Fragmentary fossil record

Australian dinosaurs are known mostly from fragmentary fossils, although these show that Australia had a unique and diverse range of dinosaurs.

Most Australian dinosaurs come from the eastern half of Australia (Queensland, New South Wales and Victoria) although isolated dinosaur bones have been found in Western Australia and South Australia.

New discoveries of relatively complete dinosaurs from Queensland are now putting Australia on the global dinosaur map and opening up a ‘new frontier’ for dinosaur research.

At the beginning of the Mesozoic, Gondwana formed the southern part of the single continent Pangaea. When Pangaea split about 200 million years ago, Gondwana began its own isolated journey and gradual break-up into the landmasses we know today – Australia, South America, Africa, India, Madagascar, Antarctica and New Zealand. This palaeo-history is recorded in identical rocks and fossils found across these modern landmasses. When we reconnect them as they were in the past, the rocks and fossils clearly match up.

Australian dinosaurs lived ‘on the edge’ at the far eastern end of East Gondwana, which at the time lay well to the south of Australia’s present position.

While the global climate was warm and humid during the Cretaceous, Australia position so far south at the time meant that it experienced much cooler temperatures. One form of evidence we have for cool temperatures in Australia at the time comes from the presence of glendonites, Glendonites resemble spiky balls of rock. Originally they were formed by the mineral ikaite, which only occurs in near-freezing temperatures. However, later this ikaite was replaced by other minerals as the rock was buried and heated over time. Many parts of Australia would have also experienced the extremes of daylight found in high latitudes today. Much of central Australia was submerged under a shallow inland (‘epicontinental’) sea, leaving the higher areas as large but isolated islands for much of the Cretaceous. This unusual habitat along with Australia’s geographic isolation during the latter part of the Mesozoic meant that many of Australia’s dinosaurs evolved as unique species adapted to extreme conditions.

gondwana fossil map

Map of Gondwana, showing break-up into modern landmasses and the distribution of key fossils across these landmasses.

Image: illustration
© Australian Museum

Recently, the Australian dinosaur record has taken a substantial leap forward. The back-breaking effort put into searching for new dinosaur species is producing spectacular results, and two new dinosaurs - the ornithopods Weewarrasaurus and Fostoria. have just been described from the opal deposits of Lightning Ridge, NSW. Revisions are also underway on other Australian dinosaurs.

Deposits at Lightning Ridge yield some of the rarest, most beautiful and precious fossils in the world.

Dinosaur bones from Lightning Ridge in New South Wales have been uniquely preserved in opal, generally as casts of the original bone.

Read more about Lightning Ridge fossils

Trackways - the preserved footprints of dinosaurs and other species - can help fill the gaps in the fossil record when body fossils are rare.

Theropod footprints from the Late Triassic to Middle Jurassic are known from Queensland, evidence that early theropods were present in Australia shortly after dinosaurs first appeared in the late Middle Triassic. Theropod footprints are also known from the Early to mid-Cretaceous of Queensland. These include the prints of theropod ichnospecies (species based on trace fossils) Skartopus and Tyrannosauropus from the Lark Quarry ‘dinosaur stampede’ site near Winton.

Learn more about Australia's theropod dinosaur fossil record.

Discover more about Australia Dinosaurs

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