The word "wallaroo" is a portmanteau of "wallaby" and "kangaroo".
Australians tend to call the larger wallaroos a Kangaroo and the smaller ones a wallaby and so they are less know due to not being recognised as a separate species.
The common wallaroo (Macropus robustus or wallaroo) is the best-known species and it has four subspecies.
of the common wallaroo: the eastern wallaroo and the euro, which are both widespread, and two of more restricted range, one from Barrow Island, the other from the Kimberley.
The black wallaroo (Macropus bernardus) occupies an area of steep, rocky ground in Arnhem Land. At around 60 to 70 cm in length (excluding tail) it is the smallest wallaroo and the most heavily built. Males weigh 19 to 22 kg, females about 13 kg. Because it is very wary and is found only in a small area of remote and very rugged country, it is little known.
Macropus antilopinus is the exception among wallaroos. It is, essentially, the far-northern equivalent of the eastern and western grey kangaroos. Like them, it is a creature of the grassy plains and woodlands, and gregarious, where the other wallaroos are solitary. I frequently see these when I travel north as they come close to camping grounds and truck stops. It is sometimes called the antilopine kangaroo.