A new species of Crocidura is described from the Ke Go Nature Reserve in Ha Tinh Province, Vietnam. Its small body size and conspicuous brownish black mystacial patches on the muzzle above the upper lips readily distinguish it from the three species of Crocidura commonly reported from Vietnam: C. fuliginosa, C. attenuata and C. indochinensis (formerly C. horsfieldii indochinensis). In body size, the Ke Go shrew most closely resembles another crocidurine, C. wuchihensis, which was originally described as a subspecies of C. horsfieldii from Hainan Island, China, but has recently been identified as a separate species also occurring in Vietnam. The new species can be separated from C. wuchihensis by its smaller body size, certain shorter cranial and dental dimensions (condylo-basal and braincase lengths, incisor to third unicuspid length, upper toothrow length) and deeply emarginate posterior border of the last premolar and each molar. Known only from the holotype, the discovery of the new Crocidura underscores our meager knowledge of Vietnamese Soricomorpha diversity and the need for continued surveys of small mammals in remnant lowland and mountain forests within the country.
2004 The Mammalogical Society of Japan