Protemnodon’s closest living relatives are kangaroos, wallabies and wallaroos and were as large or larger than the living grey kangaroo. It is characterised by its heavy built, short stout feet and relatively flat, elongate skulls, which lack the characteristic downward curve of the snout found in modern kangaroos. The shape of the feet suggests that locomotion must have been quite slow.
Protemnodon hopei was the smallest in the genus, weighing about 45 kg; the largest species, Protemnodon roechus, weighing around 170 kg
Isolated molars and other skeletal elements have been found in the Eulo sites, expanding the range of Protemnodon in the late Pleistocene into South West Queensland.