Comparative anatomical study of the type material of the genus Trichomycterus (Siluriformes, Trichomycteridae) from Southeastern Brazilian drainages

Abstract

The genus Trichomycterus (Siluriformes: Trichomycteridae) is one of the largest taxonomic bottlenecks in Neotropical fishes. The genus comprises 184 nominal species spread throughout South America. Taxonomic studies on Trichomycterus continue to this date, with many new species described yearly. Despite that, non-described species still abound and a multiplicity of validly-published names remain doubtful. A complete taxonomic revision is an unachievable duty at present, due the magnitude of the work and the resources needed. Instead, it is possible to achieve genuine progress by focusing on specific geographical areas or hydrographic basins. This project focuses on the species of Trichomycterus from the Rio Doce basin, one of the largest Eastern Brazilian drainages, with a large proportion of endemic fish species. Its biodiversity is considered as critically endangered due to anthropic actions. The present study will assess the species diversity of Trichomycterus in the Rio Doce. New morphological and DNA sequence data will be used to provide a realistic picture of the species composition in the basin. Results will be combined with data from type specimens of several Trichomycterus species deposited at the Smithsonian Institution and other institutions. Type material to be examined covers the entire spectrum of Trichomycterus type material available in North American Museums, and not only those from the Rio Doce, because species of the genus can transcend specific basins. The direct study of type material will guide the correct application of available taxonomic names to the biological entities recognized in the previous phase of the study and will allow the identification of new species. (AU)