Proper noun.

The main characteristic of Diprotodontia has to do with their teeth. Members of the order Diprotodontia have a large pair of incisors on the lower jaw, while most also have 3 pairs of incisors in the upper jaw. They lack canine teeth, as they do not need them, and there is an empty space where the canines are normally positioned.

Another characteristic unique to the Diprotodontia is the presence of fused second and third digits in their hind feet. The koala shares both of these features with other members of the order Diprotodontia.

A wombat is in the marsupial order Diprotodontia.

The koala's order is Diprotodontia.