Speciation in a biodiversity hotspot: Phylogenetic relationships, species delimitation, and divergence times of Patagonian ground frogs from the Eupsophus roseus group (Alsodidae)

Abstract

The alsodid ground frogs of the Eupsophus genus are divided into two groups, the roseus (2n = 30) and vertebralis (2n = 28), which are distributed throughout the temperate Nothofagus forests of South America. Currently, the roseus group is composed by four species, while the vertebralis group consists of two. Phylogenetic relationships and species delimitation within each group are controversial. In fact, previous analyses considered that the roseus group was composed of between four to nine species. In this work, we evaluated phylogenetic relationships, diversification times, and species delimitation within the roseus group using a multi-locus dataset. For this purpose, mitochondrial (D-loop, Cyt b, and COI) and nuclear (POMC and CRYBA1) partial sequences from 164 individuals were amplified, representing all species. Maximum Likelihood (ML) and Bayesian approaches were used to reconstruct phylogenetic relationships. Species tree was estimated using BEAST and singular value decomposition scores for species quartets (SVDquartets). Species limits were evaluated with six coalescent approaches. Diversification times were estimated using mitochondrial and nuclear rates with LogNormal relaxed clock in BEAST. Nine well-supported monophyletic lineages were recovered in Bayesian, ML, and SVDquartets, including eight named species and a lineage composed by specimens from the Villarrica population (Bootstrap:>70, PP:> 0.99). Single-locus species delimitation analyses overestimated the species number in E. migueli, E. calcaratus, and E. roseus lineages, while multi-locus analyses recovered as species the nine lineages observed in phylogenetic analyses (Ctax = 0.69). It is hypothesized that Eupsophus diversification occurred during Mid-Pleistocene (0.42–0.14 Mya), with most species having originated after the Last Southern Patagonian Glaciation (0.18 Mya). Our results revitalize the hypothesis that the E. roseus group is composed of eight species and support the Villarrica lineage as a new putative species.

Fine-scale species delimitation: speciation in process and periodic patterns in nudibranch diversity

“…nov." is composed of a complex of species. ABGD analysis underestimated species diversity among species with low divergence and is recommended as a first grouping hypothesis but it is not robust for definitive species delimitation proof (Puillandre et al, 2012;Suárez-Villota et al 2018).…”

Taxonomy, systematics and geographic distribution of ground frogs (Alsodidae, Eupsophus): a comprehensive synthesis of the last six decades of research

“…Temperate forests of southern South America (Chile and Argentina) are home to a reduced but evolutionarily diverse group of amphibians (Formas 1979, Cei 1980, Correa et al 2006, Blotto et al 2013, Streicher et al 2018). The most diversified anuran lineage of these forests is the family Alsodidae, which currently is represented there by two sister genera, Alsodes Bell, 1843 (19 species; Blotto et al 2013, Frost 2019) and Eupsophus Fitzinger, 1843 (11 species; Suárez-Villota et al 2018b). Only Eupsophus (members commonly referred to as “ground frogs”) is found exclusively in temperate forests, inhabiting mainly the forest floor (Rabanal and Nuñez 2008).…”

“…Only Eupsophus (members commonly referred to as “ground frogs”) is found exclusively in temperate forests, inhabiting mainly the forest floor (Rabanal and Nuñez 2008). Recently, a controversy about the number of species of Eupsophus has emerged in the literature (Correa et al 2017, Suárez-Villota et al 2018b), according to which there are six or eleven species, respectively. The 11 species of the last taxonomic proposal (Suárez-Villota et al 2018b) are arranged into the two species groups traditionally recognized (Fig.…”

“…Recently, a controversy about the number of species of Eupsophus has emerged in the literature (Correa et al 2017, Suárez-Villota et al 2018b), according to which there are six or eleven species, respectively. The 11 species of the last taxonomic proposal (Suárez-Villota et al 2018b) are arranged into the two species groups traditionally recognized (Fig. 1): roseus ( E.roseus (Duméril & Bibron, 1841), E.calcaratus (Günther, 1881), E.insularis (Philippi, 1902), E.migueli Formas, 1978, E.contulmoensis Ortiz, Ibarra-Vidal & Formas, 1989, E.nahuelbutensis Ortiz & Ibarra-Vidal, 1992, E.septentrionalis Ibarra-Vidal, Ortiz & Torres-Pérez, 2004, E.altor Nuñez, Rabanal & Formas, 2012, and a putative new species from Villarrica, Chile) and vertebralis ( E.vertebralis Grandison, 1961 and E.emiliopugini Formas, 1989) (Formas 1991, Nuñez 2003, Blotto et al 2013, Suárez-Villota et al 2018b).…”

“…Since 1978, when E.migueli was described (Formas 1978a), the number of species progressively increased to 11 ( E.calcaratus and E.insularis , both revalidated by Formas and Vera 1982, E.contulmoensis , E.emiliopugini , E.nahuelbutensis , E.septentrionalis , E.queulensis and E.altor ), but one of them, E.queulensis , was synonymized with E.septentrionalis by Blotto et al (2013). The number of species was reduced to six by Correa et al (2017), but the more recent proposal (Suárez-Villota et al 2018b) restored the previous taxonomy, adding an additional species not described; so currently the genus is composed of ten nominal species plus an undescribed one (see the taxonomic changes since 1961 in Fig. 1).…”