Early ontogeny and sequence heterochronies in Leiuperinae (Athesphatanura: Leptodactylidae).

GROSSO, JIMENA; KOLENC, FRANCISCO; BONINO MARCELO; BALDO, DIEGO; BORTEIRO, CLAUDIO; BARRASSO, DIEGO; CARDOZO, DARIO; RODRIGUEZ DE OLIVEIRA, MARIANA; VERA CANDIOTI, FLORENCIA

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2019 vol. 14 p. 1 - 37

1932-6203

Several works have studied the early development of Leiuperinae frogs (Anura,Leptodactylidae), but a comparative study framed in a phylogenetic context has not been attempted so far. We studied herein the morphological diversity of embryonary and larval characters of 22 species belonging to the three largest genera of Leiuperinae based on ontogenetic series. Our results showed a vast structural and heterochronic diversity, of which evolutionary transformations that involved changes in the sequence of developmental events were mapped on current phylogenetic hypotheses. In most cases, variation presented strong phylogenetic structure both at generic and intrageneric levels. Kyphosis and whitish overall color of embryos were synapomorphies for the clade grouping Physalaemus and Engystomops. The presence of a third posterior labial row in the oral disc showed to be plesiomorphic for Leiuperinae only changing in derived clades. Arrangement and developmental trajectories of the lower lip were exceptionally diverse in species of Physalaemus and Pseudopaludicola. The optimization of developmental sequences on phylogenetic trees indicated that the acceleration in row P1 differentiation was synapomorphic of Pseudopaludicola and Physalaemus. Conversely, an early developed row P2 may have occurred in the ancestor of Pleurodema. On the other hand, a few features were relatively conserved, like the adhesive glands that are universally present in Leiuperinae with a type-C configuration. Results also suggested the occurrence of covariation between morphological and developmental variation, and embryonaryecology. A large body size, poorly developed transient respiratory structures, large yolk provision and delayed development of the digestive tract convergently developed in embryos inhabiting cold, oxygenated environments. Embryos developing in warmer water bodies of xeric environments showed more complex and persistent transient respiratory structures and a fast hind limbs development. Finally, our survey provided evidence about embryonic morphology and the developmental trajectories as a valuable source of information for phylogenetic analyses and evolutionary interpretations.