Hydrolagus melanophasma James, Ebert, Long & Didier 2009

A species of the genus Hydrolagus based on the absence of an anal fin. Hydrolagusmelanophasma sp. nov. is distinguished from other chimaeroids by a blunt snout with minimal sloping from the orbit to the snout tip, a large slightly curved dorsal fin spine (25.9 % BDL) extending beyond first dorsal fin apex, and a long second dorsal fin (77.3–81.1% BDL) of uniform height throughout. The pectoral fins are large, reaching beyond the pelvic fin insertion when laid flat, trifid claspers forked for 27–27.8% of the total clasper length and the preopercular and oral lateral line canals branch separately or together from the infraorbital canal. Coloration after preservation is a uniform black with no distinct mottling or markings (Ref. 82286).

The Eastern Pacific black ghostshark (Hydrolagus melanophasma, literally a combination of "water rabbit" and "black ghost") is a species of fish in the family Chimaeridae. Despite its name, it does not belong to the clade Selachii used for the modern classification of sharks. It is, however, distantly related to the sharks in the sense that both are Chondrichthyes (cartilaginous fishes).