We perform a phylogenetic analysis to test the affinities of 'Dorcatherium' from Arrisdrift (early middle Miocene, Sperrgebiet, Namibia). Our results show Arrisdrift 'Dorcatherium' included in a clade of Miocene African forms that also contains 'D.' pigotti and 'D.' iririensis. This clade is not related to the true Dorcatherium-clade which includes the type species D. naui. Although we are not taking taxonomic decisions at the genus level until more data are used in future analyses, it is clear that the Arrisdrift form is a distinct new species that we name 'Dorcatherium' namaquensis. Keywords: Ruminants, Basal Middle Miocene, Namibia, Sperrgebiet, Evolution, Phylogeny.