Background: The taxonomic and phylogenetic relationships of the genus Phyllomedusa have been amply discussed. The marked morphological similarities among some species hamper the reliable identification of specimens and may often lead to their incorrect taxonomic classification on the sole basis of morphological traits. Phenotypic variation was observed among populations assigned to either P. azurea or P. hypochondrialis. In order to evaluate whether the variation observed in populations assigned to P. hypochondrialis is related to that in genotypes, a cytogenetic analysis was combined with phylogenetic inferences based on mitochondrial and nuclear sequences. Results: The inter- and intra-population variation in the external morphology observed among the specimens analyzed in the present study do not reflect the phylogenetic relationships among populations. A monophyletic clade was recovered, grouping all the specimens identified as P. hypochondrialis and specimens assigned P. azurea from Minas Gerais state. This clade is characterized by conserved chromosomal morphology and a common C-banding pattern. Extensive variation in the nucleolar organizing region (NOR) was observed among populations, with four distinct NOR positions being recognized in the karyotypes. Intra-population polymorphism of the additional rDNA clusters observed in specimens from Barreiras, Bahia state, also highlights the marked genomic instability of the rDNA in the genome of this group. Based on the topology obtained in the phylogenetic analyses, the re-evaluation of the taxonomic status of the specimens from the southernmost population known in Brazil is recommended. Conclusions: The results of this study support the need for a thorough revision of the phenotypic features used to discriminate P. azurea and P. hypochondrialis. The phylogenetic data presented here also contribute to an extension of the geographic range of P. hypochondrialis, which is known to occur in the Amazon basin and neighboring areas of the Cerrado savanna, where it may be sympatric with P. azurea, within contact zones. The misidentification of specimens may have led to inconsistencies in the original definition of the geographic range of P. azurea. The variability observed in the NOR of P. hypochondrialis reinforces the conclusion that these sites represent hotspots of rearrangement. Intraspecific variation in the location of these sites is the result of constant rearrangements that are not detected by classical cytogenetic methods or are traits of an ancestral, polymorphic karyotype, which would not be phylogenetically informative for this group.

The nominal anuran species Crossodactylus gaudichaudii Duméril and Bibron, 1841 and Crossodactylus aeneus Müller, 1924 are indistinguishable based on adult and larval morphology, being subject of taxonomic doubts. Here, we describe the karyotypes of C. gaudichaudii and C. aeneus, using classical and molecular cytogenetic markers. In addition, we used sequences of the H1 mitochondrial DNA to infer their phylogenetic relationships by Maximum Likelihood (ML) and Maximum Parsimony (MP) approaches and species delimitation test (by bPTP approach). The karyotypic data do not differentiate C. gaudichaudii and C. aeneus in any of the chromosome markers assessed. In both phylogenetic analyses, C. gaudichaudii and C. aeneus were recovered into a strongly supported clade. The species delimitation analysis recovered the specimens assigned to C. gaudichaudii and C. aeneus as a single taxonomic unit. Taken the cytogenetic and genetic results together with previous studies of internal and external morphology of tadpoles and biacoustic pattern, C. gaudichaudii and C. aeneus could not be differentiated, which supports the hypothesis that they correspond to the same taxonomic unit, with C. aeneus being a junior synonym of C. gaudichaudii.

Corythomantis greeningi is a casque-headed frog that occurs in xeric and sub-humid regions of northeastern Brazil. Individuals are often found on rocks on banks of temporary streams or in ponds upon “lajedos”. Suctorial tadpoles are often found clasping to the rocks in the streams so as not to be dragged by the current; therefore, they have modified external and internal morphology. Here, we describe the internal oral anatomy and the chondrocranium of the tadpole of C. greeningi and compare it to the available descriptions of Lophyohylinae and other suctorial tadpoles. The internal oral morphology in C. greeningi resembles pond-dwelling casque-headed frogs, although it has been found in temporary lotic environments. Corythomantis greeningi has unusual chondrocranial morphology relative to that of other described Lophyohylinae, including marked differences at the cornua trabeculae and palatoquadrate. Apparently, the chondrocranial morphology is related to its ecomorphology, because it is structurally more similar to other suctorial tadpoles that inhabit lotic environments than to phylogenetically related species such as Trachycephalus typhonius and Phyllodytes gyrinaethes

Amphibia, Anura, Bufonidae, Melanophryniscus moreirae : Distribution extension

The validation of many anuran species is based on a strictly descriptive, morphological analysis of a small number of specimens with a limited geographic distribution. The Scinax Wagler, 1830 genus is a controversial group with many doubtful taxa and taxonomic uncertainties, due a high number of cryptic species. One example is the pair of species Scinax constrictus and Scinax nebulosus, which share a similar morphology. Scinax constrictus is restricted to the Brazilian Cerrado savanna, while S. nebulosus is widely distributed throughout northern South America. Despite the validation of many anuran species, discriminations based only on morphological traits is quite difficult due to the high conservative morphology of some groups. In this context, the present study uses mitochondrial and nuclear genes to provide a more consistent diagnosis and test the validity of S. constrictus as a distinct species from S. nebulosus, as well as evaluate the position of these taxa within the Scinax genus. The topologies obtained herein uphold the monophyletic status of Scinax based on all molecular markers assessed in this study, in all analytical approaches, with high levels of statistical support.