Four New Eulimid Gastropods Associated with Shallow-Water Diadematid Echinoids in the Western Pacific

Abstract

A new genus, Pulicicochlea, and a new subgenus, Pseudoretusa, have been erected to accommodate Pu. (Pu.) astropyga from the echinoid Astropyga radiata, Pu. (Pu.)fusca from Diadema setosum, Pu. (Pu.) calamaris (the type of the genus) from Echinothrix calamaris, and Pu. (Ps.) faba from E. diadema. The host specificity of these gastropods and their distributions in relation to those of relevant diadematids are shown and discussed. All are external parasites; the species of Pulicicochlea s.s. probably feed on the epithelium of the host's spines and Pu. (Ps.)faba on the host's body fluids. Anatomical information is given for Pu. calamaris and Pu. (Ps.)faba (the only two examined alive), and the relationships of Pulicicochlea with other genera in the family are discussed in this light. It is suggested that the Stiliferidae is not separable from the Eulimidae.