Name extinct species and modern relative:
Distinct Specie: Diprodoton optatum
Modern Relative: (the common wombat )Vombatus ursinus
Morphology difference:
The Diprodoton was around the same size of the modern day rhinoceros, where as the common day wombat is significantly smaller in size, closer to the size of a soccer ball.
The limbs of the modern wombat are significantly shorter in proportion than the pillar-like limbs of the Diprotondon.
Unlike the modern day wombat, Diprotondons had large footpads.
The diprotodons also had a much larger skull in proportion to its body size.
Evolutionary relationship
Diprotodontid fossils dates back 25 million years ago to the late Oligocene period. These animals were about the size of a sheep and were mostly likely descened from the wynyardiids. The subfamily Diprotodontinae, including Diprotodon optatum, are a Pliocene-Pleistocene group. Diprotodon may have evolved from the Pliocene diprotodontine Euryzygoma during the late Pliocene. It has been discovered by Price in 2008 that there is only one specie of Diprotodon, the Diprotodon optatum. As the climate changed in the Pleistocene Period, it is believed that a group of the Diprotodons, through many generations, evolved into a smaller body size to adapt to the harsher climate and a scarcer food source, these were the ancestors of the modern wombat and koalas.
Abiotic influence
It is not clear what allowed the Diproton to become extinct. Fossil record suggests that it co-existed with Aboriginal people for over 20,000 years, therefore it is reasonable to suggest that human activity may have had an effect, either through change in its habitat through firestick farming by the Aboriginal people or perhaps via a slow decrease in population through selected hunting of young Diprotodons. It is most unlikely that Aboriginal people targeted adult Diprotodon as they did not have the weaponry to achieve that.