Dinosaurs were dominant for approximately 185 million years during the Mesozoic era which contained three geological periods the Triassic, Jurassic and Cretaceous.
When dinosaurs roamed, the Earth's geography was different. In the Jurassic Period (208-144 million years ago) the super-continent Pangaea began to stretch and rift, ultimately breaking into two huge continents separated by the Tethys Sea. The northern continent was called Laurasia and the southern continent was called Gondwana.
Gondwana eventually split into Antarctica, Africa, Arabian Peninsula, Madagascar, Australia, New Zealand, South America and the Indian subcontinent. Australia and Tasmania split from Antarctica 45 million years ago. During the age of dinosaurs Australia was far closer to the Antarctic, small dinosaurs with large eyes evolved to survive the cold and low light of long, freezing and dark winters. Dinosaurs and other animals were able to migrate from Australia to other continents.
Recent discoveries in Australia are providing surprising evidence of a diverse dinosaur population. In Victoria a fossilised hip bone of a T Rex ancestor was the first tyrannosaur to be found in the southern hemisphere and indicates that tyrannosaurus may have been far more widely distributed than was previously believed.
In Queensland a number of different dinosaur fossils have been discovered – they include sauropods (long necked plant eaters), theropods (meat eaters), anklyosaurus (armoured dinosaurs) and ornithopods (plant eaters).
In western Queensland rich fossil fields are yielding the remains of some of the world's largest dinosaurs, titanosaurus, huge plant eaters which may have been 30 metres in length. Lark Quarry near Winton is the site of the world's only record of a dinosaur stampede. A herd of small dinosaurs, ornithopods and coelurosaurs, wandering along the banks of a waterhole were cornered by a large carnivore, a theropod, which charged at them, sending them fleeing past their attacker in panicked attempt to escape. Their footprints which would usually have washed away were preserved by a covering of mud. The dinosaur tracks not only provide a snapshot of individual creatures' desperate struggle for survival millions of years ago, they also provided the opportunity to use modern technology to determine dinosaur dynamic behaviour and movement.
The dinosaurs were not alone; they eventually shared the land with reptiles, some mammals, flying reptiles and birds. A great inland sea which stretched from South Australia into northern NSW and southern and central Queensland was inhabited by marine reptiles including giant turtles, ichthyosaurs or "fish lizards", plesiosaurs and pliosaurs.
It is difficult to imagine that these arid areas of western Queensland were once forested with conifers, gingko, cycads and ferns surrounding inland seas, waterholes and swamps that supported a thriving population of dinosaurs and other creatures.