Ventrifossa saikaiensis Okamura 1984
Creators: name: Iwamoto, Tomio
name: Nakayama, Naohide
name: Shao, Kwang-Tsao
name: Table, Hsuan-Ching Ho
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Gadiformes
Macrouridae
Ventrifossa
Ventrifossa saikaiensis

description: Ventrifossa saikaiensis Okamura, 1984
Ventrifossa saikaiensis Okamura in Okamura and Kitajima, 1984:209 (holotype, BSKU 28004; Okinawa Trough, 28°50.0ʹN, 127°14.0ʹE, 700–740 m; 11 paratypes, Okinawa Trough).— Chiou et al., 2004b: 48–49, fig. 23 (19 spec.; Taiwan [NET]).
Ventrifossa divergens (not of Gilbert and Hubbs, 1920): Chiou et al., 2004b:46, fig.19 (2 spec.; Da-xi, Taiwan [NET]).
MATERIAL EXAMINED (58 Taiwan spec.).— NET: ASIZP 61248 (1, 250 TL), Da-xi; ASIZP 61249 (14, 102–168 TL), Da-xi; ASIZP 61307 (1, 224 TL), Da-xi; ASIZP 61310 (1, 182 TL), Da-xi; ASIZP 64094 (1, 53 HL, 260+ TL), CP 235, 764 m); ASIZP 63271 (1, 144 TL), Da-xi; ASIZP 64094 (1, 260+ TL), CP 235, 764 m; ASIZP 65608 (1, 145+ TL), CP 120, 520 m; ASIZP 65602 (1, 295+ TL), CD 138 m; ASIZP 70223 (1, 60 HL), Da-xi; ASIZP 70225 (2, 270+-395 TL), Da-xi; ASIZP 70730 (1, 170 TL), Da-xi. SWT: ASIZP 61242 (1, 272 TL), Dong-gang; ASIZP 61309 (1, 220 TL), Dong-gang; ASIZP 64119 (1, 278+ TL) and ASIZP 64253 (1, 200+ TL), CD 193, 821 m; ASIZP 65601 (2, 285 TL) and CAS 224887 (ex. ASIZP 65601, 1, 299 TL), CD 139, 718– 852 m; ASIZP 65608 (1, 145+ TL), CP 120, 520– 640 m; ASIZP 65616 (1, 185 TL), CD 138, 441 m; ASIZP 70273 (1, 295 TL), CD 138, 441 m; ASIZP 71146 (1, 267 TL), CD 271, 700– 800 m. SCS: ASIZP 64562 (1, 275 TL) and ASIZP 65562 (1, 275 TL), CD 140, 280– 452 m; ASIZP 65522 (18, 90–185 TL), CD 136, 998– 1211 m; ASIZP 61242 (1, 272 TL), Dong-gang. Other specimens (all from Okinawa Trough, East China Sea): BSKU 28004 (holotype, 305+ TL); BSKU 27576 (paratype, 285+ TL); BSKU 28005–28008 (4, 180+–290 TL).
DISTINGUISHING FEATURES.— 1D II,9–11; P i18–i22; V 8–9; total GR-I (lateral/mesial) 12–16 / 16–18, GR-II 15–18 /15–18; scale rows below midbase 1D 5.5–7.0, below 2D 6.0–7.5; lateral line scales over distance equal to predorsal length 33–44. Snout length 28–31% HL; preoral length 14–19%; internasal 21–26%; interorbital 27–32%; orbit 27–32%; postorbital 44–48%; orbit to preopercle 43–46%; suborbital 14–16%; upper jaw 45–50%; barbel 27–35%; outer gill slit 27–30%; 1D–2D interspace 43–68%. Body and head moderately deep and compressed; snout low, rather blunt and protruding little beyond large mouth; barbel long, slender. Body scales densely covered with slender, reclined, needle-like spinules in wide chevron-like rows; no spinuleless scales around 1D base. Color in alcohol medium brownish, lacking silvery reflections; blackish over gill cover; bluish-black over abdomen and chest; gill and gular membranes black; mouth and gill cavities pale, but dark in gullet; margins on suborbital shelf and leading edge of snout faintly blackish or not distinguished; barbel pale, but base dark; 1D uniformly dusky; V blackish; P and A dark dusky, but base of P black along distal margin. Coloration of lips, mouth, jaws, teeth, and gill cavities as in others of genus. Attains more than 31 cm TL.
DISTRIBUTION.— Known only from the Okinawa Trough (in East Sea), Taiwan (NET, SWT), and the South China Sea in 280–1211 m.
REMARKS.— Chiou et al. (2004b:46, fig.19) recorded two specimens (ASIZP 61309 and 61310) as V. divergens, but we re-identified them as V. saikaiensis. Among the Taiwan grenadiers, V. saikaiensis is most similar to V. divergens in having a uniformly dusky 1D, but it is easily distinguished from that species (and all other Taiwan members of Ventrifossa) in having a uniformly brownish overall coloration, with little or no silvery reflections on the sides, and dark brown scale pockets. In these color features and in its general appearance, the species resembles certain members of the genus Nezumia, especially N. atlantica (Parr, 1946) and N. africana (Iwamoto, 1970). However, the dentition, squamation, luminescent organ, gill rakers and arches, and other features clearly support its position within Ventrifossa.
description: Published as part of Iwamoto, Tomio, Nakayama, Naohide, Shao, Kwang-Tsao & Table, Hsuan-Ching Ho, 2015, Synopsis of the Grenadier Fishes (Gadiformes; Teleostei) of Taiwan, pp. 31-126 in Proceedings of the California Academy of Sciences 62 (3) on pages 116-117, DOI: 10.5281/zenodo.11512126