Phylogeny of Acomys spinosissimus (Rodentia, Muridae) from north Malawi and Tanzania: evidence from morphological and molecular analysis

New specimens of Acomys spinosissimus from northern Malawi and southern Tan zania were subjected to morphological, molecular (cytochrome b mitochondria l gene) and cytogenetical analysis in order to establish the phylogenetic p osition of these populations among A. spinosissimus, as well as their relat ionships with other species (A. subspinosus and A. wilsoni). The monophyly of the spinosissimus clade is supported by morphological and molecular phyl ogenies. Cytogenetics and morphology, but not the cytochrome b phylogeny sh ow the possible existence of two sibling species within spinosissimus. Inco ngruences are noted between molecular and morphological trees, especially c oncerning the position of the Transvaal specimens. Two different biogeograp hic scenarios for the origin and dispersal of A. spinosissimus are discusse d in the light of available palaeontological data. (C) 2001 The Linnean Soc iety of London.