Australia: The Land Where Time Began

A biography of the Australian continent 

Archosauria

Archosaurs are characterised by a specialised structure of the hand and ankle that preceded the type of ankle found all in the upright-walking dinosaurs and 2 openings in the posterior part of the skull, with 1 immediately in front of the orbits (the antorbital fenestra).

Thecodonts

The name of this group refers to the fact that their teeth are set in sockets. This characteristics evolved independently in some other reptile groups. The proterosuchian thecodonts are the most primitive of the thecodonts. The down-turned anterior margin of the premaxilla (upper jaw) is a distinguishing characteristic of the more primitive thecodonts. The upper jaw of Tasmaniosaurus is very distinctive, extending well beyond the lower jaw. Some bone splinters and fragments, and the upper jaw of a small labyrinthodont were found associated with Tasmaniosaurus. It is believed they may have been from its gut contents.

Tasmaniosaurus is thought to have had a more sprawling stance than more advanced thecodonts and to have possibly lived in water like a modern crocodile. It had a long low skull with many sharp, conical teeth.

Some proterosuchians seem to have had a more upright stance that would allow them to breathe while moving, so giving them more stamina.

Kalisuchus rewanensis Lower Triassic Arcadia Formation, the Crater, Queensland

Sources & Further reading

1. Dinosaurs of Australia and New Zealand, John A. Long, UNSW Press, 1998