Dinosaurs, reptiles and primitive mammals were present in Australia.

Thus, it seems to have preyed on this primitive mammal, possibly on a regular basis.

Relative to other primitive mammals, it is small.

This form of double (erect/sprawling) gait is also found in some primitive mammals alive today.

The primitive mammals gained a new advantage by developing reproductive mechanisms that offered increased protection to the young.

Tritheledontids or their closest relatives may have given rise to primitive mammals.

In primitive placental mammals there are four premolars per quadrant.

Reduced number of teeth compared to primitive mammals;.

It seems likely that some primitive mammals also were part of the original cargo.

Ptilodontidae is a family of primitive mammals within the extinct order Multituberculata.