Deepest known novel species of the genus Ophiuroglypha Hertz, 1927 (Echinodermata: Ophiuroidea) from the central rift zone, Philippine Sea Author Nethupul, Hasitha 947FC889-2FAA-465B-8F4C-93E4DF21BD00 Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, CAS, 57200 Sanya, China. & University of Chinese Academy of Sciences, Beijing 100039, China. Nethupul@idsse.ac.cn Author Stöhr, Sabine 412800EB-AACE-4313-9810-61F89B740405 Swedish Museum of Natural History, Dept of Zoology, Box 50007, 10405 Stockholm, Sweden. sabine.stohr@nrm.se Author Zhang, Haibin 42C09E82-18C5-446D-B4F4-A2C8F2367AC9 Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, CAS, 57200 Sanya, China. hzhang@idsse.ac.cn text European Journal of Taxonomy 2023 2023-09-26 891 167 185 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2281/9835 journal article 10.5852/ejt.2023.891.2281 32ba8e03-593e-4dbb-a965-258f61d6e665 2118-9773 8382615 A8753CAC-F181-4E6D-82F3-F4A456025447 Ophiuroglypha fendouzhe sp. nov. urn:lsid:zoobank.org:act: 31A4A22F-7F61-4510-BF10-67851B458559 Figs 1–5 Diagnosis Disc pentagonal, covered by large irregular overlapping scales. Radial shields broad, slightly wider than long, triangular, barely connected to each other at distal end, and proximal half separated by one elongated disc scale ( Fig. 3A–C ). Ventral disc covered by large, overlapping scales, slightly larger than dorsal disc ( Fig. 3D ). Jaw slender, large, contiguous, pair of pointed ventralmost teeth at apex, and up to five lateral oral papillae ( Fig. 3E ). Second oral tentacle pore large, opening outside mouth slit with four adoral shield spines and five ventral tentacle scales ( Fig. 3E–F ). Arms slender. Dorsal and ventral arm plates separated ( Fig. 3F–H ). Tentacle pores absent after seven or nine arm segments ( Fig. 3I ). Etymology The specific name is dedicated to the manned submersible vessel ‘Fendouzhe’, which collected the specimen. Material examined Holotype PHILIPPINE SEA • central rift zone; 16º56.74′ N , 129º44.33′ E ; depth 7729 m ; 20 Sep. 2021 ; collecting event: stn. SC043; Fendouzhe msv leg.; GenBank: ON783074 ; preserved in 95% ethanol; IDSSE-EEB-SW0250 . Paratypes PHILIPPINE SEA • 1 specimen ; same collection data as for holotype; GenBank: ON783074 ; preserved in 95% ethanol; IDSSE-EEB-SW0251 • 3 specimens ; same collection data as for holotype; preserved at -80°C; IDSSE-EEB-SW0252 to IDSSE-EEB-SW0254 . Description MEASUREMENTS . Disc diameter 10 mm , arm base width 0.9 mm , and arm length 56 mm ( Fig. 3 ). DISC . Disc pentagonal, covered by large irregular, and polygonal overlapping scales ( Fig. 3A–C ). Centrodorsal primary plate rounded in disc center ( Fig. 3C ). Radial shields broad, slightly wider than long, triangular, barely connected to each other at distal end, sharp pointed proximal edge, straight distal edge, and proximal half separated by one elongated disc scale (k-plate) ( Fig. 3A, C–D ). Median distal interradial area of disc formed by four to five large scales (⅓ larger than other dorsal disc scales), most of them rounded rectangular ( Fig. 3C ). Ventral disc covered by large, overlapping scales, slightly larger than on central dorsal disc ( Fig. 3B, E–F ). Distal end of genital slit bordered by small pointed genital papillae forming arm comb ( Fig. 3E–F ). Oral shield as wide as long, triangular, slightly convex at distal end, and connected to genital slit ( Fig. 3E ). Adoral shields small, narrow, rectangular, slightly curving outward from oral shield, contiguous proximally, and distally connected to first lateral arm plate ( Fig. 3E ). Jaw slender, large, contiguous, with pair of pointed infradental papillae at apex, and spearhead-shaped teeth ( Fig. 3E ). Up