Neobythites stefanovi Nielsen & Uiblein, 1993

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 : 169-170

Neobythites stefanovi Nielsen & Uiblein, 1993

( Figures 1–3 , Tables 1–3)

Neobythites stefanovi Nielsen & Uiblein, 1993: 110 .

Neobythites stefanovi: Nielsen 1995 : page 15; Nielsen 2002: 86 (in part); Kannan et al. 2013: 1 (here tentatively referred to N. steatiticus ).

Holotype. ZM MGU P18923 (male, 166 mm SL), Gulf of Aden, NW Indian Ocean, 14°48.8' N, 51°16.1' E, RV Dmitry Stefanov cr. 3, trawl 91, 245– 335 m depth; 5 Jan. 1989.

Paratypes (n = 25, 42–195+ mm SL). BMHN 1939.5. 24.1437 (female, 195+ mm SL), Gulf of Aden, 13°14.4' N, 46°14.2' E, RV John Murray, st. 35, otter trawl, 457–549 m depth, 16 Oct. 1933; SMF 26427–29 (2 females, 2 males, and 4 unsexed; 42–122 mm SL), Gulf of Aden , 12°16' N, 44°09.5' E, RV Meteor, MeS-287, beam-trawl ; 472–479 m depth, 16 Mar. 1987; USNM 302930 , female, 179 + mm SL, Gulf of Aden, 11°10.6'N, 48°11.2'E, RV Beinta, cr. 19, haul 32, 351 – 384 m depth, 19 Feb. 1987; ZM MGU P-18924 (female, 139 mm SL), Gulf of Aden, 13°15.5' N, 46°14.3' E, RV Akademik Petrovsky cr. 14, st. 34, 250 – 300 m depth, 26 Sep. 1983; ZM MGU P-18925 (male, 130 mm SL), Gulf of Aden, 15°59.8' N, 52°23.9' E, RV Dmitry Stefanov cr.3, trawl 9, 80 – 110 m depth, 19 Nov. 1988; ZM MGU P-18926 (female, 162+ mm SL), Gulf of Aden 14°49.2' N, 50°35.1' E, RV Dmitry Stefanov, trawl 78, 375 m depth, 3 Feb. 1989; ZM MGU P-18927 (female, 168 mm SL), same data as holotype; ZM MGU P- 18928 (female, 180 mm SL), Gulf of Aden , 13°13.7' N, 45°41.8' E, RV Dmitry Stefanov, cr.5, trawl 48, 355 – 365 m depth, 22 Nov. 1989; ZM MGU P-18929 (female, 190 mm SL), and ZMUC P77841 (female, 198 mm SL), Gulf of Aden, 13°09' N, 45°41' E, RV Dmitry Stefanov, trawl 51 ; 460 m; 24 Nov. 1989; ZM MGU P-18930 (female and male, 165–179 mm SL), and ZMUC P77842 (male, 168 mm SL), Gulf of Aden , 13°25.1' N 47°14.S' E, RV Dmitry Stefanov, trawl 68, 367 m depth, 28 Nov. 1989; ZM MGU P 18931 (female, male, and unsexed, 130–172 mm SL), and ZMUC P77843–44 (male and female, 163–166 mm SL), Gulf of Aden, RV Dmitry Stefanov, 1989.

Non-types (n = 22, 29– 122 mm SL). SMF 26430 (female, 122 mm SL), Red Sea, 18°35.3' N, 39°03.5' E, RV Meteor, MeS-171, beam trawl, 434–469 m depth, 23 Feb. 1987; SMF 26431 and 26434 (3 unsexed, 45–94 mm SL), Red Sea, 19°18.2' N, 38°15.5' E, RV Meteor, MeS-194, beam trawl, 537–681 m depth, 28 Feb. 1987; SMF 26432 (2 unsexed, 75–84 mm SL), Red Sea, 22°05' N, 37°09.3' E, RV Meteor, MeS-96, beam trawl, 600 m depth, 9 Feb. 1987; SMF 26433 (2 unsexed, 44–99 mm SL), Red Sea, 19°44.5' N, 37°40.2' E, RV Meteor, MeS-148, beam trawl, 517–583 m depth, 20 Feb. 1987; SMF 26435 and 26440 (2 unsexed, 49– 31 mm SL), Red Sea, 21°28.97' N, 38°15.55' E, RV Valdivia , st. 111 TA, closing trawl, 740–785 m depth, 12 Apr. 1979; SMF 26436 and 26441 (3 unsexed, 29–46 mm SL), Red Sea, 21°26.5' N, 38°38.3' E, RV Valdivia , st. 121 TA, closing trawl, 779–801 m depth, 15 Apr. 1979; SMF 26437 and 26785 (2 unsexed, 63–115 mm SL), Red Sea, 20°94.9' N, 37°26.1' E; RV Sonne 35 TA, c1osing trawl, 490–588 m, 17 Oct. 1977; SMF 26438 (42 mm SL), Red Sea, 21°10.8' N, 37°34.0' E, RV Sonne 27 TA, closing trawl, 733–757 m depth, 16 Oct. 1977; SMF 26439 (38 mm SL), Red Sea, 21°12.0' N, 37°26.8' E, RV Sonne, 25 TA, closing trawl, 724–747 m depth, 15 Oct. 1977; SMF 26442 (5 unsexed, 29–42 mm SL), Red Sea, 21°33' N, 38°21' E, RV Valdivia , 99 TA, closing trawl, 753–804 m depth, 9 Apr. 1979.

Diagnosis. No spines on hind margin of preopercle; dorsal fin-rays 89–95; anal-fin rays 73–78; pectoral finrays 24–26; precaudal vertebrae 12; total vertebrae 52–56; pseudobranchial filaments 2–6; long gill rakers on anterior arch 10–13; head length 23.0–27.5 % SL; pelvic-fin length 14.5–20.5 % SL, pelvic fins not reaching anus; orbit length 5.4–6.9 % SL, 21.5–27.5 % head length, and 1.7–2.3 times in upper-jaw length; longest gill filament 1.4–3.7 % SL and 5.4–16.0 % head length; ocellus spot placed well behind a vertical line through anus, the ocellusspot distance being 45.5–56 % SL, and the spot covering 8–12 dorsal-fin rays; dorsal and anal fins with dark margins throughout; no vertical bars on body; otolith length 4.6–5.2 % SL, sulcus length 3.4–4.1 % SL, and ostium height 20.0–28.5 % sulcus length.

Distribution. Gulf of Aden, NW Indian Ocean, at 80-549 m depth and Red Sea, 434–804 m depth.

Remarks. Kannan et al. (2013) reported on two specimens of N. stefanovi from Gulf of Manar, Tamil Nadu (NW Indian Ocean). After inspection of the photo and some of the data provided by Kannan et al. (2013), we assume that these specimens should be treated as tentatively referred to N. steatiticus .

Uiblein (1995) reported considerable differences between the populations of the Red Sea and the Gulf of Aden based on quantitative studies of meristic, morphometric and ocellus characters. Those differences were however only statistically detectable and did not support the erection of a distinct taxon in the Red Sea. We have reconsidered these earlier findings when examining the differentiation degree among the three rather similar species N. gloriae n. sp., N. steatiticus , and N. stefanovi . While these species can be well separated by five diagnostic characters (singly or in combination), the two N. stefanovi populations clearly overlap with each other in those as well as in all other characters studied ( Figure 3 , Tables 2–3).

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.