Redescription of Iluocoetes Jenyns, 1842; Proposal of a new genus, Argentinolycus, for Iluocoetes elongatus (Smitt, 1898), and description of Patagolycus melastomus gen. et sp. nov. (Teleostei, Zoarcidae)

The osteological characters of the two nominal species of Iluocoetes, I. fimbriatus and I. elongatus are quite different. The present definition of Iluocoetes based on osteological characters is not valid since it was based on characters found in I. elongates but not in I. fimbriatus, the type species of the genus. In this paper, Iluocoetes is redefined on the basis of osteological characters found in the holotype of Iluocoetes fimbriatus and other specimens of the species, and Iluocoetes elongatus is placed in another genus: Argentinolycus gen. nov. Besides, a new genus and species, Patagolycus melastomus, is described on the basis of fourteen specimens, 94-437 mm TL, collected from SW Atlantic Ocean, at depths of 164-489 m. The similarities found between Patagolycus melastomus sp. nov. and Iluocoetes fimbriatus in body colour as well as in many meristic and morphometric characters, represent a remarkable example of how challenging zoarcid taxonomy can be. The differences between these two species are highlighted. A tree showing interrelationships among the Magellanic endemic lycodine genera is included. Copyright © 2012 · Magnolia Press.