Zoological Journal of the Linnean Society , 2007, 150 , 177?210. With 7 figures ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 177?210 177 Blackwell Publishing Ltd Oxford, UK ZOJZoological Journal of the Linnean Society 0024-4082The Lin- nean Society of London, 2007? 2007 150 1 177210 Original Article PHYLOGENY OF THE ZOROASTERIDAE C. MAH *E-mail: brisinga@gmail.com Phylogeny of the Zoroasteridae (Zorocallina; Forcipulatida): evolutionary events in deep-sea Asteroidea displaying Palaeozoic features CHRISTOPHER MAH* Department of Invertebrate Zoology, National Museum of Natural History, MRC 163, PO Box 37012, Smithsonian Institution, Washington, DC, USA Received March 2006; accepted for publication August 2006 The Zoroasteridae comprise a small but widespread family of asteroids distributed throughout the deep sea. Although poorly understood, they are often collected in the hundreds, suggesting that they occupy important eco- logical roles. A phylogenetic analysis including 24 terminal taxa and 70 morphological characters was performed, resulting in a single most-parsimonious tree. The tree separated zoroasterids with open, reticulate skeletons (e.g. Myxoderma ) as more basal than those with more heavily armored, imbricate skeletons (e.g. Zoroaster ), which were more derived. In addition to agreement with established genera, a new genus is supported by the phylogeny as the sister taxon to Myxoderma . The cladistic analysis was performed in conjunction with a revisionary survey of zoro- asterid species, resulting in taxonomic changes to species in nearly every genus. Bathymetric and physiographic shifts were observed between the reticulate and imbricate zoroasterid clades. Zoroasterids possess a single marginal plate series, which occurs in basal sister-group neoasteroids (crown-group asteroids). Phylogenetic results suggest that the morphololgical resemblance between zoroasterids and Palaeozoic taxa, such as Calliasterella , is convergent but a paraphyletic Zoroasteride cannot be rejected and remains consistent with basal crown-group affinities. Although the phylogenetic position of the Eocene Zoroaster aff. fulgens was not strongly supported, its presence within a derived cluster of Zoroaster spp. suggests a relatively recent (i.e. Cenozoic) diversification into the deep sea. Taxonomic revisions, and geographical and bathymetric range extensions are also included. ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 150 , 177?210. ADDITIONAL KEYWORDS: basal diversification ? morphology ? Neoasteroidea ? onshore ? offshore ? taxonomy ? Zoroaster . INTRODUCTION Starfishes within the family Zoroasteridae are promi- nent members of the deep-sea megafauna, occurring exclusively in bathyal to abyssal habitats ( ? 200? 6000 m) in the Atlantic, Pacific and Indian Ocean basins. Zoroasterids are distinctive, possessing a small disc and long tapering arms, and can often reach large sizes with arm length approaching 20.0 cm. Colour in zoroasterids (Alton, 1966: 1709; my unpubl. obs.) varies from white to reddish orange. Zoroasterids are most diverse in the Indo-Pacific but further study (Howell et al ., 2004) has indicated that there is greater diversity in the Atlantic than was previously perceived. Although their ecological role is poorly understood, zoroasterids are frequently collected in high densities, suggesting that they occupy important positions in deep-sea ecosystems. Alton (1966: 1709) reported a collection of nearly 5000 individuals of Myxoderma platyacanthum in the Astoria Canyon off the Oregon coast. Verrill (1884: 217) reported approximately 200 specimens of the Atlantic Zoroaster fulgens ( = Z. diomedae ) from a single station. Myxoderma platyacanthum was one of the five most common invertebrates caught during a 1994 upper continental slope trawl along the west coast of the United States (Lauth, Syrjala & McEntire, 1998). Eocene Zoroaster specimens from Seymour Island, Antarctica (Blake & 178 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 177?210 Zinsmeister, 1979, 1988) were abundant and did not display any evident transport prior to final burial, sug- gesting high densities in life. Zoroasterid biology is poorly known. Seasonality and other aspects of reproductive biology in the Atlan- tic Zoroaster fulgens have been studied by Tyler et al . (1984) and Grant (1985). Howell et al . (2003) studied feeding in Zoroaster longicauda ( = Z. fulgens ) using fatty acid biomarkers. Finamore et al . (1991) extracted nine polydrydroxy steroids and two steroid glycosides from the north-east Pacific Myxoderma platyacan- thum . Oxygen consumption for Zoroaster evermani was recorded by Webster (1975). Based on gel electro- phoresis, Myxoderma sacculatum and three other genera of deep-sea asteroids displayed high genetic variability in contrast to the low variability expected from the deep-sea environment (Ayala et al ., 1975). In situ observations of the Atlantic Z. fulgens have been reported by Rice et al . (1982: 66, fig. 2e) and Howell et al . (2003: 201, fig. 4E). In situ observations by Pawson (1982: 133) revealed population densities of Z. fulgens in some sites as high as 3.9 specimens per 1000 m 2 . Ascothoracid endoparasites have been observed in Pacific and Atlantic Zoroaster species (Grygier, 1985; Stone, 1987). Taxonomic accounts, keys, and studies in classifica- tion of zoroasterids include those of Sladen (1889: 416), Fisher (1919a, 1919b), H.L. Clark (1920: 94); Downey (1970) and McKnight 1977). Fisher (1919b) summarized Indo-Pacific zoroasterids. Zoroasterids in New Zealand were summarized by McKnight (2006). Alcock (1893a, 1893b, 1895) studied zoroasterids in the Indian Ocean. Atlantic zoroasterids were studied by Downey (1970) and Clark and Downey (1992). Phylogenetic studies including zoroasterids have supported a basal phylogenetic position within the Forcipulatacea (also referred to as forcipulates), sug- gesting that the zoroasterids may demonstrate characteristics intermediate between Palaeozoic and post-Palaeozoic asterozoans. The Forcipulatacea has been supported as the sister clade to the other two major asteroid lineages, the Valvatacea and the Spinu- losacea (Blake, 1987). Downey (1970) argued for inclusion of the Palaeo- zoic Calliasterellidae, which includes Calliasterella , with the Zoroasteridae within a new order, the Zorocallida. McKnight (1977) disagreed with this placement of the Calliasterellidae and returned the Zoroasteridae to the Forcipulatida. Zoroasterids were included in the first apomorphy-based phylo- genic studies to support post-Palaeozoic Asteroidea as a monophyletic group (Blake, 1987; Gale, 1987). Zoroasterids occupy similar positions in both phy- logenies. Gale (1987) presented forcipulatidans as derived, including the zoroasterids as the sister clade to the remaining forcipulatidans. Blake (1987) placed the zoroasterids as the sister clade to the Asteriidae and the Heliasteridae, but placed the Brisingida at the base of the forcipulate clade. Blake (1987) recognized that only a single marginal plate series is present in the Zorocallina, a feature that was also present in asteroids basal to the crown-group Asteroidea, including Trichasteropsis and Calliasterella . Blake (1990) described two new Jurassic zoroasterid-like asteriids and presented implications for these taxa on a phylogeny of the Forcipulatida. Based on morphology, Mah (2000) supported zoroas- terids as the sister group to Neomorphaster , but showed a paraphyletic Pedicellasteridae as basal to the zoroasterids and more derived forcipulates. Com- parisons between late Palaeozoic asteroids and zoro- asterids were made by Blake & Elliott (2003). A phylogenetic analysis of asteroids from the Ordovician to the Recent, including Zoroaster and crown-group sister taxa, was presented by Blake & Hagdorn (2003). Knott & Wray (2000) presented a tRNA and COI- based molecular phylogeny showing Myxoderma , as an exemplar for the Zoroasteridae, as basal to other forcipulate asteroids, including brisingidans. How- ever, their results also display pterasterids and echin- asterids on a branch including mostly forcipulate taxa, suggesting the need for further work. Early hypotheses of phylogenetic relationships among the Zoroasteridae were limited to anecdotal comments. Sladen (1889: 426) observed a close affinity between Pholidaster and Zoroaster . Fisher (1919a: 485), noted that the plates composing the abactinal skeleton in Pholidaster and Cnemidaster were similar to those in Zoroaster . Downey (1970: 5) perceived Doraster as most closely related to Cnemidaster . Myx- oderma was distinguished from other zoroasterid gen- era based on a phylogenetic hypothesis proposed by Blake (1990). Howell et al . (2004) discovered reproduc- tive isolation among morphotypes within the Atlantic Zoroaster fulgens from the Porcupine Seabight. A phylogenetic revision of the Zoroasteridae will establish an evolutionary hypothesis for a major clade of deep-sea invertebrate megafauna, allowing for an assessment of macroevolutionary patterns, such as onshore?offshore migrations (i.e. bathymetric shifts) as outlined by Jablonski & Bottjer (1988) and would establish a phylogenetic framework for the disparate data available for zoroasterids. A phylogenetic hypoth- esis for the Zoroasteridae also permits exploration of relationships between basal crown-group Asteroidea and its fossil sister taxa, such as Trichasteropis (Blake & Hagdorn, 2003), allowing further insight into diver- sification events near the base of the post-Palaeozoic lineage. In addition to development of a phylogenetic hypothesis, a diagnostic key (Appendix 3) and a taxo- nomic summary of the Zoroasteridae are presented. PHYLOGENY OF THE ZOROASTERIDAE 179 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 177?210 MATERIAL AND METHODS I NGROUP AND OUTGROUP CHOICE All seven zoroasterid genera currently recognized as valid (summarized by Clark & Mah, 2001) were included as ingroup taxa. Prognaster Perrier 1891, described from juvenile individuals, is a synonym of Zoroaster (Clark & Downey, 1992: 508) and was not included in the matrix. The type species of each genus was included in the analysis. With the exception of Zoroaster , all zoroasterid genera included fewer than four putative species each, many of which are morpho- logically similar to the type. In most genera, differ- ences between species was minimal and monophyly for each genus could be tested from the included spe- cies. A full size and geographical range of species was examined where possible. Although a comprehensive revision of Zoroaster was not attempted, a significant number of species were included in the analysis (summarized in Fig. 1, Figure 1. Cladogram of the Zoroasteridae. Node numbers are indicated in bold. Bootstrap support is indicated as %. Bremer values are indicated in shadow font. Zoroaster microporus OG: Calliasterella americana OG: Trichasteropsis weismanni OG: Ampheraster marianus OG: Neomorphaster margaritaceus Myxoderma platyacanthum Myxoderma sacculatum "Doraster" qawashqari "Zoroaster" perarmatus "Zoroaster" evermanni Bythiolophus acanthinus Doraster constellatus Cnemidaster wyvilli Mammaster sigsbeei Pholidaster squamatus Zoroaster carinatus Zoroaster actinocles Zoroaster macracantha Zoroaster magnifcus Zoroaster ophiactis Zoroaster ophiurus Zoroaster spinulosus Eocene-Zoroaster fulgens Zoroaster fulgens 58% 55%80% 83% 57% 96% 93% 56% 70% 51% 64% 59% 2 4 2 40 25 39 28 27 26 38 37 31 30 29 36 35 34 33 32 180 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 177?210 Appendix 2), and those which were not were reviewed from the literature and determined to be consistent or not with phylogenetic-based definitions. Downey (1970: 13) provided a checklist summarizing several taxonomic changes in zoroasterid taxonomy up to that time. Although Clark & Mah (2001) summarized 25 putative species and subspecies of Zoroaster , their list failed to include several of the taxonomic changes summarized by Downey (1970: 13). Many species of Zoroaster are problematic. Most of the Zoroaster species described by Alcock (1893a) are either unavailable for study and/or are incompletely described. Material believed to be Alcock?s type series is present in the Mus?um national d?Histoire naturelle (MNHN) in Paris, but the status of this material was not confirmed. Zoroasterid material described by Hayashi (1943, e.g. Z. orientalis ) is apparently lost (T. Fujita, pers. comm.) and may have been destroyed during World War II. Zoroaster tenuis is based on juve- nile material and was not included in the matrix. All available Zoroaster species were entered into the anal- ysis, including the Eocene fossil Zoroaster aff. fulgens from Seymour Island, Antarctica (Blake & Zinsmeis- ter, 1979, 1988). A key to extant genera is provided (Appendix 3) along with a comprehensive species summary. Two fossil and two living taxa were included as out- groups. The two fossil species, Trichasteropsis weis- manni (M?nster, 1843) and Calliasterella americana Kesling & Strimple, 1966 were supported by Blake (1987, 1990) and Blake & Hagdorn (2003) as taxa basal to the post-Palaeozoic Asteroidea. The Triassic Trichasteropsida, including Trichasteropsis , was in- cluded as the sister taxon to the extant Forcipulatida. The Pennsylvanian Calliasterella americana shows outward morphological similarity with zoroasterids (Downey, 1970) and the genus Calliasterella has been supported as proximal to the base of the post-Palaeo- zoic asteroid lineage (Blake, 1987; Blake & Hagdorn, 2003). Pedicellasterids have been supported as basal to the derived forcipulate clades by Blake (1990), Mah (2000) and Blake & Hagdorn (2003). Because a comprehen- sive assessment of the group is unavailable and pedi- cellasterids display characters plesiomorphic to other forcipulates, pedicellasterids have not been supported as monophyletic by current studies (e.g. Mah, 2000; Blake & Hagdorn, 2003). Ampheraster marianus was included as an outgroup based on the presence of shared characters with zoroasterids, including the presence of four rows of tube feet and straight pedi- cellariae. Fisher (1928: 84) observed morphological resemblance between A. marianus and Myxoderma . The monotypic Neomorphasteridae is represented by Neomorphaster , which was supported as the sister taxon to Zoroaster by Mah (2000). Subsequent review of morphological characters in Neomorphaster , includ- ing the presence of two rather than a single marginal plate series, suggests convergence rather than close relationship with Zoroaster . Neomorphaster is in- cluded as a test of phylogenetic