Monotypic crustacean genera

Lasionectes is a monospecific genus of remipedes in the family Speleonectidae. It is one of two genera in the family, the other being Speleonectes, which was the first genus of remipedes to be described.

Tesnusocaris is an extinct, monospecific genus of remipedian crustaceans that lived in the Pennsylvanian period, one of the two representatives of the extinct remipedian order Enantiopoda. It is known from a fossil discovered in the Lower Pennsylvanian (Paleozoic, Carboniferous) Tesnus Formation of Texas. The other known enantiopod remipedian is Cryptocaris hootchi of the Mazon Creek fauna.

Hutchinsoniella macracantha is a species of crustacean known as a horseshoe shrimp. It is the only species in the genus Hutchinsoniella and was first described in 1955 by Howard L. Sanders, having been discovered in Long Island Sound; they were the first example of a new class of crustacean that was given the name Cephalocarida.