia. Their specimen, however, differs from E. kleemanni n. sp. by the frontal shield evenly covered by the small foramina with slit-like opening (often slightly curved, with very narrow rim) each placed in the small depression. Also the shape of the peristome is slightly flared with a proximal process on its rim in the species from Komodo, and more tubular in E. kleemanni n. sp. Recently, we examined two more specimens possessing the long spike-like projections associated with foramina of the frontal shield, one from Philippines (USNM 7915, Albatross Station D.5751, depth 24 fathoms) and the other from the Great Barrier Reef (James Cook University Marine Biological Expedition, St. 986, 20 July 1987, kept at the Natural History Museum, London). The Australian specimen is reminiscent E. kleemanni n. sp. by the shape of its tubular peristome and tube-like foramina, but its preservation is too poor for a definite conclusion. Northern Bay of Safaga, Red Sea m±sd r n AzL 1048.7±97.4 930–1220 16 AzW 783.3±112.2 630–960 16 OrL 194.3±7.9 190–210 8 OrW 240±26.5 200–270 8 FoN 46±8.8 31–56 13 PeL 187.5±47.9 150–250 5 PeW 427.5±20.6 400–450 5 Zootaxa 4305 (1) © 2017 Magnolia Press · 61REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 25. Exechonella kleemanni n. sp. Red Sea (A‒H: holotype DPUV 2012-0004-0001). A, general view of holotype from above. B, D, close-up of several autozooids. C, lateral view of autozooids showing shape of peristomes, conical foramina, marginal pores and frontal hollow spikes. E, autozooids on colony periphery showing shape of primary orifice, conical foramina, marginal pores and multiporous mural septula (two kenozooids shown by arrows). F, G, close-up of frontal shield. H, details of primary orifice. Scale bars: A = 1 mm; B‒H = 100 μm.CÁCERES-CHAMIZO ET AL.62 · Zootaxa 4305 (1) © 2017 Magnolia Press In contrast, the specimen from the Philippines described in this paper as E. rimopora n. sp. strongly reminiscent the aforementioned specimen from Komodo described by Winston and Heimberg (1986) as Coleopora verrucosa (see below). Distribution. E. kleemanni n. sp. was found only in the Red Sea, Northern Bay of Safaga. Exechonella rimopora n. sp. (Fig. 26, Table 25) Coleopora verrucosa: Winston & Heimberg 1986, p. 15, 16, figs 33‒34. Material examined. Holotype: USNM 545931 (colony encrusting coral fragment together with USNM 7915, Hiantopora bidenticulata Canu & Bassler, 1929). Philippines, Sirun Island, Sulu Archipelago, Albatross Station D. 5151, 5º 24’ 40” N, 120 º 27’ 15” E, depth 24 fathoms, 18 February 1908. Etymology. The name reflects the slit-like shape of the luminae of the frontal foramina in this species. Derived from the Latin word “rima” (slit). Description. Colony encrusting, unilaminar, multiserial. Autozooids convex, oval or pentagonal in shape, separated by deep grooves. Primary orifice oval, wider than long, poster (one third) slightly narrower than the anter (two thirds). Distal part of primary orifice is underlain by an inner lamina, which ends in drop-like condyles pointed to the orifice midline or downward. Orifice with proximal shelf (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) that has a slight convex or smooth area in its central part. Areas to the left and to the right from this convex/smooth area are wrinkled. Peristome short, tubular, flared out, with pustulose external surface. Its proximal part is often wider. Frontal shield slightly pustulose being perforated by 52–75 small slit-like foramina. Most of the foramina are situated in a small depression whereas some are on the top of short, elevated and flattened tube. Autozooids possess 6–11 long, spire-like, thick-walled hollow processes randomly distributed across the frontal shield. Small oval marginal pores well seen around zooidal periphery. Vertical zooidal walls narrow, represented by mural septula. Avicularia are associated with two largest foramina having lateralmost or sometimes proximolateral position. Each avicularium has a central nipple-like structure with a central pore, surrounded by tall, flat and wavy foraminal rim. Kenozooids are abundant, being recognized by 2–4 small pores. These are often associated with avicularia. Ancestrula is unknown. TABLE 25. Measurements (in µm, except number of foramina) of Exechonella rimopora n. sp. Abbreviations: autozooid length (AzL), autozooid width (AzW), number of frontal foramina (FoN), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Exechonella rimopora n. sp. belongs to E. verrucosa-complex, because of their special frontal wall with hollow projections. The new species is characterized by its frontal shield slightly pustulose being perforated by numerous small, slit-like foramina. It strongly reminiscent E. kleemanni n. sp., differing from it by several characters. (1) Although both species have slit-like foramina, they are mainly located in a shallow depression, and only rarely on the top of the flattened tubes that is typical of E. kleemanni n. sp.; (2) foramina are more numerous in E. rimopora n. sp. (52–75 vs 31–56 in E. kleemanni n. sp.), and (3) the former species has smaller zooids than the latter (819×615 µm in E. rimopora n. sp. and 1048×783 in E. kleemanni n. sp.). Philippines m±sd r n AzL 819±73.03 744–967 7 AzW 615.3±29.51 564–652 7 OrL 175.4±10.8 158–186 5 OrW 193.2±6.61 186–201 5 FoN 65±8.4 52–75 6 PeL 313.3±14.1 301–331 4 PeW 301.3±21.2 270–317 4 Zootaxa 4305 (1) © 2017 Magnolia Press · 63REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 26. Exechonella rimopora n. sp. Philippines (A‒I: holotype USNM 545931). A, C, general view of the upper (A) and the lower (c) parts of holotype from above. B, close-up of several autozooids on the colony periphery (some lateralmost foramina with avicularia shown by arrows). D, E, details of primary orifice and peristome. F, G, close-up of autozooids (lateralmost foramina with avicularia shown by arrows). H, I, close-up of lateralmost foramina with avicularia. Scale bars: A, C = 500 μm; B, D, E = 100 μm; F, G = 200 μm; H, I = 50 μm.CÁCERES-CHAMIZO ET AL.64 · Zootaxa 4305 (1) © 2017 Magnolia Press Our specimen totally corresponds to the colony from the Komodo Island, Indonesia, described and figured by Winston and Heimberg (1986) as Coleopora verrucosa. We consider them as con-specific. Distribution. Initially found in Philippines, this species extends its distribution to Indonesia. Family Actisecidae Harmer, 1957 Canu and Bassler (1929) described Exechonella discoidea as a new species from Philippines with umbonuloid frontal shield being very similar to that in