affinities between the Neomorphasteridae and the Zoroasteridae. S PECIMEN ANALYSIS The matrix (Appendix 2) included 24 taxa and 70 mor- phological characters (summarized in Appendix 1). Data were entered into MacClade 3.08 and exported into PAUP 4.10b10 (Swofford, 2003). Characters were derived primarily from skeletal morphology except for those characters differentiating Palaeozoic from post- Palaeozoic taxa, which were derived primarily from Blake & Hagdorn (2003) and Blake & Elliott (2003). Definitions and terms follow those of Blake (1987) and Clark & Downey (1992). Characters are referred to by numbers indicated in Appendix 1. Specimens were obtained primarily from collections of the National Museum of Natural History (NMNH, Washington, DC) invertebrate zoology and palaeontol- ogy collections. Other material was obtained from the California Academy of Sciences (CASIZ) in San Fran- ciscso, California, the Los Angeles County Museum of Natural History (LACM) in Los Angeles, California, Scripps Institution of Oceanography (SIO) in San Diego, California, and the Museum of Comparative Zoology (MCZ) in Cambridge, Massachusetts. Wet and dry specimens across a broad size and geographical range were examined where possible. Trees were generated using the branch-and-bound search algorithm with default rooting (tree rooted at internal node with basal polytomy). Alternative root- ing assumptions (ingroup assumed monophyletic) did not alter the tree topologies produced. Characters that were unavailable or incompatible between fossil and extant taxa were entered as question marks. Charac- ters were analysed as unordered and run under ACCTRAN character optimization. Bremer support was calculated using PAUP?s branch-and-bound search algorithm retaining sequentially higher num- bers of trees beyond those which were most parsimo- nious until branches were observed to decay from consensus tree diagrams. Exploration of other tree topologies was accomplished using the tree editor in MacClade 3.08. RESULTS G UT CONTENT ANALYSIS Wet and dried zoroasterid specimens in the National Museum of Natural History (NMNH) collections in Washington, DC, were examined for gut contents PHYLOGENY OF THE ZOROASTERIDAE 181 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150 , 177?210 (Table 1). Results are consistent with prior accounts by Carey (1972) and Jangoux (1982). Stomach con- tents were recorded for taxa representing the most diverse zoroasterid lineages. Although all genera were surveyed, gut contents were not available for every genus. Recurring prey items included gastropods (see Figs 3F, 4F) and bivalves, although crustacean remains and ophiuroid and echinoid plate fragments were also present. Inorganic sediment was present in all of the specimens examined. Foraminifera tests, pteropod shells and worm tubes were also present, but it was unclear if these were taken as prey or if these were components of the ingested sediment. Carey (1972) classified the two species of zoroast- erids in his survey of asteroid food sources in the north-east Pacific Ocean as omnivores based on the relatively incomplete sampling of food items recov- ered. A broader sampling of gut contents suggests that zoroasterids are predatory on infaunal invertebrates. Howell et al . (2003) showed that although Zoroaster longicauda ( = Zoroaster fulgens) had a fatty acid com- position similar to those of three species of brisingid asteroids, which are suspension feeders, gut contents alone indicated a benthic food source, suggesting that Zoroaster may derive its food from multiple sources. Zoroaster longicauda (= Zoroaster fulgens) has also been observed in association with deployed bathyal food falls (carcasses of the porpoise Phocoena phoc- oena) (Kemp et al., 2006), suggesting that some zoroasterids also show opportunistic scavenging behaviour. PHYLOGENETIC RESULTS The search produced a single most parsimonious tree with a tree length of 139 steps (Fig. 1), a Consis- tency Index (CI) = 0.6835 and a Retention Index (RI) = 0.8394. The Zoroasteridae is upheld as mono- phyletic. Calliasterella is supported as the sister taxon to a lineage including Trichasteropsis + Ampheraster. Neomorphaster?s relationship to the Zoroasteridae and the more basal forcipulates is unclear. Three primary ingroup clades resulted from the phy- logenetic analysis (Fig. 1). The phylogenetic results indicate that Zoroaster, Myxoderma and Doraster sensu Downey (1970) and Clark & Mah (2001) are paraphyletic. The remaining five zoroasterid genera, Bythiolophus, Doraster, Cnemidaster, Mammaster and Pholidaster, were not shown to be paraphyletic, but are either monotypic or include few species (N ? 3) showing few morphological differences. Although paraphyly was observed in Zoroaster and Myxoderma, characters supporting those clades were largely consistent with taxonomic definitions for those genera as outlined by Clark (1920) and Fisher (1928). Sagenaster gen. nov. (= Zoroaster evermanni) demon- strated close affinities to Myxoderma as originally indicated by Fisher (1905) but was supported as sep- arate from other established zoroasterid genera. Table 1. Gut contents from genera of Zoroasteridae E18505 Doraster constellatus sediment, foraminifera (foram) E18570 Doraster constellatus bivalve, gastropod E26549 Doraster constellatus bivalves E34980 Doraster constellatus gastropods, bivalves E34933 Doraster constellatus 2 gastropods, bivalves E18511 Cnemidaster sigsbeii sediment, worm tubes E34073 Cnemidaster sigsbeii gastropod, sediment E18565 Cnemidaster sigsbeii sediment, gastropod (rissoid?) E12460 Cnemidaster sigsbeii bivalve (shiny), gastropod (rissoid?) E12461 Cnemidaster sigsbeii sediment (foram and pteropod tests), crustaceans (cumacean?), gastropods (Rissoidae-cf. Alvania sp.) E14787 Myxoderma platyacanthum bivalves, echinoderm ossicles (ophiuroid) Fisher, 1928: 49 Myxoderma sacculatum ?a shrimp? E10357 Sagenaster evermanni gastropod, sediment Alton, 1966 Sagenaster evermanni echinoderm fragments, spicules, crustacean isopods, sediment Alcock, 1893 Zoroaster carinatus crustaceans, molluscs E1804 Zoroaster carinatus philippinensis dark mud, sediment, gastropod, bivalve fragments E4944 Zoroaster fulgens sediment, bivalves E26348 Zoroaster fulgens bivalves, gastropods, sediment 37009 Zoroaster microporus (HOLOTYPE) bivalve E15986 Zoroaster ophiurus mud, gastropod, worm tubes, echinoid fragments Alton, 1966 Zoroaster ophiurus ophiuroid, crustacean fragments, sediment E18505 Doraster constellatus sediment, foram test? (gastropod) E18570 Doraster constellatus bivalve, gastropod 182 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 The tree (Fig. 1) is consistent with prior hypotheses of forcipulate phylogeny (Blake, 1990) showing a split between Myxoderma and other zoroasterids. The ?reticulate? zoroasterids, Myxoderma and Sagenaster, display characters plesiomorphic with basal forcipu- lates (sensu Blake, 1990; Blake & Hagdorn, 2003), including Trichasteropsis, a Triassic basal post- Palaeozoic asteroid (Blake, 1987), and Ampheraster, a pedicellasterid supported as basal to the forcipulates (Mah, 2000). Sagenaster?s affinity to Myxoderma was outlined by Fisher (1905: 317) who initially placed Zoroaster evermanni into Myxoderma [= Zoroaster (Myxoderma)]. Bremer support for all nodes is low (Fig. 1). The node supporting monophyly of the Zoroasteridae decays in one step. Branch support for the reticulate zoroasterids supporting Myxoderma + Sagenaster gen. nov. decays in two steps. The zoroasterid genera with imbricate (i.e. plates are abutting with overlap- ping edges) skeletons are upheld by a Bremer value of four, but support for phylogenetic structure within the clade is poor, with the exception of the Cnemi- daster + Mammaster relationship, which decays in two steps. All the remaining branches decay in a sin- gle step. Bootstrap support mirrors Bremer support values (Fig. 1). The reticulate zoroasterids are moder- ately well supported (83%). Myxoderma itself shows similar support (80%). Myxoderma sacculatum and M. qawashqari are moderately supported (55%). The imbricate zoroasterids are relatively well supported (93%). The Cnemidaster + Mammaster clade is rela- tively well supported (96%), but the [{(Cnemidaster + Mammaster) + Doraster} + Bythiolophus] clade is mod- erately to poorly supported (57%). The Pholidaster + Zoroaster clade is moderately to poorly supported (56%). Zoroaster itself is similarly supported (51%). Although resolution within Zoroaster is poor, the clades for Z. carinatus (70%) and Z. fulgens (64%) are moderately well supported. The node containing the remaining Zoroaster species included in the analysis was moderately to poorly supported (59%). Calliasterella is separated from post-Palaeozoic taxa by 33 characters derived from Blake & Hagdorn (2003). Monophyly of the Zoroasteridae is supported by 16 characters (summarized in Appendix 1). These include squarish-blocky ambulacrals (8.12), the presence of superambulacrals, which are frequently reduced (8.6, 8.7), the presence of straight pedicellariae (7.1), a fan-like array of adambulacral furrow spines (4.4), alternately carinate adambulacral plates (4.1, 4.2), the presence of secondary spines (3.6), enlarged acti- nolateral spines (3.3), actinolaterally orientated acti- nal plates (3.2), sharp spine tips (1.24), recurved secondary spines (1.25), flattened abactinal plates (1.26) and the presence of primary and secondary spines (1.5, 1.23). TAXONOMIC RESULTS ? THE RETICULATE ZOROASTERIDS Zoroasterids possessing reticulate skeletons were sup- ported on node 28 and form the sister clade to the imbricate zoroasterids (Fig. 1, node 37). This included the two nominal species of Myxoderma and three species which have not been previously allied with Myxoderma (Fig. 1). These taxa were plesiomorphic with basal Forcipulatacea, including the extant Ampheraster and the Triassic Trichasteropsis. Char- acters shared between these taxa include but are not limited to reticulated abactinal and actinolateral plate patterns (1.1, 3.4, Fig. 2B, E, F), cruciform?lobate sur- face, marginal and actinolateral plates (1.2, 1.6, 1.11, 2.6, 3.10, e.g. Fig. 2G), and primary spines present on all plates (1.4, Fig. 2E, F). Taxa on node 28 possess a reticulated abactinal skeleton with relatively undiffer- entiated cruciform plates all of which bear a primary spine (Fig. 2E, F). Node 28, uniting Myxoderma and Sagenaster gen. nov., is supported by quadrate? cruciform actinolateral plates (3.10), strongly lobate cruciform marginal plates (2.6, Fig. 2F, G), presence of primary spines on marginal plates (2.4, Fig. 2E, F), presence of primary spines on carinal plates (1.18, Fig. 2E), presence of strongly lobate carinal, disc and other arm plates (1.6, 1.11, Fig. 2G), and low ridged carinal series (1.13, e.g. Fig. 2F). Although most species of Zoroaster were supported together (node 33), one species, Z. evermanni (Fig. 2E? G), displayed closer morphological affinities to Myxo- derma (Fig. 1), having a reticulate skeleton, cruciform disc and body plates, and primary spines on most to all plates. Zoroaster evermanni (node 28) is supported as the sister branch to the other four taxa included on the branch (Fig. 1) and is supported here as the new genus, Sagenaster, which is defined and summarized below. Fisher (1905) originally described Zoroaster evermanni as a member of the genus Myxoderma [originally described as subgenus Zoroaster (Myxo- derma)]. However, the internal buttress (character 8.8, Fig. 2D) present in Myxoderma is absent in Z. evermanni, and Fisher (1919a) eventually placed Z. evermanni within Zoroaster. Based on examination of the syntype series, Zoro- aster longispinus is reassigned to Myxoderma (Fig. 1). One syntype (NMNH 34385) falls into what would be considered Myxoderma along with a fouth specimen identified by W. K. Fisher (NMNH 9626). NMNH 34385 is designated the lectotype for this species. The remaining syntype specimens (NMNH 34384 and 34386) of Z. longispinus are juvenile specimens of Zoroaster sp. Those in juvenile Zoroaster have imbri- PHYLOGENY OF THE ZOROASTERIDAE 183 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Figure 2. A, abactinal surface juvenile specimen, Myxoderma sacculatum (USNM E1149). B, abactinal surface, adult specimen, M. sacculatum (USNM E3596). C, ambulacral ossicles and superambulacral ossicles (SA), M. sacculatum (USNM E3596). D, same specimen, arm viewed head-on showing ambulacrals (AMB), internal buttress (IB), Sagenaster evermanni (USNM 16023). E, abactinal surface, disk and arms. F, arm plates. G, abactinal disk and arm plates showing plate mor- phology (coelomic view, M. sacculatum USNM E13990). IB AMB A. B. D. E. F. G. C. SA 184 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 cating polygonal plates (e.g. Fig. 6G, Sumida, Tyler & Billett, 2001). Examination of juvenile specimens of Myxoderma sacculatum (R = ?1.0 cm) shows a reticulate skeleton with cruciform plates present in Z. longispinus Ludwig, 1905 (Fig. 2A). Examination of syntypes and other material of Zoroaster longispinus Ludwig, 1905 and Zoroaster perarmatus H. L. Clark, 1920 indicates that Z. perarmatus is a junior synonym of Z. longispinus Ludwig, 1905. Specimens of Z. longispinus are much smaller (R ? 