Sistemática do gênero Ageneiosus La Cépède (Siluriformes Auchenipteridae)

Abstract

The catfish genus Ageneiosus is revised and a new hypothesis of phylogenetic relationships inter- and intra-generic is proposed. The taxonomic revision was based on the examination of available type specimens and analysis to the original descriptions. Taxonomic accuracy of the species was tested by morphometric, meristic and qualitative analyses of internal and external anatomy. Valid species were considered in the study of phylogenetic relationships. The phylogenetic analysis included 239 characters coded for 41 terminal taxa. Formerly with 12 species, the genus Ageneiosus comprises currently 19 species recognized herein as valid, some of which are widely distributed across large rivers in South America. Ageneiosus pardalis is the only trans-Andean species in the genus. Ageneiosus marmoratus is a junior synonym of Ageneiosus inermis. Ageneiosus dentatus and Ageneiosus rondoni are valid species and their names are removed from the synonymy of Ageneiosus ucayalensis and Ageneiosus brevis, respectively. Six new species are recognized. The parsimony analysis resulted in a single most parsimonious tree with 631 steps, consistency index 0.52 and retention index 0.85. The monophyly of Ageneiosus is corroborated and its diagnosis includes 10 synapomorphic characters unique between the Auchenipteridae. The genus is composed of two main clades: (1) clade comprising the majority of the species with large and not ossified swimbladder and (2) clade comprising Ageneiosus pardalis and the species with reduced and ossified swimbladder in large individuals. The ressurrection of Tympanopleura is proposed to accommodate the species of the first clade. According to the hypothesis presented here, the clade Ageneiosus-Tympanopleura is the sister-group of Tetranematichthys and the clade composed of these genera is the sister-group of (Entomocorus (Auchenipterus (Epapterus, Pseudepapterus))). A key for all nineteen valid species of Ageneiosus species is provided.