Exechonella. Presence of the ovicells, however, does not allow its attribution to this genus. Earlier from the same area these authors described another cheilostome with similar frontal shield as Actisecos regularis Canu & Bassler, 1927 (also described in their 1929 paper). The latter species was redescribed by Harmer (1957), based on the specimens from Indonesia and New Guinea. This author has also introduced the family Actisecidae. To avoid confusions with exechonellid species in the future, we studied and redescribed the specimens of Canu and Bassler. Genus Actisecos Canu & Bassler, 1927 Type species: Actisecos regularis Canu & Bassler, 1927 Diagnosis. Colonies free, discoidal, small (no more than four zooidal generations were observed), slightly or strongly convex. Zooids small, elongated. Peristome long, cylindrical, swollen in the base, with pustulose surface. Primary orifice subcircular. Frontal shield centrally smooth or with sporadic tubercules that are more common on the periphery, with few (nine to 19) foramina. Basal pore chambers with 1–2 communication pore(s). Marginal pores absent. Basal autozooidal walls covered by flat kenozooids with large membranous area. No avicularia. Ovicells prominent, peristomial, terminal, developing exclusively in the peripheral zooids. Ectooecium membranous, entooecium pustulose with numerous pseudopores. Ancestrula is autozooidal in shape, surrounded by six zooids. Actisecos regularis Canu & Bassler, 1927 (Fig. 27, Table 26) Actisecos regularis: Canu & Bassler 1927, p. 11, pl. 1, fig. 13; Canu & Bassler 1929, p. 517, pl. 66, figs 1–4; Harmer 1957, p. 856‒857, pl. 60, figs 12, 16. Material examined. Lectotype: USNM 8325. Philippines, Linapacan Strait, Observatory Island, 11° 37´15´´ N, 119° 48´45´´ E, Albatross Station D.5335, depth 46 fathoms, 18 December 1908. Paralectotypes: USNM 545928. Philippines, Linapacan Strait, Observatory Island, 11° 37´ 45´´ N, 119° 46´ E, Albatross Station D.5336, depth 46 fathoms, 18 December 1908. USNM 545929. Tacbuc Point, Leyte Island, 10° 46´ 24´´ N, 125° 16´ 30´´ E, Albatross Station D.5478, depth 57 fathoms, 29 July 1909. Description. Colonies free, discoidal, small (no more than four zooidal generations have been observed). Frontal surface convex, basal surface concave, giving to the colony a flat conical form. Autozooids small, oval in shape, separated by shallow grooves. Primary orifice subcircular. Peristome tubular, often slightly swollen in the base which external surface bears pointed, uniformly distributed tubercles. Distal part of the peristome smooth. Frontal shield perforated by 9–20 well-spaced, rounded or oval foramina that occupy the most of the frontal shield. Majority of foramina with low rim. Walls of the foraminal lumen vertical or inclined with a lower opening smaller than the upper. Frontal shield between foramina with sporadic pointed tubercles, the most observed in the peripheral area of the zooid. Marginal pores (areolae) not present. Peripheral autozooids display basal pore chambers with 1–2 communication pores. The distalmost chambers predominantly have two such pores, distolateral just one. Basal part of the colony covered by flat, often irregularly shaped kenozooids with gymnocystal periphery and large central 'membranous' area. Ovicell peristomial (ooecium fused with and opened into the peristome), terminal, only developed by peripheral autozooids. Kenozooidal ooecium globose, budded by the maternal zooid. Ectooecium membranous, entooecium calcified with numerous pointed tubercules and small pseudopores predominantly without a raised rim. Ancestrula autozooidal, smaller than the rest of zooids, always having a central position in the colony, surrounded by six autozooids. Zootaxa 4305 (1) © 2017 Magnolia Press · 65REVISION OF THE RECENT SPECIES OF EXECHONELLA FIGURE 27. Actisecos regularis Canu & Bassler, 1927. Philippines (A, B: lectotype USNM 8325; C, D, F, paralectotype USNM 545928; E, G, H, paralectotype USNM 545929). A, general view of lectotype from above. B, central part of lectotype from above (ancestrula shown by arrowhead). C, D, general view of paralectotype from above (ancestrula shown by arrowhead in D). E, general view of paralectotype from below. F, close-up of several autozooids showing peristome shape and details of frontal surface. G, H, close-up of the peripheral part of colony from below showing ooecia, basal pore chambers (some shown by arrows) with communication pores and flat kenozooids. Scale bars: A, C‒E = 500 μm; B, F‒H = 200 μm.CÁCERES-CHAMIZO ET AL.66 · Zootaxa 4305 (1) © 2017 Magnolia Press TABLE 26. Measurements (in µm, except number of foramina) of the specimens of Actisecos regularis Canu & Bassler, 1927. Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), ooecium length (OeL), ooecium width (OeW), peristome length (PeL), peristome width (PeW). Mean (m), standard deviation (sd), range (r) and number of measurements (n). Remarks. Among three specimens kept at the USNM only one (USNM 8325) was mentioned as cotype having a catalogue number (Canu & Bassler 1929). We selected it as lectotype. It was collected at the Station D.5335 (Canu & Bassler 1927, 1929), whereas two other colonies (selected here as paralectotypes) were collected at the Stations D.5336 and D.5478. Communication pores are not seen within ‘membranous windows’ in basal kenozooids that suggests that they were secondarily closed. Instead, few tiny pits (pores?) were detected on the gymnocystal areas of kenozooids. External morphology of ooecia corresponds to both, “escharelliform” and “microporelliform” type (Ostrovsky 2013a), and more precise attribution will be possible when colonies with developing ooecia will be found and anatomical sections of the fresh material will be made (for methodology, see Ostrovsky & Schäfer 2003; Ostrovsky et al. 2003). We suggest, however, that Actisecos has an escharelliform ooecium since no cheilostome with an umbonulomorph frontal shield is known having microporelliform ooecium. On the other hand, no escharelliform ooecia with pseudopores has been ever described. Distribution. Actisecos regularis was found in Philippines, Indonesia, and New Guinea. Actisecos discoidea (Canu & Bassler, 1929) (Fig. 28, Table 27) Exechonella discoidea: Canu & Bassler 1929, p. 123, pl. 20, figs 5–6. ? Exechonella discoidea: Gordon 2016, p. 609. Not Exechonella sp. cf. discoidea: Cook & Bock 2004, p. 276, figs 4a–d. Material examined. Lectotype: USNM 545923. Philippines, east coast Mindanao, Nagubat Island, 9° 43´ N, 125° 48´ 15´´ E, Albatross Station D.5235, depth 44 