4.0 cm) than the larger Z. perarmatus (R = 9.5 cm). However, both specimens show identical numbers of furrow spines (three per plate), similar spination patterns, including a spine on the centrodorsal plate, and identically shaped carinal plates. Myxoderma derjungini Djakonov, 1950 is a syn- onym of Myxoderma sacculatum (Fisher, 1905). Djakonov (translated from 1950: 91, fig. 87) differen- tiated this species based on the checkered pattern of ?tubercles? (= spine bases) on alternate series of the longitudinal and transverse rows. However, spine bases in M. sacculatum, especially on the actinolat- eral plates (as figured by Djakonov, 1950: fig. 87) adjacent to the adambulacral series show variable occurrence and are broken off easily in trawl nets. In addition to this single character difference, charac- ters such as the enlarged, sacculate terminal plate, the robust spines and slimy?fleshy membrane are shared with M. sacculatum. Myxoderma sacculatum occurs over a wide bathymetric (91?2012 m) and geo- graphical range (southern California to Bering Sea) making it co-terminous with M. derjungini in the Okhotsk Sea. Based on phylogenetic results (Fig. 1) Doraster qawashqari Moyana & Larrain, 1976 is removed to the genus Myxoderma. Doraster was diagnosed by Downey (1970) as having enlarged, stellate abactinal plates, and a thickened disc with a smooth, skin-covered sur- face. A larger size range and greater number of Doraster specimens was studied revealing spination over the surface of several specimens. The presence of well-developed adradial plates in large specimens, which are absent to reduced in the smaller type spec- imens, was also observed. Large-sized Myxoderma sac- culatum (R < 20 cm) display significant variation relative to smaller specimens, including a more inflated disc and more imbricated arm and disc plates. Doraster qawashqari Moyana & Larrain, 1976 has both of these features. Primary disc and arm plates in Doraster con- stellatus differ from those in D. qawashqari. Those in the former are more weakly lobate and more imbricate than those in the latter, which are strongly lobate and show a more reticulate pattern. Characters observed by Moyana & Larrain (1976) were distorted by the large size of the specimens, which affected interpreta- tion of the characters used to diagnose D. qawashqari. These characters support placement of Doraster qawashqari within Myxoderma. A Miocene specimen identified as Doraster by Yamaoka (1987: pl. 2, fig. 4) is also probably Myxo- derma based on the apparent reticulated skeleton observed on the arms and the shape of the disc and arms. This specimen was not examined. TAXONOMIC RESULTS ? THE IMBRICATE ZOROASTERIDS Zoroasterids, including Zoroaster and the remaining zoroasterid genera possessing imbricate skeletons, were supported on node 37 (Figs 3?6). These taxa are considered derived relative to the outgroup forcipu- lates and to the reticulate zoroasterids. This clade is supported by 18 characters, including single pores (8.10, Fig. 4A), actinolaterals in transverse series (3.11, Fig. 4B), the absence of quadrate actinolateral plates (3.7), closely distributed secondary spines (3.6), densely distributed imbricate actinolaterals (3.4, 3.5), the presence of weakly lobate marginal plates (2.5), overlapping primary plates (1.22), presence of a lobate centrodorsal (and absence of quadrate centrodorsal, 1.20, 1.21), enlarged disc circlet plates (1.16, Fig. 4A, G), absence of a level carinal series (1.15, Fig. 4E), the presence of lobate carinals (1.12), the presence of polygonal?lobate arm plates (1.7), the presence of primary and secondary abactinal spines (1.4, 1.5), presence of weakly lobate disc plates (1.3), and an imbricate skeletal arrangement (1.1, Figs 3?6). Taxa on node 37 were separated into two primary lineages, which included Bythiolophus, Cnemidaster (including synonym Mammaster) and Doraster on node 31 (Figs 3, 4) and the remaining taxa supported on node 36, which included Pholidaster and all ?true? Zoroaster species (Figs 5, 6). The former clade (node 31) was supported by three apomorphies, the presence of an internal buttress (8.8, Fig. 2D), weakly lobate actinolaterals (3.8), and a discontinous arm and disc (1.19) whereas the latter clade containing Zoroaster and Pholidaster is supported by the presence of weakly lobate actinolaterals (3.8). This latter clade also supports the genus Zoroaster with one character (8.7, reduced superambulacral plates). Pholidaster is supported as the sister taxon to the ten species repre- senting Zoroaster in the matrix. Zoroaster carinatus and Z. fulgens are supported as basal members to a cluster of seven Zoroaster spp., which demonstrated few to no character differences at this level of resolu- tion. This cluster included the Eocene Zoroaster ful- gens described from Seymour Island, Antarctica. Phylogenetic data support Mammaster Perrier, 1894 as a synonym of Cnemidaster Sladen, 1889 (Fig. 4). A close relationship between the two has been suggested by Fisher (1928: 32) and Clark (1920: 95). The two genera are relatively well supported as sister PHYLOGENY OF THE ZOROASTERIDAE 185 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Figure 3. Bythiolophus acanthinus Holotype (USNM 37011). A, arm and disk. B, carinal and marginals on close-up of arm. C, carinals and marginals from paratype of Zoroaster macracanthus.(MCZ 2499) D, lateral view showing actinolateral spination. Doraster constellatus Paratype (USNM E11357). E, abactinal view, disk and arms. F, oral region with prey (PR). Ring of pedicellariae (PED, character #7.3) adjacent (USNM 34980). G, lateral view (USNM 1080506). Scale bar = 0.5 cm. A. B. C. D. E. F. G. PR PED 186 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Figure 4. Cnemidaster wyvillei (USNM 40566). A, abactinal surface. B, lateral view. C, abactinal surface, juvenile specimen. Cnemidaster ( = Mammaster) sigsbeii (USNM E34073). D, lateral view. E, arm showing single marginal plate series. F, oral view showing gastropod prey item in mouth. G, abactinal view, disk and arms. Scale bar = 0.5 cm. A. B. C. D. G. E. F. PHYLOGENY OF THE ZOROASTERIDAE 187 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 taxa (bootstrap = 96%, Bremer = 2) but are separated by only two characters, one of which is size-related. The presence of adradial plates (1.8) is described as present in Cnemidaster but absent from Mammaster. Adradial plates are present in C. wyvilli with R ? 20.5 cm but absent from moderate to small speci- mens (R ? 10 cm). Specimens of Mammaster recorded in Clark & Downey (1992) and those observed in this study do not show R larger than 7.1 cm. Small to mod- erately sized specimens of Cnemidaster display more similarity with comparably sized Mammaster than with larger Cnemidaster. Other characters indicated by Clark (1920: 96) to separate the two genera included different numbers of Figure 5. Pholidaster A, abactinal surface. P. squamatus (USNM 40280). B, P. distinctus (Holotype). C, P. squamatus arm surface close-up (USNM 40280). D, P. distinctus arm surface close up. Zoroaster microporus E, holotype, abactinal disk and arms (USNM 37009). F, abactinal arm surface close-up. Scale bar = 0.5 cm. A. C. B. D. E. F. 188 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Figure 6. Zoroaster carinatus (NMNH E1804) A, abactinal surface, disk and arms. B, close up-arms. Zoroaster fulgens C, abactinal surface, disk and arms (NMNH 11264). D, abactinal surface, variant form with spines, disk and arms (NMNH 1017683). E, eocene fossil from Seymour Island, disk and arms. (NMNH 256068). F, deep-water variant morphology from South Atlantic, disk and arms. (NMNH E47615). G, juvenile specimen, abactinal surface. (NMNH E18533). H, internal view showing absence of internal buttress (NMNH E38657). Scale bar = 0.5 cm. A. B. C. D. E. F. G. H. PHYLOGENY OF THE ZOROASTERIDAE 189 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 actinolateral rows and an enlarged first carinal plate in Mammaster, relative to the marginal plate series. Development of actinolateral rows is size-dependent, making this an unreliable character where the num- bers of actinolateral plate series overlap and the pres- ence of an enlarged carinal plate was not observed in the specimens of Mammaster examined. Two species of Zoroaster listed in Clark & Mah (2001) have been included in Cnemidaster by Downey (1970: 14), including Z. squameus Alcock 1893 and Z. zea Alcock 1893. A third species, Z. gilesi Alcock 1893, is also a likely species of Cnemidaster based on the mas- sive semiglobular plates described on the disc (Alcock, 1893a: 108). Alcock (1893a: 110) described Z. gilesi, Z. sqameus and Z. zea as belonging to a well-defined group with shared abactinal plate arrangements. A second species, B. macracanthus (= Zoroaster macracantha H.L. Clark 1916) was added to the previously monotypic Bythiolophus by Rowe & Gates (1995: 115). Comparison between the holotype of Bythiolophus (Fig. 3A) and paratypes of Z. macracantha indicate that this assignment is unwarranted and B. macracanthus is returned to Zoroaster. Bythiolophus has alternating large and small marginal plates (Fig. 3B), vs. Zoroaster which has consistently sized marginals (Fig. 3C). Return of this species to Zoroaster is supported by phylogenetic results (Fig. 1). Additionally, Zoroaster macracantha was consid- ered a synonym of Z. spinulosus by Fell (1958: 19), who had not examined type material. Comparison between the paratypes of both species suggests close affinities but with distinct morphologies. Zoroaster macracantha has thicker arms with more heavily developed primary spines on the marginal plates. Digital images of the holotype of Pholidaster dis- tinctus (Fig. 5B) were compared with specimens of abraded P. squamatus identified by W. K. Fisher (Fig. 5A), which were missing the distinctive scalar spines present on the body surface. Several of these specimens (e.g. NMNH 40573, 40562) showed abra- sion, probably from trawl collection, resulting in naked plates identical to those present in P. distinctus. Pholidaster distinctus is a synonym of P. squamatus making the genus Pholidaster monotypic. Howell et al. (2004) recognized three reproductively isolated morphotypes in Zoroaster fulgens in the Por- cupine Seabight where previously Z. fulgens was only thought to be a single species with wide morphological variation. Zoroaster species included on node 32 show close morphological affinities but are often distributed over large distances. Characters in these Zoroaster species are often continuous and show few discrete dif- ferences (see matrix in Appendix 2). Several species which were recognized as potential synonyms (e.g. Z. spinulosus and Z. macracanthus, Z. hirsutus and Z. magnificus, Z. adami and Z. carinatus) were retained as valid pending further phylogenetic data addressing species concepts in Zoroaster. Some spe- cies (Z. adami and Z. carinatus) coded identically in the data matrix and were removed. TAXONOMIC SUMMARY OF THE ZOROASTERIDAE AND OUTGROUP TAXA SUBORDER ZOROCALLINA DOWNEY, 1970 Zorocallida-Downey 1970: 1; Downey 1973: 95; Moy- ana & Larrain 1976: 104. Zorocallina-Blake 198: 502, 518. FAMILY ZOROASTERIDAE SLADEN 1889 Zoroasteridae-Sladen 1889: 416; Alcock 1893b: 173; Perrier 1894: 112; Fisher (1906): 1102; H.L. Clark 1916: 68; Fisher 1919a: 470; Fisher 1919b: 387; Fisher 1928: 32; H. L. Clark 1920: 94; Macan 1938: 414; Hayashi 1943: 161; Fell 1958: 18; Bernasconi 1964: 266; Spencer & Wright 1966: U74; Downey 1970: 1; Downey 1973: 95; Moyana & Larrain 1976: 104; McKnight 1977: 159; Maluf 1988: 124; Clark & Downey 1992: 401; Rowe & Gates 1995: 115; Liao & Clark 1995: 140; Clark & Mah 2001: 230. Diagnosis: Discs small with elongate, tapering arms. Single row of marginal plates. Papular pores in longi- tudinal and transverse rows. Disc and arm plates reticulate or imbricate in arrangement. Smaller sec- ondary spines cover most plates. Actinolateral spines (i.e. below marginal plate series) with larger primary spines appressed or facing abactinally. Superam- bulacral plates present. Pedicellariae straight (absent in Pholidaster). Adambulacrals alternately carinate. Tube feet in four rows becoming two rows distally. BYTHIOLOPHUS FISHER, 1916 Bythiolophus Fisher, 1916: 31; 1919a: 389; 1919b: 2,471, 481, 484; Fisher, 1928: 33 (in key); H.L. Clark, 1920: 99; Downey, 1970: 5 (in key); Spencer & Wright, 1966: U74; Clark & Mah, 2001: 230. Type species: Bythiolophus acanthinus Fisher, 1916. Diagnosis: Disc broad, arms thick with imbricated plates. Internal buttress present. Marginal plates alternately large and small. BYTHIOLOPHUS ACANTHINUS FISHER, 1916 (FIG. 3A, B) Bythiolophus acanthinus Fisher, 1916: 3, 1919b: 25, 485, pl. 135, fig. 1a?c; pl. 139, figs 1, 2; Downey, 1970: 14; Clark & Mah, 2001: 230. 190 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Occurrence: Celebes (Sulawesi), Indonesia, 1022.0 m. Material: Indonesia. NMNH 37011 HOLOTYPE Muna Island, Greater Sunda Islands, 5?35?S, 122?20?E, 1022 m. Coll. 16.xii.1909. (1 wet spec. R = 10.1, r = 1.1) CNEMIDASTER SLADEN, 1889 Cnemidaster Sladen, 1889: 423; Fisher, 1919a: 389; 1919b: 471, 480, 481, 485; Hayashi, 1943: 174; Spen- cer & Wright, 1966: U74; Clark & Mah, 2001: 230. Mammaster Perrier, 1894: 114 (in key); Fisher, 1919a: 389; 1919b: 471, 481; Spencer & Wright, 1966: U75; Downey, 1970: 12; Clark & Downey, 1992: 403; Clark & Mah, 2001: 231. Type species: Cnemidaster wyvilli Sladen, 1889. Diagnosis: Disc plates enlarged, swollen, rounded. Disc thick, discontinuous with arms in smaller speci- mens (below R = 7.0). Disc and arm plates imbricate. Disc and arm surface largely bare, covered with mem- branous skin. Internal buttress present. CNEMDIASTER GILESI (ALCOCK, 1893) COMB. NOV. Zoroaster gilesi Alcock, 1893: 108; H.L. Clark, 1920: 101; Clark & Mah, 2001: 234; Clark & Mah, 2001: 233; Sastry, 2005: 47 143 174. Occurrence: Andaman Sea, 896?915 m. CNEMIDASTER NUDUS (LUDWIG, 1905) Zoroaster nudus Ludwig, 1905: 164. Cnemidaster nudus H.L. Clark, 1920: 98; Downey, 1970: 14; Maluf, 1988: 43 124; Nybakken et al., 1998: 1777. Occurrence: Farallon Islands (Central California), Cabo San Lucas, Mexico to Chile, 1366?2598 m. Material: Central California. LACM Farallon Islands slope, 37?38.40?N, 123?21.53?W to 37?38.36, 123?19.90?W, 2300?2375 m. Coll. 29.vii.1991. [R = ?11.4, r = 1.3 (1 wet spec.)]. Mexico. NMNH 34381 Offshore of Ventana Bay, Baja California. 23?59?N, 108?40?W, 1820 m. Coll. 20.iv.1891. [1 wet spec. R = 12.0, r = 1.3 (arms broken)] NMNH 34387, Cerralvo Island, Baja California. 24?22?30?N, 109?3?20?W, 2598 m. Coll. 20.iv.1891. [R = 3.9, r = 0.7 (arms broken)] LACM 9161, Off Rio Elata, Sinaloa, Mexico. 23?40?30?N, 107?38?30?W to 23?37?N, 107?51?48?W. 1384?1366 m. Coll. 11.v.1959. [1 dry spec. R = ?6.5, r = 1.1 (arms broken)] SIO E170, SW of Cabo San Lucas 22?42.5?N, 110?21.0?W to 22?41.4?N, 110?12.0?W. 1893?1957 m, Coll. 28.vi.1965. [2 dry specs. R = 6.1, r = 1.3; R = 7.5, r = 1.3 (arm tips broken)] SIO E 1602, SW of Cabo San Lucas, 22?45?N, 110?23.0?W. 1917?2014 m. Coll. 28.vi.1965. [1 wet spec. R = 9.3, r = 1.3 (arm tips broken)] Chile. NMNH E446 Off Arica, Chile. 18?44.7?S, 70?40.7?W to 18?40.2?S, 70?35.1?W, 1097?1152 m, Coll. 7.v.1972. (1 wet spec. R = 4.4 r = 0.6). CNEMIDASTER SIGSBEEI (PERRIER, 1894) Zoroaster sigsbeci Perrier, 1880: 436 [lapsus for sigs- beei (Perrier 1881)] Zoroaster sigsbeei Perrier, 1881: 5; 1884: 195. Mammaster sigsbeei Perrier, 1894: 125; Perrier, 1894: 125; H.L. Clark, 1920: 73, 1941: 67; Downey, 1970: 12; Clark & Downey, 1992: 403; Clark & Mah, 2001: 231; Lalana et al., 2004: 10. Occurrence: Gulf of Mexico-S. Florida, Caribbbean Sea-Bahamas, Puerto Rico, Cuba, Venezuela, Gulf of Guinea, 310?1318 m. Material: Gulf of Mexico: NMNH E12460 Florida Keys, Gulf of Mexico, 366 m [6 dry specs. R = 4.0, r = 0.9, R = 4.9, r = 1.0, R = 6.6, r = 1.0, R = 4.4, r = 1.0, R = 4.7, r = 1.1, R = 3.7, r = 0.9 cm (arm tips broken)] NMNH E 18510 Vero Beach, Florida, 27?50?N, 79?15?W, 522 m, Coll. 17.vii.1965. (1 dry spec. R = 6.5, r = 1.0 cm) NMNH E 13208 SE of Pensacola, Florida. 