Larval and adult lung morphology of Trachycephalus typhonius (Anura: Hylidae)

Morphological studies are useful to develop analysis with taxonomic, phylogenetic, ecological, physiological and evolutionary approaches. During the life cycle, Anurans carry out gas exchange through different structures such as gills, skin and lungs. In general, the development of lungs during the larval period is scarce known and most studies analyse the morphology and ultrastructure of the lung wall at the adult stage. This study describes the development and morphology of the lung of Trachycephalus typhonius during the prometamorphic and metamorphic periods and adult stage. Lung development starts at premetamorphic stages and continues along the prometamorphic and metamorphic periods with the development of the lung wall vascularization and pulmonary septa. There are remarkable differences comparing the lung framework at the end of metamorphosis to the one in the adult stage, regarding different-order septa and lung wall structure with a well-developed vascular network. Therefore, the final organization occurs during the juvenile period. This work is the first approach to the study of lung development during larval stages in this species and complements previous studies on lung morphology. Also, contributes to the knowledge of lung morphogenesis and could be useful to interpret the respiratory physiology in different environmental conditions.