Lancefield Megafauna

A large fossil deposit from the Pleistocene epoch was discovered at Lancefield Swamp, containing the remains of many species of extinct megafauna, including ; Macropus titan, a giant kangaroo;Diprotodon, a rhinoceros-sized wombat; and Genyornis, a giant flightless bird.

The swamp site is located in the Lancefield Park Recreation Reserve.

In 1843, the Melbourne engineer and well-digger James P. Mayne discovered a trove of fossilised bones of large but now extinct animals on land that became part of Lancefield Park. Additional bones were retrieved in the years following this discovery, but the excavation was then abandoned owing to ground water inundation and bones were not unearthed again at Lancefield Swamp until the 1960s.

Since then, several excavations have investigated why so many bones have accumulated at Lancefield Swamp. The site contains one of the richest deposits of megafauna fossils in Australia and remains of major scientific importance in understanding why the Australian megafauna has all but disappeared.

The bones of thousands of animals are preserved in the clay of Lancefield Swamp. This includes extinct kangaroos and wallabies, such as a larger, 150 kg form of the Eastern Grey Kangaroo (Macropus titan), the equally-large giant short-faced kangaroo (Sthenurus) and Propleopus, a 70 kg relative of the musky rat-kangaroo whose diet probably included meat.

Other animals found at Lancefield Swamp lack present-day relatives. Zygomaturus, for instance, had the stature of a hippopotamus and weighed more than 500 kg, while Diprotodon resembled a rhinoceros and weighed up to 3 metric tons. The bones of a flightless bird (Genyornis newtoni)—which stood about 2 metres tall, weighed more than 200 kg and is thought to have died out around the same time as humans arrived in Australia—have also been found at Lancefield Swamp, as have the signs of bone-gnawing by several carnivorous marsupials including the marsupial ‘lion’ Thylacoleo, which weighed around 100 kg.

While most of the bones at Lancefield Swamp are of adult kangaroos, in 2005 scientists found complete jawbones of adult and juvenile Diprotodon. But why did these bones accumulate at Lancefield Swamp?

During the first systematic excavations in the 1970s, pieces of charcoal were recovered from underneath the bone layer and estimated by radiocarbon dating to be approximately 26,000 years old. This suggested that megafauna may have existed for some time after the arrival of humans in Australia. The discovery of a stone blade at the site further fuelled speculation that Aboriginal people may have killed or cut up megafauna remains at Lancefield Swamp.

Later excavations in the 1990s examined abrasion and the sediments within which bones were found, both at the site discovered by Mayne as well as at another excavation some 100 meters away. This suggested that the bones may have been deposited by water, possibly during a major flood. Direct dating of tooth fragments also indicated that, at between 30,000 – 60,000 years, the bones could be significantly older.

Excavations in 2004 and 2005 reopened and extended the previous excavations. While the fossils at one of the locations showed the wear typical of water transport, bones at other locations were still in good condition and bone fragments arranged close together, which means that transport by water for these bones is unlikely. The new excavations, which opened an additional 10 square metres of ground, did not find any human artefacts associated with the megafauna remains, and few signs of carnivore gnawing. It is very unlikely that Lancefield Swamp was a ‘kill site’ for humans, although other carnivores may have feasted on animals attracted to the waterhole.

The estimated ages of a larger sample of teeth again yielded a wide range of dates, between approximately 40,000 – 80,000 years ago. Taken together, the evidence has been interpreted to suggest that Lancefield Swamp may have provided an important waterhole over many millennia, perhaps particularly in times of draught and as the climate became dryer. The age distribution of the kangaroos, with the absence of juveniles and elderly, is consistent with the idea that only stronger animals survived in times of drought only to die at the last waterhole in the area.

by Adam Bostanci

Acknowledgements: Sanja van Huet, Joe Dortch

Diprotodon weighed about 3 tonnes
Illustration by Anne Musser

Procoptodon, a giant kangaroo

Artist: Peter Trusler
Source: Museum Victoria