Exploring the speciation continuum of slow worms: location and extent of the Anguis fragilis/veronensis hybrid zone in southeastern France

What is it about?

Based on mitochondrial and nuclear genetic barcoding, we accurately delineated the hybrid zone between the slow worms Anguis fragilis and Anguis veronensis along the Rhône and Durance rivers in southeastern France, with evidence for hybridization, yet a relatively steep transition between pure populations. In the light of recent phylogenomic analyses on the genus Anguis, our results tend to support the current species status of A. veronensis, and more generally fit the pattern that hybridizability correlates with genetic and phenotypic divergence, providing insights on to the mechanisms driving species formation. In this respect, the role of the Rhône as a biogeographic barrier appears marginal, despite the river being one of Europe’s biggest.

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