fathoms, 9 May 1908. Paralectotypes: USNM 545924, USNM 545925, USNM 545926, USNM 545927. Philippines, east coast Mindanao, Nagubat Island, 9° 43´ N, 125° 48´ 15´´ E, Albatross Station D.5235, depth 44 fathoms, 9 May 1908. Description. Colonies free, discoidal. Frontal surface convex, basal surface slightly concave, especially in the centre (ancestrular area). Autozooids small, oval in shape, separated by shallow grooves. Orifice subcircular, slightly wider than long, condyles not observed. Peristome tubular, with slightly swollen base, external surface with pointed tubercles. Frontal shield perforated by 9–19 well-spaced, rounded or oval foramina that occupy the most of the frontal shield. Each foramen with a slightly raised rim. Frontal shield between foramina with sporadic Philippines m±sd r n AzL 466±109 200–643 53 AzW 330±43 251–500 51 FoN 15±3 9–20 38 FoD 37±5.5 30–50 49 OD 18±4.4 13–25 49 PeL 221±53 130–314 36 PeW 222±30.2 160–314 36 OeL 246±16 229–271 10 OeW 286±18 257–314 10 AncL 310 ‒ 1 AncW 300 ‒ 1 Zootaxa 4305 (1) © 2017 Magnolia Press · 67REVISION OF THE RECENT SPECIES OF EXECHONELLA pointed tubercles, mostly observed in the peripheral area. Marginal pores not present, only two small pores located one on each side of peristome were seen in some autozooids. Peripheral autozooids display basal pore chambers with a single communication pore. Basal part of the colony covered by flat, often irregularly shaped kenozooids with gymnocystal periphery and large central 'membranous' area. Ovicell peristomial, only developed by peripheral autozooids. Kenozooidal ooecium globose, budded by the maternal zooid. Ectooecium membranous, entooecium calcified with numerous pointed tubercules and small pseudopores often surrounded by a raised rim. Ancestrula autozooidal, smaller than the rest of zooids and having central position in the colony, surrounded by six autozooids. TABLE 27. Measurements (in µm, except number of foramina) of specimens of Actisecos discoidea (Canu & Bassler, 1929). Abbreviations: ancestrula length (AncL), ancestrula width (AncW), autozooid length (AzL), autozooid width (AzW), diameter of a foramen including rim (FoD), number of frontal foramina (FoN), diameter of the opening of a foramen (OD), ooecium length (OeL), ooecium width (OeW), primary orifice length (OrL), primary orifice width (OrW), peristome length (PeL), peristome width (PeW). Mean, standard deviation, range and number of measurements (in brackets). Remarks. Harmer (1957) introduced the family Exechonellidae based on the umbonuloid nature of the frontal shield. From that time several genera and species have been assigned to the family, either fossil or recent, some of which have been questioned or reassigned to other families. Among them is “Exechonella” discoidea that form small free-living colonies with radiating budding pattern and peristomial ovicells. Despite an obvious similarity in colony form and zooidal appearance Canu and Bassler (1929) assigned this species to Exechonella, not to Actisecos, although A. regularis was described in the same Philippine volume. There are five specimens of this species kept in the USNM collection. All originate from the same sample. The specimen USNM 545923 was selected as lectotype whereas the rest as paralectotypes. Actisecos discoidea strongly resembles A. regularis. The recognized differences are that (1) colony conical in A. regularis and almost flat in A. discoidea; (2) ooecial pseudopores are normally without a rim around them in the former species and with a raised rim in the second; (3) distal part of the peristome is smooth in A. regularis and tuberculate or uneven in A. discoidea; (4) there are mostly two communication pores at the distalmost basal pore chambers in A. regularis and one in A. discoidea. Dumont (1981) and Winston (1986) [based on Dumont’s paper] mentioned this species in the Red Sea, but it is probably confusion resulted from a general similarity of the frontal wall in Actisecos and Exechonella. Gordon and d’Hondt (1997) described one colony from New Caledonia under the name of Actisecos regularis. This specimen represents a new Actisecos species. Finally, Cook and Bock (2004, p. 267) described as Exechonella sp. cf. discoidea a specimen that is undoubtedly belongs to E. ampullacea species-complex (see above). Distribution. Actisecos discoidea is only known from the Philippines. Philippines m±sd r n AzL 443±64.4 188–571 61 AzW 315±40.1 188–413 61 OrL 132±8.5 123–140 3 OrW 139±11 128–150 3 FoN 14±2.2 9–19 56 FoD 45.3±5.4 35–65 65 OD 20±2.5 15–25 65 PeL 85±47.6 90–260 24 PeW 195±18.1 165–240 24 OeL 166±52.4 100–225 8 OeW 212±6.9 200–219 8 AncL 300 ‒ 1 AncW 255 ‒ 1CÁCERES-CHAMIZO ET AL.68 · Zootaxa 4305 (1) © 2017 Magnolia Press FIGURE 28. Actisecos discoidea (Canu & Bassler, 1929). Philippines (A, B: lectotype USNM 545923; C, D, F, paralectotype USNM 545924; E, G, paralectotype USNM 545925; H, paralectotype USNM 545927). A, B, general view of lectotype (A) and paralectotype (C) from above. B, central part of lectotype from above (ancestrula shown by arrowhead). D, F, peripheral part of colony showing peristomes (mostly broken in F) and ooecia. E, general view of paralectotype from below. G, close-up of the peripheral part of colony from below showing details of partial ooecium, basal pore chambers (some shown by arrows) with communication pores and flat kenozooids. H, details of primary orifice and frontal shield. Scale bars: A, C, E = 500 μm; B, D, F, G = 200 μm; H = 100 μm. Zootaxa 4305 (1) © 2017 Magnolia Press · 69REVISION OF THE RECENT SPECIES OF EXECHONELLA Discussion Morphological characters and species discrimination. In general, Exechonella is an easily recognizable genus because of its zooidal shape and large size with characteristic frontal shield perforated by numerous foramina. On the other hand, discrimination of its species is a taxonomical problem because of the reduced number of distinctive characters that was noticed by Cook and Bock (2004). Before our study, at least 12 Recent species of Exechonella, some with a pan-tropical distribution, had been described (Bock 2016). It is clear now that their number is much higher and some species are in fact groups of closely related species. Thus, the next step in identification is an attribution of a particular colony to a species complex—a group of species possessing a similar (often, very similar) morphology. While some species share characters of two and even three complexes (see example of Exechonella catalinae n. sp. above), most of them can be attributed to a single group