![]() ![]() These characteristics make Brachycephalus an excellent model for studying the evolution of anti-predator defense mechanisms associated with toxins. On the contrary, flea-toads have an inconspicuous brown coloration and their putative toxicity has so far not been assessed. ephippium) and bradykinin-potentiating peptides (BPP) have been reported in B. Several pumpkin-toadlets are also known to contain toxins: TTX has been reported in B. The coloration of pumpkin-toadlets is usually bright, orange/yellow but sometimes greenish/brownish dorsally, and always with some orange components at least on the hands and feet and/or on the ventral surface. The relatively more elongated skull of the flea-toads is also reflected in a skeletal multivariate morphospace. All pumpkin-toadlets are characterized by a “bufoniform” appearance, with a robust body and pectoral girdle, head as wide as long and short snout the flea-toads instead have a “leptodactyliform” appearance with slender body and pectoral girdle, head longer than wide and long snout ( Supplementary Figure S1). Brachycephalus species are divided into two groups according to their body plans, popularly known as pumpkin-toadlets (34 species) and flea-toads (4 species). Species in this genus are essentially diurnal, leaf-litter inhabitants, miniaturized, and characterized by direct development. One example is the Brazilian genus Brachycephalus which currently comprises 38 described species, all endemic to the Atlantic Forest biome between 15° and 26° latitude from sea level up to 2000 m ( Figure 1). They are also the only class of terrestrial vertebrates known to contain tetrodotoxin analogues (TTX ). 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.Īmphibians have long been a prime group for research on the evolution of aposematism and contain a large number of species that exhibit putative warning signals. ![]() 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. 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. In addition, the study of the mitochondrial gene order revealed that three species ( B. ![]() 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. We use new RNAseq data of 17 individuals from nine Brachycephalus species to infer their evolutionary relationships from a phylogenomic perspective. 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. Pumpkin-toadlets are known to contain tetrodotoxins and therefore, their bright colors may perform an aposematic function. 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. ![]()
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