The differential diagnosis between two sibling Pseudopaludicola species (Anura, Leptodactylidae, Leiuperinae)

A recently published phylogeny corroborated the monophyly of the genus Pseudopaludicola and recognized a clade that included two species that share the same chromosome number: P. ameghini and P. ternetzi. However, historically these two sibling species have undergone many taxonomic changes and so far they do not have a clear taxonomic diagnosis in relation one another. In this study we carry out a male specimen analysis and an acoustic comparison between both. We recorded and analyzed 44 adult males of P. ternetzi: 18 males from Ituiutaba (MG), eight from Minaçu (GO), and 18 from Pontal do Araguaia (MT). We also analyzed 11 adult males of P. ameghini: five from Chapada dos Guimarães (MT; type locality), two from Santo Antonio do Laverger (MT), and four from Cáceres (MT). A sample of 610 notes was analyzed using Raven Pro 1.5. For the multivariate, multidimensional analysis/plots and statistical tests, we used three R packages: randomForest, rfPermute and coin, respectively. Pseudopaludicola ternetzi can be easily distinguished from P. ameghini by its higher pulse and note rates (both traits with non-overlapping values). We also found significant differences (p < 0.01) between them in other temporal traits such as note duration, internote interval, pulses per note, pulse duration and interpulse interval. The two species could not be distinguished in peak of dominant frequency (p = 0.6). In addition, we recognize that both species have a similar external morphology and high intraspecific variation on dorsal color patterns, which may have led to misleading identifications based on their external morphology. Moreover, both species can also be differentiated from the remaining 19 Pseudopaludicola species by their acoustic traits.