Neobythites steatiticus Alcock, 1894

Uiblein, Franz & Nielsen, Jørgen G., 2018, Review of the steatiticus - species group of the cuskeel genus Neobythites (Ophidiidae) from the Indo-Pacific, with description of two new species, Zootaxa 4387 (1), pp. 157-173 : 165-169

Neobythites steatiticus Alcock, 1894

( Figures 1–3 , Tables 1–3)

Neobythites steatiticus Alcock, 1894: 181 , pl. IX

Neobythites steatiticus: Norman 1939: 76 (non steatiticus ); Nielsen 1995: 11 and 2002: 84 (in part); Jawad 2014: 1 (non steatiticus ).

Holotype. ZSI 13435 (female, 129 mm SL), Bay of Bengal , NE Indian Ocean, 15°4'7'' N, 80°25'7'' E, RV Investigator , st. 137, Agassiz trawl, 234 m depth, 3 Mar. 1893.

Non-types (n = 5, 113– 162 mm SL). BMNH 1895.1 .3.3 (former ZSI 13477), (female, 143 mm SL), Bay of Bengal, 13°1'6'' N, 80°36'56'' E, RV Investigator , st. 170, Agassiz trawl, 193 m depth, 16 Feb. 1894 ; USNM 46756 (former ZSI 13475), (female, 113 mm SL), USNM 256238 (former ZSI 13474), (female, 127 mm SL), and BMNH 1895.1 .3.4 (female, 114 mm SL), Bay of Bengal , 13°51'12'' N, 80°28'12'' E, RV Investiga tor, st. 162, Agassiz trawl, 261–450 m depth, 30 Jan. 1894 ; ZMUC P 771752 (unripe, 162 mm SL), off Myanmar, 16°27' N 93°57' E, RV Dr. Fridtjof Nansen, st. 42, bottom trawl, 274–277 m depth, 6 May 2015 .

……continued on the next page Tentatively referred. Tuticorin Research Center, Tamil Nadu, India, 2, 178– 180 mm SL, Gulf of Manar, 8°44'46'' N, 78°37'24'' E, bottom trawl, 200–250 m depth, 22 Feb. 2010.

Diagnosis. (Tentatively referred specimens from Gulf of Mannar not included). 0–1 weak spine on hind margin of preopercle; dorsal fin-rays 88–94; anal-fin rays 73–77; pectoral fin-rays 24–27; precaudal vertebrae 12; total vertebrae 53–57; pseudobranchial filaments 2–3; long gill rakers on anterior arch 11–14; head length 28.0– 31.0 % SL; pelvic-fin length 14.0–15.0 % SL, pelvic fins not reaching anus; orbit length 4.8–5.2 % SL, 16.0–18.5 % head length, and 2.3–2.8 times in upper-jaw length; longest gill filament 4.4–5.9 % SL and 15.0–19.0 % head length; ocellus spot placed well behind a vertical line through anus, the ocellus-spot distance being 46.0–51.5 % SL, and the spot covering 7–10 dorsal-fin rays; median part of anal-fin dark and distal and proximal parts light; dorsal fin mostly unpigmented; up to 6 broad, rather distinct dark vertical bars on body; otolith length 5.0–5.2 % SL, sulcus length 3.6–3.7 % SL, and ostium height 21.0–24.5 % sulcus length.

Distribution. Known from both sides of the Bay of Bengal, NE Indian Ocean, at 193–450 m depth.

Remarks. According to Alcock (1899) ZSI held the holotype and eight additional specimens, five of which are here examined. Kannan et al. (2013:1) published the first record in Indian waters of Neobythites stefanovi . However, the illustration shows more resemblance to N. steatiticus so we treat it here as tentatively referred to N. steatiticus . Some specimens that in earlier literature were referred to N. steatiticus are now transferred to other Neobythites species: Norman (1939: 76) referred three specimens to N. steatiticus . Two of these from the Gulf of Aden have been transferred to N. stefanovi and one from off Zanzibar to N. kenyaensis Nielsen, 1995 . Nielsen (1995: 11 and 2002: 84) mentioned six specimens caught in the Gulf of Oman (all from BMNH) which now are referred to N. gloriae n. sp.

The specimen collected during the RV Dr. Fridtjov Nansen cruise off Myanmar represents the first record from the eastern Bay of Bengal. The photo taken on board immediately after capture is the first to document fresh colour of the species ( Figure 1G 2 ). It reveals considerable similarity with ocellus, fin and body colour patterns shown in two different drawings of N. steatiticus provided by Alcock (1893, 1898) based on shortly preserved specimens. The slightly larger ocellus of the specimen from off Myanmar (10 vs. 7–9 dorsal-fin rays covered by the spot) contributes to the distinction of N. steatiticus from N. gloriae n. sp. ( Figure 3 , Tables 2–3).

Jawad (2014) reported N. steatiticus from the Arabian Gulf off Iraq. However, judging from the dark blotch near the origin of the dorsal fin (vs. no anterior blotch), the position of the mid-body ocellus above or in front of anus (vs. well behind anus), and head length (21.5 vs. 28.0–31.0 % SL) this is neither a N. steatiticus nor a member of the steatiticus species group.

Figures

FIGURE 1. Indo-Pacific Neobythites steatiticus species group. All photographs at left side and F show preserved fishes; the remaining five photographs at right side show fresh fishes, photographed on board immediately after capture. A) Neobythites gloriae n. sp. USNM 309008, HT, 158 mm SL, inner Gulf of Oman; B) N. lombokensis, ZMUC P 77744, HT, 93 mm SL, SE off Lombok, preserved (B1) and fresh (B2; side reversed); C) N. longipes, ZMUC P77740, 98 mm SL, SE off Lombok, preserved (C1) and fresh (C2); D) N. malayanus, ZMUC P77742, 138 mm SL, SE off Lombok, preserved (D1) and fresh (D2); E) N. malhaensis, ZMUC P77840, PT, 135 mm SL, Saya de Malha bank, preserved; F) N. meteori, ZMH 5621, HT, 102 mm SL, off Sokotra, preserved; G) N. steatiticus, ZMUC P771752, 162 mm SL, off Myanmar, preserved (G1) and fresh (G2); H1) N. stefanovi, ZMUC P77841, PT, 198 mm SL, Gulf of Aden, preserved; H2) N. stefanovi, SMF 26785, 111 mm SL, Red Sea, fresh. Photographers: Oddgeir Alvheim (G2), Thomas Gloerfelt-Tarp (B2, C2, D2), Marcus Krag (A, B1, C1, D1, E, G1, H1), Ralph Thiel (F), Michael Türkay (H2). The blue bars indicate 1 cm length for the respective specimen.

FIGURE 2. Distribution of studied specimens of Neobythites, with numbers indicating multiple sampling events.

FIGURE 3. Relationships between SL, morphometric body-shape characters, and number of dorsal-fin rays covered by ocellus spot in Neobythites gloriae n. sp., N. steatiticus, and two populations of N. stefanovi.