Tadpole of the Amazonia frog Edalorhina perezi (Anura: Leptodactylidae) with description of oral internal and chondrocranial morphology.

The genus Edalorhina consists of two species of small forest-floor frogs inhabiting the Amazon basin. The tadpole of Edalorhina perezi, the most widely distributed species, was previously described based on a single and early stage (Gosner 25) individual. Herein, we provide a description of the tadpole in Gosner stages 35-36 including internal morphology data (i.e., buccopharyngeal cavity and larval skeleton) based on samples from two populations from Ecuador. Edalorhina shares a generalized morphology with most members of its closely related taxa; however, it is distinguished from the other species by having an almost terminal oral disc. The presence of a dextral vent tube is considered a synapomorphy for the clade consisting of Edalorhina, Engystomops, and Physalaemus. Within this clade, the combination of two lingual papillae, a filiform median ridge, and the lack of buccal roof papillae are diagnostic of E. perezi and putative autapomorphies of Edalorhina. Chondrocranial anatomy provides characteristics, that is, presence of and uniquely shaped processus pseudopterygoideus and cartilago suprarostralis with corpora and alae joined by dorsal and ventral connections that readily differentiates the genus from other Leiuperinae.