A member of the Saint Bathans fauna, it is notable for being a late-surviving "archaic" mammal species, neither a placental nor a marsupial.
The femur possesses a round head and poorly defined neck, oriented slightly dorsomedially with respect to the long axis of the shaft, and separated from the greater trochanter by a marked trough.
The alignment of the femur in life is hard to ascertain, but it is thought that the animal had a semi-sprawling stance, more abducted than in therian mammals but nowhere near as much as in monotremes.
Worthy et al. 2006 tentatively deemed the Saint Bathans mammal as a theriiform, being more derived than morganucodontans, eutriconodonts and monotremes but not as much as multituberculates, on the basis of its femoral anatomy.
[2] However, unlike modern New Zealand it also had a varied herpetofauna: besides an early tuatara, the Saint Bathans fauna also includes meiolaniid and pleurodire turtles and possibly mekosuchine crocodylids and snakes.