Metacarpal expansion in Centrolenidae TAYLOR, 1951 (Amphibia: Anura): ontogenetic and sexual variation and the relationship with arboreal habit

Abstract

The Anura group shows a nearly cosmopolitan distribution with higher diversity in tropical regions. Occupying diverse habitats, such as forests, rivers and deserts, anurans development a varied life habitats, showing adaptations for the aquatic, terrestrial and arboreal environment. Regarding arboreal habit, we can mention multiples morphologic specializations that allow arboreal stratum occupancy, such as the presence of adhesive digit pads, longer fingers and hands, ability to close the hand around substrate, modifications on the base of the IV digit metacarpal, the elongation of extensores brevis profundus muscles and the presence of extensores brevis distalis muscles. The specialization for such habit appears mainly in 12 families predominantly arboreal and it's known that evolved multiple times in Anura phylogeny. Thus, this study aims to understand the evolution of one specialization related to arboreal habit in family Centrolenidae: the metacarpals expansions and the ontogenetic and sexual variation, as well as the association with muscles. (AU)