Neobythites gloriae, Uiblein & Nielsen, 2018

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 : 158-159

Neobythites gloriae n. sp.

( Figures 1–3 , Tables 1–3)

Neobythites steatiticus: Nielsen 1995 (in part, Arabian Gulf, Gulf of Oman).

Neobythites stefanovi: Nielsen & Uiblein 1993 and Nielsen 1995, 2002 (in part, Gulf of Oman).

Holotype. USNM 309008 (male, 158 mm SL), Gulf of Oman, NW Indian Ocean, 25°02' N, 56°52' E, RV Anton Bruun , cruise 4B, st. 264A, bottom trawl, 272–291 m depth, 2 Dec 1963.

Paratypes (n=8, 130– 150 mm SL). BMNH 1904.5 .25.1 (1 male, 150 mm SL), Gulf of Oman , 25°32' N, 57°47' E, 320 m depth ; BMHN 1910.1.31.7–10 (3 females and 1 male, 132–145 mm SL), Gulf of Oman , 25°35' N, 57°47' E, 311 m depth ; BMHN 1910.1 .31.23 (1 female, 130 mm SL), Arabian Gulf , 10' W of Dubai, United Arab Emirates, 26 m depth ; USNM 440378 (1 male, 140 mm SL), and ZMUC P771754 (1 female, 131 mm SL), same data as for the holotype .

Diagnosis. No spines on hind margin of preopercle; dorsal fin-rays 90–93; anal-fin rays 72–76; pectoral finrays 24–27; precaudal vertebrae 12; total vertebrae 54–56; pseudobranchial filaments 3–4; long gill rakers on anterior arch 11–13; head length 25.5–28.0 % SL; pelvic-fin length 13.5–17.0 % SL, pelvic fins not reaching beyond anus; orbit length 5.3–5.9 % SL, 19.5–23.5 % head length, and 2.0–2.2 times in upper-jaw length; longest gill filament 3.9–4.9 % SL and 15.5–19.0 % head length; ocellus spot placed well posterior to a vertical line through anus, the ocellus-spot distance being 49.0–51 % SL, and the spot covering 6–8 dorsal-fin rays; margins of posterior fifth to a quarter of dorsal fin and posterior half to two thirds of anal fin dark pigmented; no vertical bars on body; otolith length 4.8–5.0 % SL, sulcus length 3.4–3.7 % SL, and ostium height 21.0–26.5 % sulcus length.

Description (based on holotype, differences in paratypes mentioned in round brackets). Rather elongate fish with complete lateral line in preserved specimens; on the anterior half of body, the lateral line runs with 8–10 scale rows to dorsal edge, decreasing posteriorad; head and body fully covered with cycloid scales; origin of dorsal fin above hind margin of opercle; origin of anal fin slightly in front of midpoint of fish; tip of pectoral fins ending just above origin of anal fin; pelvic fins reaching almost to origin of anal fin; blunt snout slightly shorter than diameter of eye; upper jaw ending well behind eye; anterior nostril ending in a short tube and the larger posterior nostril in a mere hole; no spines on preopercle; strong opercular spine; anterior gill raker with 1–2 (2–3) blunt and 3–4 (2–3) long rakers on upper branch; one long raker in angle and lower branch with eight long and 6 (7) blunt rakers; gill filaments 1.5–3.0 (1–4) times as long as long rakers; distinct pseudobranchial filaments 3 (3–4).

Otolith. Otolith oval, its height 1.6 (1.5–1.7) times in its length; sulcus large, 1.3 (1.3–1.4) times in otolith length; ostium 1.5 times in sulcus length; ostium height 3.3 (2.6–3.3) times in ostium length.

Dentition. Premaxillaries and dentaries with small, pointed teeth in 3–4 irregular rows anteriorly, decreasing to 1–2 rows posteriorad. Teeth in outer rows somewhat longer. Vomer triangular with many small, close-set teeth. Palatines with several rows of small, close-set teeth. Two median basibranchial tooth patches, the anterior elongate and the posterior much smaller and circular.

Axial skeleton (from radiographs). Precaudal vertebrae 12 and caudal vertebrae 42 (42–45) and all neural and haemal spines pointed; first neural spine one third length of second spine, that is longer than the following spines; bases of neural spines more or less enlarged; parapophyses present on posterior 7–8 precaudal vertebrae; pleural ribs on vertebrae 3–11 (3–4 to 10–12); epipleural ribs on vertebrae 3–8.

Colour. Preserved fish (holotype [ Figure 1A ] and paratypes). Body mottled brown, abdomen silvery bluish, lateral line pale brown, rather indistinct; head pale brown with brown preopercular area behind eye, gill cover transparent, eyes bluish; ocellus spot dark brown, its horizontal diameter about orbit length, placed well behind a vertical line through anal-fin origin; dorsal and anal fins with pale- to dark-brown distal margins along posterior fifth to quarter of dorsal fin and posterior half to two-thirds of anal fin; margins becoming darker towards dark caudal-fin tip.

Etymology. The new species name honors the wife of the first author, Gloria Jansen Echevarria.

Distribution. Inner Gulf of Oman, NW Indian Ocean, at 272–320 m depth, and southern Arabian Gulf, United Arab Emirates, at 26 m depth.

Comparisons. Neobythites gloriae n. sp. differs from all congeners by the following combination of characters: a single ocellus placed on dorsal fin at mid-body, preopercular spines lacking, 11–13 developed gill rakers, head length 25.5–28.0 % SL, gill filament length 3.9–4.9 % SL, orbit length 19.5–23.5 % head length and 45–50 % upper-jaw length, and otolith sulcus length 3.4–3.7 % SL.

Neobythites gloriae n. sp. is most similar to N. stefanovi , sharing the following characters: dorsal fin with one ocellus, preopercular spine absent, pelvic fins ending anterior to anus, similar number of long rakers on anterior gill arch, eyes five times or less in head length, and similar otolith sulcus length. Neobythites gloriae differs from N. stefanovi having longer gill filaments (3.9–4.9 vs. 1.4–3.7 % SL) and a slightly smaller ocellus spot (spot covering 6–8 vs. 8–12 dorsal-fin rays). These two characters in combination with head length, orbit length, and ocellus-spot distance best distinguish N. gloriae from N. steatiticus and N. steatiticus from N. stefanovi ( Figure 3 ; Tables 1–3).

Remarks. The description of Neobythites gloriae n. sp. is based on three former N. stefanovi paratypes from the inner Gulf of Oman ( Nielsen & Uiblein 1993) and six specimens previously identified as N. steatiticus ( Nielsen 1995) . Apart from this earlier misidentified material, no additional specimens and no photographs of fresh fish were available for our study. The depth of 26 m reported for the single Arabian Gulf specimen (BMHN 1910.1.31.23), indicated as questionable by Nielsen (1995), is here confirmed based on original data recordings available from NHM.

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.