Hidden diversity in spring snails from the andean altiplano, the second highest plateau on earth, and the Atacama Desert, the driest place in the world

Abstract

Background: The Chilean Altiplano and the Atacama Desert in northern Chile harbor isolated hydrological systems or oases where it is possible to find minute aquatic snails of the genus Heleobia whose taxonomy is uncertain and where many populations remain unknown. Here, we obtained samples from 30 localities distributed in the region and used molecular (12S and 16S mitochondrial genes) and morphological (penis) characters to investigate diversity of this poorly known fauna. Results: Molecular phylogenetic analysis consistently recovered five clades, one of which constitutes a cryptic species previously assigned to a species recognized in the area. Four other clades contained sequences of one nominal species consistent with its type locality and at least two additional candidate species, which were corroborated by a particular penis morphology. Furthermore, some morphological differences in penis morphology were observed in two Altiplano populations not resolved by the DNA sequences, providing support for two additional candidate species in the genus. A molecular clock analysis allowed tracing the origin of lineages back to the Early Pleistocene. Conclusions: We found support for recognizing four nominal species, one undescribed species and at least other four candidate species of the genus Heleobia in northern Chile. We also suggest that the current level of species diversity of Heleobia in the region is underestimated by the use of conchological criteria to recognize species and by the limited sampling conducted to date. © 2013 Collado et al.; licensee Springer.