Rediscovering the dragon's paradise lost

The world's largest living lizard species, the Komodo dragon (Varanus komodoensis), is vulnerable to extinction and yet little is known about its natural history. New research by a team of palaeontologists and archaeologists from Australia, Malaysia and Indonesia, who studied fossil evidence from Australia, Timor, Flores, Java and India, shows that Komodo Dragons most likely evolved in Australia and dispersed westward to Indonesia. The research, which also details new fossil specimens indicating the presence of a new species of giant varanid found on the island of Timor, is published September 30 in the open-access, peer-reviewed journal PLoS ONE.

Author Scott Hocknull, Senior Curator of Geosciences at the Queensland Museum, said Australia is a hub for lizard evolution.

"The fossil record shows that over the last four million years Australia has been home to the world's largest lizards, including a five metre giant called Megalania (Varanus prisca)," Mr Hocknull said.

"Now we can say Australia was also the birthplace of the three-metre Komodo dragon (Varanus komodoensis), dispelling the long-held scientific hypothesis that it evolved from a smaller ancestor in isolation on the Indonesian islands.

"Over the past three years, we've unearthed numerous fossils from eastern Australia dated from 300,000 years ago to approximately four million years ago that we now know to be the Komodo dragon.

"When we compared these fossils to the bones of present-day Komodo dragons, they were identical," he said.

The varanids are a group of giant monitor lizards, which are the world's largest terrestrial lizards and which were ubiquitous in Australasia for over 3.8 million years, having evolved alongside large-bodied, mammalian carnivores, such as Thylacoleo, the 'marsupial lion'. Growing to 2-3 metres in length and weighing around 70 kilos, the Komodo dragon is the last of the truly giant monitor lizards. New fossil discoveries show that the ancestor of the Komodo dragon evolved on mainland Australia, around 3-4 million years ago and then dispersed west to Indonesia. Historically, Australia was home to many other giant monitor lizards, including Megalania (Varanus prisca)—once the world's largest terrestrial lizard but which died out around 40,000 years ago.

"This research also confirms that both giant lizards, Megalania (Varanus priscus) and the Komodo dragon (Varanus komodoensis) existed in Australia at the same time," Mr Hocknull said.