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

Telmatobius halli was the first representative of its genus to be described exclusively for Chile, yet for 85 years no new individuals could be located due to the vagueness with which its type locality was described. The type series was collected by one of the members of the International High Altitude Expedition to Chile (IHAEC) of 1935. Recently, three studies successively claimed to have located the type locality in different places. The third study proved, according to the chronicles of the IHAEC, that the actual locality is Mino, at the origin of the Loa River, where currently there are no published records of Telmatobius. In this study, additional documentary antecedents and graphic material are provided that corroborate that Mino is indeed the type locality of T. halli. Additionally, the recently rediscovered Telmatobius population from Mino and the environment it inhabits are described. The external characteristics of the frogs are consistent with the description of T. halli. Furthermore, molecular phylogenetic analyses were performed that showed that T. halli, T. dankoi, and T. vilamensis, all known only from their type localities in Chile, comprise a clade without internal resolution. A detailed comparison of the diagnoses of the three species revealed that the few phenotypic differences between these taxa were based on characteristics that vary widely within and between populations of the genus, hence their conspecificity is proposed. The implications of this synonymy for the taxonomy, biogeography, and conservation of the Telmatobius from the extreme south of its distribution in Chile are discussed.

Automated summary

Telmatobius halli was rediscovered at its type locality of Mino, originating from the Loa River, in Chile. Phylogenetic analyses revealed that T. halli, T. dankoi, and T. vilamensis form a clade. The few phenotypic differences between these species are proposed to be based on characteristics that vary widely within populations, suggesting their conspecificity.