29?27?N, 86?57?W, 752 m, Coll. 23.vii.1967. [1 dry spec. R = ?2.2, r = 0.5 cm (arm tips broken)] NMNH E 34922, Off of Florida, 29?14?N, 86?59.42?W, 900 m, Coll. 6.viii.1968. (1 dry spec. R = 1.2, r = 0.3 cm) Caribbean Sea: NMNH E 18512 Bahamas, SW of Grant Bahama Island, 26?6?N, 79?19?W, 449 m, Coll. 25.ix.1967. (1 dry spec. R = 7.7, r = 1.3 cm) NMNH E 18513 Bahamas, SW of Grant Bahama Island, North- west Providence Channel, 26?19?N, 79?00?W, 498 m, Coll. 1.x.1967. (1 dry spec. R = 2.9, r = 0.6 cm) NMNH E 18511 East of Cay Sal bank, Bahamas, 23?34?N, 79?16?W, 520 m. Coll. 15.vi.1968. (1 dry spec. R = 6.7, r = 1.1) NMNH E 18514, Cay Sal bank, Bahamas, 24?04?N, 79?42?W, 549 m. Coll. 22.vi.1967. (1 dry spec. R = 3.0, r = 0.7) NMNH E 18565 East of Cay Sal Bank, 23?35?N, 79?24?W, 516 m, Coll. 27.vi.1970, [2 dry specs. R = ?7.0, r = 1.3, R = 5.3, r = 0.9 cm (arm tips broken)] NMNH E 13662 NE of Honduras, 16?43?N, 82?38?W, 430?613 m, Coll. 12.vii.1970. (1 dry spec. R = 2.7, r = 0.6 cm) NMNH E 03967 Puerto Rico, coll. 1933. (1 dry spec. R = 7.3, r = 0.9) NMNH 12459 Testigo Islands, Venezuela 11?35?N, 62?37?W, 402?421 m, Coll. 19.iv.1960. (1 dry spec. R = 2.0, r = 0.5 cm) Gulf of Guinea: NMNH E 34073 South of Lagos, Nigeria, 4?15?N, 4?27?E, 1280?1318 m, Coll. 26.v.1965. (1 dry spec. R = 7.1, r = 1.0 cm) CNEMIDASTER SQUAMEUS (ALCOCK, 1893) Zoroaster squameus Alcock 1893: 109; 1895: pl. IV, fig. 2. PHYLOGENY OF THE ZOROASTERIDAE 191 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Cnemidaster squameus H.L. Clark, 1920: 98; Fisher, 1919b: 18, 481; Macan, 1938: 415; Clark & Mah, 2001: 231. Occurrence: Laccadive Sea and off Aden 1900?2000 m. CNEMDIASTER WYVILLI SLADEN, 1889 Cnemidaster wyvilli Sladen, 1889: 424; Fisher, 1919b: 18, 25, 480, pl. 134, fig. 3.3a, pl. 138; H.L. Clark, 1920: 98; Hayashi, 1943: 175; Nybakken et al., 1998: 1777; Clark & Mah, 2001: 231. Occurrence: Japan, Celebes, Arafura Sea of Borneo, 1370? 1990 m. Material: Indonesia-Malaysia. NMNH 40555, NW of Unauna Island, Celebes. Indonesia. 0?08?S, 121?19?E, 1992 m, Coll. 18.xi.1909. [1 wet spec. R = ?5.0 r = 0.9 (arms broken, spec. disarticulated)] NMNH 40566 South of Darvel Bay, Sabah, Celebes Sea. 4?19?54?N, 118?58?38?E, 1628 m. Coll. 26.ix.1909. (1 wet spec. R = 20.5, r = 1.7) NMNH 40818 East of Waleabahi Island, Celebes. 0?22?N, 123?3?30?E, 1760 m, Coll. 14.xi.1909. (1 wet spec. arms disarticulated, r = 1.0) NMNH 40298 East of Waleabahi Island, Celebes, Gulf of Tomini, 0?22?N 123?3?30?E, 1760 m. Coll. 14.xi.1909, [1 wet spec. R = 11.3, r = 1.8 (arm tips bro- ken)] NMNH 40299 North of Togian Island, Celebes, Gulf of Tomini. 0?16?28?N, 121?33?30?E, 1525 m. Coll.17.xi.1909. (1 wet spec. R = 11.8, r = 0.8) CASIZ 8587 Binang Unang Island, Gulf of Tomini, 0?04?00?S, 121?36?00?E, 1392.0 m. Coll. 18.xi.1909. (1 wet spec. R = 11.3, r = 1.3) Japan. NMNH 31958, Manazuru Zaki, Sagami Bay, Honshu Island. 35?8?N, 39?10?E, 916?1370. coll. 5.v.1900. (2 wet specs. R = 3.3 r = 0.5; R = 2.0, r = 0.4) CASIZ 115933 Off Honshu Island, Manazuru Zaki, 916?1370 m, Coll. 5.v.1900. [1 wet spec. R = 12.8, r = 1.1 (arm tips broken)] CNEMIDASTER ZEA (ALCOCK, 1893) Zoroaster zea Alcock, 1893: 110; 1895: Pl. II, 2,2a.; Clark & Mah, 2001: 235. Cnemidaster zea Fisher, 1919b: 18, 481, 483; H.L.Clark, 1920: 98; Downey, 1970: 14. Occurrence: S. India, 1090 m. DORASTER DOWNEY, 1970 (FIG. 3E?G) Doraster Downey, 1970: 5; Moyanna & Larrain, 1976: 103; Walenkamp, 1979: 87; Clark & Downey, 1992: 402; Clark & Mah, 2001: 231. Type species: Doraster constellatus Downey, 1970. Diagnosis: Disc and arm plates imbricate. Disc enlarged, swollen. Spinelets cover disc, arm surface (frequently absent). Disc plates strongly stellate. Internal buttress present. DORASTER CONSTELLATUS DOWNEY, 1970 (FIG. 3E?G) Doraster constellatus Downey, 1970: 5; Moyana & Lar- rain Prat, 1976: 103; Clark & Downey, 1992: 402; Clark & Mah, 2001: 231. D. cancellatus Jangoux, 1978: 98 (lapsus for D. constellatus) Occurrence: SW orf Nantucket Shoals, Gulf of Mexico, Atlantic Panama, Surinam, 350?914 m. Material: North Atlantic. NMNH 1080502, SW of Nan- tucket Shoals, Massachsetts, 39?18?30?N, 71?23?30?W, 2601 m, Coll. 11.viii.1885 (13 wet specs.) Gulf of Mex- ico-NMNH E23145 East of Corpus Christi, Texas. 27?38?N, 95?35?W, 412 m. Coll. 7.v.1956. (1 dry spec. R = 12.1, r = 1.4) NMNH E34980, East of Mississippi Delta, Louisiana. 29?07?N, 88?11?W, 549 m, Coll. 3.vi.1959. (1 dry spec. R = 12.6 r = 1.2) NMNH E18554, East of Mississippi Delta, Louisiana. 29?12?N, 88?03?W, 366 m, Coll. 3.vi.1959. (1 dry spec. R = 10.1 r = 0.9) NMNH E18506, East of Mississippi Delta, Louisiana. 29?14?N, 87?54?W, 366 m, Coll. 22.v.1956. (1 dry spec. R = 12.8 r = 1.7) NMNH E10742 PARA- TYPES, Mississippi Delta, Louisiana. 29?03?15?N, 88?16?W, 592 m, Coll. 11.ii.1885. (2 dry specs. R = 6.6, r = 0.8; R = 11.6). NMNH E11353 PARATYPE SW of Grenada, 11?36?N, 62?52?W, 393?421 m, Coll. iv.1960, [1 dry spec. r = 10.2, r = 1.4 (arms broken)] Caribbean Sea-NMNH E18519, East of Chinchorro Bank, Quin- tana Roo, Mexico, 18?30?N, 87?37?W, 715?787 m, Coll. 17.iii.1968. (1 dry spec. R = 15.4, r = 1.9) NMNH 1080556, Gulf of Mosquitos, Panama, 9?20?N, 81?24?W, 860?914 m, Coll. 25.v.1962. [2 dry specs. R = 14.3, r = 2.1; R = 4.8, r = 1.0 (arms broken on one spec)] NMNH 26524, Gulf of Mosquitos, Panama, 9?6?N, 81?15?W, 777 m, Coll. 29.x.1970. (1 dry spec. R = 4.2, r = 0.8). NMNH 1080506, Gulf of Mosquitos, Panama, 9?7?N, 81?10?W, 732 m, Coll. 31.v.1962. (1 dry spec. R = 17.1, r = 2.1) NMNH E12441 Rosalind Bank between Honduras and Jamaica, Honduras. 16?35?N, 80?04?W, 732 m, Coll. 18.v.1962. [1 dry spec. R = 12.6, r = 2.4 (arms broken)] NMNH E12447 Rosalind Bank between Honduras and Jamaica, Honduras. 16?35?N, 80?10?W, 576 m, Coll. 18.v.1962 [2 dry specs. R = 26.6, r = 2.2, R = ?13.1, r = 1.7. (arms broken)] NMNH E26552 Off Santa Marta, Colombia. 11?13?N, 74?26?W, 631 m, Coll. 9.xi.1970 [1 dry spec. R = ?12.6, r = 1.7 cm (arm tips broken)] NMNH E18507, North of Aramatka Point, Guajira Peninsula, Colombia, 12?13.18?N, 18?72.52?W, 408?576 m, Coll. 29.vii.1968. [2 dry specs, R = ?6.7, r = 1.2, R = 3.6, r = ?0.7 (arm tips broken)] NMNH E12443 East of Paraguana Peninsula, Vene- 192 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 zuela 15?39?N, 61?10?W, 649 m, Coll. 5.iii.1966 [5 dry specs, R = 9.5 r = 1.6; R = 7.1, r = 1.3; R = 5.6, r = 0.9; R = 12.7, r = 1.4; R = 14.6, r = 1.5 (arm tips, arms bro- ken)]. NMNH E12444 East of Paraguana Peninsula, Venezuela 11?53?N, 69?25?W, 640 m, Coll. 3.x.1963. [3 dry specs, R = ?16.5 r = 2.2; R = ?18.8, r = 2.3; R = 16.3, r = 2.2; (arm tips, arms broken)] NMNH E18570 East of Testigo Islands, Venezuela, 11?36?N, 62?46?W (no depth indicated). Coll. 19.iv.1960 [2 dry specs. R = ?11.2, r = 1.4; R = ?17.5 (arm tips broken)] French Guiana. NMNH E18508, North of Cayenne. 7?5?N, 52?47?W, 366 m, Coll. 14.ix.1958. [1 dry spec. R = ?2.5, r = 1.1 (arms broken)] MYXODERMA FISHER, 1905 Zoroaster (Myxoderma) Fisher, 1905: 316. Myxoderma Fisher, 1919a: 389, 391; 1919b: 471; 1928: 44; Spencer & Wright, 1966: U75; Aziz & Jangoux, 1984: 193; Clark & Mah, 2001: 231. Type species: Zoroaster (Myxoderma) sacculatus Fisher, 1905. Diagnosis: Disc and arm skeleton reticulate. Plates cruciform, forming open papular fields. Primary spines present on all plates. Internal buttress present. MYXODERMA ACUTIBRACHIA AZIZ & JANGOUX, 1984 Myxoderma acutibrachia Aziz & Jangoux, 1984: 192; Clark & Mah, 2001: 231 Occurrence: Macassar Strait, 01?58?54?S, 119?09?72 E, 715?800 m (no specimens examined). MYXODERMA LONGISPINUM LUDWIG, 1905 COMB. NOV. Zoroaster longispinum Ludwig, 1905: 180; Maluf, 1988: 44, 125; Clark & Mah, 2001: 234 Zoroaster perarmatus H.L. Clark, 1920: 102; Maluf, 1988: 45, 125, Clark & Mah, 2001: 235 Occurrence: Gulf of California S to Panama and the Galapagos, off N. Peru, 980?1571 m. Material examined: Mexico. NMNH 34385 designated herein as LECTOTYPE. Concepcion Bay, Gulf of California. 26?48?N, 110?45?20?W, 1571 m. Coll. 22.iv.1891. (1 wet spec. R = 2.7, r = 0.5) NMNH E 9626. East of San Marcos, Baja California. 27?9?N, 111?42?W, 1567 m. Coll. 20.iii.1889. (1 wet spec. R = 3.4, r = 0.7) Peru: NMNH E4905 (HOLOTYPE for Z. perarmatus). Aguja Point, Peru, South Pacific. 5?47?S, 81?24?W, 980 m. Coll. 12.xi.1904. (1 dry spec. R = 9.8, r = 1.3 cm) MYXODERMA PLATYACANTHUM (H.L. CLARK, 1913) (W/SYNONYM SSP. RHOMALEUM FISHER, 1919) Zoroaster platyacanthus H.L. Clark, 1913: 199. Myxoderma platyacanthum Fisher, 1919a: 392; H.L. Clark, 1920: 99; 1923: 152; Fisher, 1928: 52; Alton, 1966: 1709; Aziz & Jangoux, 1984: 193; Maluf, 1988: 44, 124; Lissner & Hart, 1993: 109; Clark & Mah, 2001: 231. Myxoderma platyacanthum rhomaleum Fisher, 1919a: 393; 1928: 45, 54, pl. 14, fig. 3.3a, pl. 15, fig. 2; pl. 16, fig. 1; pl. 23, fig. 1; pl. 24, fig. 2; pl. 25, fig. 3. Occurrence: Queen Charlotte Island (Canada), Ore- gon, Californa to Mexico, 256?2904 m. Material: British Columbia (Canada): CASIZ 8636, Queen Charlotte Islands: Moresby Island, 2904 m on grey mud, 52?39.00?30.00?N, 132.00?38.00?0.00?W, Coll. 3.ix.1890. (19 wet specs. R = 6.0, r = 0.9; R = 7.2, r = 1.1; R = 7.5, r = 0.9; R = 6.3, r = 0.9; R = 5.3, r = 0.8; R = 6.3, r = 0.8; R = 5.9, r = 1.0; R = 4.6, r = 0.8; R = 5.7, r = 0.9; R = 4.9, r = 0.7; R = 6.3, r = 0.8; R = 3.1, r = 0.6; R = 5.9, r = 0.8; R = 5.4, r = 0.6; R = 6.3, r = 0.8; R = 5.9, r = 0.8; R = 4.8, r = 0.8; R = 6.5, r = 0.8; R = 6.2, r = 1.0) Oregon: NMNH E10355, SW of mouth of Columbia River, 46?0.1?N, 124?50.8?W. 549 m, Coll. 9.v.1963. (1 dry spec. R = 6.1, r = 1.3 cm); NMNH E16027, SW of mouth of Columbia River, 46?0.0?N, 124?47?W, 410 m, Coll. 25.i.1963 (1 dry spec. R = 7.6, r = 1.4); NMNH E10354, SW of mouth of Columbia River, 46?0.0?N, 124?58.8?W, 503 m, Coll. 14.v.1963 (1 dry spec. R = 2.9, r = 1.8). NMNH E16031, Winchester Bay 43?46?N, 124?57?W, 507 m, Coll. 19.x.1888. [3 dry specs. R = 7.6, r = 1.3, R = 8.0, r = 1.1, R = 6.6, r = 1.3 (arm tips broken)] Washington: NMNH E10353, Astoria Canyon, 46?13.6?N, 124?44.2?W, 1006 m, Coll. 13.iii.1963. (1 dry spec. R = 4.2, r = 1.2) California: CASIZ 115924 Eel Canyon, Humboldt County, 704 m, on mud, Coll. xii.1966 (6 wet specs. R = 5.0, r = 1.0, R = 4.2,r = 0.6, R = 4.1, r = 0.8, R = 5.9, r = 1.1, R = 5.6, r = 1.1 R = 6.1, r = 0.9) CASIZ 115900 Gulf of Farallones, 37?26.70?N 123?1.30?W, 519?660 m, Coll. 18.xii.1985 (2 wet specs. R = 5.4, r = 0.9; R = 5.1, r = 0.9); CASIZ 115911 Gulf of Farallones, 37?35.30?N 123?14.50?W, 1491?1405 m, Coll. 14.xii.1985 [2 wet specs. R = 4.4, r = 0.8, R = 5.4, r = 1.0 (arm tips bro- ken)]; CASIZ 115908 Santa Barbara Channel to Santa Cruz Island 91?366 m (2 wet specs. R = 2.9, r = 0.5, R = 3.4, r = 0.6); CASIZ 115920 Off San Luis Obsipo County, 35?1.80?N 121?10.20?W, 576 m, Coll. 7.ix.1976 (1 wet spec. R = 5.7, r = 1.3). Mexico: NMNH 31640 San Pablo Point, Baja California. 27?7.8?N, 114?33.10?W, 519 m, Coll. 15.iii.1911 (1 dry spec. R = 6.7, 0.95 cm). SIO E 249 S of Isla San Pedro, Mex- ico. 27?40?N, 111?29.6?W to 27?32.1?N, 111?20.1?W. 931?952.0 m. Coll. 16.i.1961. [3 wet specs. R = 7.2 r = 1.0, R = 7.9 r = 1.0, R = 7.7 r = 0.8 (arms broken)]. PHYLOGENY OF THE ZOROASTERIDAE 193 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 MYXODERMA QAWASHQARI (MOYANA & LARRAIN PRAT, 1976) COMB. NOV. Doraster qawashqari Moyana & Larrain Prat, 1976: 105; Codoceo & Andrade, 1978: 159; Clark & Mah, 2001: 231. Occurrence: Mexico, Peru, to S. Chile, 300?2454 m. Material: Mexico. SIO E 1005 Off Pta. Chivato sur 27?18?N, 111?24?W, 1829?1875 m. Coll. 15.vi.1970 [2 wet specs. R = ?12.4, r = 1.6, R = ?14.5, r = 1.7 (arms broken)]; SIO E1006 Off Pta. Lobos. Sonora, Mexico. 27?13?N, 111?28?W, 1829?1875 m. Coll. 14.vi.1970 [3 wet specs. R = 11.1, r = 1.2, R = 14.3, r = 1.4, R = 14.9, r = 1.7 (arms broken)], Peru. NMNH 1084273 Off Lima, Peru. 11?50?S, 77?58?W, 935?907 m (1 dry spec. R = 16.2, r = 1.3). Chile. NMNH E16255 Paratype, Bahia Tarn Chile, Golfo de Penas. 42?45?S, 75?45?W, 300 m, Coll. 1.x.1972. (1 dry spec. R = 16 cm, r = 1.3 cm) NMNH 1080458, SW of Paita, Piura Peru. 5?07?S, 81?27?W to 4?59?S, 81?27?W, 365?457 m. Coll. 3.vi.1966 (58 dry specs. Size range from R = 5.3, r = 0.7 to R = 2.2, r = 0.4). CASIZ 115935 Off Chile. 42?36?, 75?28?W, 2454.0 m, Coll. 12.ii.1888. [1 wet spec. R = 9.5, r = 1.1 (arm tips broken)] CASIZ 115936 Off Chile. 38?8?00?, 75?53?00? 1238.0 m, Coll. 14.ii.1888 (1 dry spec. R = 9.2, r = 0.9 (arm tips broken)]. SIO E446 Off Arica, Chile. 18?44.7?S, 70?40.7?W to 18?40.2?S, 70?35.1?W, 1097?1152 m, Coll. 7.v.1972 (2 wet specs. R = 9.6 r = 1.5, R = 13.5 r = 1.3); SIO E620 West Cortz Basin (on escarpment). 32?27.7?N, 119?33.8?W to 32?27.9?N, 119?34.1?W, 1445.0 m. Coll. 7.v.1975. (1 wet spec. R = ?22.0 cm, r = 2.1). SIO E 997, Off Arica, Chile. 18?44.7?S, 70?40.7?W to 18?40.2?S, 70?35.1?W, 1097? 1152 m, Coll. 7.v.1972. (1 wet spec. R = 10.5 r = 1.7) MYXODERMA SACCULATUM (FISHER, 1905) (WITH SYNONYM SSP. ECTENES FISHER, 1919) Zoroaster (Myxoderma) sacculatus Fisher, 1905: 316. Zoroaster evermanni H.L. Clark (not Fisher) 1913: 198. Myxoderma sacculatum Fisher, 1919a: 392; H.L. Clark, 1923: 152; Fisher, 1928: 45, 49; Baranova, 1957: 175; Alton, 1966: 1709; Maluf, 1988: 44, 125; Clark & Mah, 2001: 232. Myxoderma derjungi Djakonov, 1968: 91. Occurrence: Okhotsk Sea, Bering Sea to southern California. 91?2012 m. Material examined: Alaska. CASIZ-24100, Bowers Bank, Bering Sea, Aleutian Islands, 54.00?33?N 178?44?W, 1068 m, Coll. 4.vi.1906. (dry specimen-arm fragment only) CASIZ 115903 Bering Sea 57?50.92?N 173?57.72?W, 720?750 m, Coll. 21.vi.1979. (1 wet spec. R = 13.3 r = 2.2) Oregon. NMNH E28078, SW mouth of Columbia River, 45?44?12?N, 125?8?48?W, 1555 m, Coll. 29.v.1964. [1 wet spec. R = ?25.0, r = 2.1 (arms broken)] NMNH E 14760, SW mouth of Columbia River, 1372 m, coll. 9.vi.1962. [1 wet spec. R = ?30.0, r = 2.6 (arms broken)]. California. NMNH 32451 West of San Nicolas Island, Channel Islands, 33?24.36?N, 120?12.30?W, 1170 m, Coll. 26.iv.1911. (2 dry specs. R = 10.6, r = 1.1, R = 6.6, r = 0.9 cm) NMNH 3596 San Diego. 32?40.30?N, 117?31.30?W, 1504 m. Coll. 19.i.1889. [4 dry specs. R = 8.6, r = 1.1, R = 7.7, r = 0.9, R = 6.1, r = 0.9, R = 6.7, r = 1.0 (arm tips broken)] NMNH E 01149 West of San Nicolas Island, Channel Islands, 33?15?N, 119?30?W, 1983?2012 m, Coll. 13.iv.1904. (8 wet specs. R = 4.0, r = 0.8, R = 3.2, r = 0.7, R = 1.7, r = 0.5; R = 1.8, r = 0.4; R = 1.2, r = 0.3, R = 1.3, r = 0.3, R = 1.2, r = 0.3, R = 1.1, r = 0.2 cm) CASIZ 102207, Humboldt County off Trinidad Head on sandy mud, 329 m, Coll. xii.1966. [3 dry specs. R = 4.7, r = 0.9, R = 4.5, r = 0.7; R = 4.3, r = 0.8 (arm tips broken)] CASIZ 115927, Farallon Islands on mud, rocks, 1280?1500 m, Coll. 12.xi.1950. [1 wet spec. R = 18.1, r = 1.7 (arm tips broken)] CASIZ 115914, Santa Barbara Channel to Santa Cruz Island 91? 