Morfologia e histologia de calosidades nupciais em Leiuperinae e Paratelmatobinae (Amphibia: anura: Leptodactylidae): descrição, busca de caracteres filogenéticos e comentários evolutivos

Abstract

Nuptial pads are present in a wide range of anuran species. These structures are composed by epidermal and dermal thickening, with the presence of nuptial glands or not. Nuptial pads are linked with amplex optimization, male fights and pheromone production. Although few studies on nuptial pads have been made, significative variation in density, topology and ultrastructure were found for many taxa, with possible applications in systematics. Leptodactylid frogs comprise a family where nuptial pads are conspicuous and variable, but lacking detailed investigations. Therefore, the description, character assessments, and optimization of chosen characters into molecular phylogenies was made for two subfamilies of Leptodactylidae: Leiuperinae and Paratelamatobinae. The pollex of 42 specimens was photographed, dissected and addressed to scanning electron micrography (SEM) and histology/hystochemistry (toluidin blue, periodic acid-Sciff [PAS] and alcian blue pH 2.5 and 0.5). Nuptial pads without dark keratinization are a homoplasic autapomorphy of Paratelmatobius lutzii and Physalaemus rupestris. The shape of the epidermic projections (EPs) is a homoplasic putative sinapomorphy of Crossodactylodes and Leptodactylus (large spines), and Scytrophrys and Leiuperinae (flagstone-like). The carpal area not covered by nuptial pads is a homoplasic autapomorphy of Pa. cardosoi. An undivided nuptial pad is a homoplasic autapomorphy of Ph. henselii and Ph. lisei. The naked phalanx (i.e., not covered by nuptial pads) is a homoplasic putative sinapomorphy of the Ph. signifer clade (except for Ph. henselii and Ph. lisei). The proximal phalanx completely covered in Paratelmatobinae and Ph. signifer clade (except for Ph. nattereri) is a homoplasic putative sinapomorphy; and the distal phalanx covered in Paratelmatobius (except for Pa. lutzii) a putative sinapomorphy. The inner metacarpal tubercle not covered by nuptial pads is a homoplasic putative sinapomorphy of the Ph biligonigerus group. The absence of nuptial glands and dermal papillae are autapomophies of Crossodactylodes and L. petersii. Therefore, nuptial pads occur as homoplasic putative sinapomorphies (mostly), not homoplasic putative sinapomorphies, and autapomorphies, giving support to many clades and distinguishing species within genera. We can conclude that nuptial pads can be important in future morphological phylogenies for recovering evolutionary relationships among the Leptodactylidae.