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

Abstract

The genusEupsophus(ground frogs) inhabits exclusively the temperate forests of southern South America (Chile and Argentina). The current delimitation of the genus was reached in the late 1970s, when only two species were recognized, but since then the number of described species steadily increased, reaching a maximum of 11 by 2012. Subsequent studies that applied explicit species delimitation approaches decreased the number of species to six in 2017 and raised it again to 11 the following year, including an undescribed putative species. Despite these taxonomic changes, the two species groups traditionally recognized,roseusandvertebralis, have been maintained. Another recent contribution to the taxonomy of the genus was the explicit recognition of the extremely high level of external phenotypic variation exhibited by species of theroseusgroup, which undermines the utility of some diagnostic characters. Here we provide a critical review of the extensive taxonomic and systematic literature on the genus over the last six decades, to examine the evidence behind the recurrent taxonomic changes and advances in its systematics. We also update and complete a 2017 review of geographic information, provide additional qualitative observations of external characters commonly used in the diagnoses of species of theroseusgroup, and reassess the phylogenetic position of a putative new species from Tolhuaca (Chile), which was not included in the last species delimitation study. The present review shows that: 1) there is no congruence between the patterns of phenotypic and genetic/phylogenetic differentiation among species of both groups; 2) in theroseusgroup, the intraspecific variation in some external characters is as high as the differences described among species; 3) there is little morphological and bioacoustic differentiation within species groups, and inconsistencies in the chromosomal evidence at the genus level; 4) under the latest taxonomic proposal (2018), species of theroseusgroup still lack consistent and reliable diagnoses and their distribution limits are poorly defined; and 5) the population from Tolhuaca represents an additional undescribed species under the most recent taxonomic framework. Finally, we discuss the implications of these findings for the taxonomy and biogeography of the genus, pointing out some areas that require further research to understand their patterns and processes of diversification.

Geographic boundaries and natural history notes of the microendemic endangered frog Eupsophus migueli Formas, 1977 (Alsodidae) in the Mahuidanche Range, southern Chile

“…They argue that the karyotype, the maximum frequency of the spectral elements of the mating call, the morphometric analyses, and the lack of knowledge about the reproductive cycle and the larva of E. migueli, do not allow the differentiation of two species (see Núñez et al 2012). Subsequently, Suárez-Villouta et al (2019) based on a new molecular analysis (including coalescence tests) concluded that the eight species recognized in the "roseus" group before the work of Correa et al (2017) were valid, which was corroborated by Correa and Durán (2019). In summary, in this work we consider the "roseus" group to contain eight described species.…”

The definitive rediscovery of Telmatobius halli (Anura, Telmatobiidae) at its historic type locality and its synonymy with T. dankoi and T. vilamensis

“…As in the case of other Chilean amphibian genera (Alsodes Bell, 1843; Eupsophus Fitzinger, 1843) (Blotto et al 2013;Correa and Durán 2019), the taxonomy of the genus Telmatobius is complex due to high levels of intra-and interpopulation variation in morphological features (e.g., Trueb 1979;Wiens 1993;De la Riva et al 2005;Barrionuevo 2017), especially in characters that are traditionally used to distinguish anuran species (De la Riva et al 2005). Thus, molecular studies have played an important role in the systematics of this taxonomic group in Chile during the past few years (Sáez et al 2014;Victoriano et al 2015;Fibla et al 2017, 2018-reviewed by Sáez and Méndez 2020.…”

Third time’s the charm: The definitive rediscovery of Telmatobius halli Noble, 1938 (Anura, Telmatobiidae) at its historic type locality

“…Like in the case of other Chilean amphibian genera (Alsodes Bell, 1843; Eupsophus Fitzinger, 1843) (Blotto et al 2013;Correa and Durán 2019), the taxonomy of the genus Telmatobius is complex, due to high levels of intrapopulation and interpopulation variation in morphological features (e.g . Trueb 1979;Wiens 1993;De la Riva et al 2005;Barrionuevo 2017), especially in characters that have been used for diagnosis in the description of some species (De la Riva et al 2005).…”