Evaluation of the taxonomic status of populations assigned to Phyllomedusa hypochondrialis (Anura, Hylidae, Phyllomedusinae) based on molecular, chromosomal, and morphological approach

Abstract

BackgroundThe 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.ResultsThe 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.ConclusionsThe 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.

Intraspecific developmental variation in the life cycle of the Andean Treefrog (Boana riojana): A temporal analysis

“…Among amphibians, different morphotypes within a species have been described and related to intraspecific changes in the timing of development (Collins, Zerba & Sredl, 1993), dietary conditions (Pfennig, 1990), geographical variation (Bruschi et al, 2013), or in response to predators (Kishida & Nishimura, 2005;Van Buskirk, 2017;Touchon & Robertson, 2018). The two morphs of B. riojana occurred simultaneously in the same sites and at the same developmental stages and body sizes, and with the same tooth formula, so, it is unlikely that they represent two different species or that diet or geographical variation may be directing the early appearance of the two morphotypes.…”

Variation in brain anatomy in frogs and its possible bearing on their locomotor ecology

“…Next we plotted the phylogeny in the morphospace using the 'phylomorphospace' function in R (R Core Team, 2016) implemented in the 'phytools' library (Revell, 2012). We used a consensus phylogeny based on Frost et al (2006), Roelants et al (2007), and Bruschi et al (2013) (Fig. 1).…”

“…1 Phylogenetic tree representing the relationships among the species included in our study. The tree is a composite tree based on Frost et al (2006), Roelants et al (2007), and Bruschi et al (2013). To the right of the tree are indicated the different locomotor modes and lifestyles of the species.…”

Cytogenetic analysis of Phyllomedusa distincta Lutz, 1950 (2n = 2x = 26), P. tetraploidea Pombal and Haddad, 1992 (2n = 4x = 52), and their natural triploid hybrids (2n = 3x = 39) (Anura, Hylidae, Phyllomedusinae)

“…Among 19 species of Phyllomedusa cytogenetically analysed, only P . tetraploidea is polyploid [15,28-30]. All of the remaining species are diploid with 26 bi-armed chromosomes, with the exception of P .…”

“…Unlike most hylids carrying one Ag-NOR [15,35-37], Phyllomedusa species, with some exceptions, generally exhibited multiple sites and variability in the number and location of the Ag-NOR sites has been observed [20,28-30,32-34,38]. At least three of the five known species of the P .…”