Population genomic analyses reveal hybridization and marked differences in genetic structure and demographic history of Scurria limpet sister species with parapatric distributions across the southeastern pacific

The study of sister species that occur in parapatry around biogeographic transition zones can help understand the evolutionary processes that underlie the changes in species composition across biogeographic transition zones. The South Eastern Pacific (SEP) coast is a highly productive coastal system that exhibits a broad biogeographic transition zone around 30–35ºS. Here, we present a comparative genome-wide analysis of the sister species Scurria viridula and Scurria zebrina, that occur in parapatry and whose poleward and equatorward range edges intersect in the 30–35ºS SEP biogeographic transition zone. We sampled 118 specimens sourced from nine sites from Tocopilla (22ºS) to Chiloé (41ºS) including one site where both species overlap and analyzed over 8,000 biallelic single nucleotide polymorphisms. We found evidence of hybridization between these species in the contact zone and found significant but contrasting population structures for both species. Our results indicate that the gen..., ,