Larynx evolution in paradoxical frogs (Anura, Hylidae, Pseudini): digging into a rarely explored character system

Abstract The larynx is a highly complex structure responsible for sound production during vocalization, a key element of anuran biology and evolution. Larynx morphology shows an astounding diversity in anurans; however, its structure has been studied in detail in only a few species. In this study, we describe the structure of the larynx in Scarthyla and most species of Pseudis (Hylidae, Hylinae, Pseudini) and related clades based on dissections and histological techniques. We propose homology hypotheses related to the arytenoid and cricoid cartilages, associated musculature, and vocal cords, which can be used to study laryngeal evolution in other groups of frogs. Character-state reconstruction on available phylogenetic hypotheses enabled us to infer new synapomorphies for the tribe, for each of the two genera, and for species groups within Pseudis. We also comment on advertisement call characteristics in relation to laryngeal morphology in the tribe.