Egglestonichthys melanoptera ( Visweswara Rao, 1971 )

Chen, Jia-Jie, Zeng, Sheng, Passmore, Roland, Tian, Wei, Luo, Yi-Ming, Zhong, Jun-Sheng, Yang, Meng-Ling, Yang, De-Yuan, Ye, Jin-Qing & Chen, Yuan-Ge, 2025, A new record of the blackfin goby (Egglestonichthys melanoptera, Gobiidae) from China, with complete mitochondrial genomes of two Egglestonichthys species and their phylogenetic implications, Zoosystematics and Evolution 101 (3), pp. 1057-1069 : 1057-1069

Egglestonichthys melanoptera ( Visweswara Rao, 1971)

Diagnosis.

D VI-I, 10; A I, 8-9; P (R / L) 22 / 21; V I- 5; C 17; in 9 / 8 pattern; branched caudal rays 8 / 7; longitudinal scales 44; TRB 19; predorsal scales 37; circumpeduncular scales 16. First dorsal-fin pterygiophore formula 3-22110 (Fig. 1 D ). Vertebrae (including urostyle) 10 + 16 = 26. Two anal pterygiophores before haemal spine of first caudal vertebra. One epural. Fins black. Caudal fin almost 1 / 2 SL. Pelvic frenum absent. Body without darker bands. Head sensory papillae developed.

Description.

Based on 1 specimen, 84.13 mm SL. Counts and proportional measurements are given in Table 1 .

Body moderately robust, rounded anteriorly, compressed posteriorly; dorsal / ventral margins shallowly arched. Depth at first dorsal origin 37.24 % SL; caudal peduncle depth 8.73 % SL. Head broad (29.62 % SL), wider than body depth; snout blunt (1.23 times eye diameter), terminating at eye superior margin. Preopercular width 71.59 % HL. Mouth terminal (~ 45 ° to body axis), jaws subequal (lower slightly prominent), reaching mid-eye level; upper jaw 41.08 % HL. Lips smooth (upper lip 2.2 times eye diameter). Eyes dorsolateral (18.45 % HL), no supraorbital ridge. Interorbital convex (25.77 % HL; 1.40 times eye diameter; 1.13 × SnL) (Table 2 ). Chin smooth, lacking mental folds / barbels. Paired nostrils separated; anterior tubular, positioned at upper lip posterior margin (short tube, no ventral / anterior orientation); posterior rounded pore-like, adjacent to eye anterodorsal margin (Fig. 2 A ). Gill openings wide, vertically extended anteriorly to mid-eye.

Body and head fully scaled (cycloid); predorsal region (snout tip to first dorsal-fin origin), operculum, preoperculum, cheek, isthmus, breast, abdomen, and pectoral fin base scaled.

Lateral line absent; cephalic sensory canals and pores absent. Sensory papillae system comprising: suborbital row a with four long and four shorter transverse multi-papillate rows; longitudinal row b extending medially from first long row of a to row c; transverse row c positioned between longitudinal rows b and d; longitudinal row d running from c to upper lip posterior margin (connecting ul). Preoperculo-mandibular series e uniserial, ascending to ul at mouth angle. Preorbital pe with dual rows: lower connecting to ul, upper reaching anterior nostril base. Thirty-five short i rows below e; three i rows per side extending to mid-isthmus. Mental row f longitudinal on anteroventral mandible (not reaching mid-isthmus). No dorsal cephalic papillae observed (Fig. 2 C ).

Dorsal fins separate, elevated. First dorsal fin short-based, origin posterior to pectoral fin base; soft spines with third spine longest, extending to second dorsal origin. Second dorsal fin longer-based, taller than first, fourth ray longest not reaching caudal base. Anal fin origin opposite second dorsal, base shorter than height; mid-rays not reaching caudal base. Pectoral fins broad and elongated, exceeding head length, posterior margin surpassing anus; no dermal flaps on leading edge. Pelvic fins elliptic-pointed, shorter than pectorals, base 1 / 5 length; fused into thin-membraned disc. Caudal fin elongate-pointed, longer than head length. Anus positioned anterior to anal fin origin, aligned with third ray of second dorsal fin.

Fresh colouration

(Fig. 1 D ). Body uniformly grey without bands, cephalic region darker; pectoral and caudal fins jet black; dorsal, anal, and ventral fins dark brown to black. Preserved specimens exhibit greyish-brown body colouration with fins maintaining black to rich chestnut-brown tones.

Distribution and ecology.

Egglestonichthys melanoptera is documented from the Godavari Estuary, eastern India ( Visweswara Rao 1971); Parangipettai, southeastern India ( 50–100 m depth; Ragul et al. 2024); Myanmar waters ( 50–74 m, muddy substrates; Psomadakis et al. 2020); Vietnam; Samar Sea, Philippines ( 50–70 m); Orokolo Bay, Papua New Guinea ( Larson and Hoese 1997); and the southeastern coast of Hainan Island, China ( 60 m depth; this study). The species demonstrates an Indo-West Pacific distribution pattern, predominantly inhabiting continental shelf depths of 50– 100 m.

Figures

Figure 1. A. Part of the catch, including E. bombylios, after a 30 - minute haul with a 21 - metre bottom trawl off the coast of Hainan Island, China. Photo by Yuange Chen; B. Locality map for known records of E. bombylios (black crosses) and E. melanoptera (solid black circle); C. E. bombylios Larson & Hoese, 1997 (accession numbers: OR 260439, voucher no. E 201313, 52 mm SL, Dongshan Bay, Fujian Province, China, 12 Sep. 2013). Fresh colouration (D) and radiograph (E) of E. melanoptera, voucher no. ECSFRI 23184, 64 mm SL, Hainan Island, China. Scale bar: 5 mm.

Figure 2. Head of Egglestonichthys melanoptera in lateral (A), ventral (B), dorsal (C) view stained Cyanine blue 5 R and pelvic fin (D), DHS 23184, SL 84.13 mm. Scale bar: 1 mm.