Phylogenomics of Anguis and Pseudopus (Squamata, Anguidae) indicates Balkan-Apennine mitochondrial capture associated with the Messinian event

A dated phylogenetic hypothesis on the evolutionary history of the extant taxa of the Western Palearctic lizards Anguis and Pseudopus is revised using genome-wide nuclear DNA and mitogenomes. We found overall concor-dance between nuclear and mitochondrial DNA phylogenies, with one significant exception - the Apennine A. veronensis. In mitochondrial DNA, this species forms a common clade with the earliest diverging lineage, the southern Balkan endemic A. cephallonica, while it clusters together with A. fragilis in nuclear DNA. The nuclear phylogeny conforms to the morphology, which is relatively similar between A. veronensis and A. fragilis. The most plausible explanation for the mitonuclear discordance is ancient mitochondrial capture from the Balkan ancestor of A. cephallonica to the Apennine population of the A. fragilis-veronensis ancestor. We hypothesize that this capture occurred only in a geographically restricted population. The dating of this presumed mitochondrial introgression and capture coincides with the Messinian event, when the Balkan and Apennine Peninsulas were presumably largely connected. The dated nuclear phylogenomic reconstruction estimated the divergence of A. cephallonica around 12 Mya, while the sister clade representing the A. fragilis species complex consisting of the sister species A. fragilis-A. veronensis and A. colchica-A. graeca further diversified around 7 Mya. The depth of nuclear divergence among the evolutionary lineages of Pseudopus (0.5-1.2 Mya) supports their subspecies status.

Automated summary

A study revises the dated phylogenetic hypothesis on the evolutionary history of Western Palaeartic lizards using nuclear DNA and mitogenomes, finding overall concordance between the two methods except for A. veronensis. Mitochondrial DNA suggests a common clade between A. veronensis and A. cephallonica, while nuclear DNA clusters A. veronensis with A. fragilis. The discordance is explained by ancient mitochondrial capture in a geographically restricted population during the Messinian event. The study also provides dating estimates for the divergence of different lizard species.