A New Platydoris Gastropoda Nudibranchia From The Galapagos Islands

Platvdoris carolynaen.sp. is described from the Galapagos Islands and compared with the two eastern Pacific species of PlatyJoris and with P. scabra.the only member of this genus with wide distributional limits.Platydorids are rasping sponge feeders that live in tropical and temperate oceans.The distribution and nomenclature of the 36 known species is reviewed briefly.The nudibranch fauna of the Galapagos Islands has been neglected by previous workers.Apparently, only two species, Doris peruviana Orbigny 1837 and Onchidium k'slici Stearns 1893, have been reported (Pilsbry and Vanatta, 1902: 556; Stearns, 1893: 383).Yet, in March 1971 members of the Ameripagos Expedition to the Galapagos Islands collected at least 15 species of nudibranchs, some of them fairly common, at various localities in the islands (Sphon and MuUiner, 1972).Included among these was a previously undescribed species of Plat}'doris that was found at several localities, and which may be endemic to these islands.In this paper, we describe this new species, and briefly review the distribution and nomenclature of Pkitydoris. BIOGEOGRAPHYMembers of the genus Pkitydoris are sluggish, retiring invertebrates that cling tightly tc crevices on the underside of rocks and coral heads.They are found in tropical and temperate waters from 40° N latitude to 32° S latitude.All but one of the thirty-six known species have limited ranges, usually consisting of one shoreline, one island chain, or one location (Fig. 1).Platydoris scabra (Cuvier, 1804) is the exception, ranging in tropical waters from 38° E longitude to 155° W longitude.The majority of the platydorids are found in the Indo-Pacific.They are rasping sponge-feeders, and the great abundance and diversity of sponges may account for the large number of platydorids found in these seas as compared to the Atlantic or Eastern Pacific.