Morphometric Differentiation among West African Populations of the Rodent Genus Dasymys (Muroidea, Murinae), and its Taxonomic Implications

Abstract

Craniodental variation among West African samples of Dasymys is reassessed based on the larger museum series now available. Two morphological kinds can be discerned in this region and are referable to the locally available epithets Dasymys rufulus Miller (1900), described from Mount Coffee, Liberia, and Dasymys foxi Thomas (1912), named from Panyam, Nigeria. The degree of craniodental differentiation between these two phena matches that documented for other congeneric pairs of murid rodent species inhabiting parts of West Africa. Dasymys rufulus differs from D. foxi by its overall smaller size, especially as observed in its smaller, narrower cranium and less robust molars. In West Africa, samples of D. rufulus are broadly distributed from east of the Niger River, Nigeria, west to northern Sierra Leone; whereas, the known examples of D. foxi are restricted to the Jos Plateau in Nigeria. Dasymys rufulus and D. foxi are provisionally accorded specific status until taxonomic studies of Dasymys populations from other parts of Africa are undertaken to determine their relationships and distributional limits. It is doubtful that either form, but especially D. rufulus, is synonymous with D. nudipes or D. incomtus.