Evolução e diversificação da morfologia larval na tribo Dendropsophini (Anura: Hylidae: Hylinae)

Abstract

The diversity of Dendropsophini tadpoles has provided important taxonomic and systematic information for the tribe. Some speculations about morphological and ecological evolution have been made, but the knowledge about the anatomy and evolutionary patterns of the larvae of this group is restrict. In this study, we performed a comparative analysis of the external and internal morphology of these larvae and commented on the systematic and evolutionary implications for the tribe. We analyzed the external morphology, oral cavity, and musculoskeletal anatomy of 49 species - including representatives of all species groups and many clades of the tribe - which were coded in 118 characters which were optimized into the most inclusive phylogenetic hypothesis of the tribe. We found several putative synapomorphies for the tribe, for the genera Dendropsophus and Xenohyla, and for most species groups, for which homoplasy-free phenotypic synapomorphies were unknown. The morphological variation among species groups suggests different levels of adaptation to macrophagy and carnivory, demonstrating the relationship of diversification to ecological patterns. Two extreme, distinct and specialized carnivory morphotypes, marked by reduced buccal cavity, reduced hyobranchial and robust mandibular muscles, evolved in the tribe, in Dendropsophus marmoratus and D. microcephalus species groups. Both groups with particularities, like a keratinized structure on the buccal roof in the D. marmoratus group, and an oral disc modified into a protractile tube in the D. microcephalus group. The specializations in the two groups show convergences with macrophagous and carnivore tadpoles of other distantly related anuran lineages. The other representatives of Dendropsophini seems to have retained plesiomorphic conditions of the tribe, suggesting a less specialized diet. Our results draws attention to the importance of using larval characters in systematics, for understanding the evolution of the tribe, suggesting the diet as a key point in the diversification of Dendropsophini tadpoles.