A chromosomal and integrative taxonomic revision of Anatolian blind mole rats (Nannospalax): Elevating cytotypes to species

Abstract Chromosomal evolution is a principal mechanism of speciation in subterranean mammals, particularly blind mole rats ( Nannospalax ). Extensive cytogenetic research across Anatolia has revealed striking karyotypic variation, yet its evolutionary and taxonomic significance remains incompletely resolved. Here, we synthesize cytogenetic, molecular, morphological, and behavioral evidence to evaluate how chromosomal change structures lineage diversification. Robertsonian rearrangements, pericentric inversions, and centromeric shifts emerge as primary drivers of reproductive isolation, frequently in the absence of overt morphological differentiation. Complementary evidence from seismic communication and baculum morphology further supports the interpretation of cytotypes as reproductively and evolutionarily cohesive units. Within this integrative framework, we revise species limits in the Nannospalax complex and describe 17 new species: N. gazii sp. nov., N. karatasi sp. nov., N. abiissent sp. nov., N. occidentalis sp. nov., N. tenebrosus sp. nov., N. mursalogluae sp. nov., N. flavus sp. nov., N. eflani sp. nov., N. kemali sp. nov., N. medialis sp. nov., N. inspirata sp. nov., N. guleki sp. nov., N. victoriosus sp. nov., N. kastamonuensis sp. nov., N. montanus sp. nov., N. artus sp. nov., and N. irenaeus sp. nov. We further show that geographic isolation, ecological divergence, and interacting pre- and postzygotic barriers can accelerate diversification within Anatolia, a recognized hotspot for spalacine evolution. By reconciling signals across datasets, our synthesis supports a “cytotype-equals-species” framework as a parsimonious working model for Nannospalax diversification and clarifies long-standing taxonomic ambiguities within Anatolian lineages. We also outline testable predictions for future genome-scale and bioacoustic analyses, including expectations for contact-zone dynamics, hybrid fitness, and the genomic distribution of rearrangement breakpoints. More broadly, this revision advances understanding of cryptic speciation in fossorial mammals and provides an evidence-based rationale for conservation prioritization in subterranean biodiversity hotspots across Eurasia.