Cryptic lineage diversity within Forest Dormice (Mammalia: Dryomys nitedula) revealed by deep genetic divergence among different subspecies on the Iranian Plateau and in adjacent areas

Abstract

Dryomys nitedula has been considered a polytypic species which is distributed in the Palearctic region. Previous studies have shown the taxonomic status and phylogenetic relationships between different subspecies of D. nitedula needs to be further investigated. Here, we applied mitochondrial and nuclear DNA markers to evaluate phylogenetic relationship among geographical subspecies of D. nitedula in Iranian Plateau and adjacent areas and tried to resolve taxonomic issues. Molecular analyses revealed four major clades and several subclades: Kopet Dagh–Zagros clade (A) comprising Kopet Dagh subclade (A1); Zagros subclade (A2); Caucasian clade (B) including Lesser Caucasus and Alborz subclade (B1); central and eastern Great Caucasus subclade (B2); western Great Caucasus and Russian subclade (B3); European–Apennine clade (C) including E Europe subclade (C1); Calabrian subclade (C2), and Eastern Alps subclade (C3), respectively. Finally, occurrence of a lineage with distinct evolutionary history was confirmed in the central Iranian Plateau, clade (D). Our results based on mitochondrial and nuclear DNA obviously support that D. n. pictus (clade D) is a deeply divergent lineage and should be treated as a separate species. Phylogenetic relationships and genetic distances within D. nitedula indicate a complex evolutionary history within the Western Palearctic region, with many local populations indicated having been isolated since at least Pleistocene, and suggest that treating D. nitedula complex as several species is warranted.