Dinosaurs

Overview

Dinosaurs are the rockstars of the fossil record. Their spectacular scale and variety make them eternally popular with museum visitors. There is, however, much more to them than just the bones on exhibit. Dinosaurs are a window to a world vastly different to our own, with major implications for how we understand our changing planet.

The ‘age of dinosaurs’ is technically called the Mesozoic era, and is divided into three periods: the Triassic, Jurassic and Cretaceous.

Dinosaurs evolved during the Triassic period (251.9-201.3 million years ago), when the landmasses of the world were joined as one super-continent called Pangaea. After a mass extinction at the end of the Triassic wiped out most other large land animals, the dinosaurs went on to diversify and dominate during the next time period: the Jurassic (201.3-145 million years ago). After the Jurassic came the Cretaceous period (145-66 million years ago), which saw the evolution of some of the most famous dinosaurs, such as Tyrannosaurus and Triceratops. Most dinosaur fossils from Queensland are from the Cretaceous period. By this time Pangaea had broken in two, and Australia was part of a fragmenting southern supercontinent called Gondwana. Because of this, dinosaurs from Australia tend to be related to those from other lands that were also part of Gondwana, such as Antarctica, India, and South America. The Cretaceous period ended with another major mass extinction, which ended the reign of the dinosaurs. One group of dinosaurs survived, however, and are still among us today. They are birds.

Scientific study

Palaeontology is the study of the animals and plants that lived in the distant past. Fossils of vertebrate animals are predominantly bones, but can also include footprints, bite marks, and coprolites (fossilised dung).

Images

Collection highlights

Queensland has Australia’s most extensive outcrops of Mesozoic-aged sedimentary rocks. This means that Queenslanders have an above-average chance of finding dinosaur fossils. Indeed, the majority of the dinosaurs in Queensland Museum’s collection were found by curious members of the public, rather than professional palaeontologists.

Dinosaur fossils from Queensland include many Australian record-holders, such as the oldest, largest, and most complete. Here are some highlights from Queensland Museum’s Mesozoic collection:

Dinosaur footprints
One of Australia’s most famous fossil sites is the dinosaur trackways at Lark Quarry, near Winton in central Queensland. Queensland Museum has both original tracks removed from the site during excavation, and replicas of the trackways. The original trackway can be seen at the Dinosaur Stampede National Monument at Winton. Additionally, the museum has similar material from nearby Seymor Quarry. Footprints are actually the only evidence that we have of the presence of dinosaurs in Queensland at certain times. Fossil footprints from Ipswich are the only evidence of dinosaurs in the Triassic of Australia, while trackways found in multiple mines in central and south-east Queensland are the only evidence of theropod and ornithopod dinosaurs in the Jurassic of Queensland. In many cases the original footprints could not be removed, so the museum has casts of these tracks.

Muttaburrasaurus
Possibly the most popularly-known Australian dinosaur, casts of the skeleton of Muttaburrasaurus langdoni can be seen in museums around the country. Muttaburrasaurus is an ornithopod, a group of plant-eating dinosaurs that flourished during the Cretaceous, producing famous species such as Iguanodon and Parasaurolophus. The bones of Muttaburrasaurus were found in rocks that formed on the bottom of an inland sea; it’s thought that the carcass of Muttaburrasaurus washed out to sea before sinking and being buried in the mud.

Sauropods
Sauropods are long-necked herbivores that include the largest land animals of all time. Queensland has a wealth of sauropod fossils; two notable specimens in Queensland Museum’s collection are Rhoetosaurus brownei and Wintonotitan wattsi. Rhoetosaurus is Australia’s most complete dinosaur from the Jurassic period. Wintonotitan is one of several sauropods from the Cretaceous-aged rocks of the Winton district of central Queensland.

In the shadow of the dinosaurs
Dinosaurs weren’t the only animals alive during the Mesozoic. Giant amphibians called ‘temnospondyls’ inhabited Queensland’s waterways during the Jurassic period. Two species are known: Siderops kehli and Austropelor wadleyi. At the time of their discovery, they were the only evidence that temnospondyls had survived the major mass extinction event at the end of the Triassic.

Temnospondyls are much more common in Triassic-aged rocks in central Queensland, where they greatly outnumber all other tetrapods (vertebrates with four limbs). Alongside these amphibians are reptiles and distant relatives of mammals: the lepidosauromorph Kudnu mackinlayi, the procolophonid Eomurruna yurrgensis, the archosaur-relatives Kadimakara australiensis and Kalisuchus rewanensis, an unnamed dicynodont, and a possible cynodont. The dominance of temnospondyls in the Triassic of Australia is something of an anomaly when compared to the rest of the world, where reptiles related to crocodiles were more common. In Australia these are rare, and crocodile relatives seem to have not become a major part of freshwater ecosystems until the Cretaceous.

Mesozoic crocodile relatives are better known from the Cretaceous, with the spectacular skeleton of the small crocodylomorph Isisfordia duncani from the Winton Formation. By this time, the temnospondyls were extinct, with crocodiles taking their place as the major predators in freshwater habitats until the present day.

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Research overview

Queensland Museum has been a centre for research on Australian dinosaurs since the 1920s, with the excavation and naming of the first dinosaur to be found in Queensland: the sauropod Rhoetosaurus. Despite a century of study, Queensland’s Mesozoic rocks are only just beginning to give up their secrets. Numerous questions remain to be answered.

How did Queensland’s Mesozoic fossil deposits form? Why do we have abundant fossils of some animals, but comparatively few of certain others? Is this due to some bias in the way the fossils were preserved, or is it a real feature of the living ecosystem? What role did these extinct animals play in their ecosystems? Were giant dinosaurs ecologically equivalent to large mammals today, or were they fundamentally different? Answering questions like these will require new fossil discoveries, but also re-examination of fossils already in the museum’s collection.

The use of new technologies is allowing palaeontologists to glean a wealth of new information from fossils. Traditionally, fossils needed to be painstakingly removed from the encasing rock, a process that can take months or years of work. Today, imaging technologies such as synchrotron x-ray micro-CT scanning allows palaeontologists to literally see through the rock to view the enclosed fossils, and even see the internal structure of the fossils, revealing anatomical details that would be otherwise invisible.

Understanding the geological context of fossils is vital to understanding the meaning of the fossils themselves. Improved dating of fossil-bearing rock formations in Queensland is helping to place them in a global setting. For example, recent redating of Triassic rocks has suggested that they are actually somewhat younger than previously thought. This makes them roughly contemporaneous with the oldest dinosaur fossils from South America, and raises the possibility that some of the world’s oldest dinosaurs may one day be found in Queensland.

Discovery of new dinosaur fossils in Queensland has always been driven by keen-eyed landholders and pastoralists. Discoveries of fossils are a source of civic pride in many parts of Queensland, and Queensland Museum is active in assisting the establishment of community-run regional museums where these fossils can be cared for, displayed and studied. These museums are now greatly accelerating the rate of new dinosaur discoveries in Queensland. Palaeontologists at Queensland Museum contribute scientific expertise to these endeavours, which has so far resulted in the naming of the megaraptoran theropod Australovenator wintonensis, and the titanosaurid sauropods Diamantinasaurus matildae and Savannasaurus elliottorum at the Australian Age of Dinosaurs Museum and Australia’s largest dinosaur: Australotitan cooperensis at the Eromanga Natural History Museum.

Publications

• In Search of Ancient Queensland (2015)