Anatomia comparada do aparelho de Weber do grupo calophysus (siluriformes: pimelodidae)

Abstract

Currently, the Pimelodidae family includes the Calophysus group, composed of the genera: Aguarunichthys Stewart, 1986; Calophysus Müller & Troschel, 1843; Cheirocerus Eigenmann, 1917; Luciopimelodus Eigenmann & Eigenmann, 1888; Megalonema Eigenmann, 1912; Pimelodine Steindachner, 1877; and Pinirampus Bleeker, 1858. Serious taxonomic problems, together with its commercial importance, made studies necessary to diagnose and delimit the species that make up the group. Among the objectives of this work, we have to understand the kinship relationships within the Calophysus group so that it is possible to establish its internal relationships, taking into account the morphological and phylogenetic studies already published. The analyzed material is deposited in the INPA Fish Collection, with the Pimelodidae family being one of the most representative in terms of the number of listed lots. The cladistic methodology was followed according to Hennig (1950, 1966), focusing on the morphological characters of the Weber Apparatus region of individuals of the Calophysus group. In addition, diaphanized individuals were used, who underwent the Potthoff protocol (1984), which basically consists of bleaching the muscles and bones. With this study, it was possible to expand the osteological knowledge of the species that make up the group of interest. Having 16 characters described that were coded for 9 taxa and submitted to a parsimony analysis, resulting in two more parsimonious trees. Thus, we have that the structure of the Apparatus of Weber is highly modified in several species of the group. However, the characters analyzed here were not enough, requiring the addition of other characters that make up the group or even the Pimelodidae family. Keywords: Catfish; biodiversity; ichthyology; fishes; systematic.