The Taxonomic Status of Physalaemus cuqui Lobo, 1993, with the Description of a New Species of Physalaemus (Anura: Leptodactylidae) from Argentina and Paraguay

We review the taxonomy of two historically problematic taxa of Neotropical frogs belonging to the Physalaemus cuvieri group: P. albonotatus and P. cuqui. A thorough revision of morphological, bioacoustic, cytogenetic, and genetic characters throughout their ranges indicated that P. cuqui is a junior synonym of P. albonotatus. In addition, our analyses allowed the identification and description of a new taxon that was historically confused with the latter. The new species is externally indistinguishable from P. albonotatus, and both species are allopatric. Their distinction can be made only with their advertisement calls and on molecular grounds. Finally, to help stabilize the complex taxonomy of the P. cuvieri group, we provide a redescription of P. albonotatus with a neotype designation. This decision is based on the fact that we were unable to track extant type specimens in different herpetological collections that would be associated with the original description of this taxon, which is actually a composite of species. A comprehensive list of works dealing with both species is included, indicating whether they are referred to either P. albonotatus or the new species.