Morphometric evidence of the monotypic status of the african long-nosed mongoose Xenogale naso (Carnivora, Herpestidae).

Xenogale naso has a discontinuous distribution between three nominal subspecies: X. n. naso, X. n. almodovari and X. n. microdon. Examination of extant specimens shows that X. naso occurs throughout forested areas of Central Africa, including the `'South Central'' faunal region. A morphometric analysis of 122 skulls, indicates that the three nominal subspecies cannot be distinguished cranially, nor any specimens originating from the `'South Central'' region. X. naso should be regarded as a monotypic species and evolved in an area close to the three faunal regions, `'West Central'' (WC), `'South Central'' (SC), and `'East Central'' (EC). We believe it dispersed in a centrifugal manner. Indeed, if X. naso had originated from isolated peripheral refuges in mountain areas, centripetal dispersal would have favoured subspeciation in other faunal regions. These data support the theory that, during the dry climatic period of the Late Pleistocene, the lowland forests of the Central Zaire Basin constituted areas of refuge.