with certainty. In contrast, species discrimination within the complexes is often very complicated because their characters are often shared or overlapped. This situation becomes even worse because of the variability of some characters within a species (within and between localities) and even within the same colony. For instance, the edge of the collar-like peristome is typically smooth/even in E. azeezi n. sp., but low, pointed projections on it were seen in one colony. Similar situation has been observed in E. vieirai n. sp. The shape of the primary orifice may vary considerably within a colony being more round or more oval. Since namely this character was among the most important for the species discrimination within species complexes, a check of several zooids was required to recognize a typical (dominating) variant. Such a procedure was used when discriminating very similar species from the Exechonella brasiliensis-complex. In this case, the typical orifice has an angular poster outline in E. azeezi n. sp. and a rounded poster outline in E. similis n. sp. Similarly, variation in the shape of condyles was required to select a typical variant for many species. To note Cook and Bock (2004) mentioned that the condyles were absent in some colonies of E. magna, and we also did not see them in some zooids in several species. In our material the E. ampullacea-complex (in addition to E. ampullacea itself) includes E. reniporosa n. sp., E. variperforata n. sp., E. safagaensis n. sp., E. maldivensis n. sp. and E. erinacea. Three more species that we attribute to this complex based on the literature data are E. tuberculata, E. anuhaensis and the species described by Cook and Bock (2004, p. 267) as Exechonella sp. cf. discoidea Canu & Bassler, 1929. All these species possess the bottle-like zooids with long tubular peristomes, ‘pocket’-like structure near condyles (not recognized in some species because of the long peristomes), numerous mid-sized foramina and lack of avicularia. In all but one (E. erinacea, although only one specimen was available for study) species the proximal part of the frontal shield is ‘reduced’ in some zooids making a sort of ‘gaps’ in the ‘corners’ between zooids. The main differences between the species are the size, shape and, sometimes, number of the frontal foramina as well as presence and shape of the frontal projections (foraminal spines) associated with them. The special shape and structure of the hollow frontal projections (spikes) formed by the fusion of the gymnocystal rims of 2–4 foramina, was a major reason to unite E. verrucosa, E. kleemanni n. sp., E. spinosa, E. rimopora n. sp. and E. loslosensis (see Tilbrook 2006) into one species-complex. In addition to the generally similar zooidal shape and low peristome, these species also have foramina with small round or slit-like openings on their bottom. Avicularia are present in at least three species, and our material of E. kleemanni n. sp. and E. spinosa was too poorly-preserved to recognize these polymorphs. E. kleemanni n. sp. and some zooids in E. rimopora n. sp., however, differ from other species in having the tube-like shape of the foramina, similar to species from the E. albilitus-complex (see below). In E. verrucosa zooids are surrounded by the narrow gymnocystal rim that is not seen in the other species of this complex, but present in all species of E. antillea-complex. Such overlaps show that a number of characters could evolve independently, that is also seen in E. catalinae n. sp. possessing characters of E. antillea, E. brasiliensis and E. albilitus species-complexes. On the other hand, the common characters could also point to the relationships between species-complexes that will require further studies. Molecular techniques could answer the question if the species with ‘intermediate’ morphology is closer to this or that species complex. A tube-like (but shorter than in the species of E. ampullacea-complex) peristome is characteristic for the species of E. albilitus-complex. In our material all three attributed species—E. elegantissima n. sp., E. nikitai n. sp. and E. vavrai n. sp.—possess ‘a shelf’ (a distalmost part of the zooidal frontal shield proximally surrounded by a wall of the peristome) and widely scattered tube-like or conical foramina. The same characters are seen in E. CÁCERES-CHAMIZO ET AL.70 · Zootaxa 4305 (1) © 2017 Magnolia Press albilitus. Among these four species, avicularia-like structures were seen only in E. vavrai n. sp. Specific shape of the frontal foramina as well as the shape of the peristome were among the major characters for the species discrimination. It should be added that the presence of the ‘shelf’ is also characteristic of E. verrucosa species- complex as well as Exechonella catalinae n. sp. The latter species differs from the species of the E. albilitus- complex in the shape of the foramina that more reminiscent the species from E. brasiliensis and E. antillea species- complexes. Exechonella antillea itself and the complex of similar species is a taxonomic nightmare that in our material included E. pumicosa, E. vieirai n. sp., E. floridiana n. sp., E. harmelini n. sp., E. panamensis n. sp. and E. californiensis n. sp. that all have moderately convex zooids of similar shape with short collar-like peristome and closely-spaced frontal foramina. Except E. panamensis n. sp. possessing numerous spines on the foramina and a peristome, the species discrimination was based on the pattern of the foraminal positioning and fusion and on the primary orifice shape that is rather similar (and variable) among the species of this complex, however. All these species have avicularia and a gymnocystal rim around the frontal shield. Cook (1967) stressed a close resemblance of E. gigantea and E. antillea. Unfortunately, the magnification in the illustrations of Cook is very low, and we attribute E. gigantea to this complex only provisionally. Instead E. papillata Cook and Bock, 2004 can be with certainty attributed to the E. antillea-complex because of the similar zooidal/peristome shape, common fusion of the foraminal rims and a gymnocystal rim around the frontal shield. We also attribute to this species-complex the Miocene E. minutiperforata Di Martino, Taylor & Portell, 2017 despite the lack of avicularia in the material described (Di Martino et al. 2017). Orifice shape was one of the main characters allowing the species recognition in the case of E. brasiliensis- complex. Apart of E. brasiliensis itself, it includes E. azeezi n. sp., E. similis n. sp. and E. claereboudti