Name: Osete CC

Biodeserts supervisor: Santos X

Co-supervisor: Pascual M

Title: Uncovering the phylogeography of the habitat-specialist land snail Xerocrassa montserratensis

Institution: University of Barcelona

Status: Completed

Abstract

Species with high habitat specialization and potential low dispersal abilities are expected to have high genetic structure. Xerocrassa montserratensis is an endangered land snail endemic of Catalonia (Spain). Its distribution is highly fragmented and restricted to xerophilous stony slopes of conglomerate ground with little vegetation. In this scenario, we hypothesize that the species will present a high genetic differentiation among its populations due to the long distances, for a species with low mobility, among its suitable habitat areas. To examine this hypothesis, a total of 152 individuals from eight populations, covering the whole range of the species, were sampled. We sequenced the mitochondrial gene Cytochrome Oxidase I (COI) to uncover the genetic relationship among X. montserratensis populations. The haplotype tree identified four genetic groups partially coincident with its geographical distribution. The central group contains shared haplotypes among different populations and seems to be the ancestral one, whereas the remaining three groups are each one restricted to a single locality (Els Munts, Montcau and Sant Jeroni). Els Munts is the most geographically and genetically isolated locality and its genetic differentiation may correspond to a long range expansion and posterior isolation. However, the geographic distance not always explains the genetic differentiation: Montcau is not geographically isolated from the central group although it is highly genetically differentiated probably due to a historical fragmentation and posterior secondary contact; and Marina, despite being separated from the central localities, shares haplotypes with them, suggesting passive large dispersal through the streams. Our study uncovers a complex phylogeographic scenario that can be explained by geomorphological dynamics and unexpected dispersal ability. Moreover this study also helps understanding the taxonomic status of the three subspecies previously described: X. m. montserratensis, X. m. delicatula and X. m. betulonensis. These results can be useful for the application of conservation programs of endangered species such as X. montserratensis.