Gonadal development in the Neotropical high Andean frog Dendropsophus labialis (Amphibia: Hylidae)

Amphibians are one of the most threatened groups of vertebrates whose populations are declining due to many reasons including, among others, the presence of chemicals associated with human intervention and in particular, with agriculture. These chemicals are deposited where amphibian larvae develop provoking morphological abnormalities in different organs, such as the gonads, which have been used as biological indicators of these chemicals in the environment. Therefore, descriptions of normal gonadal development among anurans are important not only to increase our knowledge about the reproductive biology of species but also to identify the type of gonadal abnormalities. The main objective of this work was to describe the morphological changes that occur during gonadal differentiation in the Neotropical high Andean frog Dendropsophus labialis, an endemic species from the Eastern Andes of Colombia. We analyzed 211 individuals including larvae and adults. This species has a differentiated pattern of gonadal development and accelerated rates of ovary and testis differentiation since mature oocytes and seminiferous tubules are present during pre-metamorphic larval stages. In comparison with other phylogenetically related species, D. labialis has one of the most accelerated rates of gonadal differentiation described so far. We confirmed that the gonadal development is to some degree independent of somatic development and we described a case of a gonadal abnormality.