Abstract

Rattus assimilis, R, greyii, and R. fuscipes of southern Australia interbreed readily in captivity with no reduction in viability of either the parental or the hybrid generation. Their present-day allopatry is presumably of recent origin, and the persistence of close genetic affinity, as reflected in their morphology, behaviour, ecology, and reproductive mechanisms, justifies their conspecific status as members of the single species Rattus fuscipes (Mus fuscipes Waterhouse, 1839). Rattus lutreolus is clearly a species distinct from R. fuscipes.