Aspidosiphonidae is a family of peanut worms. It is the only family in the monotypic order Aspidosiphonida, which is in the class Phascolosomatidea.

Description

The family Aspidosiphonidae is characterized by an oval disk with short tentacles, arranged in a crescent-shape made of an enclosed nuchal organ. It has a canal of sacs in the coelom, lying in a continuous band. The anal and caudal shield (at the anterior end) are both made up, not of chitin, but of a horny protein. It is of note that most, but not all, of the Aspidosiphonidae family has a caudal shield. The family also has two nephridia.

Species

Aspidosiphon

Cloeosiphon

Lithacrosiphon