Phylogeography of Terricola Voles in the Caucasus and Eastern Anatolia, with a New Southernmost Record of Microtus daghestanicus (Rodentia, Cricetidae, Arvicolinae)

Abstract

Microtus daghestanicus (Shidlovskiy, 1919), one of the least studied members of the subgenus Terricola “subterraneus" species group, remains poorly understood with respect to its phylogeography and genetic structure. Here, we reevaluated its evolutionary relationships, genetic diversity and distribution of the species using mitochondrial cytb sequences (71 haplotypes of 77 samples) together with new field records from Türkiye. Maximum-likelihood and Bayesian analyses produced nearly similar topologies and separated three well-defined lineages corresponding to M. daghestanicus, M. fingeri (Neuhäuser, 1936), and M. subterraneus (Sélys, 1836). Two mitochondrial lineages were identified within M. daghestanicus: a Caucasian lineage (Russia–Georgia) and an Anatolian lineage including Ardahan, Artvin, Kars, and a newly recorded population from Hakkari. The Hakkari record represents the first verified occurrence of the species in southern part of Eastern Anatolia and marks the southern limit of the species’ known range, extending the known distribution and highlighting the Anatolia–Caucasus phylogeographic separation. Pairwise K2P distances and F_st values indicated pronounced genetic differentiation among taxa, whereas neutrality tests showed no significant deviations from mutation–drift equilibrium. Generally, observed genetic structure is consistent with long-term geographic isolation across the Pontic–Caucasian region. Our results provide a foundation for understanding the taxonomy and distribution of M. daghestanicus.