Ophichthus nansen Psomadakis 2018, sp. nov.

• Main Author: Psomadakis, Peter N.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2018
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Actinopterygii; Anguilliformes; Ophichthidae; Ophichthus; Ophichthus nansen; Fridtjof Nansen
• Online Access: https://doi.org/10.5281/zenodo.5990971; http://treatment.plazi.org/id/96368788CE6BFF8952E98B51FE88FCD0

Ophichthus nansen McCosker & Psomadakis sp. nov. New English name: Nansen’s snake eel (En) (Figs. 1 – 3) Material examined. Holotype : USNM 438268, 389 mm TL, a ripe male, off Ayeyarwady Delta, Myanmar (14 o 41.49 N, 95 o 29.32 E), R/ V Dr. Fridtjof Nansen , Sta. 88, bottom trawl, 103 – 106 m depth, 13 May 2015, collected by P. N. Psomadakis. Diagnosis. A moderately elongate species of Ophichthus with: tail 62%, head 10.3%, and body depth at gill opening 3.4% of TL; dorsal-fin origin above mid-pectoral fin; pectoral fin elongate, but not filamentous, longer than upper jaw; posterior nostril a hole above upper lip, covered by a flap that extends to or below edge of mouth; barbels present behind anterior and posterior nostrils; eye large, its posterior margin in advance of rictus of jaw; pores small but conspicuous, SO 1 + 4, IO 4 + 2, POM 6 + 2; teeth small, close-set and conical, biserial on anterior vomer and jaws; coloration dark gray-brown, paler ventrally, pectoral and median fins black; vertebral formula 11- 53-146. Counts and measurements of the holotype (in mm). Total length 389; head 39.9; trunk 109.1; tail 240; predorsal distance 47; pectoral-fin length 14; pectoral-fin base 3.5; body depth ca. 13.5 at gill openings; body width ca. 14 at gill openings; body depth at anus ca. 12.5; body width at anus ca. 12.5; body depth at branchial basket 18; body width at branchial basket ca. 14.5; snout 8.8; tip of snout to rictus 11.2; snout overhang beyond tip of lower jaw 2.2; eye diameter 3.4; interorbital width 5.2; gill opening height 5.5; isthmus width 9.7. Vertebral formula 11-53-146. Description. Body moderately elongate (Figure 1), subcircular to level of anus, then becoming more compressed, its depth at gill openings 29 in TL. Branchial basket moderately expanded. Head 2.7 in trunk. Head and trunk 2.6, head 9.7, and tail 1.6 in TL. Snout slightly rounded, moderately acute when viewed from above; a short groove bisecting underside of snout nearly to tip of upper jaw; snout, lips and chin densely covered ...