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

<i>Heleobia</i> is 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 the <i>Heleobia chimbaensis</i> complex on the Atacama Desert coast. The range included subdivided populations of the species, the subspecies <i>Heleobia chimbaensis conica</i>, and the allopatric snails from Los Perales, first recognized as a population of <i>H. chimbaensis</i> and 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 identified <i>H. chimbaensis</i>, <i>H. chimbaensis conica</i> and 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 name <i>Heleobia peralensis</i> sp. nov. is provided here. While the geographic isolation and limited dispersal seem to have influenced the diversification and current distribution of <i>H. chimbaensis</i> in Atacama, the origin of <i>Heleobia peralensis</i> sp. nov. remains unclear because of uncertain relationships. A conservation status assessment according to IUCN criteria and NatureServe methodology suggests that both <i>H. chimbaensis</i> and <i>Heleobia peralensis</i> sp. nov. face a high risk of extinction. http://www.zoobank.org:pub:91770DA4-B16F-46AD-A6D6-9638065ED899