Prochaetodermatidae of the eastern Atlantic Ocean and Mediterranean Sea (Mollusca : Aplacophora)

The Prochaetodermatidae is a family of spiculose, vermiform aplacophoran mo lluscs primarily of the deep-sea benthic fauna. They are ecologically impor tant both in numbers and dominance as well as by their omnivory. In an ongo ing effort, the authors are describing this significant deep-sea group from collections that have been made worldwide from continental shelves to hada l depths of >5,000 m. Here the eastern Atlantic and Mediterranean species a re described, a matter of 14 species, half of them new. The genus Prochaetoderma is here redefined and restricted with a redescript ion of the type species and designation of a neotype. Whereas prochaetoderm atid species were first all considered as belonging to Prochaetoderma, diff erences in spicule morphology fall into 5 discrete genera. Herein are given precise diagnoses and a key to the following genera, accompanied by the sp ecies described here: Prochaetoderma Thiele, 1902: P. raduliferum (Kowalevs ky, 1901), ?P. atlanticum new species, P. boncheti new species, F. yongei S cheltema, 1985; Chevroderma Scheltema, 1985: Ch. turnerae, Ch. gauson, Ch. scalpellum, all Scheltema, 1985; Claviderma new name: Cl. brevicaudatum new species, CE. gladiatum (Salvini-Plawen, 1992), Cl. tricosum new species: N iteomica Ivanov, 1996b: N. hystrix new species; and Spathoderma Scheltema, 1985: S. clenchi Scheltema, 1985, S. alleni new species, S. grossum new spe cies. In total, 3,568 specimens have been examined from depths between 50 and >5, 000 m from the West European Basin, including the Bay of Biscay, the Medite rranean Sea, and the Iberian, Cape Verde, Guinea, Angola, and Cape Basins.