Ophichthus aphotistos McCosker & Chen 2000

Ophichthus aphotistos McCosker & Chen 2000: 354 (Tung-Kong Channel, Taiwan, holotype CAS 209192).

Diagnosis. An elongate species of Ophichthus, subgenus Omochelys, with: tail 59–60%, head 7.7–8.1%, and body depth at gill opening 2.5–2.9% of TL; dorsal-fin origin behind pectoral fin by the pectoral-fin's length; pectoral fin rounded, not elongate and not well-developed; eye moderate, above center of upper jaw, its posterior margin well ahead of rictus; posterior nostril a hole above the upper lip, covered by a flap that extends to or below edge of mouth; upper lip lacks barbels between anterior and posterior nostrils; pores small but conspicuous, SO 1+4, IO 4+2, POM 2+6; teeth small and conical, biserial on anterior vomer and jaws; coloration uniform gray brown to nearly black, pectoral and median-fin margins gray black; mean vertebral formula 17.6/59/160.3, total vertebrae 158–162 (n= 3).

Size. Largest known specimen is 628 mm, a spent female.

Distribution. Known from the type series, from 700–800 m depth, collected off Taiwan.

Remarks. Ophichthus aphotistos is the sole deepwater Indo-Pacific species of the subgenus Omochelys . It would not be mistaken for any other deepwater Indo-Pacific Ophichthus on the basis of its elongation, posterior dorsal-fin origin, biserial jaw dentition and vertebral formula. The holotype of O. aphotistos has 18/ 59/161 vertebrae.

Ophichthus aphotistos is most closely related to the deepwater O. cruentifer (Goode and Bean 1896) of the northwestern Atlantic Ocean, from which it differs in its coloration and vertebral formula (McCosker & Chen 2000), and to the eastern Atlantic deepwater O. pullus McCosker (2005), from which it differs in its dentition, in its head length, dorsal-fin origin, pectoral-fin length, and vertebral number.

Material examined. CAS 209192, the holotype, 580 mm TL, from Tung-Kong Channel, SW Taiwan (22o22'N, 120o19'E), 700–800 m; and USNM 356862, 628 mm, and NSYSU 3657, 480 mm, paratypes, collected with the holotype.