Demographic structure and genetic diversity of Mauremys leprosa in its northern range reveal new populations and a mixed origin

Abstract

Freshwater turtle species are still poorly understood, and many species are in decline due to unsustainable trade as well as human alteration and degradation of freshwater ecosystems. Mauremys leprosa is a freshwater chelonian endemic to the Mediterranean Basin. Whereas the fossil record demonstrates that this species used to be distributed to well beyond the Spanish border in France, it is today restricted to the border region with Spain, at the Baillaury River in the Pyrenees, with some isolated observations from slightly farther into France. The species consequently holds an “Endangered” status according to the French IUCN Red list. Here we report for the first time the presence and demographic structure in its northern range and demonstrate that its distribution expands beyond the Pyrenees Mountains, throughout French Catalonia. Sequence analyses of the mitochondrial DNA (mtDNA) cytochrome b (cyt b) gene from 216 specimens mainly from France and Spanish Catalonia resulted in a patchwork pattern of haplotypes that supports a mixed origin of the species in France. We encountered two extreme haplotypes, with specimens with the endemic Spanish Catalonian haplotype A18 belonging to M. leprosa leprosa and others being clearly referable to M. leprosa saharica (cyt b haplotypes from clade B) that is otherwise typical from below the Atlas Mountain Range in Morocco. Short- and long-term directions for research as well as conservation management actions are suggested for this insufficiently studied species