Neobathyclupea melanoptera Prokofiev, Gon & Psomadakis, 2016, new species

Neobathyclupea melanoptera, new species

(Figs. 1, 2 A, 3A, 4A, 6A)

? Bathyclupea malayana (non Weber 1913): Shcherbachev et al. 1986: 205 (10°21' S, 56°18' E).

Holotype. SAIAB 203556, 302 mm, 17.1493° N, 94.1045° E, 767–772 m, bottom trawl, RV Dr. Fridtjof Nansen, survey 2015404, sta. 35, 16:11-16:41, 5 May 2015.

Paratype. ZMMGU 23822, 258 mm, 12°22'8 N, 53°02'7 E, 1000–1120 m, RV Vityaz-II, 17th cruise, sta. 2565, bottom trawl 29 m no. 5, sample 13, 07:43-08:50, 28 October 1988.

Comparative material. See under N. malayana. Material of other species of the family listed in Prokofiev (2014a) with the following additions: Neobathyclupea gracilis: IOM uncat., 161 mm, 18°48'4 S, 149°59' E, 660 m, FRV Lira, 14 June 1968; IOM uncat., ca. 140 mm, off Java, FRV Orlik sta. 3, 2 December 1963 (a badly damaged, distorted and somewhat dried specimen, formerly referred to N. malayana). Bathyclupea hoskynii: SAIAB 203557, 130 mm, 14.06216° N, 94.31816° E, 455–457 m, bottom trawl, RV Dr. Fridtjof Nansen, survey 2015404, sta. 68, 10 May 2015. Bathyclupea cf. nikparini: IOM uncat., 102 and ca. 140 mm, off northwestern Madagascar.

Diagnosis. A species of Neobathyclupea with head length 2.6 times in SL, mouth cavity uniformly black, snout longer than orbit (Fig. 2 A), dorsal rayed pterygiophore pattern /1/1/1/1+1/1/1+1/1/ (Fig. 6 A), 26–27 anal-fin rays, 15 gill-rakers on 1st arch, large pseudobranch (29–30 elements), all fins black (Figs. 1, 3 A).

Description. Counts and measurements of the two type specimens are given in Table 1. Body moderately elongate and strongly compressed; head large; dorsal profile of body from snout to dorsal-fin origin straight. Bonyorbit diameter 1.1 in snout length. Nostrils grouped together at mid-distance between tip of snout and anterior edge of orbit, at level of upper edge of pupil; nostrils slightly oval, posterior one somewhat larger and separated from anterior one by space of about its own diameter. Mouth oblique, at about 60–70° to horizontal axis of body; posterior end of upper jaw between the verticals of anterior edges of orbit and of pupil; lower jaw joint below anterior edge of orbit and slightly behind lowest point of maxillary plate; posterior edge of maxillary plate straight to weakly convex, its exposed dorsal edge undulate anteriorly, rising moderately to plate’s rounded upper angle; lower angle of maxillary plate rounded; supramaxilla elongate, narrow, with rounded posterior end and pointed anterior end. Lower jaw symphysis with pointed, bony chin nub; tongue bilobed, lobes broadly rounded and wellseparated. Lower jaw with single series of small, incurved conical teeth, those near symphysis largest; upper jaw with broad band of small conical teeth posteriorly, tapering to single series with teeth becoming gradually larger anteriorly, reaching similar size to lower jaw teeth at symphysis; vomer (v-shaped) and palatines with one or two series of small conical teeth, when two, the outer series teeth larger. Opercular bones smooth; opercle without spine, its upper part forms a short rounded lobe extending posteriorly over proximal part of pectoral fin; lobe with many weak radial striations protruding from its posterior edge, making it slightly crenulated; preopercle angle extending back slightly beyond its vertical edge. In holotype, ventral margin of preopercle appears irregular as a consequence of damage, but is likely to be smooth when complete and clearly without denticles. The ventral margin of Preopercle of paratype possesses a series of denticles (Fig. 4 A) inclining posteriorly, increasing in size posteriad, lacking ridge-like extensions continuing onto preopercular lobe. Vertical margin of preopercle smooth.

