Gaper snake eel
 The Gaper snake eel (Neenchelys retropinna) is an eel in the family Ophichthidae (worm/snake eels). It was described by David G. Smith and James Erwin Böhlke in 1983. It is a marine tropical eel which is known from the Indo-Western Pacific. It dwells at a depth range of 55 to 64 metres (180 to 210 ft) and inhabits soft substrates on the continental shelf.