KREFFT'S TORTOISE Emydura krefftii (Gray, 1871)
This 25 cm tortoise is found throughout Queensland.
Some specimens have distinct yellow markings on the head, whilst on others these are absent. It is essentially a river dwelling species.
On Fraser Island (Queensland), this species is extremely common in sandy lagoons. Specimens here do not attain the same adult size as mainland tortoises. Research shows this is due to changed environmental conditions on the island and the restricted gene pool adapting to local conditions without outside interference.
This species lays eggs in spring, which subsequently hatch in summer. The 2.5 cm hatchlings emerge some 80 days after laying. In the past this species was used by Queensland aboriginals as a major source of food.

The above was from the book Australian Reptiles and Frogs by Raymond Hoser and now available on a fantastic CD-Rom along with a vast amount of other information, papers and the like on reptiles, frogs and other wildlife.