Dorsal fin originates above 5th–6th anal-fin ray; anal-fin origin at or slightly before middle of body; pectoral fin reaching posteriorly to below end of dorsal-fin base and above middle of anal-fin base (10th–11th ray); pelvic fins inserted at vertical about mid-distance between upper pectoral-fin base and preopercular edge; anus immediately in front of anal-fin origin; caudal fin emarginate. Predorsal and dorsal-fin pterygiophore formula /0/0/0//0'+0'/0'+0'/0'/ 0'/0+/1/1/1/1+1/1/1+1/1/; four anteriormost anal-fin pterygiophores in front of first haemal spine; pleural ribs of 9th vertebra well-developed, as long as preceding pair in the paratype and even longer in holotype. Holotype with no ribs on 10th vertebra, but paratype has pair of strongly reduced ribs. Paratype with 6 pyloric caeca somewhat twisted at tips (holotype not counted).

Colour of fresh holotype (Fig. 1): body blackish dark brown with purple tinge; scales with black edge; head and fins jet black (skin missing from upper half of body and part of snout and cheek); eye black.

Colour in alcohol: similar to fresh colour, but without the purple tinge; mouth cavity and tongue black; gill chamber black; gill arches and gill rakers dark brown. Peritoneum jet-black, stomach and intestine pale (in paratype).

Etymology. From Greek “melas” (black) and “pteron” (wing, fin) referring to the characteristic fin coloration.

Remarks. The two specimens of the type series were collected in the western (12.36889° N, 53.03528° E) and eastern (14.682833° N, 93.384666° E) parts of the Indian Ocean, north of the Equator. However, in the western Indian Ocean the new species is probably distributed southward at least to the Seychelles Plateau. Shcherbachev et al. (1986) reported four specimens (214–265 mm) they then identified as? Bathyclupea malayana collected between the Seychelles and Madagascar (10°21' S, 56°18' E). Although we were unable to find and examine these specimens, Shcherbachev et al. (1986) described a snout that is longer than the orbit and dark fin coloration which agree better with the presently described species than with any other congener.

Character N. melanoptera N. malayana

Holotype Paratype Southwestern Indian Ocean Southwestern Pacific Ocean

SL (mm) 302 258 155–230 160–220 In % of SL

Head length* 38.5 38.8 31.0–37.0 32.1–33.0 Greatest body depth* 26.9 25.2 20.6–24.4 23.2–24.8 Caudal peduncle depth 9.2 7.8 6.6–10.4 9.4–9.7 Caudal peduncle length 12.7 12.8 (11.4) 12.2–17.7 14.0–16.1 Predorsal distance 59.9 61.2 55.6–57.4 (59.1) 54.8–58.0 Preanal distance 50.8 50.4 (43.4) 44.9–50.0 44.9–48.4 Prepelvic distance 33.8 34.4 22.8–28.6 23.1–24.5 Ventro-anal distance 19.7 16.0 18.8–24.0 21.8–23.8 Pectoral fin length 28.15 31.8 25.9–29.5 (31.6) 25.8–28.3 Dorsal-fin base length 12.6 11.5 9.6–12.2 9.7–11.0 Anal-fin base length 32.9 37.2 36.2–42.0 38.7–39.2 Snout length* 12.8 13.2 7.1–11.3 9.4–9.9 Bony-orbit diameter* 12.2 11.8 10.2–13.6 11.5–12.3 Interorbital width 6.5 5.8 4.3–6.3 5.2–6.5 Upper jaw length 16.8 15.5 (11.5) 12.2–14.5 13.6–14.2 Upper jaw height 5.2 4.8 (3.6) 4.1–5.9 5.2–5.8 Supramaxillary length 5.3 5.3 3.8–5.3 3.9–5.0

......continued on the next page Character N. melanoptera N. malayana Notes: - indicates not measured; deviating measurements found in a single fish are given in parentheses. Measurements indicated by asterisk (*) and all counts were taken from 20 specimens of N. malayana; other measurements were taken from the 13 least damaged specimens of this species.