Megafauna

Overview

Fossils of giant animals have been found across Queensland and Australia, however, they are not from dinosaurs or marine reptiles. Palaeontologists call them ‘megafauna’, which simply means ‘giant animal’. Megafauna evolved long after the Age of Dinosaurs in the later part of the Cenozoic Era, from around 15 million years ago until their extinction approximately 40,000 years ago. Unlike dinosaurs, megafauna do not form a singular related group. Instead, megafauna include giant types of mammals, reptiles and birds. Megafauna fossils were first acquired by Queensland Museum in 1862 and many specimens have been discovered since. Queensland’s megafauna include the world’s largest marsupial (Diprotodon) and lizard (Megalania), alongside giant horned tortoises, tree kangaroos, snakes, possums and even frogs!

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 Museum’s vertebrate fossil collection is one of the largest in the southern hemisphere. This is partially because Queensland has some of the most productive Cenozoic fossil sites in Australia. These include:

Eastern Darling Downs
Cenozoic fossils from Queensland first came to the attention of scientists when fossil bones were found on the Darling Downs in south-east Queensland during the middle nineteenth century. Fossils from the Darling Downs are mostly Pleistocene in age (0.0117 – 2.58 million years ago), and include the most famous species of Australian megafauna: the largest-ever marsupial Diprotodon optatum, the giant walking kangaroo Procoptodon goliah, the giant goanna ‘Megalania’ Varanus priscus, and the ‘ninja turtle’ Ninjemys oweni.

South Walker Creek
While the Pleistocene megafauna of southern Australia has been studied by palaeontologists for almost two centuries, those from the tropical north are still largely unknown. The discovery of fossil bones near Nebo, central highlands of northern Queensland, provides the most detailed record of tropical northern megafauna during the late Pleistocene. These fossils are among the youngest known for many megafaunal species, dating to roughly 40,000 years ago. A range of extinct megafauna species have been found, including the remains of largest-known kangaroo, giant wombats, three crocodilian species and two giant carnivorous lizards.

Mount Etna
Caves to the north of Rockhampton within the Mount Etna Caves National Park contain the largest and most species-rich Pleistocene rainforest fauna in Australia. The fossil deposits record significant periods of past environmental change when rich rainforest environments gave way to open arid environments in response to intensifying aridity. The fossil deposits preserve a rich Pleistocene record of extinct species, many of them new to science. The megafauna from these sites include giant tree kangaroos, possums, the Komodo Dragon, snakes a land-dwelling crocodile. However, some giants were unexpected, like the giant frog Etnabatrachus maximus and the giant rodent Uromys aplini. The fauna also includes very rare species, like the extinct koala Invictokoala monticola and the Pygmy marsupial lion Thylacoleo hilli.

Chinchilla
Fossils from Chinchilla on the western Darling Downs are the largest single collection of vertebrate fossils from the Pliocene epoch (2.58-5.333 million years ago) of Australia. Numerous species have been discovered among these fossils, including the oldest quoll (Dasyurus dunmalli), the broad-cheeked diprotodont Euryzygoma dunense, the giant tree kangaroo Bohra wilkinsonorum, and the early Australian rodent Pseudomys vandycki. The discovery of Komodo Dragon (Varanus komodoensis) fossils from Chinchilla provided palaeontologists with the first evidence to demonstrate that the species had its origins in Australia around 4 million years ago. Subsequent genetic studies of Komodo Dragon and its closest relatives has since corroborated this study.

Riversleigh
The Riversleigh World Heritage Area in northwest Queensland has produced some of our most important Cenozoic fossils. Among the Riversleigh fossils are the ancestors of many of Australia’s famous animals, including kangaroos, emus, koalas, and wombats. Other notable and surprising finds from Riversleigh include the giant platypus Obdurodon tharalkooschild, the sheep-sized tree climbing marsupial Nimbadon lavarackorum, the kitten-sized ‘marsupial lion’ Microleo attenboroughi and the ancestral marsupial mole Naraboryctes philcreaseri. Fossils from Riversleigh are on display at the Riversleigh Fossil Discovery Centre in Mount Isa.

Murgon and Geebung
Fossils from Boat Mountain near Murgon (south-east Queensland) are among the oldest Cenozoic vertebrate fossils in Australia. They include Australia’s oldest frogs, and marsupials that are more closely related to those now living in South America than any now found in Australia. The Murgon fossils show some similarities to those found at Geebung, on the northside of Brisbane, in 2013. Fossil-bearing rock from this site is stockpiled at the museum, and is a current focus of study.

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Research overview

Scientific research is required to unlock the ancient secrets in fossils. Palaeontologists at Queensland Museum are studying Queensland’s Cenozoic fossils to discover the history of Australia’s unique animals, and how they were shaped by our changing environment.

The fossil record tells us that Australia was once much wetter, with extensive rainforests in places that are now dry. Study of the animals that inhabited these rainforests, and their eventual fate, is a focus for researchers working on fossils from Riversleigh, Murgon, Geebung, and Mount Etna. Over the course of the Cenozoic, the intensification of a drying climate and changes to the environment fragmented and reduced the distribution of rainforest. Over the last 500,000 years rainforests along the eastern seaboard of Queensland have significantly reduced due to further drying and increased landscape fire. Today, unnatural climate change impacts the few remaining areas of rainforest in Australia. Studying fossils from the ancient rainforests may give us information vital for saving what remains.

Potential causes of the extinction of Australia’s megafauna during the Upper Pleistocene (between 11,700 – 129,000 years ago) are still a focus of intense research and debate globally. Queensland Museum palaeontologists have identified the likely reasons for the extinction of tropical megafauna through research on the South Walker Creek megafauna site. They found that a combination of environmental changes, all detrimental to megafauna survival, occurred in relatively quick succession impacting the largest species within the environment. The conditions best fit for megafauna survival did not return, and thus the extinction of megafauna from these environments was sustained. The key findings demonstrated that the extinction of megafauna across the continent likely occurred at different times, rates and from multiple causes affecting local regions uniquely. No singular cause can explain the continental-wide extinction of Australia’s megafauna.

Publications

• In Search of Ancient Queensland (2015)