This mammal is generally believed to have been small and brown, and had a bushy tail. The researchers liken it to another early primate, Dryomomys, for which more fossil material is available. Based on that and the newly found bones, Purgatorius weighed about 1.3 ounces, making it roughly the size of the smallest living primates: the mouse lemurs of Madagascar.
The mammal had a lot of teeth, including relatively low-crowned molars, which were specialized for eating fruit, although it probably ate other things too.
Tree living served this and other primates well, such that all but a few existing species remain at least partly arboreal. Humans are part of the rare exceptions, since our more recent ancestors left the trees some 60 million years after Purgatorius' lifetime.
John Fleagle, a professor in the Department of Anatomical Sciences at Stony Brook University, told Discovery News that "arboreality in Purgatorius is no great surprise," given that early other mammals, such as flying lemurs and tree shrews, had hand proportions suitable for tree navigation.