366 m (1 wet spec. R = 2.1, r = 0.4). CASIZ 117841 Off Humboldt County, 1123.0 m. Coll. 13.xi.1975. (2 dry specs. R = 22.0, r = 1.5, R = 17.6, r = 1.8) PHOLIDASTER SLADEN, 1889 (FIG. 5A?D) Pholidaster Sladen, 1889: 426; Fisher, 1919a: 388; 1919b: 471, 484, 485; Spencer & Wright, 1966: U75; Clark & Mah, 2001: 232. Type species: Pholidaster squamatus Sladen, 1889 (designated by Fisher, 1919a). Diagnosis: Disc and arm plates imbricate. Disc and arms covered by flattened scales covering nearly all plates save for the carinal arm series and primary cir- clet on disc. Carinal plates along arms bare. Superam- bulacral plates reduced. Internal buttress absent. Pedicellariae absent. PHOLIDASTER SQUAMATUS SLADEN, 1889 (FIG. 5A?D) Pholidaster squamatus Sladen, 1889: 427; Fisher, 1919b: 4,18, 484; H.L. Clark, 1920: 98; Marsh, 1976: 221; Jangoux, 1981: 475; Clark & Mah, 2001: 232. Pholidaster distinctus Sladen, 1889: 429; Fisher, 1919b: 18; Clark & Mah, 2001: 232. Occurrence: Philippines, Indonesia, W and NW Aus- tralia, 90?256 m. Material examined: Philippines. NMNH 40573. Mas- bate Passage, Baleno, Masbate Island. 12?25?18?N, 123?37?15? Coll. 21.iv.1908. [1 wet spec. R = ?7.0, r = 0.7 (arms broken, spec. partially disartculated)] 194 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 NMNH 40562. NE of Cataingan, masbate Island, Samar Sea. 12?4?15?N, 124?4?36? E (mixed stations). Coll. 20.iv.1908. [6 wet specs. R = 5.9, r = 0.7; R = 5.2, r = 0.7; R = ?5.0, r = 0.7; R = 5.0, r = 0.7; R = 3.7, r = 0.7; R = 3.8, r = 0.7 (arm tips broken)] NMNH 40215 Destacado Island, Northern Samar, Samar Sea, 12?12?35?N, 124?2?48?E, 247 m. Coll. 13.iii.1909. [7 wet specs. R = 6.1, r = 0.8; R = 6.1, r = 0.7; R = 5.8, r = 0.7; R = 6.1, r = 0.7; R = 6.2, r = 0.7; R = 5.6, r = 0.6; R = 5.5, r = 0.6 (arm tips broken] NMNH E50370, Bohol Strait, Bohol. 90 m. Coll. 22.xi.1979. [2 wet specs. R = 10.0, r = 0.8; R = 9.1, r = 0.8 (arm tips broken)] SAGENASTER MAH GEN. NOV. Etymology: Latin (sagena) for fish-net, referring to the reticulate or net-like skeleton in this genus. Type species: Zoroaster evermanni Fisher, 1905. Diagnosis: Disc and arm skeleton reticulate. Plates cruciform, forming open papular fields. Primary spines present on all plates. Internal buttress absent. SAGENASTER EVERMANNI (FISHER, 1905) (W/SYNONYM EVERMANNI MORDAX FISHER, 1919) (FIGS 2E, F) Zoroaster (Myxoderma) evermanni Fisher, 1905: 317; not H.L. Clark, 1913: 198 (= Myxoderma saccula- tum). Zoroaster evermanni Fisher, 1919a: 390; H.L. Clark, 1920: 100; 1923: 152; Fisher, 1928: 40, pl. 13, fig. 3, pl. 14, figs 1.1a, 1b, pl. 18, fig. 4; pl. 19, fig. 1; pl. 20, figs 3, 4; Alton, 1966: 1709; Carey, 1972: 41; Lambert, 1978a: 23; 1978b: 64; Maluf, 1988: 44, 125; Nybakken et al., 1998: 1777; Clark & Mah, 2001: 233. Zoroaster evermanni mordax Fisher, 1919a: 391, 1928: 34, 43, pl. 13, fig. 4; pl. 14, fig. 2; pl. 19, fig. 2. Occurrence: Aleutian Islands (Alaska), Queen Char- lotte Island (Canada), Oregon, Washington to S. Cali- fornia, Mexico, 100?2710 m. Material: Alaska: CASIZ 115898, Aleutian Islands, Unalaska Island, 54.00?21.50?N, 167.00?47.50?W, 905?910 m, Coll. 14.vi.1979 (wet spec. R = 17.2, r = 1.6). Oregon: NMNH E 10356, SW of mouth of Columbia River, 45?51.5?N, 124?42?W. 823 m, Coll. 6.iii.1962. (1 dry spec. R = 12.6, r = 0.9 cm) NMNH E 10359 SW of mouth of Columbia River, 45?52.3?N, 124?52?W. 823 m, Coll. 13.v.1963. (1 dry spec. R = 9.1, r = 0.9 cm) NMNH E16023, SW of mouth of Columbia River, 45?52?N, 124?54?W. 823 m, Coll. 27.v.1962 (1 dry spec. R = 9.2, r = 0.9 cm); NMNH E 10360, SW of mouth of Columbia River, 45?40.5?N, 124?55?W, 1372 m, Coll. 2.viii.1963. (1 dry spec. R = 3.2, r = 0.35 cm) NMNH E 10357, SW of mouth of Colum- bia River, 45?52?N, 124?54?W. 732 m, Coll. 23.i.1963. (1 dry spec. R = 14.2, r = 0.8 cm) NMNH E 16019, SW of mouth of Columbia River, 45?56?N, 124?51?W. 682 m, Coll. 12.iii.1962. [1 dry spec. R = ?8.2, r = 0.8 cm (arm tips broken)] NMNH E 10358, SW of mouth of Colum- bia River, 45?57.3?N, 124?48.7?W. 594 m, Coll. 10.v.1962. [1 dry spec. R = ?16, r = 0.9 cm (arm tips broken)] NMNH E 16007, SW of mouth of Columbia River, 46?14?N, 124?44?W. 979 m, Coll. 13.iii.1962. [2 dry specs. R = ?12.5, r = 1.0 cm, R = 7.2, r = 0.8 cm (arm tips broken)] CASIZ 122302, Off Oregon coast, 44?20?N, 125?5?W, 823?914.0 m, Coll. 10.xii.1961 (1 wet spec. R = 11.8, r = 0.7). CASIZ 121506 Cascadia Plain, 45?55.50?N, 125?38.8?W, 2030.0 m, Coll. 20.iii.1970. (5 wet specs. R = 2.0, r = 0.3, R = 1.1, r = 0.2, R = 0.8, r = 0.2; R = 1.1, r = 0.2, R = 0.4, r = 0.1) California: CASIZ 113317 Humboldt County on mud, 704?841 m, Coll. vi.1977. (3 dry spec. R = 8.8, r = 1.2, R = 12.2, r = 1.1; R = 9.7, r = 0.8) CASIZ 113318 Eureka, Humboldt County on soft green-black mud, 100?1005 m, Coll. i.1977. (2 dry specs. R = 10.6, r = 0.8, R = 11.2, r = 0.8) CASIZ 11319, Eureka, Hum- boldt County on soft green-black mud, 823 m [2 dry specs. R = 10.5, r = 1.1, R = ?15, r = 1.1 (arm tips bro- ken)] CASIZ 115950 Off Point Loma Lighthouse, San Diego on green mud, fine sand, 294?933 m, Coll. 5.iii.1904. [1 wet spec. R = 13.9, r = 1.1 (arm tips bro- ken)] CASIZ 115910 Gulf of Farallones, 913?1000 m, Coll. 16.xii.1985. (2 wet specs., R = 3.1, r = 0.4, R = 2.6, r = 0.6) CASIZ 115925 Off Bodega head, Sonoma County, 549?567.0 m Coll. 16.iii.1965. [1 wet spec. R = ?14.8, r = 1.0 (arms broken)] TERMINASTER HESS, 1974 Asterias Quenstedt, 1876: 49, pl. 91, fig. 155. Terminaster Hess, 1974: 647; Hess, 1986: 47. Type species: Asterias cancriformis Quenstedt, 1876. Diagnosis: Disc small. Disc and arm with imbricate skeleton. Plates polygonal to weakly lobate. Large pri- mary spines present. Terminal plate enlarged. TERMINASTER CANCRIFORMIS (QUENSTEDT, 1876) Asterias cancriformis Quenstedt, 1876: 49, pl. 91, fig. 155. Terminaster cancriformis Hess, 1974: 647; 1986: 47. Occurrence: English Oxford Clay, Callovian to Middle Oxfordian (Mid to Late Jurassic) marls of the French and Swiss Jura. TERMINASTER SPINULOSUS KUTSCHER & HARY, 1991 Kutscher & Hary, 1991: 62 PHYLOGENY OF THE ZOROASTERIDAE 195 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Occurrence: Isolated ossicles from the Sinemurien (Early Jurassic) of SE Luxembourg, NE of the Paris Basin. ZOROASTER THOMSON, 1873 (WITH SYNONYM PROGNASTER PERRIER, 1891) Prognaster Perrier, 1891: 1226; 1896: 22 (Probably not Perrier, 1894 according to Fisher, 1928: 32); Fisher, 1919b: 388; H.L. Clark, 1920: 96, 98; Downey, 1970: 14. Zoroaster Thomson, 1873: 154; Sladen, 1889: 416; Fisher, 1919b: 471, 484, 485; Verrill, 1915: 27; H.L. Clark, 1920: 100; Fisher, 1928: 33; Ber- nasconi, 1964: 266; Spencer & Wright, 1966: U74; Downey, 1970: 14; Harvey et al., 1988: 167; Clark & Downey, 1992: 403; Liao & Clark, 1995: 140; Clark & Mah, 2001: 232. Type species: Zoroaster fulgens Thomson, 1873. Diagnosis: Disc small. Disc and arm with imbri- cate skeleton. Carinal plates ridge-like. Primary spines present or absent on carinals, marginal plate series. Superambulacrals reduced. Internal buttress absent. ZOROASTER ACTINOCLES FISHER, 1919 Zoroaster actinocles Fisher, 1919: 390; 1928: 37; Clark & Mah, 2001: 233 Occurrence: Aleutian Islands, California to Chile. 1617?2710 m. Material examined: Alaska. CASIZ 120350 Patton Sea- mount, Gulf of Alaska. [1 wet spec. R >15.4, r = 2.1 (arms broken)] NMNH 37039 HOLOTYPE, North of Amukta Pass, Island of Four Mountains, Aleutian Islands, Bering Sea. 53?12?N, 171?37?W, 2226 m, coll. 29.v.1906 (1 wet spec. R = 16.1, r = 1.1) California. CASIZ 769 Monterey Fan Valley, 36.00?33.70?N, 122.00?27.20?W, 2430?2710 m, Coll. 21.iii.1975. (8 wet spec. R = 9.7, r = 0.8; R = 7.6, r = 0.8; R = 8.8, r = 0.8; R = 6.1, r = 0.7; R = 6.1, r = 0.6; R = 5.2, r = 0.6) CASIZ 115905 East Cortes Bank, 32.00?15.90?? 118.00?41.20?W, 1617?1678 m, Coll. 20.i.1985. (2 wet specs. R = 13.4, r = 1.0, R = 12.3, r = 1.0) Chile. CASIZ 115934 Off Chile, 45?35?N, 75?55?W 1920.0 m, Coll. 11.ii.1888. (1 wet spec. R = 11.1, r = 1.1) NMNH 1084274 west mouth of Straits of Magellan. 53?13?S, 75?41?W to 53?16?S, 75?41?W. 1500?1666 m. Coll. 5.i.1966. (2 dry specs. R = 15.1, r = 1.3; R = 12.5, r = 1.0). ZOROASTER ADAMI KOEHLER, 1909 Zoroaster adami Koehler, 1909: 108; Fisher, 1919b: 18, 472, 175; H.L. Clark, 1920: 101 (in key); Clark & Mah, 2001: 233; Sastry, 2005: 47, 143, 157. Occurrence: Philippines. Madagascar, Andaman Sea, 700?1040.0 m. Material examined: Philippines. CASIZ 104213, NE of Calagua Islands. 14?41?7?, 123?24?12? 435?451.0 m. Coll. 27.ix.1995 (1 wet spec. R = 7.7, r = 0.7). Madagas- car. CASIZ 115902 Off Nosy Be. 12?31?30?, 48?5?3?. 700?710.0 m, coll. 24.xi.1988. (3 wet spec. R = 5.2, r = 0.4; R = 6.6, r = 0.6; R = 7.6, r = 0.6) ZOROASTER ALFREDI ALCOCK, 1893 Zoroaster alfredi Alcock, 1893: 102; 1893: 173; H.L. Clark, 1920: 101 (in key); Macan, 1938: 415; Clark & Mah, 2001: 233. Occurrence: Bay of Bengal, Arabian Sea, 2380?3350 m. ZOROASTER ALTERNICANTHUS MCKNIGHT, 2006 Zoroaster alternicanthus McKnight, 2006: 42. Occurrence: New Zealand region, 33?52?, 150?427 m. ZOROASTER ANGULATUS ALCOCK, 1893 Zoroaster angulatus Alcock, 1893: 105; Fisher, 1919b: 472, 477; H.L. Clark, 1920: 101 (in key); Macan, 1938: 415; Clark & Mah, 2001: 233. Occurrence: Gulf of Mannar, Maldive-Laccidive area, 910?1460 m. ZOROASTER BARATHRI ALCOCK, 1893 Alcock 1893: 103; Fisher, 1919b: 21, 473, 475; H.L. Clark, 1920: 101 (in key); Clark & Mah, 2001: 233. Occurrence: Bay of Bengal, 2780 m. ZOROASTER CARINATUS ALCOCK, 1893 (SSP. PHILIPPINENSIS FISHER, 1916 SYN. BY JANGOUX & AZIZ, 1988) Zoroaster carinatus Alcock, 1893: 107; 1895: pl. IV, fig. 1.1a; Rowe & Gates, 1995: 116.; Clark & Mah, 2001: 233; Sastry, 2005: 47, 143, 165; McKnight 2006: 40. Zoroaster carinatus philippinensis Fisher, 1916: 30; Fisher, 1919b: 18, 472, 477, 479, pl. 116, fig. 3, pl. 135, fig. 3a, pl. 137; H.L. Clark, 1920: 102 (in key); Jangoux, 1981: 459; Jangoux & Aziz, 1988: 648; Rowe & Gates, 1995: 116; Liao & Clark, 1995: 140. Occurrence: Philippines, South China Sea, New Cale- donia, Western Australia, Indian Ocean, Andaman Sea. 152?1104 m. Material: Central Pacific. NMNH 40297, Deagan Island, Masbate Island, Samar Sea, Philippines. 12?15?N, 123?57.30?E, 146 m. Coll. 20.iv.1908. (1 dry spec. disarticulated). NMNH 40586 Lucena City, Tayabas Bay, Luzon Island, Quezon. 13?49?40?N, 196 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 121?40?15?E, 152 m. Coll. 24.ii.1909. [1 wet spec. R = 6.6, r = 0.7 (arm tips broken)]; NMNH 40380 Ticao Island, Masbate Passage, 12?31?30?N, 123?35?24?E, 1104 m. Coll. 21.iv.1908. (1 wet spec. R = 7.7, r = 0.9) NMNH E1804 No data (probably Philippines). (5 dry specs. R = 9.9, r = 0.8; R = 8.7, r = 0.8; R = 7.4, r = 0.8; R = 7.6, r = 0.7; R = 8.1, r = 0.7). Indian Ocean. NMNH E50357, NE of Mombasa, Kenya. 2?56?S, 40?28?E, 240 m, Coll. 8.xi.1964 (3 dry specs. R = 7.4, r = 0.9; R = 8.0, r = 0.9; R = 8.2, r = 0.9). NMNH E 50358, NE of Mombasa, Kenya. 2?54?S, 40?23?E, 34 m (340 m), Coll. 7.xi.1964. (5 dry specs. R = 7.5 r = 0.9; R = 7.7, r = 0.9; R = 8.1, r = 0.9; R = 8.2, r = 0.9; R = 6.5, r = 0.7) NMNH E50371 East of Zanzibar Island, Tanzania. 2?50?S, 40?31?E, 190 m. Coll. 8.xi.1964. (1 wet spec. R = 8.2, r = 1.1) NMNH 1080461, west of Phuket Island, Malay Peninsula, Thailand. 7?40?N, 97?9?E, 370 m, Coll. 21.iii.1963. [15 dry specs. R = 1.7, r = 0.3; R = 3.1, r = 0.3; R = ?12.5, r = 0.8; R = ?11.0, r = 0.8; R = 9.5, r = 0.8; R = ?10, r = 0.8; R = ?11.0, r = 0.8; R = ?9.0, r = 0.7; R = 10.8, r = 0.6; R = ?10.8, r = 0.8 (arms broken, twisted)] ZOROASTER FULGENS THOMSON, 1873 Zoroaster fulgens Thomson, 1873: 153; Studer, 1883: 130; Sladen, 1889: 418; 1891: 694; Perrier, 1894: 116; Koehler, 1896: 42; H.L. Clark, 1901: 237; Farran, 1913: 19; Fisher, 1919b: 471; H.L. Clark, 1920: 101 (in key); Mortensen, 1927: 132; Downey, 1970: 14; Rice et al., 1982: 66; Gage et al., 1983: 269, 286; Har- vey et al., 1988: 167; Hoz & Garcia, 1991: 135, 136; Hansson, 1998 (checklist); Clark & Mah, 2001: 234; Sumida et al., 2001: 29; Howell et al., 2004: 977. Zoroaster aff. fulgens (Eocene) Blake & Zinsmeister, 1979: 1151; 1988: 495. Zoroaster ackleyi Perrier, 1880: 436; 1881: 6; 1881b: 59; 1894: 117; Verrill, 1915: 28; H.L. Clark, 1920: 101 (in key); Fisher, 1928: 491; John & Clark, 1954: 139. Zoroaster diomedeae Verrill, 1884: 217. Zoroaster longicauda Perrier, 1885: 198; 1894: 120; Howell, Billett & Tyler, 2002: 1906. Prognaster grimaldii Perrier, 1891: 1226; 1891b: 259; 1896: 23, pl.2; Richard, 1900: 75, fig. 23. Zoroaster trispinosus Koehler, 1895: 442; 1896: 33; 1909: 108. Zoroaster bispinosus (as lapsus for trispinosus) Koe- hler, 1909: 316 Occurrence: North Atlantic (off Massachusetts), Faeroe Channel, Rockall Trough (north-east Atlantic), to Bahamas, Gulf of Mexico, and Surinam. South Atlantic to Shag Rocks, South Georgia Sea, to Indian Ocean (South Africa) 220?4810 m. Material: North Atlantic. NMNH E 38674 Hudson Canyon, off New Jersey. 38?29?48?N, 72?32? 54?W, 2625?2640 m. Coll. 30.vii.1975. (2 dry specs. R = 9.9, r = 1.1; R = 13.1, r = 1.4) NMNH 14274 Georges Bank, Massachusetts, 41?9?40?N, 66?2?20?W, 2296 m. Coll. 4.ix.1883. [2 dry specs. R = 11.2, r = 1.5; R = ?10, r = 1.2 (arm tips broken)] NMNH E18533, Off Andros Island, Tongue of the Ocean, Bahamas. 24?26?N, 77?34?W, 1565 m, Coll. 28.ix.1967 (4 dry specs. R = 1.3, r = 0.2; R = 1.9, r = 0.3; R = 10.0, r = 1.6; R = 9.9, r = 1.1). NMNH E18534, North of Little Bahama Bank, 27?30?N, 78?38?W, 490 m. Coll. 5.ii.1964 (1 dry spec. R = 3.8, r = 0.5). NMNH E38657, East of Virginia Beach, Virginia. 36?42?N, 74?4?30?W, 2400?2450 m, Coll. 24.vii.1975. [3 dry specs. R = 16.7, r = 1.2; R = 17.4, r = 1.7; R = 18.6, r = 1.7 (arms broken, or twisted in several specs.)] Gulf of Mexico. NMNH 1017683, off Florida. 28?16?N, 86?36?16?E, 838?847 m. Coll. 20.v.1985. [16 dry specs. R = 4.7 r = 0.7; R = 9.2, r = 1.0; R = 6.1, r = 0.7; R = 9.7, r = 0.9; R = 10.1, r = 1.0; R = 8.4, r = ?0.9; R = 3.6, r = 0.6; R = 3.2, r = 0.5; R = 1.9, r = 0.4; R = 11.6, r = 0.9; R = 13.1, r = 1.1; r = 9.2, r = 0.8; R = 9.9, r = 0.9; R = 10.3, r = 0.9 (arm tips broken on several)] Caribbean Sea. NMNH E18538 Off of Roque Islands, Venezuela. 