to five lateral oral papillae. Distalmost papilla (ventral compartment plate) much broader than others, and proximal two to three papillae spearhead-shaped to oval, and distal lateral oral papilla (buccal scale) lesspointed and broader ( Fig. 3E ). Second oral tentacle pore large and opening outside mouth slit, with five ventral tentacle scales and four adoral shield spines at each side. Genital slits conspicuous and extending from oral shield to disc periphery ( Fig. 3E–F ). Fig. 3. Ophiuroglypha fendouzhe sp. nov. , holotype (IDSSE-EEB-SW0250). A . Dorsal aspect. B . Ventral aspect. C . Central disc (overlapping disc scales). D . Dorsal arm base. E . Ventral disc, and mouth. F . Ventral arm base. G . Dorsal arm. H–J . Ventral arm (partially broken arm spine highlighted in the Fig. I). K–L . Lateral arm. Abbreviations: arc = arm comb; ars = arm spine; as = adoral shield; asp = adoral shield spine; cpp = central primary plate; dap = dorsal arm plate; gs = genital slit; lap = lateral arm plate; m = madreporite; op = oral plate; os = oral shield; otp = oral tentacle pore; rs = radial shield; tp = tentacle pore; ts = tentacle scale; vap = ventral arm plate; vts = ventral tentacle scale. Scale bars: A–B = 2 mm; C, E–F =1 mm; D, G–L = 500 μm. ARMS . Five slender, and non-moniliform arms. Dorsal arm plates small, diamond-shaped, straight to slightly fan-shaped with convex distal edge, pointed proximal edge, as wide as long, and widely separated, except on first and second arm segments ( Fig. 3D, G ). First two ventral arm plates slightly wider than long, pentagonal, and contiguous. Following ventral arm plates wider than long, pentagonal to triangular, distally straight to slightly curved, proximally triangular, and increasingly separated along arm ( Fig. 3E–F, H ). Lateral arm plate with mostly three and rarely four arm spines. All arm spines small, smooth, pointed tip, similar in length, and approximately ½ arm segment long ( Fig. 3G–L ). Distally, middle arm spine slightly curved inwards ( Fig. 3I–L ). First tentacle pore with three or four tentacle scales ( Fig. 3F–L ). Second and third tentacle pores with four to two tentacle scales ( Fig. 3F ). Fourth to fifth tentacle pores with three to one tentacle scales ( Fig. 3F ). Number of tentacle scales decreases to one scale, and absent after seven or nine arm segments ( Fig. 3H, L ). COLOR . Creamy white in alcohol specimen ( Figs 3 , 5 ). OSSICLE MORPHOLOGY . (IDSSE-EEB-SW0251) Three arm spine articulations placed at distal edge of lateral arm plate, with clear muscle opening and small nerve opening ( Fig. 4A–B ). Tube foot pore developed as large within-plate perforation on lateral arm plates from base to middle part of arm, where tentacle scales begin to disappear from arm segments ( Fig. 4A–B ). Middle half of inner side of lateral arm plate with depression and two round knobs ( Fig. 4C ). Vertebrae with moderate zygospondylous articulation, proximal end with podial basins ( Fig. 4D–H ). Dorsal side of vertebrae distally triangular and proximally slightly curved, shallow longitudinal groove along midline ( Fig. 4F–H ). Ventral side of vertebrae with long and broad ambulacral groove with pair of lateral ambulacral canals ( Fig. 4F–H ). Paratype variations Four paratype specimens were collected from the same location. They are similar to the holotype (disc diameters 8.0–10.0 mm), but one paratype has a sub-pentagonal disc and an obvious round centrodorsal primary plate ( Fig. 5A ).All paratypes are identical to the holotype with respect to the other morphological characters and this small variation is considered intraspecific ( Fig. 5 ). Distribution and habitat So far only known from the type locality.