A tiny fossil discovered in central eastern Australia turned out to be a piece of bone from the natural body armor of a giant monitor lizard – possibly an ancient Komodo dragon. According to researchers who dated the fossil, the apex predator overlapped, at least in time, with the continent’s early human inhabitants. The findings were published in Quaternary Science Reviews.
The 1 centimeter (0.4 inch) fossil (pictured below) was unearthed after meticulous sorting and sieving at the Colosseum Chamber of the fossil-rich Capricorn Caves near Rockhampton. It was an osteoderm, a bone underneath the skin of large lizards called varanids that reinforces their scales, acting like body armor. "We can't tell if the bone is from a Komodo dragon – which once roamed Australia – or an even bigger species like the extinct megalania monitor lizard, which weighed about 500 kilograms [1,100 pounds] and grew up to six meters [20 feet] long," Gilbert Price from the University of Queensland said in a statement.
Radiocarbon and uranium thorium dating techniques put the skin bone at about 50,000 years old, making it the geologically youngest known giant lizard on the entire continent. It’s at least 30,000 years younger than the previous youngest (and reliably dated) record. "The find is pretty significant, especially for the timeframe that it dates," Price added. The lizard coincides with the arrival of Australia's first human colonizers.
During the last Ice Age in the Pleistocene, massive lizards and 9 meter (30 foot) long inland crocodiles wandered Australia. "It's been long-debated whether or not humans or climate change knocked off the giant lizards, alongside the rest of the megafauna," Price explained. "Humans can only now be considered as potential drivers of their extinction."
Image in the text: Osteoderm (skin bone) of the giant monitor lizard from Colosseum Chamber at the Capricorn Caves. Gilbert Price