n. sp. that otherwise possess very similar zooidal shape, collar-like peristome, lateral avicularia and shape and distribution pattern of the frontal foramina. The size and number of the latter was another important distinction. Cook and Bock (2004) united fossil (type-) species E. grandis and recent E. antillea, E. brasiliensis and E. papillata into one group. Indeed, E. antillea- and E. brasiliensis-complexes consist of similar species with avicularia and a low collar-like peristome having a central fold-like projection proximally. The main difference between these species groups is the size of the foramina (larger in E. brasiliensis-complex) and pattern of the foraminal placement (with less free space between foraminal rims and a general tendency to fuse in E. antillea- complex). One more difference is the shape of the foraminal gymnocystal rim that is more prominent in the species of the E. brasiliensis-complex and flattened in E. antillea-complex. Judging from the illustrations of Duvergier (1921, Pl. 3, figs 2‒3) and Gordon (bryozoa.net) E. grandis can be attributed to E. brasiliensis-complex. The second group of Cook and Bock (2004) includes several fossil and recent species that were described under the name Exechonella magna from Australia and Philippines (discussed in Tilbrook 2006). The general zooidal morphology with large foramina is reminiscent of E. brasiliensis, differing (apart from the other characters) by the proximally directed triangular (adventitious) avicularia with a cross-bar typical for many cheilostomes. Exechonella magna (as Hiantopora) was originally described by MacGillivray (1895, p. 62, pl. 8, fig. 23, p1. 10, fig. 27) from the Miocene of Australia. Cook and Bock (2004) redescribed a lectotype using one of the specimens of MacGillivray. Additionally they attributed to this species several fossil (also Miocene) and Recent specimens from Australia including those described by Brown (1956) and Wass and Yoo (1983). The former authors described the differences between the specimens but attributed them to the large morphological variability across localities and populations (as they also thought about E. antillea) (Cook & Bock 2004). Comparison of illustrations from the aforementioned papers showed that fossil and recent specimens clearly represent different species based on the shape of the peristome, and size and number of foramina. Also, Miocene specimens of MacGillivray (1895) and a Pliocene specimen (described as E. paucipunctata) of Brown (1956) are different species too. Moreover, the lectotype of E. magna from the Miocene deposits of the Muddy Creek is clearly different from the specimen from the Miocene deposits of the Balcombe Bay (compare figs 2D and 3A in Cook & Bock 2004). Further, a comparison of the published images of the Recent specimens from Australia (Cook & Bock 2004; Wass & Yoo 1983) with those described by Canu and Bassler (1929, pl. 19, figs 1‒4) (USNM 7966) from Philippines and by Tilbrook (2006, fig. 18e‒f) (SBMNH 365265‒266, 501‒87) from Solomon Islands, showed that while they all differ from the fossil E. magna of MacGillivray, the Recent Australian specimens are closer to each other (and might be conspecific) as are the specimens from Philippines and Solomon Islands thus representing at Zootaxa 4305 (1) © 2017 Magnolia Press · 71REVISION OF THE RECENT SPECIES OF EXECHONELLA least two more species. It also should be noted that the first record of an E. magna-like specimen (as Lepralia foraminigera, Hincks, var.) can be found in Kirkpatrick (1890) who described it from the [South] China Sea (discussed in Harmer 1957). Careful restudy and redescription of all these specimens is required to generalize our knowledge on Exechonella magna species-complex. Cook and Bock’s (2004) E. tuberculata-complex includes three recent species (see Remarks for E. safagaensis n. sp. above). In agreement with this, we distinguished the E. ampullacea-complex that includes E. tuberculata and all the similar species with flask-like zooids with tall tubular peristome, possessing frontal projections and without them. Since E. tuberculata has strongly developed projections and, thus, is less ‘typical’ for this species-complex appearance, we suggest it is better to use the name E. ampullacea to characterize this group. Two interesting morphological questions concern avicularia (see below) and foramina. In respect to the recent specimen attributed by Cook and Bock (2004, p. 275) to E. magna, these authors wrote that this species possesses open foramina (“cuticle is inserted at the edge of the foramina”) whereas in many other instances “it is continuous across the face of the foramina” (p. 269). The latter statement was based on the direct observations of live colonies (Cook 1985, p. 46) and dry non-cleaned material (Cook & Bock 2004, p. 269, fig. 4C). In contrast, cleaned material examined during our study of the relationships between gymnocystal and ‘internal wall’ parts of the frontal shield seems indicate that the foraminal luminae should be open in most cases (specifically those, having a gymnocystal rim around the foramen). In particular, we checked the frontal shield undersides of E. maldiviensis n. sp. and E. safagaensis n. sp.. They both showed the gymnocystal surface and open luminae. Gymnocystal rim surrounding the luminae on the upper side of the shield show that the cuticle is inserted right on its edge thus leaving the foraminal opening open. SEM-images of the frontal shields underside made by Dr P. Bock also show opened foramina in E. papillata, E. magna and Exechonella sp. (see www.bryozoa.net). Also Harmer (1957, p. 652) wrote in this connection that “foramina apparently traversing the exposed frontal wall and not containing living tissue”. Anatomical studies are required to solve this question. Evolutionary trends in skeletal morphology. One of the existing scenarios explaining evolution of the umbonuloid frontal shield connects its origin with a coalescence of the frontal costae which lost their frontal calcification. Consequently their coeloms fused to form the common hypostegal coelom in the cribrimorph ancestor (Harmer 1901; Silén 1942; Sandberg 1977). Gordon (2000) who widely analyzed hypotheses of the frontal shield formation in Cheilostomata, criticized the above idea, however, because of the lack of evidence of such fusion in the umbonulomorphs Arachnopusiidae, Exechonellidae and Adeonidae. Instead, this author suggested that development of the frontal kenozooids above the spinocyst could be the basis of such evolutionary novelty in the