Sipunculus (Sipunculus) nudus Linnaeus, 1766  

The original description by Linnaeus (1766) of S. nudus reported the type locality as the European ocean. Nevertheless in the revision of the genus Sipunculus, Cutler & Cutler (1985) refers only to the type of S. titubans, a species considered by them as conspecific with S. nudus. This type specimen was collected in Puntarenas, Costa Rica.