2026/04/21 by Jimena Grosso, Diego Baldo, Diego Andrés Barrasso +10
Environmental Science · Earth and Planetary Sciences · Psychology · #Amphibian and Reptile Biology #Evolution and Paleontology Studies #Primate Behavior and Ecology
paper · doi:10.1093/zoolinnean/zlag081
Abstract Nobleobatrachia represents the most species-rich radiation of anurans worldwide. Although early diversification probably began in southern South America before expanding into tropical regions, developmental data for early-branching South American lineages remain scarce. To address this gap, we integrated data on clutch structure, larval morphology, hatching behaviour, and complete developmental series, analysing these traits within a phylogenetic framework. Our results identify two primary factors shaping early ontogeny in Nobleobatrachia: the developmental microenvironment and the duration of embryonic development within the egg. Ancestral-state reconstructions indicate that exotrophy is plesiomorphic for Nobleobatrachia, with endotrophy evolving secondarily, and that ancestral clutches were laid in water and hatched early. In contrast, many early-branching South American taxa have non-aquatic clutches and delayed hatching, often accompanied by loss of adhesive glands, accelerated hindlimb growth, and reduced opercular development. Additional putative synapomorphies were recovered within Neoaustrarana, like kyphotic dorsal curvature in the embryos of Cycloramphidae and Batrachyla and elongated gills in Cycloramphidae. Overall, our findings highlight the central role of heterochronic shifts in shaping developmental trajectories and provide new insights into the evolutionary history and ecological diversification of Nobleobatrachia.