Morphological characterization of the buccopharyngeal region in tadpoles of Physalaemus ephippifer (Steindachner, 1864), Anura, Leptodactylidae

Abstract

Studies on the microanatomy of the tadpole oral apparatus are limited, particularly for Amazonian species. Therefore, the present study aimed to describe the ontogenetic development, as well as the buccopharyngeal morphology, of the oral apparatus of Physalaemus ephippifer tadpoles. Egg clutches were transported to the laboratory and maintained in plastic containers filled with water at an average temperature of 24 °C, where embryonic and larval development took place. Periodic sampling was conducted according to developmental stage, and specimens were analyzed using light and scanning electron microscopy. At stage 18, the stomodeum was formed. By stage 21, thickening of the lower and posterior lips was observed, together with the development of the upper and lower horny beaks. At stage 23, five lips with denticles became apparent. By stage 25, the oral apparatus was fully developed, exhibiting a dental formula of 2(2)/3(1). The internal cavity contained several papillae, and both the dorsal and ventral velum were observed at the posterior end of the buccopharyngeal cavity. The development of the oral apparatus in P. ephippifer follows a pattern similar to that observed in other Physalaemus species; however, the main difference lies in the timing of structural development. This study contributes to a better understanding of the taxonomic identification and feeding behavior of this species and provides additional knowledge about the regional amphibian fauna.

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