Genetic analysis reveals candidate species in the Scinax catharinae clade (Amphibia: Anura) from Central Brazil

Abstract

Scinax (Anura: Hylidae) is a species-rich genus of amphibians (113 spp.), divided into five species groups by morphological features. Cladistic analyses however revealed only two monophyletic clades in these groups: Scinax catharinae and Scinax ruber. Most species from the S. catharinae clade are found in Atlantic rainforest, except for Scinax canastrensis,S. centralis, S. luizotavioi, S. machadoi,S. pombali and S. skaios. In the present work, specimens of Scinax collected in Chapada dos Guimarães, central Brazil, were morphologically compatible with species from theS. catharinae group. On the other hand, genetic analysis based on mitochondrial (16S and 12S) and nuclear (rhodopsin) sequences revealed a nucleotide divergence of 6 to 20% between Scinax sp. and other congeners from the Brazilian savannah (Cerrado). Accordingly, Bayesian inference placed Scinax sp. in the S. catharinae clade with high support values. Hence, these findings strongly indicate the presence of a new species in the S. catharinae clade from the southwestern portion of the Brazilian savannah. To be properly validated as a novel species, detailed comparative morphological and bioacustic studies with other taxa from Brazil such asS. canastrensis, S. centralis, S. luizotavioi, S. machadoi, S. pombali and S. skaios are required.

Identification of the taxonomic status of Scinax nebulosus and Scinax constrictus (Scinaxinae, Anura) based on molecular markers

“…The divergence value recorded for the COI gene was of over 10%, a comparatively high value for differences between amphibian species (Vences et al, 2005a;Guarnizo et al, 2015). This differentiation was also supported by more conservative markers used in other studies (Nair et al, 2012;Nogueira et al, 2016) and in the present study, i.e., 16S and Rhodopsin. Based on an experimental analysis, Vences et al (2005b) concluded that the mitochondrial 16S rRNA gene satisfies the prerequisites for a universal DNA barcode marker for amphibians and may be superior to COI sequences for the identification of vertebrate clades.…”

“…A number of the species described in the Scinax Wagler (Anura: Hylidae) genus require genetic validation, and the application of molecular markers has not only contributed to the identification of new species, but also in the differentiation of cryptic lineages (Nunes et al, 2012;Lourenço et al, 2013;Sturaro and Peloso, 2014;Nogueira et al, 2016).…”

“…The molecular phylogeny obtained by Lourenço et al (2013) confirmed that the Scinax specimens collected at the Chapada dos Guimarães National Park, in central Brazil, which are morphologically similar to species from the S. catharinae group (sensu Faivovich et al, 2005), do, in fact, represent a new species. Nogueira et al (2016) emphasize the need for further comparative analyses between these species, integrating morphological and bioacoustics data.…”

“…As a group, Neotropical amphibians present relatively conserved morphological characteristics and, in many cases, reliable diagnostic traits are difficult to identify (Nogueira et al, 2016), which often implies the existence of cryptic species, which have been increasingly identified in recent years (Guarnizo et al, 2015;Pinto et al, 2019). This means that the species-level diversity of many genera has long been underestimated.…”

High Species Richness of Scinax Treefrogs (Hylidae) in a Threatened Amazonian Landscape Revealed by an Integrative Approach

“…ruber Clade means it is already relatively species-rich. However, because evolutionary relationships among the species are still poorly known, addtional undescribed species may occur in this clade [7, 10, 20–21]. Our herpetological survey in southern Amazonia indicated that Scinax species richness has been underestimated, especially in poorly-sampled regions of the Purus-Madeira interfluve, and the east bank of the upper Madeira river, which are currently threatened by an extensive deforestation [22–24].…”