CLAUSOGNATHIIDAE, A NEW FAMILY OF GNATHOSTOMULIDA FROM BELIZE

Clausognathia suicauda, a new genus and species of Gnathostomulida, is described from subtidal sand in the vicinity of Carrie Bow Cay, Belize, and a new family, Clausognathiidae, is created within the lower Bursovaginoidea-Scleroperalia. The novel features of Clausognathia consist of the combination of a filospermoid rostrum and sensorium with a scleroperalian pharynx and male system; the relatively anterior position of the male organ; and the differentiation of the hindgut as a solid, lumen-less tissue composed of large, succulent cells. The latter feature might function as a chordoid organ, or be the site of prokaryotic endosymbionts.