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Animals from Bluff Downs
Following a trend that was to climax in the Pleistocene many animals of the Pliocene grew very large. A variety of kangaroos would certainly have fallen prey to the savage terrestrial crocodile Quinkana babarra. The Bluff Downs Giant Goanna Megalania would have made short work of giant herbivores such as Zygomaturus, Palorchestes and Euryzygoma. And so too would the Bluff Downs Giant Python Liasis sp. which at 8m in length was the largest snake ever to live on this continent.
The skull of the giant Pliocene herbivore Euryzygoma with its unusual protruding cheek bones (top) and a molar tooth of the mysterious koala-like Koobor (bottom) [Photos: Brian Mackness].
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Also at Bluff Downs were the ancestors of modern animals including animals unlike any known today. Koobor jimbarretti was a strange koala-like animal that still puzzles researchers. Flamingoes, which are no longer found in Australia, waded in the shallows for food. Ancestral dasyurids (marsupial carnivores), kangaroos, wombats and bandicoots all flourished here, as did Thylacoleo crassidentatus, the precursor of the leopard-sized Pleistocene Marsupial Lion T. carnifex.
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Why is Bluff Downs so important?
 While Australia drifted in isolation for more than thirty million years a unique diversity of animals had developed. In the sticky mud of a wetland in northern Queensland strange relics from ancient times and the precursors of the modern Australian fauna left their bones. Four million years later, two fishermen discovered what is now recognised to be one of the most significant fossil sites of Pliocene age in Australia on the banks of Allingham Creek at Bluff Downs Station
A view of Bluff Downs wetland 3.8 million years ago. A sthenurine kangaroo nervously watches a saltwater crocodile ambushes a large marsupial herbivore Euryzygoma. Looking on ravenously is an 8m giant python Liasis and a giant goanna Megalania. Flamingoes wade in the shallows beyond. [Reconstruction: Anne Musser]
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What happened in Australia?
The lake and stream deposits at Bluff Downs contain the bones of dozens of kinds of fascinating animals. Four million years ago the Australian landmass continued drifting northward, although fluctuating between warmer wetter periods, and cooler and drier ones. At Bluff Downs a wetland environment, similar to modern-day Kakadu, was home to a rich diversity of animals. Their fossils provide crucial information about this important stage in the evolution of the Australian continent and its animals.
Pliocene 3.8 million years ago
Time line and position of the continents during formation of the Bluff Downs fossil locality.
Northward movement to within a few degrees of its present day position led to dramatic changes to the climate of the Australian continent. In response to increasing coolness and dryness, lush forests of the Miocene had given way to extensive woodlands and importantly, grasslands and deserts which had profound effects on Australian ecosystems. Forests and their ancient denizens were gradually retreating before the advance of a new flora and fauna. The Pliocene epoch lasted from approximately 8 million years ago to approximately 2 million years ago.
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Finding Fossils
 After the removal of overburden, bones are quarried from the rich layers of soft clay forming the northern bank of Allingham Creek. The fossil bones are hardened with water-soluble glue as the surrounding clay is carefully removed. Large and fragile fossils are wrapped in a protective shell of plaster to make them safe for the trip back to the laboratory.
Palaeontologists excavate fossil bones from the Bluff Downs quarry. [Photo: Henk Godthelp]
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