Taxonomic revision of the Long-tailed Mole (Talpidae: <i>Scaptonyx</i>) with description of a new species from the Gaoligong Mountains

<i>Scaptonyx fusicauda</i> Milne-Edwards, 1872, is a mole species and a burrowing animal occurring from central China to northeastern Myanmar and northern Vietnam. This is the only extant species currently known in the genus <i>Scaptonyx</i> (Talpidae), but recent studies have revealed highly diverse lineages within this taxon. However, the broken type specimen and unspecified type locality of this species have hindered comparison between specimens towards a taxonomic evaluation. We reviewed the literature documenting the expeditions of the collector Armand David and narrowed down the type locality of this species to Minshan Mountain, western Sichuan, China. We compared <i>S. fusicauda</i> topotypes with specimens from 2 separated mountain ranges in western Yunnan, China-<i>S. f. affinis</i> Thomas, 1912 from the Baima Mountain and an undescribed species (<i>S.</i> sp. 1) from the Gaoligong Mountains. Specimens from the 3 localities can be distinguished by multiple external, craniomandibular, and dental characteristics. Phylogenies based on mitochondrial and nuclear genes also provided consistent topologies supporting <i>S. fusicauda</i>, <i>S. f. affinis,</i> and <i>S.</i> sp. 1 as distinct monophyletic species. <i>Scaptonyx</i> sp. 1 split from the sister clade (<i>S. fusicauda</i> + <i>S. f. affinis</i>) ca. 19.79 Ma, while <i>S. f. affinis</i> split from <i>S. fusicauda</i> ca. 9.56 Ma. Following these findings, we recognize <i>S. f. affinis</i> as a distinct species, <i>S. affinis</i>, and describe <i>S.</i> sp. 1 as a new species<i>. Scaptonyx fusicauda</i> occurs in the Sichuan Basin to the west, <i>S. affinis</i> from the mountains in the east of the Salween River to central China and northern Vietnam, and <i>S.</i> sp. 1 in the Gaoligong Mountains on the watersheds of the Irrawaddy and Salween rivers-encompassing western Yunnan, China, and northeastern Myanmar.