Systematic revision and species diversification of the genus Episoriculus (Mammalia: Eulipotyphla: Soricidae), with descriptions of two new species

Small insectivorous shrews of the genus <i>Episoriculus</i> (Soricidae: Nectogalini) are distributed primarily across the Himalaya-Hengduan Mountains. The taxonomy of the genus has remained unstable because earlier classifications relied mainly on morphology and geographically restricted materials. We conducted extensive field surveys across the region, sequenced two mitochondrial and six nuclear genes, and generated complete mitogenomes for representative operational taxonomic units (OTUs) to evaluate phylogenetic relationships. We also measured five external and 19 craniodental characters to evaluate morphometric variation. The analyses identify two previously unrecognized species, <i>E. gaoligongensis</i> sp. nov. from the Gaoligong Mountains and Medog, and <i>E. damuensis</i> sp. nov. from Medog, southeastern Xizang. Our integrative evidence further supports recognition of eight valid species within <i>Episoriculus</i>: <i>E. caudatus</i>, <i>E. leucops</i>, <i>E. macrurus</i>, <i>E. sacratus</i>, <i>E. soluensis</i>, <i>E. umbrinus</i>, <i>E. gaoligongensis</i> sp. nov., and <i>E. damuensis</i> sp. nov. We treat <i>E. baileyi </i>as a subspecies of <i>E. leucops</i> and clarify morphological delimitation criteria and distribution ranges for these taxa. Divergence-time estimates suggest that major splits within <i>Episoriculus</i> occurred from the Miocene to the Pleistocene, broadly consistent with a history shaped by interacting geological, climatic, ecological, and geographic processes in the Himalaya-Hengduan Mountains. More broadly, our results highlight the importance of integrative taxonomy and caution against relying on short mitochondrial fragments alone when delimiting species in rapidly diversifying montane mammals.