A tiny bone from underneath a lizard's skin has helped sketched a new picture of life for the first humans living in Australia during the last ice age.
In short, there was a monster in their midst, one that could have grown to almost 20 feet long.
A research team from the University of Queensland (UQ) uncovered a 0.4-inch (1-centimeter) osteoderm -- a bone found under the skin -- just 6.5 feet (2 meters) below ground during a dig in a cave. It's the youngest record of giant lizards in Australia and marks the first evidence that huge apex-predator lizards and the continent's first humans lived at the same time.
UQ paleontologist Gilbert Price and his team date the bone to about 50,000 years ago, which matches up with the arrival on scene of the country's first Aboriginal people.
"Our jaws dropped," Price said in a press release. "The find is pretty significant, especially for the time-frame that it dates."
Australia was home to huge lizards and even 27-foot-long (8.2-meter) crocodiles during the last ice age. But their later disappearance has not been conclusively pinned on humans.
"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."
Of course, a key question remains. What creature owned the bone the researchers found?
"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 [1,102 pounds] and grew up to six meters [19.7 feet] long," Price said.
Today, the scientists note, the biggest lizard in Australia is the perentie, which maxes out at about 6.5 feet long.
The bone Price and his team found was unearthed during a dig inside one of the Capricorn Caves near Rockhampton, in northeastern Australia.
Price and his colleagues have published their findings in the journal Quaternary Science Reviews.