Thaumatichthyidae, the wolftrap anglers, is a small family of marine ray-finned fishes, also called the wolftrap seadevils, classified within the suborder Ceratioidei, the deep-sea anglerfishes. They have distinctive upper jaws with movable premaxillaries that can be lowered to form a cage-like trap around the much shorter lower jaw.
Thaumathichthyidae was first proposed as a monotypic family in 1912 by the American ichthyologists Hugh McCormick Smith and Lewis Radcliffe,[1] with Thaumatichthys as its only genus.[2] The 5th edition of Fishes of the World classifies this family in the suborder Ceratioidei of the anglerfish order Lophiiformes.[3] Within the Ceratioidei this family is a sister taxon to the Oneirodidae.[4]
Thaumatichthyidae is derived from its type genus, Thaumatochthys. This name is a combination of "thauma", meaning "wonder" or "marvel", and ichthys, the Greek word for "fish". The name alludes to the strange shape of T. pagidostomus with its large head that is almost as long as the rest of the body, the esca and illicium being inside the mouth to lure the prey into the huge trap-like mouth.[5]
Thaumatichthydae has the following two genera classified within it:
Thaumatichthyidae anglerfishes resemble their close relatives the dreamers of the family Oneirodidae. The main differences are that the lower jaw projects well beyond the upper jaw and the upper part of the operculum is bifurcated. In comparison to other Ceratioid anglerfishes the wolftrap anglerfishes do not have the front end of the jawbones join at the midline of the mouth, where there is a wide elastic membrane. They have very long, inwardly hooked premaxillary teeth. They also have tooth-like denticles on the esca. The pectoral fin has between 14 and 20 soft rays while the caudal fin has 9 soft rays, the 3 middle rays being forked. The maximum published standard length is for Thaumatichthys axeli, while the smallest is in the case of Lasiognathus saccostoma. Larvae have been recorded at while the largest free-living males are .
Thaumatichthyidae anglerfishes are found at depths down to in the Atlantic and Pacific Oceans.