Delimitation of Endangered Telmatobius Species (Anura: Telmatobiidae) of the Chilean Salt Puna

Abstract

Clarifying the taxonomic status and distribution of endangered species is crucial to their conservation. In this study, we contrasted different lines of evidence (morphology, mtDNA, and nucDNA: microsatellites and SNP) to clarify the taxonomic status of endangered Telmatobius water frog species and unidentified populations that inhabit the Salt Puna in Chile. We studied population differentiation and species divergence by performing morphometric, population genetic and species delimitation analyses. The results confirmed the species status of Telmatobius fronteriensis and T. philippii, as they exhibited morphometric, mitochondrial and genomic SNP divergence. Although Bayes factor delimitation analysis indicated that the Telmatobius populations of Ascotán and Carcote could represent a new species, their few mitochondrial differences and similar morphology with respect to T. philippii suggested otherwise. Instead, they can be considered an evolutionarily significant unit of T. philippii that has differentiated from the type locality. These results extend the geographic distribution of T. philippii, which is categorized as critically endangered by the IUCN.

Keywords: Andean Altiplano; Tauca paleolake; amphibians; species delimitation; taxonomy.

Figure 3

Results of the multivariate and phylogenetic analyses. (A) Scatter plot of PC1 to PC2 of PCA obtained using morphometric data; (B) scatter plot of PC1 to PC2 of PCA obtained using SNP data; (C), maximum likelihood tree recovered using Cytb; (D) maximum likelihood tree using SNP data. Within (D), the letters a–f indicate the clades considered in Table 3 (BFD analysis). The colours in the scatter plots and ML trees indicate specimens sampled from the same geographical unit.

Figure 1

Study area. Map indicating Telmatobius sampled localities (sites) in the Chilean Salt Puna. The circle in A and the square in B indicate the type localities of T. fronteriensis and T. philippii, respectively, whereas the unidentified localities (triangles in B, C and D) correspond to Telmatobius sp. Ascotán spring (S) names follow [40]. Carcote S2 correspond to “Aguas Calientes” spring in [37].

Figure 2

Results of the population genetic analyses. Median-joining network inferred using the amplified fragment of the mitochondrial CR (A) and microsatellite PCA scatter plot presenting the two first PCs (B). The percentage of genetic variance explained by each PCA component is indicated between parentheses.

Figure 4

Summary scheme of the species delimitation results. The Densitree at the left represents 9000 species trees of the “splitter hypothesis” (considering Theta = 1) obtained in the path sampling analysis in BEAST2.

Figure 5

Morphological variation in T. philippii. (A,B) Female T. philippii specimen of Ascotán. (B–D) Female T. philippii specimen of Amincha. The bar at the right of each specimen has a length of 20 mm.