More than one species of the naked mole-rat, a new biomedical model.

The naked mole-rat Heterocephalus, a hairless, subterranean rodent from the Horn of Africa, has attracted scientific interest due to its cooperative breeding, poikilothermy, longevity, resistance to cancer, and tolerance to pain and hypoxia, among others. Genomic analyses of H. glaber, traditionally considered a single species, reveal three highly divergent lineages. One of these, identified as H. phillipsi Thomas 1885, shows deep genetic divergence (~4.1 Ma) and distinct morphology, notably reduced third molars, warranting recognition as a distinct species. The remaining two lineages, previously designated as the subspecies H. g. glaber Rüppell 1842 and H. g. ansorgei Thomas 1903, diverged around 2.3 Ma and their morphological differentiation is less pronounced. Each of the lineages occupies distinct environmental conditions, with H. phillipsi inhabiting extremely harsh habitats. The finding of an unexpected diversity within this key biomedical model opens new avenues across various fields of research.