Assessing biodiversity within the range of Heleobia chimbaensis (Caenogastropoda: Cochliopidae) on the Atacama Desert coast

Abstract

Heleobiais the most specious genus in the family Cochliopidae, in which many species are morphologically similar. Here we used morphological, microstructural and phylogenetic criteria to investigate species delimitation within theHeleobia chimbaensiscomplex on the Atacama Desert coast. The range included subdivided populations of the species, the subspeciesHeleobia chimbaensis conica, and the allopatric snails from Los Perales, first recognized as a population ofH. chimbaensisand more recently considered a candidate species of the group. Traditional shell characters, morphometric analysis, operculum, and protoconch were either uninformative or ambiguous to separate taxa. However, the phylogenetic analysis identifiedH. chimbaensis,H. chimbaensis conicaand four additional populations of the species as a monophyletic group while the population from Los Perales was recovered as a distantly evolutionary significant unit for which the nameHeleobia peralensissp. nov. is provided here. While the geographic isolation and limited dispersal seem to have influenced the diversification and current distribution ofH. chimbaensisin Atacama, the origin ofHeleobia peralensissp. nov. remains unclear because of uncertain relationships. A conservation status assessment according to IUCN criteria and NatureServe methodology suggests that bothH. chimbaensisandHeleobia peralensissp. nov. face a high risk of extinction.