The deep-sea ceratioid anglerfish genus Lasiognathus (family Thaumatichthyidae),
known only from females, is revised on the basis of all known material.
Four species are recognized: L. beebei Regan and Trewavas, known from five
specimens; L. waltoni Nolan and Rosenblatt, known only from the holotype; L.
saccostoma Regan, five known specimens; and L. intermedius, a new species described
here on the basis of seven specimens. Lasiognathus ancistrophorus Maul
is considered a junior synonym of L. saccostoma. Diagnoses and descriptions are
given for all taxa; known distributions are plotted; and a key to the species is
provided.