Misjudged for long: a new toad of the Rhinella veraguensis species group (Anura: Bufonidae) from the Yungas forests of Bolivia

We re-evaluate the taxonomic status of specimens of Rhinella collected from rainforests on the eastern Andean slopes and foothills of central Bolivia. The respective populations have been allocated to different nominal taxa, namely Rhinella fissipes and R. leptoscelis, in the past. By detailed morphological comparisons, including the type specimens of crucial taxa, as well as a phylogenetic analysis based on the mitochondrial 16S rRNA gene, we here demonstrate that the focal populations represent a divergent lineage within the Rhinella veraguensis species group, being apparently closely related to R. rumbolli from northern Argentina, but only distantly related to R. leptoscelis, with which they share several morphological character states. Also, the specimens of the focal lineage differ by a unique combination of morphological character states from all known nominal species currently assigned to the R. veraguensis group. Consequently, we describe this lineage as a new species. We discuss the history of its changing taxonomic allocations and demonstrate that former conclusions were barely justified and wrong. We also provide a description of the osteology of this species using computer tomography (micro-CT). Furthermore, we discuss the status of the nominal taxon Bufo pleuropterus Schmidt, 1857, currently considered to represent a junior synonym of Rhinella margaritifera (Laurenti, 1768), and provide arguments for the specific distinctness of these two taxa. Consequently, we regard Rhinella pleuroptera (Schmidt, 1857) a valid species. Based on its external morphology, which is rather similar to that of R. inca, we speculate that R. pleuroptera is possibly related to species in the R. veraguensis group, although this remains in need of further research.