11?50?N, 66?10?W, 1059 m, Coll. 23.vii.1968 (3 dry specs. R = 2.3 r = 0.5; R = 1.5, r = 0.4; R = 1.9, r = 0.3), NMNH E18539, East of St. Vincent Island, 13?20?48?N, 61?2?30?W, 658?841 m (1 dry spec. R = 0.9, r = 0.2) Guyana-Surinam. NMNH E18529, NE of Paramaribo, 7?21?N, 53?15?W, 549 m. Coll. 21.iii.1965. [2 dry specs, R = 6.5, r = 0.7; R = 7.7, r = 0.8 (arms broken on specs.)] NMNH E19310 N of Georgetown, 8?14?N, 57?38?W, 1408 m. Coll. 15.vii.1968. (1 dry spec. R = ?10, r = 1.3 (arm tips broken)] NMNH E18536 NE of Paramaribo, 8?33?N, 54?18?W, 1253 m. Coll. 12.vii.1968. (1 dry spec. arms disarticulated, r = 0.8) South Atlantic. NMNH E47618, Shag Rocks, South Georgia Island, Scotia Sea. 50?51?12?S, 43?3?12?W, 1351?1362 m. Coll. 9.v.1975. (2 dry specs. R = 9.6, r = 1.1; R = 17, r = 1.6) NMNH E47615, NW of South Georgia Island, Scotia Sea. 51?2?12?S, 42?47?36?W, 1481?1546 m, Coll. 9.v.1975. [4 dry specs. R = ?23, r = 2.0; R = 19.6, r = 2.1; R = ?24, r = 2.1; R = 23.4, r = 1.8 (arms twisted, broken on some)] NMNH E47586, Shag Rocks, South Georgia Island, Scotia Sea. 50?51?12?S, 43?3?12?W, 1351?1362 m. Coll. 9.v.1975. [5 dry specs. R = 17.1, r = 1.4; R = 20.3, r = 2.1; R = 17.7, r = 1.5; R = 16.2, r = 1.5; R = ?23, r = 1.8 (arms broken twisted)] Indian Ocean (South Africa). SIO E 2941, off tip of South Africa, 53?21.1?S, 24?56?E, 1100?1400 m. Coll. 21.i.1984 (1 wet spec. R = 12.1, r = 1.6); SIO E 2943, off tip of South Africa, 46?30.8?S, 33?51?E, 2700? 3900 m, Coll. 27.i.1984 (R = 16.0, r = 1.3). Fossil material: NMNH 256068. Eocene, Upper La Meseta Formation, Antarctica, Seymour Island. Disc and arm fragments. PHYLOGENY OF THE ZOROASTERIDAE 197 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 ZOROASTER GILESI (SEE CNEMIDASTER) ZOROASTER HIRSUTUS LUDWIG, 1905 Zoroaster hirsutus Ludwig, 1905: 172; H.L. Clark, 1920: 101 (in key); Fisher, 1928: 37; Clark & Mah, 2001: 233. Comments: Similar to Zoroaster magnificus, a possible synonym, but differs in size and primary circlet plate morphology. Occurrence: Mexico, 3436 m. Material: Mexico. NMNH 34382, Punta Maldonado, 14?46?N, 98?40?W, 3436 m, Coll. 10.iv.1891. [1 wet spec. R = 22.0, r = 1.3 (arms broken)] ZOROASTER MACRACANTHA H.L. CLARK, 1916 Zoroaster macracantha H.L. Clark, 1916 68; 1920: 101 (in key); Fell, 1957: 33; Fell, 1958: 19. Bythiolophus macracanthus Rowe & Gates, 1995: 115; Clark & Mah, 2001: 230. Occurrence: South Australia: 146?1006 m. Material: MCZ 2499-PARATYPE. Great Australian Bight. 129?28?E, 146?219 m (1 dry spec. R = 16.2, r = 1.5); NMNH 1084275 Chatham Rise, 43?40?S, 179?28?E, 403 m, Coll. 24.i.1954. [1 dry spec. R = ?15.5, r = 2.1 (arms broken)] ZOROASTER MAGNIFICUS LUDWIG, 1905 Zoroaster magnificus Ludwig, 1905: 159; H.L. Clark, 1920: 104 (in key); Fisher, 1928: 37; Maluf, 1988: 44, 125; Clark & Mah, 2001: 234. Zoroaster longispina? (in part from syntype series) Ludwig, 1905: 180. Zoroaster sp. juv.? Ludwig, 1905: 177. Occurrence: Farallon Islands (Central California), Panama to Galapagos, 2775?3667 m. Material examined: California. LACM 37?39.05?N, 123?27.36?W to 37?39.20?N, 123?25.60?W. 2775? 2840 m. Coll. 28.vii.1992 [1 wet spec. R = ?14.5, r = 1.3 (arm tips broken)]; LACM 37?39.05?N, 123?27.36?W to 37?39.20?N, 123?25.60?W. 2775?2840 m. Coll. 28.vii.1992 [1 wet spec. R = ?16.0, r = 1.3 (arm tips bro- ken)] South and Central America. NMNH E944 SYN- TYPE (PARALECTOTYPE) SE of Galapagos Islands, 4?33?S, 87?42?30?W, 3667 m, Coll. 9.xi.1904 [1 wet spec. R = 29.5, r = 14.0 (arms broken)]; NMNH 34383 SYN- TYPE SW of Coiba Island, Panama. 6?17?N, 82?5?W, 3058 m, Coll. 24.ii.1891. [2 wet spec. R = 27, r = ?13; R = 26.5, r = ?13 (arms broken, specs. damaged)] ZOROASTER MICROPORUS FISHER, 1916 Zoroaster microporus Fisher, 1916: 30; 1919b: 21, 27, 472, 473, 475, pl. 134, fig. 4a, pl. 139, fig. 4; H.L. Clark, 1920: 101 (in key); Hayashi, 1943: 171; Clark & Mah, 2001: 234. Occurrence: Japan. Indian Ocean-Moluccas. 1280 m. Material examined: Japan. CASIZ 115932 Honsu, Kinka San Lighthouse 38?11?30?N, 142?12?E, 730 m, Coll. 10.x.1906. [1 wet spec. R = 10.8 r = 1.0 (arm tips broken)] Indian Ocean. NMNH HOLOTYPE 37009, Buru Island, Moluccas, Indonesia, 3?53?20?S, 126?48?E, 1280 m. Coll. 10.xii.1909. (1 wet spec. R = 20.5, r = 1.2). ZOROASTER OPHIACTIS FISHER, 1916 Zoroaster ophiactis Fisher, 1916: 29, 1919b: 18, 27, 471, 472, 473, 475, pl. 135, fig. 2a?b, pl. 136, fig. 1; pl. 139, fig. 3; H.L. Clark, 1920: 101 (in key); Hayashi, 1943: 168; 1973: 94 (english section), 71 (japanese section); Imaoka et al., 1990: 63; Clark & Mah, 2001: 234. Occurrence: Philippines, Celebes to Japan. 500? 1678 m. Material: Philippines. CASIZ 104217, SE Luzon, Lagonoy Gulf. 13?21?N, 124?12?E, 1037.0 m. Coll. 24.ix.1995. (1 wet spec. R = 12.8, r = 1.1) Indonesia. CASIZ 18407 HOLOTYPE (partial) Dodepo Island, Teluk, Celebes. 0?16?28?, 121?33?30?, 1525 m, Coll. 17.xi.1909. (1 wet arm fragment) South China Sea. NMNH 40351, SW of Tungsha Island 20?05?N, 116?5?E, 958 m, Coll. 8.viii.1908. (1 dry spec.disarticulated) ZOROASTER OPHIURUS FISHER, 1905 Zoroaster ophiurus Fisher, 1905: 315; 1919: 390; H.L. Clark, 1913: 199; 1920: 102 (in key), 1923: 152; Fisher, 1928: 34; Baranova, 1957: 175; Alton, 1966: 1709; Carey, 1972: 41; Lambert, 1978a: 23; Maluf, 1988: 45, 125; Clark & Mah, 2001: 233. Occurrence: Bering Sea, S. to N. Peru, 695?2230 m. Material: Oregon. NMNH E16008 SW of mouth of Columbia River, 45?42?36?N, 125?12?36?W. 1920 m, Coll. v.1964. [1 dry spec. R = ?21.0 cm, r = 1.0 cm (arms broken)] NMNH E10362 SW of mouth of Columbia River, 45?50.4?N, 125?11.2?W, 1646 m, Coll. 2.ix.1963. (1 dry spec. R = 2.0, r = 0.3 cm). NMNH E 15986, SW of Mouth of Columbia River, 45?38?36?N, 125?18?W. 2103 m [22 dry specs. R = 17.5, r = 1.1; R = 10.6 r = 1.1; R = ?17 r = 1.1; R = 13.5, r = 1.1; R = ?15, r = 1.2; R = ?17, r = 1.4; R = ?17.6 r = 1.3; R = 13.6, r = 1.1; R = ?18 r = 1.1; R = ?16.7, r = 1.1; R = 14.4, r = 1.2; R = 13.7, r = 1.3; R = 11.7, r = 1.3; R = 17.8, r = 1.1; R = 16.3, r = 1.2; R = 14.3, r = 1.2; R = ?13.0, r = 1.2; R = 13.4, r = 1.1; R = ?13.2, r = 1.1; R = ?7.8, r = 1.1; R = ?16.5 r = 1.1 (siX-rays) (arms broken or twisted)] California. LACM Farallon 198 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Islands slope, 37?38.40?N, 123?21.53?W to 37?38.36?N, 123?19.90?W, 2300?2375 m. Coll. 29.vii.1991. (1 wet spec. R = 3.1, r = 0.6). CASIZ 115916 West Cortes Bank, 32?13?N, 119?15.6?W, 1583?1678 m, Coll. 19.i.1985. (1 wet spec. R = 8.3, r = 0.7) CASIZ 115918 Monterey fan valley, Monterey Bay, off Point Cypress 36?33.70?N, 122?27.20?W, 2430?2710.0 m, Coll. 21.iii.1975 (1 wet spec. R = 9.6 r = 0.9). CASIZ 115923 off southern California on grey mud 32?17?N, 119?17?W, Coll. 17.i.1889. [1 wet spec. R = ?3.2, r = 0.2 (arms broken)] Mexico. NMNH 32450, SW of San Car- los Point, Baja California. 29?23?N, 116?14?W, 1607 m. Coll. 29.iv.1911. [1 dry spec. R = 12.5, r = 0.9 (arm tips broken)] NMNH 33252 SW of Punta Abreojos, Baja California. 26?14?N, 114?, 1701 m. Coll. 22.iv.1911. (2 dry specs. R = 2.6, r = 0.5, R = 3.0, r = 0.5) ZOROASTER ORIENTALIS HAYASHI 1943 (WITH FORMA GRACILIS) Zoroaster orientalis Hayashi, 1943: 162; Clark & Mah, 2001: 234. Occurrence: Off Omaesaki Japan, 274?869 m. Comments: Holotype material is probably lost. ZOROASTER PLANUS ALCOCK, 1893 Zoroaster planus Alcock, 1893: 104; Fisher, 1919b: 472, 477; H.L. Clark, 1920: 101 (in key); Clark & Mah, 2001: 234; McKnight, 2006: 43. Occurrence: Laccadive Sea, 2200 m. ZOROASTER SINGLETONI MCKNIGHT, 2006 Zoroaster singletoni McKnight, 2006: 41. Occurrence: New Caledonia Basin, 1392?2162 m. ZOROASTER SPINULOSUS FISHER, 1905 Zoroaster spinulosus Fisher, 1906: 1102; 1919b: 472; H.L. Clark, 1920: 101 (in key); Fell, 1958: 19; 1960: 65; McKnight, 1967: 292, 302; H.E.S. Clark, 1970: 4 (in checklist); McKnight, 1975: 59; 1993: 185; Rowe & Gates, 1995: 116; Chave & Malahoff, 1998: 87; Mah, 1998a: 69; Clark & Mah, 2001: 234; McKnight, 2006: 42. Occurrence: Alaska, Hawaiian Islands, S. Australia, and Tasman Sea, White Island, New Zealand, 350? 1680 m. Material: Alaska. CASIZ 113329, West point of Yunaska Island 53?46?N, 171?37?W, 2226.0 m, Coll. 29.v.1906. (1 dry spec-arm fragment only) Hawai?i. NMNH 21187 HOLOTYPE, West of Kalaupapa, Molokai Island. 21?14?45?N, 157?5?5?W, 600?757 m. Coll. 18.iv.1902 (1 wet spec. R = 11.7, r = 1.1) NMNH 31382 PARATYPE, Hanamaulu Bay, Kauai Island. 22?2?10?N, 159?18?15?W, 620?936 m. Coll. 2.viii.1902. (1 wet spec. R = 11.8, r = 1.0) NMNH 32210 PARATYPE, Between Molokai and Oahu Islands, Kawai Channel. 21?22?35?N, 157?24?40?W, 792?817 m, Coll. 24.vii.1902 (1 wet spec. R = 15.0, r = 1.2); CASIZ 171711 Pioneer Bank, 25?48.12?N, 173?25.92?W. 1797 m. Coll. 8.x.2003 (1 wet spec. R = 17.3, r = 1.2). New Zealand. NMNH 1084276, 8 miles east of White Island, Bay of Plenty, North Island. 630?550 m, Coll. 30.ix.1963. [4 dry specs. R = 10.3, r = 1.4, R = 8.5, r = 1.3, R = 8.8, r = 1.2, R = 10.2, r = 1.1 (arms broken)] ZOROASTER TENUIS SLADEN, 1889 Zoroaster tenuis Sladen, 1889: 421; Koehler, 1907: 141; 1908: 566; Fisher, 1919b: 472; H.L. Clark, 1920: 101 (in key); A.M. Clark, 1962: 67; Clark & Mah, 2001: 234. Occurrence: N. of New Guinea and Southern Ocean between Gough and Bouvet Islands, 3190? 1960 m. Comments: Based on juvenile specimens. A likely syn- onym of Z. fulgens. ZOROASTER VARIACANTHUS MCKNIGHT, 2006 Zoroaster variacanthus McKnight, 2006: 39. Occurrence: Challenger Plateau, western-central New Zealand, 914 m. ZOROASTER SP. 1 Zoroaster sp. A.M. Clark, 1977: 134. Occurrence: Indian Ocean, east coast of Africa, 200? 1000 m. Noted by A.M. Clark (1977: 134) as being a ?poor specimen? (and presumably unidentifiable). ZOROASTER SP. 2 Zoroaster sp. McKnight, 2006: 44. Occurrence: Cavalli Seamount, east of northern New Zealand, 560?630 m. OUTGROUP TAXA: MATERIAL EXAMINED PEDICELLASTERIDAE PERRIER, 1884 AMPHERASTER FISHER, 1923 Ampheraster Fisher, 1923: 253; 1928: 80; Downey, 1971: 51; 1973: 90; Clark & Downey, 1992: 407; Clark & Mah, 2001: 237. AMPHERASTER MARIANUS (LUDWIG, 1905) Sporasterias mariana Ludwig, 1905: 231. PHYLOGENY OF THE ZOROASTERIDAE 199 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Ampheraster marianus Fisher, 1923: 253; 1928: 81; Clark & Downey, 2001: 237 Occurrence: W. Mexico north to Washington. 510? 1240 m. Material examined: California. NMNH E 8926 Off Poinht San Pedro, Channel Islands, Santa Cruz. 34?, 119?, 818?933. Coll. 14.iv.1904. (2 dry specs. R = 4.3, r = 0.5; R = 4.6, r = 0.5, and other arm fragments, dis- articulated specimens). NEOMORPHASTERIDAE FISHER, 1923 NEOMORPHASTER SLADEN, 1885 Glyptaster Sladen, 1885: 612 (nom. nudum, no species named) (non Glyptaster Hall, 1852 (Crinoidea)]. Calycaster Perrier, 1891: 1226; 1891: 258. Gastraster Perrier, 1894: 102; Fisher, 1918: 103; 1923: 250; 1930: 206; Mortensen, 1927: 137. Neomorphaster Sladen, 1889: 436; Fisher, 1923: 596; 1930: 211; Clark & Downey, 1992: 405; Clark & Mah, 2001: 236. NEOMORPHASTER FORCIPATUS VERRILL, 1894 Neomorphaster forcipatus Verrill, 1894: 269; 1895: 206; Clark & Downey, 1992: 405; Clark & Mah: 236. Occurrence: S of Nantucket to Hudson Canyon, 1400? 2000 m. Material examined: Bahamas. NMNH E18509. South of Pinders Point, Grand Bahama Island. 26?17?N, 78?41?W. 513?715 m. Coll. 3.iii.1965. (1 dry spec.s R = 9.1, r = 1.7 cm). DISCUSSION CHARACTER ANALYSIS AND PALAEOZOIC AFFINITIES Body morphology within the Zoroasteridae is broadly similar to the morphology observed in several Palaeo- zoic asteroids. Comparisons between the Zoroasteride and ancient asteroid taxa can be traced to Thomson (1873: 154), who observed similarity between Zoro- aster fulgens and Arthraster dixoni (Cretaceous), which had previously been classified in the fossil Cal- liasterellidae. Downey (1970) observed a close similar- ity between Doraster and Calliasterella. Comparisons between zoroasterids and Palaeozoic taxa within a phylogenetic context have been addressed by Blake (1987, 1990), Blake & Elliott (2003) and Blake & Hag- dorn (2003). Initially, the similarity of the imbricated skeleton provided the basis for initial comparisons (e.g. Downey, 1970) but has become more focused on homologous plate series and skeletal structures shared between taxa (e.g. Blake & Elliott, 2003; Blake & Hagdorn, 2003). Marginal plates have been regarded as significant in studies of asteroid classification and evolution. For example, the Phanerozonia, a major group of asteroids including the Valvatida, Paxillosida and Notomyotida (Sladen, 1889), was defined largely on the basis of the enlarged marginal plate series present in those groups. The marginal plate series was traditionally defined as the single or double horizontal series defin- ing the ambitus of the body in most asteroids (Spencer & Wright, 1966: U29; Clark & Downey, 1992: xxi). However, a formal criterion for recognizing marginal plate series was absent, until Blake (1978: 241) estab- lished marginal plates as the series of plates (usually two) along each side of the arm extending from either side of the terminal plate. This placed marginal plates within an ontogentic framework rather than a strictly locational one. A single marginal plate series (Fig. 4E) was recog- nized in the Zoroasteridae (Blake, 1987, 1990), where previously it had been assumed that all living aster- oids possessed two series of marginal plates. Scanning electron microscopy of marginals in post-settlement and juvenile specimens of Zoroaster fulgens (Sumida et al., 2001) shows no indication of a second marginal series in early ontogeny. A single row of marginal plates is apparently present in the enigmatic Xyloplax (Infraclass Concen- tricycloidea, Mooi, Rowe & David, 1998; Mah, 2006a, b) and suggests affinity with crown-group Asteroidea. A single marginal plate series is present in several Palaeozoic asteroids and somasteroids (Blake & Elliott, 2003), suggesting that the character is plesio- morphic for the crown group. This is consistent with distribution of this character in the resultant phylo- genetic tree. It is important to note that Palaeozoic asteroid faunas are poorly known. Preservational bias can be a significant factor when considering character distributions for phylogenetic estimation between post-Palaeozoic and Palaeozoic taxa. Although zoroasterid genera have only a single plate series, they show significant variation. Mar- ginal plates in Myxoderma and Sagenaster (node 28) are more cruciform-lobate (character 2.6, Fig. 2G) and are therefore similar to marginal plates in forcipulataceans with reticulated skeletons (e.g. Asterias, Ampheraster). Marginal plate shape in the clade containing Zoroaster, Bythiolophus, Doraster and Cnemidaster (node 37) are rounded to polygonal and similar in shape (Figs 3G, 