Initial Phylotranscriptomic Confirmation of Homoplastic Evolution of the Conspicuous Coloration and Bufoniform Morphology of Pumpkin-Toadlets in the Genus <i>Brachycephalus</i>
Mariana L. Lyra,
Juliane P. C. Monteiro,
Loïs Rancilhac,
Iker Irisarri,
Sven Künzel,
Eugenia Sanchez,
Thais H. Condez,
Omar Rojas-Padilla,
Mirco Solé,
Luís Felipe Toledo,
Célio F. B. Haddad,
Miguel Vences
Affiliations
Mariana L. Lyra
Instituto de Biociências, Departamento de Biodiversidade (Campus Rio Claro), Universidade Estadual Paulista (UNESP), Avenida 24A, N 1515, Bela Vista, Rio Claro 13506-900, SP, Brazil
Juliane P. C. Monteiro
Instituto de Biociências, Departamento de Biodiversidade (Campus Rio Claro), Universidade Estadual Paulista (UNESP), Avenida 24A, N 1515, Bela Vista, Rio Claro 13506-900, SP, Brazil
Loïs Rancilhac
Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
Iker Irisarri
Institute for Microbiology and Genetics, Department of Applied Bioinformatics, University of Goettingen, Goldschmidtstr, 1, 37077 Göttingen, Germany
Sven Künzel
Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
Eugenia Sanchez
Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
Thais H. Condez
Unidade Passos, Universidade do Estado de Minas Gerais (UEMG), Avenida Juca Stockler 1130, Passos 37900-106, MG, Brazil
Omar Rojas-Padilla
Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6681, Porto Alegre 90619-900, RS, Brazil
Mirco Solé
Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, BA, Brazil
Luís Felipe Toledo
Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas 13083-862, SP, Brazil
Célio F. B. Haddad
Instituto de Biociências, Departamento de Biodiversidade (Campus Rio Claro), Universidade Estadual Paulista (UNESP), Avenida 24A, N 1515, Bela Vista, Rio Claro 13506-900, SP, Brazil
Miguel Vences
Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
The genus Brachycephalus is a fascinating group of miniaturized anurans from the Brazilian Atlantic Forest, comprising the conspicuous, brightly colored pumpkin-toadlets and the cryptic flea-toads. Pumpkin-toadlets are known to contain tetrodotoxins and therefore, their bright colors may perform an aposematic function. Previous studies based on a limited number of mitochondrial and nuclear-encoded markers supported the existence of two clades containing species of pumpkin-toadlet phenotype, but deep nodes remained largely unresolved or conflicting between data sets. We use new RNAseq data of 17 individuals from nine Brachycephalus species to infer their evolutionary relationships from a phylogenomic perspective. Analyses of almost 5300 nuclear-encoded ortholog protein-coding genes and full mitochondrial genomes confirmed the existence of two separate pumpkin-toadlet clades, suggesting the convergent evolution (or multiple reversals) of the bufoniform morphology, conspicuous coloration, and probably toxicity. In addition, the study of the mitochondrial gene order revealed that three species (B. hermogenesi, B. pitanga, and B. rotenbergae) display translocations of different tRNAs (NCY and CYA) from the WANCY tRNA cluster to a position between the genes ATP6 and COIII, showing a new mitochondrial gene order arrangement for vertebrates. The newly clarified phylogeny suggests that Brachycephalus has the potential to become a promising model taxon to understand the evolution of coloration, body plan and toxicity. Given that toxicity information is available for only few species of Brachycephalus, without data for any flea-toad species, we also emphasize the need for a wider screening of toxicity across species, together with more in-depth functional and ecological study of their phenotypes.
