Comparative Integumentary Morphology in Four Species of Pipa (Anura: Pipidae) from Colombia

Abstract

As most neotropical pipids, the four species of Pipa present in Colombia are poorly understood despite their particular biology. The tegument of these New-World pipids presents particular structures which variations have been hardly analyzed. Therefore, we aim to describe the morphological variations of the dermal flap, barbels, fingertips, and the lateral line pattern among these four species, focusing on changes during the ontogeny. The results of the study show that the dermal flap was exclusively found in P. pipa, while barbels are usually present in P. pipa but seldom in P. snethlageae. The lateral line pattern in the dorsum is shared by the four species, but P. pipa present more neuromast lines along the snout than P. snethlageae. These species were different from P. parva and P. myersi, which cannot be distinguished based on external morphology, as they were more similar in all lateral line elements and exhibited the same fingertip morphology. On the other hand, the fingertips of young individuals of P. pipa and P. snethlageae presented four simple distal lobes which bifurcate twice during the ontogeny, so that adults present sixteen lobes. The difference between species is observed in the fingertip morphology: P. pipa has all four lobes distally placed, but P. snethlageae has one pair more proximal. The tegument structures analyzed here have a taxonomic utility using external morphology for P. pipa and P. snethlageae, but for P. parva and P. myersi additional studies are necessary. For future research, evaluating the function and anatomy of these structures is important to the understanding these integumentary structures in Pipa.