cribrimorphs. The second scenario is substantiated by the skeletal evidence in both, fossil and Recent cheilostomes (Gordon & Voigt 1996). The pattern of the frontal wall calcification resembling radiating lobes has been described by Cook (1967) in Exechonella tuberculata from Australia. Also, the radial rows of the foraminal luminae separated by parallel furrows are seen in Exechonella sp. from Ghana (as E. antillea, “cribrimorph” form) (Cook 1985). After all, these furrows surrounding the foraminal rows and fusing with each other, create the appearance of the frontal shield very similar to Bellulopora (Gordon 2000; Ostrovsky & Taylor 2005). In addition, Cook wrote about umbonuloid “frontal calcified body wall…formed by anastomosing processes, leaving uncalcified foramina…” (p. 130). Studying the total mounts of the living colonies of Exechonella antillea under the light microscope, Fransen (1986, fig. 29a) noticed the radiating sutures connecting foraminal luminae in the calcified wall of the frontal shield. Restudy of Fransen’s material confirmed this finding (Fig. 8). In contrast with the opinion of Gordon (2000) these sutures could be regarded as traces of the costal fusion. We suggest that the cumulative evidence (pattern of the frontal shield calcification together with position of foramina and presence of sutures connecting them) seen in different species points to the possible way of the umbonuloid shield origin in Exechonella. Preparation of the total mounts in a wide range of species could help to prove this hypothesis suggesting that umbonulomorphs are polyphyletic (as was initially proposed by Gordon 2000). Further, comparative skeletal morphology points to the evolutionary changes towards more solid frontal shield (and thus better protection) in Exechonella. Comparison of the size and the number of foramina in different species points to the existence of the species with (1) few large foramina, (2) many relatively small foramina and (3) a few small foramina. Since majority of the extinct Exechonella species from the Eocene and Miocene deposits (e.g. E. magna, E. paucipunctata, E. laticella, E. orbifera, E. grandis, Exechonella sp.) including the earliest known fossil Exechonella—E. chathamensis—possess relatively few foramina with large luminae (MacGillivray 1895; Brown CÁCERES-CHAMIZO ET AL.72 · Zootaxa 4305 (1) © 2017 Magnolia Press 1956; Cheetham 1966; Canu & Bassler 1920; Duvergier 1921; Cook & Bock 2004; Gordon & Taylor 2015) this character seems to be primitive. Large foramina are also characteristic of ‘Phylactella’ magniporosa Canu, 1918 attributed to Exechonella by Canu and Bassler (1929), but the exact position of this Miocene species is unclear. While Recent species from the E. magna-complex also have such large foramina, species from E. brasiliensis- and E. ampullacea-complexes show a range of morphologies from the frontal shields with fewer relatively large foramina (E. brasiliensis, E. anuhaensis) to those with moderate-sized and more numerous foramina (E. claereboudti n. sp., E. maldiviensis n. sp.). E. verrucosa and species of E. antillea-complex also possess numerous foramina, but in comparison to the E. ampullacea-complex the foraminal rim is much wider and, correspondingly, the foraminal luminae are much smaller transforming to pores or slits. In the species of the E. albitus-complex the number of foramina is strongly reduced and their rims from flattened changed to elevated, conical or tube-like while lacunae became small pores. In E. kleemanni n. sp. from E. verrucosa-complex the foramina are numerous, but they are also elevated with small slit-like lacunae. In contrast, slit-like foraminal openings lay in a small depression in E. rimopora n. sp. from the same species-complex. Thus, it seems that different Exechonella lineages show a general trend towards the reduction of the foraminal luminae in size and, in some lineages in number and, thus, strengthening of the frontal shield. It should be mentioned that some Miocene species as E. annulatopora, E. lucernula (both as Lepralia) (Manzoni 1869), E. prelucioides (as Cheilopora) (Canu & Bassler 1920) and Exechonella sp. (Di Martino & Taylor 2015) had numerous, relatively small foramina. In E. minutiperforata the number of small pore-like foramina could reach a hundred (Di Martino et al. 2017). Naturally, all these changes were surely accompanied by the changes in the degree of the frontal membrane development, and theoretically it is possible that foraminal luminae were finally closed in some species. Additionally, species of E. ampullacea- and E. verrucosa-complexes possess foraminal spines that are solid or hollow calcified projections developed in association with gymnocystal foraminal rims. Moreover, E. ampullacea- complex shows the entire range of the ‘spinosity’: two species have no spines at all (E. ampullacea, E. anuhaensis), and a large foraminal spine develops in each foramen in E. tuberculata and E. erinacea. The rest of the species show different variants of spine development, from small, developed in few foramina to large and common. More complex hollow frontal spines/spikes formed by the fusion of several foraminal rims are seen in E. verrucosa species-complex. Similar spine-like and hollow processes were described in the Miocene Exechonella sp. from Kalimantan (Di Martino & Taylor 2015). Frontal spines developing in association with the foraminal rim also present in E. panamensis n. sp. from E. antillea-complex. This species also possesses spike-like processes on the peristome compensating for the lack of the protective oral spines. Interestingly, peristomial processes are found in the species with frontal spines (E. verrucosa species-complex) as well as without them (in some colonies of E. vieirai n. sp. which also belongs to the E. antillea-complex). Low spike-like projections were recorded in E. claereboudti n. sp. and on some peristomes of E. azeezi n. sp. (both from E. brasiliensis species-complex). Presence of the peristomial spines can be considered as a protective measure against predators. Similar protection could be obviously provided by the long tube-like peristome. While in the species of E. magna-, E. antillea- and E. brasiliensis-complexes it is low and collar-like (as in all aforementioned extinct species), the peristome is considerably higher and tube-like in the species of E. albilitus-complex. Finally, species of the E. ampullacea-complex are characterized by long, tube-like peristome. Species of Exechonella, including E. chathamensis that is an earliest known