The white-tailed rat (Mystromys albicaudatus) also known as the white-tailed mouse, is the only member of the subfamily Mystromyinae in the family Nesomyidae. This species is sometimes placed in the subfamily Cricetinae due to similarities in appearance between the white-tailed rat and hamsters, but molecular phylogenetic studies have confirmed that the two groups are not closely related. The subfamily Mystromyinae is sometimes placed within the family Muridae along with all other subfamilies of muroids.