Molecular phylogenetics uncovers two new species in the genus Phyllobates (Anura, Dendrobatidae): the terrible frog gets two new sisters

Abstract

True poison-dart frogs (Phyllobates, Dendrobatidae) evolved the ability to secrete batrachotoxins, the most powerful alkaloids known to date. The genus comprises five species whose systematics, at first glance, appeared clear. The most derived clade would include two Colombian species (P. terribilis and P. bicolor) with the highest toxicity, the largest body size, and predominantly yellow body colouration. The other three species (P. aurotaenia, P. vittatus, and P. lugubris) are less toxic on average, have smaller size, and are predominantly black with bright dorsolateral stripes. Recent research has revealed the existence of two major lineages among the three Colombian species. The northern lineage appears to result from a complex evolutionary history, including perhaps introgression among yellow and black taxa. The southern lineage instead revealed the existence of new clades closely related to P. terribilis, black and yellow, that arguably deserve their recognition as new species. Here, available evidence is combined to support the erection of southern populations of P. aurotaenia as a new highly toxic species, sister to P. terribilis, and much closer to it than to any other yellow or black-bodied species, Phyllobates samperi sp. nov. Their common ancestor is sister to an additional yellow species, which we also describe here as Phyllobates bezosi sp. nov. Both new species can be externally diagnosed using colouration. Our previous and current analyses also suggest the existence of additional taxa and corroborate multiple transitions in colouration across these hypertoxic taxa.