Thalassema steinbecki Fisher, 1946

Vargas, Rita & Kawauchi, Gisele Y., 2010, Sipunculans and Echiurans of Isla del Coco (Cocos Island), Costa Rica, Zootaxa 2557, pp. 60-68 : 65-66

Thalassema steinbecki Fisher, 1946

Material examined. Silverado, 25 May 2008, one specimen, 15 mm.

Description. Members of the Echiuran family Echiuridae possess an unbranched proboscis and sac-like anal vescicles and they also do not display sexual dimorphism. The genus Thalassema is characterized as Echiuridae with one to three pairs of gonoducts, no anal setae, elongate or spirally coiled gonostomal lips are lacking and longitudinal muscles are not in bands. Thalassema steinbecki has two pairs of gonoducts a rectal caecum, and smooth gonostomal lips forming an incomplete circle. This specimen is in poor shape and only a few weak papillae were seen just posterior to the proboscis which is subequal in length to the body.

Habitat. Subtidal calcareous rock, 11m.

Remarks. Dean and Cutler (1998) first recorded this species from the Gulf of Nicoya in Pacific Costa Rica.

Distribution. Thalassema steinbecki has been reported in the eastern Pacific from Ecuador to California (Dean 2009).