4B, C, E) to those in Palaeozoic taxa, such as Calliasterella or Neopalae- aster (see Blake & Elliott, 2003). Several other char- acters, such as enlarged primary disc and carinal plates (e.g. characters 1.14, 1.16, Fig. 4A, G), a sharply demarcated disc (1.19, Fig. 4G), and the imbricated arrangement of the skeleton (character 1.1, Figs 3?6) also show apparent similarity between 200 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 the crown-group zoroasterids and Palaeozoic taxa (Blake & Elliott, 2003). Disc and arm plates in Palaeozoic genera such as Calliasterella or the Triassic Trichasteropsis (Blake & Elliott, 2003; Blake & Hagdorn, 2003) are blockier and much more massive (characters 1.16, 1.26, 8.11) than those observed in adult imbricate zoroasterids. Juve- nile imbricate zoroasterids also have large, blocky plates (Sumida et al., 2001; Blake & Elliott, 2003) but juvenile asteroids often show disproportionately enlarged structures that become more proportional as ontogeny develops. Distribution of characters among zoroasterid genera suggests that the outward appearance observed is only superficially similar to the appearance observed in Palaeozoic taxa. Two characters, the imbricate skel- eton (1.1) and the single marginal series (2.1), are reconstructed as plesiomorphic to crown-group aster- oids. Other characters showing apparent similarity are interpreted as non-homologous or potentially convergent. As indicated above, there are significant character differences between Palaeozoic and post- Palaeozoic asteroids. Alternative tree topologies present other possible hypotheses for post-Palaeozoic diversification within the forcipulatacean lineage. Calliasterella was placed as the sister clade to the Zoroasteridae and to the imbricate zoroasterids (node 35-Zoroaster, etc.). Either tree topology added only one step to the total tree length. Similarly, a tree topology uniting all the taxa with reticulate skeletons, placing Myxoderma + Sagenaster as the sister group to Ampheraster + Tri- chasteropsis on a monophyletic clade leading to a paraphyletic Zoroasteridae adds only one step more to the tree length. The relatively low Bremer and bootstrap values supporting zoroasterid monophyly would not be inconsistent with these tree topologies. The relatively low support values might also be attributable to plesiomorphy of characters in the Zoroasteridae, similar to the character distribution of Xyloplax (Mah, 2006). A paraphyletic Zoroasteridae would be consistent with affinities to basal post- Palaeozoic asteroids. Mah (2000) placed Neomorphaster as the sister branch to the Zoroasteridae. Neomorphaster was also supported by this analysis as the sister group to the Zoroasteridae. However, Neomorphaster can be joined to node 38 at the base of the clade containing Trichas- teropsis and Ampheraster, or as the sister clade to Calliasterella with the addition of one extra step. Adding Neomorphaster as the sister branch to Ampheraster adds five extra steps (N = 142). Although putatively basal to the Zoroasteridae and other forcipulates, the phylogenetic position of Neo- morphaster remains unclear pending further research. BATHYMETRIC SHIFTS AND THE SIGNFICANCE OF POST-PALAEOZOIC FOSSILS If bathymetric ranges are mapped onto the phyloge- netic tree (Fig. 7), a significant shift is observed between the clade containing those zoroasterids with a reticulate skeleton (Myxoderma, Sagenaster, node 26) and those zoroasterids with an imbricate skeleton (Zoroaster, Cnemidaster, Doraster, Bythiolophus). Clades with a delicate reticulate skeleton inhabiting shallow-water environments are basal relative to the more derived taxa with a more heavily armored imbri- cate skeleton in deeper, abyssal environments. The morphological shift between the reticulate and the imbricate zoroasterids is similar to the pattern observed in the Brisingida (Mah, 1998b). Reticulate brisingidans, such as Odinella and Brisingaster, occur within a shallower depth range relative to the more heavily armored members of the Freyellidae, which occupy almost exclusively abyssal habitats. Bathymetric ranges (Fig. 7) for the reticulate clade are 91?2904 m, whereas the bathymetric range for the imbricate clade is 90?4810 m. Reticulate and imbri- cate zoroasterids display overlapping bathymetric ranges. However, for asteroid species recorded from the Porcupine Seabight, Howell et al. (2002) observed that there is a much narrower centre of distribution in which abundance of adult individuals is highest, despite much wider total adult depth ranges. Alton (1966: 1688) observed the peak abundance of Myxoderma platyacanthum and M. sacculatum between 397?878 m and 1372?1555 m, respectively. Peak abundance in Sagenaster (= Zoroaster) ever- manni was observed between 502 and 1490 m, whereas abundance in the imbricate Zoroaster ophiu- rus was only observed below 1865 m. Howell et al. (2002) observed peak abundance for Zoroaster fulgens and Z. longicauda (considered by Clark & Downey, 1992 as a synonym of Z. fulgens) at 1450?1550 m and 3650?3750 m, respectively. The range of occurrence in reticulate zoroasterids is shallower than that observed in the imbricate zoroasterids. Incomplete preservation of features in the Jurassic Terminaster cancriformis (Quenstedt) precluded its inclusion in the matrix. However, characters figured by Hess (1974, 1986) suggested placement on the phylogenetic tree. Hess (1986) figures several promi- nent enlarged primary spines in Terminaster and compares the enlarged terminal plates with those in Myxoderma sacculatum. Enlarged terminals occur in both juvenile zoroasterids and across several phyloge- netically disparate zoroasterid genera (e.g. Myxo- derma and Zoroaster). The primary spines apparently occur on nearly all arm and disc plates, a feature present in Myxoderma and Sagenaster. However, Ter- minaster possesses only polygonal to slightly lobate PHYLOGENY OF THE ZOROASTERIDAE 201 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 plates, which are present only in the ?imbricate? zoro- asterids (node 37). The absence of enlarged disc plates and relatively small disc size do not support affinities with the taxa included on node 29 (Bythiol- ophus, Doraster, Cnemidaster). This suggests a posi- tion basal to node 35 or close to node 34 near the base of Pholidaster + Zoroaster. Terminaster was col- lected from marls, which have been interpreted as shallow (< 100 m, Hallam, 1998: 684), suggesting a shift between shallow- to deep-water environments (> 100 m) after the Jurassic. Onshore?offshore trends within individual zoroast- erid lineages were less well defined. Several taxa dis- played shallower bathymetric occurrence relative to their sister taxa (Fig. 7), but patterns suggesting diversification of multiple taxa into either shallow- or deep-sea environments was unclear. For example, Doraster occurs in a shallower bathymetric range (350?640 m) relative to the deeper-water Cnemidaster (including synonym Mammaster) (310?1990 m). How- ever, Bythiolophus, the sister clade to the Doraster + Cnemdiaster clade, occurs in a much deeper bathymet- Figure 7. Phylogram of the Zoroasteridae with bathymetric ranges mapped for each taxon. Note taxonomic revisions applied to included taxa (tree and node positions parallel to those in Fig. 1). OG: Calliasterella americana OG: Trichasteropsis weismanni OG: Ampheraster marianus OG: Neomorphaster margaritaceus Myxoderma platyacanthum 256-2904 m Myxoderma sacculatum 91-2012 m Myxoderma qawashqari 300-2454 m Myxoderma longispinus 980-1571 m Sagenaster evermanni n.gen. 294-2710 m Bythiolophus acanthinus 1022 m Doraster constellatus 350-914 m Cnemidaster wyvilli 1370-1990 m Cnemidaster sigsbeei 310-1318 m Pholidaster squamatus 90-256 m Zoroaster carinatus 152-1104 m Zoroaster actinocles 2220-2226 m Zoroaster macracantha 403-1006 m Zoroaster magnifcus 2775-3667 m Zoroaster ophiactis 500-1678 m Zoroaster ophiurus 695-2230 m Zoroaster spinulosus 350-1680 m Eocene-Zoroaster aff. fulgens shallow-water, littoral Zoroaster fulgens 220-4810 m Zoroaster microporus 1280 m C ontinental Shelf ra nge: 91-2904 m A byssalPlain/Soft-Bottom s. ra nge:90-4810 m Terminaster Jurassic shallow-water 5 changes 202 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 ric range (450?1006 m) relative to Doraster. Pholi- daster is supported as the sister taxon to Zoroaster, and occurs in relatively shallow depths (90?256 m). Although Zoroaster carinatus occurs in relatively shallow depths (152?1104 m), Z. microporus, the sis- ter taxon to the remaining Zoroaster species, does not (1280 m). Also included in the matrix was the Eocene Z. aff. fulgens described by Blake & Zinsmeister (1979), which occurred in littoral, shallow-water sediments. Although identified as Z. fulgens, assessment of its species affinities was considered tentative (Blake & Zinsmeister, 1979). All modern Zoroaster, including Z. fulgens, occupy deep-water environments (? 200? 4000 m) indicating a bathymetric shift between the Eocene Zoroaster from shallow-water sediments at Seymour Island and those Zoroaster living today in bathyal to abyssal depths. Deep-sea taxa are often documented from shallower depths (e.g. Pearse & Lockhart, 2004) in the Southern Ocean as a result of the cold-water masses extending to shallow shelf regions. However, schlerochronology of the bivalve Cucullaea raea, which co-occurred with Z. aff. fulgens at the La Meseta formation (Buick & Ivany, 2004), and stable istope proxies (Dutton & Lohmann, 2002) sup- port warmer, more temperate, waters in the Eocene relative to those at Seymour Island today. Evidence from these studies is consistent with palaeoenviron- mental changes in Antarctica (reviewed in Dingle & Lavelle, 2000) associated with the development of the circum-Antarctic current (Kennett, 1977) following the separation of eastern Antarctica from Australia (summarized in Clark & Crame, 1989), which resulted in glaciation and cooling events at the Eocene/Oli- gocene boundary (Zachos et al., 2001). Although the phylogenetic position of the Eocene species on node 30 is equivocal, its derived placement suggests a possibly terminal offshore?onshore migration. The phyloge- netic position would be consistent with a localized extinction of Zoroaster in Antarctica. Benthic taxa have been considered particularly vulnerable to tem- perature change (Peck, 2005). With the exceptions of the Eocene Z. fulgens and a listing of a juvenile spec- imen of Zoroaster tenuis Sladen from between Gough and Bouvet Islands (on the periphery of the South Atlantic) (Koehler, 1909), zoroasterids have not been recorded from the Southern Ocean (A. M. Clark, 1962). Placement of the Eocene Z. fulgens (Fig. 6E) as the sister taxon to the extant Z. fulgens adds a single step, whereas adding it to the base of node 31 or at the base of Z. carinatus adds two steps. Moving the Eocene Z. fulgens to the base of Z. microporus or any further away from node 32 adds at least five steps to the total. Thus, it seems that a more basal position for the Eocene Z. fulgens is plausible. Such a position would be consistent with scenarios outlining Antarctica as a ?diversity pump? for distribution of species into the deep-water environments of the Atlantic, Indian and Pacific Oceans (Gage, 2004). Blake & Zinsmeister (1979, 1988) and Blake & Aronson (1998) described several asteroid taxa from Seymour Island, Antarc- tica, recorded from shallow-water sediments that today occupy continental shelf (?20?180) or deep- water (> 200 m) environments, including Ctenopho- raster, Tessellaster, Paragonaster and Sclerasterias. TIMING OF EVENTS, PHYSIOGRAPHY AND HISTORICAL BIOGEOGRAPHY The two fossil taxa considered in the tree constrain phylogenetic events within the Zoroasteridae. Timing dictated for these constraints was compared with shifting Mesozoic and Cenozoic coastlines (Smith, Smith & Funnell, 1994), including significant geolog- ical events such as the opening of the Atlantic Ocean. Fossil occurrence and geological events are broadly consistent with the phylogenetic tree. Global occurence patterns suggest a hypothesis of Pacific and Indian ocean taxa colonizing the younger Atlantic. An identical pattern also was observed in the Goniasteridae (Halpern, 1970; Mah, 2006a). The phy- logeny is consistent with a shift between reticulate zoroasterids (Myxoderma and Sagenaster) and imbri- cate zoroasterids (e.g. Zoroaster, Cnemidaster) from the continental shelf to slope and abyssal plain environments. In conjunction with onshore?offshore patterns described above, the phylogeny (Fig. 7) supports a physiographic shift between those zoroasterids with reticulated skeletons (Myxoderma and Sagenaster) liv- ing almost exclusively on the continental shelf or on continental slopes vs. the imbricate taxa (e.g. Zoro- aster), which are found primarily on soft-bottom abys- sal plains. Myxoderma forms a species complex along shelf or near-shelf regions along the perimeter of the North- east?Central Pacific; from the Okhotsk Sea and the Aleutians along the North and South American coasts extending south to Chile. This is consistent with Aziz & Jangoux (1984: 193) who stated that Myxoderma composed a species complex based on M. platyacan- thum, M. sacculatum and M. acutibranchia. Myxo- derma acutibrachia Aziz & Jangoux, 1984 extends the range of the complex to Macassar Straight (between Borneo and Sulawesi). Myxoderma has not been recorded from the Indian Ocean, the Hawaiian Islands, Japan or off mainland Asia. Sagenaster, the sister taxon to Myxoderma, also occurs on shelf or near-shelf regions along the Northeast Pacific coast from Alaska to Mexico. Reticulate zoroasterids have not been recorded from the Atlantic. PHYLOGENY OF THE ZOROASTERIDAE 203 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 Taxa within the imbricate zoroasterid clade show diversification into the Pacific, Indian and Atlantic Ocean basins and occur primarily on muddy bottoms on slope or near-slope regions and abyssal plains and are not commonly recorded from the continental shelf. Bythiolophus has been collected only in the central Pacific. Doraster is known only from the Atlantic. Pholidaster has only been recorded from the Philip- pines and off the coast of Western Australia (Indian Ocean). Cnemidaster and Zoroaster occur in the Atlantic, Pacific and Indian oceans. The widespread geographical distribution and the relatively few mor- phological differences between species are consistent with other deep-sea asteroids, such as the Porcellan- asteridae, a cosmopolitan group in abyssal depths (Madsen, 1961). Although Myxoderma and Zoroaster are