A Malayan view of Rattus edwardsi and R. sabanus (Rodentia: Muridae)

Abstract

Rattus edwardsi ciliatus (Bonhote) and R. sabanus vociferans (Miller) are two large rats occurring in Malayan mainland forests. The allopatric taxa edwardsi and sabanus have proved difficult to distinguish by morphological characters, including external appearance and skeletal anatomy. Their taxonomic status has in fact been questioned. The Malayan mainland forms R. edwardsi ciliatus (Bonhote) and R. sabanus vociferans (Miller) can generally be separated by body and tail coloration. Their body and skull dimensions, however, overlap considerably. Ecological data indicate that these rats exhibit habitat exclusion. Breeding and behaviour studies support this view. Karyotype and serological studies provide conclusive evidence for the distinctness as well as the close affinity of these two species.