In 2008 the Chillagoe Alliance successfully applied for Q150 Funding to place a reproduction of ‘Dave’, an ancient marine reptile found in the local area, at the entrance to the township.
Why was ‘Dave’ found in remote inland Australia?
In the late Jurassic period 40 million years ago the Great Artesian Basin and its northem extension the Carpenteria Basin, formed in the interior of the continent. These basins occupied most of Queensland and extended into Northern Territory. It extended as far east as the Chillagoe area and was initially a very large shallow freshwater lake, which was deepest in the area of the present Gulf of Carpentaria.
Global warming produced a major sea level rise to about 160 metres above current sea level, in the Early Cretaceous around 130 miliion years ago. The lake became a shallow sea extending
inland at least as far as Wrotham Park Station, 60 kilometres west of Chillagoe. A fall in sea level towards the middle of the Cretaceous period about 100 millions years ago saw the fresh water lake system develop again.
Coral, ammonites and marine animals such as plesiosaurs and elasmosaurs thrived in the warm shallow marine conditions. Elasmosaurs such as ‘Dave’ were marine creatures with four flippers and a very long neck. They commonly reached lengths of
up to 14 metres and a weight of up to 2 tonnes. These marine reptiles were part of the family Sauropside and are therefore relatives of the dinosaurs. Elasmosaurs swallowed gizzard stones, not only to grind food, but to change the animal’s buoyancy in water. Skeletons of elasmosaurs have been found in other locations in Queensland, however the most complete Elasmosaur found in Australia to date is Dave’.
‘Dave’ was a relatively small Elasmosaur, about 5 metres from head to tail, and is one of the few early true elasmosaurs known worldwide. About 80 percent of ‘Dave’s’ skeleton has been recovered, including three of its four flippers, long neck, hip,
shoulders, the main part of its body, some tail bones but unfortunately not the head. Interestingly, the most complete elasmosaur found in Australia did not contain any gizzard stones.
Scientists are not sure how ‘Dave’ died, but think the animal probably floated upside down in the water for a short time. Gases formed inside the body, by the decomposition process, probably kept it buoyant. Eventually, the gas pressure caused the body to rupture, spilling the stomach contents out. This may explain why no gizzard stones were found in the skeleton.
The body then sank to the bottom rapidly and although slow-moving currents probably disturbed some of the bones, it was quickly covered over by mud and sand. ‘Dave’ may have been eating something very unusual when he died.
Added to the mystery of the missing gizzard stones are the crushed up bits of hard shel1 in the animal’s stomach contents. Scientists have always assumed that plesiosaurs ate fish and squid, but ‘Dave’ appears to have been eating clams. If scientists could examine ‘Daves’ teeth, they might be able to solve the riddle; unfortunately, ‘Dave’s’ head is still missing.