The enigma of the Oltenia blind mole-rat ( Spalax istricus ) within the collapsing steppe biome

The Oltenia blind mole-rat Spalax istricus is a poorly known and potentially extinct European rodent, and substantial additions are still required to understand its status. We review the available evidence on the species, provide the first nucleotide sequence data, and report results of extensive field surveys conducted in 2024–2025. Only seven museum vouchers of S. istricus are known, collected between 1901 and 1983 from four counties in Romania and deposited in four museum collections. From two of these, collected in 1982–1983, we successfully reconstructed 1,122 bp cytochrome b (cytb) sequences. Phylogenetic analysis including all seven currently recognized species of Spalax recovered S. istricus as sister group to S. antiquus , with Spalax graecus holding sister position with respect to this clade. The Kimura 2-parameter (K2P) distance between S. istricus and S. antiquus (∼0.03) is among the lowest interspecific divergences reported in the genus, supporting treatment of S. istricus as a subspecies of S. antiquus . Field surveys covering 211 sites across Oltenia failed to confirm the species’ presence. Given the cryptic ecology of mole-rats and their potential to persist undetected, we refrain from drawing firm conclusions regarding the current conservation status of Spalax antiquus istricus .