A revision of the patagonian genus Xymenopsis Powell, 1951 (Gastropoda : Muricidae)

The genus Xymenopsis Powell, 1951 is revised and restricted to 4 Recent spe cies: Xymenopsis muriciformis (Ring and Broderip, 1832), X. corrugatus (Ree ve, 1848), X. buccineus (Lamarck, 1816) and X. subnodosus (Gray, 1839). Of the 34 nominal species that have been described as or assigned to Xymenopsi s by various authors, 3 belong to the buccinid genus Pareuthria and 1 is a trophonine muricid not closely related to Xymenopsis. The taxonomic affinit ies of each of the remaining 30 names (one is a replacement name) are discu ssed. Eleven holotypes and ten lectotypes (nine newly designated) are illus trated, many for the first time. Types of 3 taxa were destroyed during Worl d War II and another 5 types are lost. Neotypes are designated for Fusus bu ccineus Lamarck, 1816, the oldest name to be applied to any species of Xyme nopsis, as well as for Buccinum subnodosa Gray, 1839, Trophon brucei Strebe l, 1904, Trophon fenestratus Strebel, 1904, Trophon paessleri turrita Streb el, 1904, Trophon ringei Strebel, 1904 and Trophon standeni Strebel, 1904. This is done to remove any ambiguity regarding the identity of these taxa, and thus stabilize the nomenclature of Recent species of Xymenopsis. The gr oss anatomy and morphology of the radula, egg capsule, protoconch, and shel l ultrastructure of the type species of Xymenopsis are described and illust rated. Xymenopsis is compared to, and differentiated from, the genera Xymen e, which is restricted to New Zealand, and Trophon, with which it co-occurs in the Magellanic province.