Australia: The Land Where Time Began

A biography of the Australian continent 

Jurassic Plesiosaurs of Australia

Plesiosaurs (Plesiosauria) were long-necked marine reptiles from the Mesozoic that had box-like bodies and 4 flippers for propulsion. There were 2 functional body types, a small-headed form with a long neck, plesiosauromorphs, and large-headed, short-necked pliosauromorphs. Plesiosaur fossils have rarely been found in Australia in Jurassic deposits, though in the Jurassic and Cretaceous they were distributed around the world. The Razorback Beds near Mt. Morgan, Queensland have produced among the oldest known remains of a small pliosaurimorph in the lowest Jurassic strata at this site, though it is fragmentary. The vertebral morphology of this specimen is somewhat similar to that of species such as Bishanpliosaurus youngi, a primitive non-marine rhomaleosaurid pliosaurimorph. Its definitive relationships are unclear, as the specimen from Mt. Morgan is still to be described.

The Evergreen Formation near Wandoan, southeast Queensland has produced 2 fossil plesiosaurs that were extremely fragmentary. In the Colalura Sandstone, Middle Jurassic (Middle Bajocian) of Bringo railway cutting near Geraldton, Western Australia, a number of isolated vertebrae and a finger bone of a plesiosaur were found. Among these specimens was what is believed to probable be a dorsal vertebra of an elasmosaurid, that would make it the earliest known specimen of this group found in Australia.

Sources & Further reading

1. Kear, B.P. & Hamilton-Bruce, R.J., 2011, Dinosaurs in Australia, Mesozoic life from the southern continent, CSIRO Publishing.