exechonellid as well as the other genera currently attributed to Exechonellidae (Bock 2016) are devoid of ovicells. Fransen (1986) described internal brooding in E. antillea stressing the polypide degeneration during incubation and the embryo occupying the zooidal cavity. Restudy of the Fransen’s material confirmed a presence of internal embryonic incubation in this species. While anatomical structure of the brooding device remains non-studied, we suggest that it is an internal brood sac in which a thin wall enveloping an embryo is recognizable in the total mounts (Fig. 8B). Such a sac has been described in a number of cheilostomes, independently evolving numerous times in various clades both anascan and ascophoran (Ostrovsky et al. 2006, 2007, 2009a, c; Ostrovsky 2013b). Preparations of Fransen contain two zooids with large early embryos (one consisting of two macromeres only) in the brood sac pointing to the presence of macrolecithal oogenesis in E. antillea. While only early oocytic doublets were seen in two ovaries studied, the large size of the embryos (250 μm in diameter) (and thus, ripe eggs) and the thin wall of the brood sac point to the probable absence of extraembryonic nutrition in this species. Anatomical and ultrastructural research is Zootaxa 4305 (1) © 2017 Magnolia Press · 73REVISION OF THE RECENT SPECIES OF EXECHONELLA required, however, to confirm this suggestion since internal brooders with weakly developed placental analogues are known among Cheilostomata (Ostrovsky et al. 2009b; Ostrovsky 2013a‒b). Cook (1985) mentioned two colonies of Exechonella sp. (as antillea) from Ghana as having distinctly dimorphic zooids with presumed brooding function. While such polymorphism is well-known in some internal brooders (reviewed in Ostrovsky 2013a), it was never reported in any fossil or Recent Exechonella species. In the same time, description, measurements and illustration of these zooids which orifices “are all distinctly larger than the orifice of surrounding zooids of the same astogenetic generation” (Cook 1985, p. 130) could be an evidence of true sexual polymorphism in this species. Restudy of the Cook’s material as well as more colonies with such zooids are required to prove this idea. Di Martino and Taylor (2015) attributed to Exechonellidae the new genus Oviexechonella with peristomial ovicells from Miocene of Kalimantan. While general skeletal morphology clearly points to the umbonuloid frontal shield in this cheilostome, we think it would be better placed in the Actisecidae Harmer, 1957 which representatives possess peristomial ovicells (see above). A similar suggestion could be made with respect to Anarthropora horrida Kirkpatrick, 1888 which was subsequently attributed to Teuchopora by Harmer (1957) and Exechonella by Hayward (1988) (discussed in Tilbrook 2006). Thus, we suggest that the internal brooding is a synapomorphy of Exechonellidae. Foraminal spines are developed in most species of the E. ampullacea-complex in which avicularia are absent. These polymorphs are also missing in most (all?) species of of the E. albilitus-complex having smallest diameter and number of the frontal foramina (and, thus, more solid frontal shield). In contrast, species with the largest foraminal diameter (belonging to E. magna-complex) have well-developed adventitious avicularia of the typical structure that might be expected in the species with less-protected frontal area. E. brasiliensis- and E. antillea- complexes that are intermediate between the two above groups in respect to the number and size of the foramina, possess unusual avicularia with a nipple-like central element. Such avicularia are also present in the species of the E. verrucosa-complex possessing hollow foraminal spines including Miocene Exechonella sp. (Di Martino & Taylor 2015). Thus, these unusual avicularia present in the species with spines as well as without them suggesting that these structures are not defensive devises. Examination of the total mounts of E. antillea (kindly sent us by Dr Fransen, see above), confirmed observation of this author on the bundles of muscles connected with a semi-round operculum that closes the foraminal lumen associated with these polymorphs (Fransen 1986). At present, their function is unknown. Lateral position and the large size of the foramina bearing avicularia, together with a size, position and shape of the mandibles could indicate their ‘ventilation’ function connected with the water circulation from the external medium to the compensation space. The same total mounts showed that most foramina are occluded by bundles of diatome algae (Fig. 8G), thus possibly preventing the free-flow of water through them. While polymorphic zooids were not described in the earliest known E. chathamensis from the Early Eocene (Gordon & Taylor 2015), the typical adventitious avicularia are present in E. orbifera (Canu & Bassler 1920) from the mid-Eocene and E. magna from mid-Miocene (MacGillivray 1895). Similarity in the avicularian structure between those two species mentioned and the conventional type known in many other cheilostomes implies their inheritance by Exechonella from its extinct ancestor. Further, such avicularia were either independently lost or modified in different clades within this taxon. Bad preservation of these polymorphs occurring in two other fossil species (E. prelucioides, E. laticella) does not allow identification of their type (Canu & Bassler 1920). Lidgard et al. (2012, see also Lidgard 2008) suggested that evolution of a number of innovations, including protection, in the Cheilostomata was influenced by micropredators. The large zooidal size that is characteristic in Exechonella, changes in the frontal shield structure, evolution of simple and more complex foraminal spines and the origin of the peristomial spines together with long peristomes and internal brooding fit well with this idea. Biogeography and hidden bryodiversity. During the last years several authors pointed to the existence of so- called species-complexes among Cheilostomata, many of which were treated earlier as widely distributed or even cosmopolitan species. The best example of testing this idea was a complex approach to study cosmopolitan Celleporella hyalina in which cryptic speciation was confirmed using molecular, morphological and experimental (mating) methods (Gómez et al. 2007a‒b). Some recent examples are represented also by the studies of the genera Hippopodina, Stylopoma and Bryopesanser (Tilbrook 1999, 2001, 2006, 2012), Puellina (Harmelin 2006) and Microporella (Harmelin et