Gymnothorax tile ( Hamilton, 1822 )

Mohapatra, Anil, Smith, David G., Ray, Dipanjan, Mishra, Subhrendu Sekhar & Mohanty, Swarup Ranjan, 2017, Gymnothorax pseudotile sp. nov. (Muraenidae: Muraeninae) from Bay of Bengal India, Zootaxa 4286 (4), pp. 586-592 : 589-591

Gymnothorax tile ( Hamilton, 1822)

Muraenophis tile Hamilton, 1822: 18 , 363 (Ganges River estuaries near Calcutta, India). No types known. Lycodontis literata McClelland, 1844: 186 , 206, 215, pl. 7 (fig. 2) (Calcutta market, India). No types known. Strophidon maculata McClelland, 1844: 203 , 215, pl. 8 (fig. 1). Replacement name for M. tile .

Muraena vermiculata Richardson, 1848: 92 ( India) . Holotype BMNH 2008.4 .21.2.

Muraena gracilis Richardson, 1848: 92 (India) . Lectotype BMNH 2008.4 .9.5, designated by Böhlke & Smith, 2002: 113. Thyrsoidea microdon Kaup, 1856: 62 ( Pondicherry, India) . Holotype MNHN B-2469.

Gymnothorax borneensis Bleeker, 1863: 169 (Borneo) . Holotype RMNH 3797.

Material examined. India: BMNH 2008.4 .9.5 (1, 307 mm, lectotype of Muraena gracilis ) ; BMNH 2008.4.9.6 (1, 255 mm, paralectotype of Muraena gracilis ); BMNH 2008.4.21.2 (1, 435 mm, holotype of Muraena vermiculata ); MNHN B.2469 (1, 464mm, holotype of Thyrsoidea microdon ); MARC/ZSI F4530 (1, 711 mm); MARC/ZSI F4531 (1, 409 mm); MARC /ZSI F4533 (1, 645 mm); ZSI F 13843(1,450 mm). Myanmar: USNM 372146 (1, 175 mm), at mouth of Yangon River, 29 Oct 1997 . Malaysia: USNM 278309 (3,135– 184 mm), Strait of Malacca, Parit Jawa , 4 Dec 1985 ; USNM 278418 (3, 93– 232 mm), south-western Malay Peninsula, southside of Muar River, Muar , Johore, 25 Nov 1985 ; USNM 278436 (1,87 mm), same, 2 Dec 1985; USNM 278465 (2, 154– 230 mm), same, 27 Nov 1985. Indonesia: RMNH 3797 (1, 217 mm, holotype of Gymnothorax borneensis, Borneo ; USNM 75894 (1, 470 mm), westcoast of Borneo, Sangkulirang , 19 Dec 1913 .

Diagnosis. Teeth moderately stout, intermaxillary teeth in 5 rows; dorsal-fin origin over or slightly before gill opening; dorsal and anal fins high with a pale margin; predorsal vertebrae 9–11.

Description. Proportions in TL: preanal 1.7–2.3, predorsal 7.6–9.8, head 6.6–8.8, depth at gill opening 14–29, depth at anus 16–26.Proportions in head length: snout 5.8–8.0, eye 9.8–17, upper jaw 3.1–3.9, lower jaw 3.4–4.4, eye 9.8–17. Pores: branchial 2, supraorbital 3, infraorbital 3, mandibular 6. Vertebrae: predorsal 9–11, preanal 55– 59, total 119–131.

Body moderate, anus near mid-length. Head moderate; snout blunt with large eye located near middle of jaw; lower jaw slightly shorter than upper jaw. Gill opening rounded, on side below midline. Dorsal and anal fins relatively high, dorsal-fin origin over or slightly before gill opening. Teeth moderately stout, not long and needlelike; intermaxillary teeth in five rows across, the outer teeth smaller than intermediate teeth; three large median teeth; maxillary teeth biserial, inner teeth fewer and larger; dentary teeth biserial anteriorly, uniserial posteriorly, inner teeth fewer and larger; vomerine teeth uniserial at anterior and posterior end, irregularly biserial in middle. Brown with moderate to small irregular white or yellow spots; dorsal and anal fins without pale margin.

Distribution. Known from the northern Indian Ocean and western Pacific, from India to Malaysia, Philippines, and Indonesia. Also recorded from Papua New Guinea by Fricke et al., 2014. Occurs primarily in estuarine habitats, entering brackish and fresh water.

Remarks. This species closely resembles Gymnothorax pseudotile ; the distinctions are discussed above. The two specimens from Borneo have fewer vertebrae (119 and ca. 121) than those from elsewhere (125–131). Our sample size is too small to assess the significance of this, and there are no other obvious differences. The type specimens of the three synonyms described from India ( Muraena vermiculata , M. gracilis , and Thyrsoidea microdon ) are reported to have fewer vertebrae (122–126) than our specimens from the same area (125–129) (data from Böhlke & Smith, 2002). We have not been able to check these specimens ourselves, and we have no explanation for the discrepancy.