recorded from the Aleutian Islands and in the Gulf of Alaska, none is recorded from the Arctic Ocean. Body fossils of Terminaster (Hess, 1974, 1986) are interpreted as morphologically intermediate between reticulate and imbricate zoroasterids. If placed at node 34 (Fig. 7) it suggests a minimum age for the node of 155?160 Ma (Callovian?Oxfordian). At this stage dur- ing the Jurassic, the South Atlantic had not yet opened and several continents in the Southern Hemisphere, including Antarctica, Australia, South America and Africa, were still conjoined (Smith et al., 1995). The presence of Doraster in the formative northern region of the Atlantic Ocean is not inconsistent with the age of the imbricate zoroasterid lineage indicated above. Cnemidaster was the only zoroasterid studied which displays morphological continuity across the Panama- nian Seaway. Although full seaway closure has been estimated at 3.1?3.5 Ma (early Pliocene, Duque-Caro, 1990), exchange between the Indo-Pacific and Atlantic populations of Cnemdiaster probably occurred earlier, with deep-water connections between the Pacific and the Atlantic ending in the early to middle Miocene (16.1?15.1 Ma) and Caribbean faunal affinities on the Pacific side of South America ending in the middle Miocene (12.9?11.8 Ma, Duque-Caro, 1990). Support in the phylogeny for Doraster as Cnemidaster?s sister taxon suggests diversification into the Indo-Pacific region from the tropical Atlantic. ACKNOWLEDGEMENTS This paper benefited from discussions with Daniel Blake, University of Illinois, Urbana Champaign. Specimen transactions were facilitated by Cindy Ahearn (NMNH), Cathy Groves (LACM), Bob Van Syoc (CASIZ), Larry Lovell (SIO), Dave Bohaska and Forrest Gahn (NMNH) and Harry Filkhorn (LACM). Thanks to Andrew Cabrinovich, British Museum of Natural History, for photo images of the Pholidaster distinctus holotype. Identifications of gastropod food items was provided by Don Tippett (NMNH). Daniel Blake, Dave Pawson and an unknown reviewer pro- vided useful comments on the manuscript. Support for this research was provided by the Smithsonian NMNH Postdoctoral Fellowship for 2005. REFERENCES Alcock A. 1893a. Natural History notes from the HM Indian Marine Survey Steamer Investigator.7. An account of the col- lection of deep-sea Asteroidea. Annals and Magazine of Nat- ural History 11 (6): 73?121. Alcock A. 1893b. Natural History notes from the H.M. Indian Marine Survey Steamer Investigator, 9. Cmdr. C.F. Oldham, Royal.N., Commanding. An account of the deep-sea collection made during the season of 1892?93. Journal of the Asiatic Society of Beng 62 (2): 171?178. Alcock A. 1895. Illustrations of the zoology of the Royal Indian Marine Survey Steamer. 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Secondary abactinal arm spine distribution. 0, absent; 1, distributed evenly (Fig. 2E, F); 2, dis- tributed densely (Fig. 3B, C). 1.6. Arm plates cruciform. 0, not cruciform lobate; 2, strongly cruciform lobate (Fig. 2E?G). 1.7. Arm plates polylobate. 0, plates not poly lobate; 1, plates polylobate (Figs 3E, 4A?G, 6 A, D, F). 1.8. Adradial plates. 0, absent; 1, present (Fig. 4A?C). 1.9. Carinal plates, peripheral. 0, absent; 1, present (Fig. 5A?D). 1.10. Carinal plates, quadrate. 0, absent; 1, present (Fig. 5A?E). 1.11. Carinal plates, strongly lobate. 0, absent; 1, present (Figs 2B, E?G). 1.12. Carinal plates, weakly lobate. 0, absent; 1, present (Fig. 4A, C, D, G). 1.13. Carinal series, low ridged. 0, absent; 1, present (Fig. 2A, E, F). 1.14. Carinal series, ridged. 0, absent; 1, present (Fig. 6B, C, D, G). 1.15. Carinal series, level. 0, absent; 1, present (Figs 4A, C, E, 5E, F). 1.16. Circlet disc plate size. 0, similar to other disc plates (Fig. 2B, E); 1, enlarged (Figs 3A, E, 5A, E, 6D, F); 2, enlarged and swollen (Fig. 4C, G); 3, robust, blocky (only in Calliasterella). 1.17. Compared primary disc-arm plate size. 0, simi- lar (Fig. 2B, E?G); 1, dissimilar (Fig. 4C, G). 1.18. Primary carinal spines. 0, absent; 1, present (Fig. 6C). 1.19. Arm-disc continuity. 0, continuous (Figs 2E, 5A); 1, discontinuous (Fig. 4C, G). 1.20. Centrodorsal plate, strongly lobate. 0, absent; 1, present (Fig. 2E?G). 1.21. Centrodorsal plate, weakly lobate. 0, absent; 1, present (Fig. 6D, F, G). 1.22. Primary disc plates, prominence. 0, continuous with skeleton (Fig. 2B, E?G); 1, overlapping other plates (Figs 3A, E, 4A, B, 5A, E) 1.23. Number of spine types. 0, one spine type; 1, two spine types. 208 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 1.24. Spine tip morphology. 0, granular; 1, blunt; 2, sharp (Figs 2E?F, 6C). 1.25. Secondary spine morphology. 0, straight; 1, recurved. 1.26. Abactinal plate morphology. 0, blocky-robust; 1, cruciform-reticulate; 2, laterally flattened (only in Neomorphaster); 3, dorsoventrally flattened (Fig. 2B, E?G). 1.27. Carinal plates thickened. 0, absent; 1, present (only in Neomorphaster). 2. Marginal plate characters 2.1. Number of marginal plate series. 0, single series (Fig. 4E); 1, two series. 2.2. Marginal plate robustness. 0, phanerozonate; 1, cryptozonate. 2.3. Marginal plate size distribution. 0, sizes sequen- tial (Fig. 3C); 1, sizes alternating (Fig. 3B). 2.4. Primary spine on marginal plate. 0, absent; 1, present (Figs 2E?F, 6C). 2.5. Marginal plate, weakly lobate. 0, absent; 1, present. 2.6. Marginal plate, strongly lobate. 0, absent; 1, present (Fig. 2F). 2.7. Marginal plates thickened. 0, absent; 1, present (only in Neomorphaster). 3. Actinal surface characters 3.1. Actinal plates. 0, absent; 1, present. 3.2. Actinal plate orientation. 0, absent; 1, facing actinally; 2, facing actinolaterally 3.3. ctinolateral spines, enlarged. 0, absent; 1, present (Fig. 3D, G). 3.4. Actinolateral plate arrangement. 0, reticulate; 1, imbricate; 2, tightly imbricate. 3.5. Actinolateral plate density. 0, evenly distributed; 1, densely distributed, esp. near adambulacrals; 2, absent. 3.6. Secondary spination. 0, evenly distributed; 1, closely distributed; 2, absent. 3.7. ctinolateral plates quadrate. 0, absent; 1, present; 2, actinal plates absent. 3.8. Actinolateral plates weakly lobate. 0, absent; 1, present; 2, actinal plates absent. 3.9. Actinolateral plates polygonal. 0, absent; 1, present (Fig. 3G); 2, actinal plates absent. 3.10. Actinolaterals strongly lobate. 0, absent; 1, present; 2, actinal plates absent. 3.11. Actinolateral plates in transverse series. 0, absent; 1, present; 2, actinal plates absent. 3.12. Actinolateral plates thickened. 0, absent; 1, present; 2, actinal plates absent. 4. Furrow and adambulacral region characters 4.1. Adambulacral plates carinate. 0, weakly cari- nate; 1, strongly carinate (Fig. 4F); 2, non- carinate. 4.2. Adambulacral plates alternately carinate. 0, not alternating; 1, alternating (Fig. 4F). 4.3. Adambulacrals overlap. 0, proximally; 1, distally. 4.4. Adambulacral spine series. 0, not in array-like formation; 1, array-like formation. 5. Soft tissue characters 5.1. Pulpy membranous covering. 0, absent; 1, present. 5.2. Smooth membranous covering. 0, absent; 1, present (Fig. 4A, B). 6. Body morphology characters 6.1. Disc thickness. 0, moderately thickened; 1, heavily thickened (Fig. 4B, C). 6.2. Number of tube foot rows. 0, two; 1, four (proxi- mally). 6.3. Oral region depressed. 0, level with oral surface; 1, oral region deeply sunken (Fig. 3F, 4F). 7. Pedicellariae characters 7.1. Pedicellariae types. 0, absent; 1, straight and crossed; 2, straight only (Figs 3F, 4F). 7.2. Pedicellariae distribution. 0, absent; 1, body sur- face and adambulacral furrow. 7.3. Dense oral ring of pedicellariae. 0, absent; 1, present (Fig. 3F). 8. Internal skeletal characters 8.1. Oral ring fused. 0, not fused; 1, fused. 8.2. Axillary plate. 0, absent; 1, present. 8.3. Body ossicle size and number. 0, large and few; 1, small and numerous. 8.4. Ambulacral pores deflected. 0, proximally deflected for pore; 1, podial pore deflects both sides. 8.5. Adoral carina. 0, absent; 1, weakly expressed; 2, strongly expressed. 8.6. Superambulacral plates. 0, absent; 1, present (Fig. 2C, D). 8.7. Superambulacral reduction. 0, not reduced (Fig. 2C, D); 1, reduced; 2, absent. 8.8. Internal buttress. 0, absent (Fig. 6H); 1, present (Fig. 2D). 8.9. Papular rows. 0, reticulate; 1, ordered rows (Fig. 6A?D). 8.10. Papular fields. 0, enlarged field (Fig. 2B, E?G); 1, single pore (Fig. 6B, C). 8.11. Blocky skeleton. 0, blocky, robust; 1, not blocky, robust. 8.12. Ambulacral shape. 0, compressed; 1, squarish- blocky (Fig. 2C, D); 2, broad rectangular. PHYLOGENY OF THE ZOROASTERIDAE 209 ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 APPENDIX 2 DATA MATRIX Taxon 1111111111222222222233333333334444444444555555555566666666667 1234567890123456789012345678901234567890123456789012345678901234567890 Calliasterella 100?000000000003001001???00000000000012?2222222000??10000?000000201?02 Trichasteropsi 000?11010010100000010000?10000001011000?0101000110??01000?111110200010 Ampheraster 0101010100101000000100010101101010110002110000011000010110111110200010 Neomorphaster 2001001100000100000100010211100101110202100001011000011110111120201110 M. platyacanthu 0101110100101000010100121300101010121000110000111110011210111121011011 M. sacculatum 0101110100101000010100121300101010121010110000111110011210111121011011 Z. evermanni 0101110100101000010100120300101010121000110000111100011210111121001011 Z. longispinu 0101110100101000010100121300101010121000110000111110011210111121011011 D. qawashqari 01011101001010000101001213001010101210101100001111??011210111121011011 B. acanthinus 1011201000010011001011121300110100121111000110111100011210111121011111 D. constellatus 1013201100010101000011121300100100121111000100111100111211111121011111 C. wyvillei 1012001100010012101021121300100100121111000100111101111211111121011111 M. sigsbeii 1012001000000012101021121300100100121111000100111101111211111121011111 P. squamatus 1010201110010011000011121300100100121111001010111100011000111121001111 Z. carinatus 1013201100010101000011121300100100121111001010111100011210111121101111 Z. actinocles 1013201100010101010011121300101100121111001010111100011210111121101111 Z. fulgens 1013201100010101000011121300101100121111001010111100011210111121101111 Z. macracantha 1013201100010101010011121300101100121111001010111100011210111121101111 Z. magnificus 1013201100010101010011121300101100121111001010111100011210111121101111 Z. microporus 1013201101000011000011121300100100121111001010111100001210111121101111 Z. ophiactis 1013201100010101010011121300101100121111001010111100001210111121101111 Z. ophiurus 1013201100010101010011121300101100121111001010111100011210111121101111 Z. spinulosus 1013201100010101010011121300101100121111001010111100011210111121101111 Z. fulgens-EOC 1013201100010101010011121300101100121111001010111100011210111121101111 210 C. MAH ? 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 177?210 APPENDIX 3 KEY TO THE ZOROASTERIDAE (0a) Two series or marginal plates with both series continuing from interradius to terminal plate. Primary spines present. Secondary spines absent. Adambulacral plates weakly carinate (i.e. carinal projection close to surface of the adambulacral plate-not projecting furrow), not alternating. Superambulacrals absent. Crossed and straight pedicellariae present. Actinolateral spines not enlarged. Abactinal plates reticulate, ordered or unor- dered. Discs size variable. Arm number five or more. .............................................................................. Asteriadina (0b) One series of marginal plates. Adradial plate series discontinues distally before reaching terminal plate. Primary and secondary spines present. Adambulacral plates strongly carinate (i.e. carinal projection markedly above sur- face of adambulacral plate, projecting into furrow), alternately in large (adult) specimens, completely carinate (but slightly lower, more angular) in smaller specimens. Superambulacrals present in all, but reduced distally in Zoro- aster. Enlarged actinolateral spines. Straight pedicellariae present in all but Pholidaster. Plates in well-ordered longitudinal, transverse rows. Discs small, arms elongate, tapering. Arm number always five. ................................ ......................................................................................................................................Zorocallina (Zoroasteridae) 1 (1a) Squamulate spines (Fig. 5A, C), pedicellariae absent. .......................................................... Pholidaster (Fig. 5A?C) (1b) Spines not squamulate. Straight pedicellariae present ................................................................................................ 2 (2a) Skeleton reticulate (Fig. 2B, E?G). Primary spines on all plates (Fig. 2E?F). Plates quadrate to cruciform-like (Fig. 2G). Abactinal, actinolateral plates all similar or identical in form. .................................................................. 3 (2b) Skeleton imbricate. Primary spines absent from all plates, but present on primary series (carinals, marginals, etc.). Skeleton well developed. Actinolateral plate series differentiated from adradial, carinal series. ............................ 4 (3a) Buttress present (Fig. 2D). ...................................................................................................... Myxoderma (Fig. 2A, B) (3b) Buttress absent (Fig. 6H). ........................................................................................................ Sagenaster (Fig. 2E, F) (4a) Buttress absent (Fig. 6H). Disc small, arms slender, not thickened proximally, elongate. ....Zoroaster (Figs 5E, 6) (4b) Buttress present (Fig. 2D). Disc thickened, enlarged, arms thickened proximally. .................................................... 5 (5a) Marginal plate series alternating in size. Sharp spines on adradials. .................................. Bythiolophus (Fig. 3A) (5b) Marginal plates all of one size. Adradials, if present, never with enlarged spines. ................................................... 6 (6a) Disc thickened, but plates not swollen. Plates stellate (Fig. 3E). Disc surface continuous with plane of arms (Fig. 3G). Fine spination covers body surface (sometimes denuded) (Fig. 3G). Adradials present in larger specimens, residual in smaller ones. Distinct ring of pedicellariae in mouth (Fig. 3F). ............................ Doraster (Fig. 3E, G) (6b) Disc plates swollen, polygonal to rounded, enlarged, rising above plane of arms, sharply set off from arms. Abactinal spines few to absent. Thick layer of skin overlies surface...........Cnemidaster (Mammaster is a synonym) (Fig. 4)