An enigmatic population of Alsodes (Anura, Alsodidae) from the Andes of central Chile with three species-level mitochondrial lineages

Abstract

The genus Alsodes is the most diverse amphibian taxon of southern Andes, where a series of endemic species occur from north to south (∼33° to 48°30′S), mainly on the western slopes (Chile), with little overlap of geographic ranges. In this study, we describe a new population of Alsodes from the western slopes of the Andes (Fundo El Rosario, 36°52′S), located in a section of this mountain range where it is not clear which congeneric species inhabit. Phylogenetic analyses show that this population presents a mix of mitochondrial DNA related to three nominal species, A. hugoi, A. igneus and A. pehuenche, although the last is mainly present. However, the population presents external characteristics attributable to A. hugoi and A. igneus, differing notably from A. pehuenche. The population inhabits a stream surrounded by temperate deciduous forests at 1130 m elevation, an environment similar to that of A. hugoi and A. igneus, but very different from that of A. pehuenche (high Andean steppe environments between 2000 and 2500 m). This finding represents an enigma from the evolutionary and biogeographical point of view, because it might involve hybridization and/or introgression phenomena between more than two species. As the taxonomic status of this population cannot be determined with the available genetic and morphological evidence, we speculate about its probable origin, taking into account the scarce knowledge of the geographic distributions of the species of Alsodes in the area.

Keywords:

• Alsodes hugoi
• A. igneus
• A. pehuenche
• Andean foothills
• mitochondrial lineages

Notes

Acknowledgements

The authors are very grateful to Alberto Almeida, owner of Fundo El Rosario, who allowed them to conduct this study on his property.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 We are aware that the individuals from Fundo El Rosario may not constitute what is commonly understood as a biological population, that is, ‘a group of individuals of the same species living together in a particular place’ (e.g. Berryman 2002), because with the available evidence we cannot rule out that they represent more than one taxon. However, we did not find any equivalent term to refer us collectively to this group of individuals. Reference: Berryman AA. 2002. Population: a central concept for ecology? Oikos 97(3):439–442.

Additional information

Funding

This work was partially supported by the Universidad de Concepción under Grant of Project Semilla VRID UdeC [219.113.096-S], awarded to Jesús Morales.