al. 2011) all of which were based on skeletal morphology. Detailed SEM-study of the tiny morphological characters also in the type specimens preserved in the museum collections allowed CÁCERES-CHAMIZO ET AL.74 · Zootaxa 4305 (1) © 2017 Magnolia Press characterization of the species complexes making the geographic distribution of many of their components more realistic. Our current research on Exechonella is prominent is this respect. Five species complexes recognized during our study show wide geographic distribution, while the vast majority of their species are endemics. Especially interesting is an example of E. antillea that was formerly described from the tropical waters of the Caribbean, on the eastern and western coasts of Atlantic Ocean, in the Mediterranean, Red Sea and California. Our current analysis revealed a species-complex comprising at least five species (E. antillea, E. pumicosa, E. vieirai n. sp., E. panamensis n. sp. and E. floridiana n. sp.) with distribution restricted to the Caribbean Sea and adjacent coastal waters of the western Atlantic, E. harmelini n. sp. from the eastern Mediterranean and E. californiensis n. sp. from the eastern Pacific. A specimen from Bocas del Toro that is reminiscent of E. pumicosa, could belong to another new species. Other specimens previously attributed to E. antillea in the literature (see above) presumably belong to at least two species (including E. gigantea) from west African coastal waters (Cook 1967, 1985) and E. papillata from southern Australia. In the Exechonella ampullacea-complex seven species found in certain areas of the Pacific (E. ampullacea, E. variperforata n. sp. and E. reniporosa n. sp. found in the Great Barrier Reef, E. tuberculata and E. sp. cf. discoidea in the southern Australia, E. erinacea in the Philippines and E. anuhaensis in the Solomon Islands), and two others in the Red Sea (E. safagaensis n. sp.) and the Indian Ocean, Maldives (E. maldiviensis n. sp.). It is possible to suggest that in both the above mentioned species-complexes the centre of speciation was located in a certain area (Caribbean, west Pacific), that could ‘export’ the new species to the other parts of the world ocean. However, much more data on the recent species distribution are required for any conclusions. The species of the E. brasiliensis-complex are found in three different oceans ‒ near the Atlantic coast of Brazil (E. brasiliensis), in the Red Sea and north Indian Ocean (E. azeezi n. sp., E. claereboudti n. sp.) and in the west Pacific (E. similis n. sp.). One more undescribed species from this complex has been collected from the Ningaloo Reef, western Australia (www.bryozoa.net). Whereas two species from the E. albilitus-complex were found in the Red Sea (E. elegantissima n. sp. and E. vavrai n. sp.), one species from the Maldives (E. nikitai n. sp.), and another from the Great Barrier Reef (E. elegantissima n. sp.), E. albilitus itself is known from the Solomon Islands, Pacific Ocean. Among the species from the E. verrucosa-complex, two are known from the Philippines (E. verrucosa, E. rimopora n. sp.), a third from the Solomon Islands (E. loslosensis), a fourth from the Red Sea (E. kleemanni n. sp.) and the fifth from the Atlantic Ocean (E. spinosa). Specimens from Bocas del Toro, Panama, and from Komodo (Winston & Heimberg 1986) could represent two more species. Whereas most of the above-mentioned species are endemics, two show a wider distribution. E. azeezi n. sp. found in the Red Sea and at the Maldive Islands, and E. elegantissima n. sp. has been recorded in the Red Sea and the Great Barrier Reef. Recently, a similar situation was described in the case of some tropical species of the genus Microporella. While most of the species were know either from only one locality or from a certain area, one species showed very wide distribution suggesting an artificial transportation (Harmelin et al. 2011, see also Harmelin et al. 2012). During our study 18 new Recent species of Exechonella were described which expands the known diversity. Analysis of the literature presented above points to the existence of at least several more species (in the Caribbean, Atlantic and Indo–Pacific). For instance, judging from the published descriptions, the E. magna-complex includes several recent species from Philippines (Canu & Bassler 1929), South China Sea (Harmer 1957), Solomon Islands (Tilbrook 2006) and Australia (Wass & Yoo 1983; Cook & Bock 2004) described under this name (see also above). While some of the specimens kept in the museums may represent the same species, others are clearly different (discussed in Tilbrook 2006). A similar situation obviously exists with a number of species described under the names E. tuberculata, E. antillea and E. brasiliensis (see above), and careful reinvestigation of the specimens from the largest bryozoan collections (such as in the Natural History Museum, London, and Museum of Tropical Queensland, Townsville) is badly needed to resolve accumulated problems. Also, keeping in mind the size of unsampled tropical areas we expect a considerable increase of the recorded Exechonella species in future. Acknowledgements We sincerely thank Drs J.-G. Harmelin, Centre d'Océanologie de Marseille, Université de la Méditerranée, D.P. Zootaxa 4305 (1) © 2017 Magnolia Press · 75REVISION OF THE RECENT SPECIES OF EXECHONELLA Gordon, New Zealand Institute of Water and Atmospheric Research, Wellington, P.E. Bock, Museum Victoria, Melbourne, L.M. Vieira, Universidade Federal de Pernambuco, Recife, C.H.J.M. Fransen, The National Museum of Natural History, Leiden, R. Cumming, Museum of Tropical Queensland, Townsville, M. Ekins, Queensland Museum, Brisbane, and N. Sokolover, Tel Aviv University, for sending us photos, specimens and kind advise. L.M. Vieira also reviewed the manuscript, and D.P. Gordon provided very valuable help and advice on taxonomical matters. Drs A. Hoggett and L. Vail, Lizard Island Research Station, Australian Museum, kindly provided all the necessary help during field works on the Great Barrier Reef. Dr. J. Winston, Smithsonian Institution, Washington, D.C., generously facilitated material from her personal collections and reviewed the manuscript. Dr E. Di Martino, The Natural History Museum, London, kindly shared the data on the bryozoan collection of the University of Bordeaux, and Mr B. Cahuzac, University of Bordeaux, was very helpful explaining the problematic circumstances surrounding publication of the type species. Drs J. Souto-Derungs and T. 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