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Initial Phylotranscriptomic Confirmation of Homoplastic Evolution of the Conspicuous Coloration and Bufoniform Morphology of Pumpkin-Toadlets in the Genus Brachycephalus

Authors :
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
Source :
Toxins, Vol 13, Iss 11, p 816 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

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.

Details

Language :
English
ISSN :
20726651
Volume :
13
Issue :
11
Database :
Directory of Open Access Journals
Journal :
Toxins
Publication Type :
Academic Journal
Accession number :
edsdoj.0ea8bcdf6c7545b1aed84084cf26a39c
Document Type :
article
Full Text :
https://doi.org/10.3390/toxins13110816