Tadpoles representatives of major lineages of frogs were obtained from scientific collections. After species confirmation, they were studied regarding their external and internal morphology; they were inspected under stereoscope microscope, manually dissected, cleared and stained, and/or submited to scaning electron microscope and micro-CT methods. Characters were individualized from oral apparatus, tail and body morphology, musculo-skeletal system, buccopharyngeal cavity, and visceral components.
A phenotypic matrix was compiled and 378 phenotypic characters proposed to explain the observed diversity. Data was obtained for over 400 species covering the phylogenetic, ecological, and morphological diveristy of frogs. Several new states were described for the first time. Character were optimized into a phylogeneticy hypothesis and several novel synapomorphies identified.
The phenotypic matrix was converted into a distance matrix and used to reconstruct the morphospace occupied by anurans, as well as for the analysis of phenotypic disparity. The available time-calibrate hypothesis was based on a dataset containing several errors, such as mislabelling of genes and contaminations with human DNA, which could affect the estimation of the rates of evolution. Thus, select a subset of terminals and corrected the molecular matrix. I ran a total evidence analysis and evaluated the unique, homplastic, and private phenotipic synapomorphies at major clades.
Phenotypic synapomorphies were recovered at all levels of inclusiviness. Apomorphic transformations were observed in all major clades of frogs. There were instances of convergent evolution across the anuran tree of life, particularly within neobatrachians. Anurans occupied different regions of the morphospace, with different regions occupied by different clades. Six major clustering can be observed: 1) Caudata; 2) Ascaphidae; 3) Costata; 4) Xenoanura; 5 Anomocoela; and 6) Neobatrachia. Those clusters are highly in accordance with the phylogeny of frogs. Anomocoela and Neobatrachians occupied similar regions of the morphospace. Xenoanura and Microhylids explored different regions of the morphospace, not occupied by representatives of other clades. Phenotypic disparity was quite similar in those clusters, with the highest value in Xenoanura. . Early evolution of anurans and more inclusive clades, such as Lalagobatrachia, is marked by the acquisition of unique and private synapomorphies. Evolution of less inclusive clades is marked mainly by homoplastic synapomorphies. The results shows that anuran had an early burst, marked by the acquisition of novel, unique character-states, with an occupation of different portions of the morphospace. Neobatrachians, the most diverse and speciose clades of frogs, is initially concentrated in a portion of the morphospace, with a secondary colonization of other regions by microhylids. Notwithstanding, apomorphic transformations occurred in similar proportion in that clade as in the most basal lineages, although many transformations are homoplastic. The results support the notion that anurans diversification have been continuous through time, although phenotypic innovations became less common and convergent evolution became an important player; this is highlighted by the fact the phenotypic disparity did not change drastically through time. Thus, the mega-evolutionary hypothesis is partially supported by tadpole morphology.
Results of MEGAN have been presented in national and international conferences. They have also been disclosed in social media. Additionally, I organised multiple scientific events, including the, II International Symposium Tadpole Evolution, that had almost 400 attendants from different regions of the World; this online and free of charge event, was the most comprehensive event about tadpole biology ever and reached people from different culture, academic levels, and social backgrounds.
