23-Foot ‘River Boss’ Croc Fossil Found in Australia

Slender-nosed extinct reptile would have patrolled freshwater ecosystems between two and five million years ago

Gunggamarandu maunala
An artist's rendering of Gunggamarandu maunala. Eleanor Pease

Australia, known for being home to massive saltwater crocodiles in the present, also hosted super-sized crocs millions of years ago. Researchers studying fossils found in southeast Queensland in the 19th century have discovered a new species of ancient crocodile they say may have measured around 23 feet in length, reports Soofia Tariq for the Guardian. That’s slightly longer than the biggest confirmed saltwater crocodiles but still well shy of the 40-foot extinct croc Sarcosuchus imperator.

The new Australian crocodile has been dubbed Gunggamarandu maunala, a name that incorporates words from the Barunggam and Waka Waka Indigenous languages spoken near where the fossil was found and translates to “hole-headed river boss.” Researchers described the new species, which is thought to have lived between two and five million years ago, based on a chunk of the back part of its skull in a paper published last week in the journal Scientific Reports.

The team arrived at their estimate of Gunggamarandu maunala’s size by first extrapolating the probable size of its skull, which they say probably measured at least two and a half feet long. The giant reptile is the largest extinct crocodilian ever found in Australia, write study authors Jogo Ristevski and Steven W. Salisbury, Queensland University paleontologists, in the Conversation.

"We also had the skull CT-scanned, and from that we were able to digitally reconstruct the brain cavity, which helped us unravel additional details about its anatomy,” says Ristevski in a statement.

Wakka Wakka elder Adrian Beattie tells Lucy Robinson of the Australian Broadcasting Corporation (ABC News) that the discovery is significant to the local Aboriginal community. "It's astounding," Beattie tells ABC News. “I'm picturing him now, one hell of a big crocodile. He'd be certainly something to respect."

Ristevski also tells ABC News that based on what they can see of its anatomy, Gunggamarandu maunala is part of a group of slender-snouted crocodiles called the tomistomines that had previously never been found in Australia.

"Prior to our study tomistomine fossils had been discovered on every continent except Antarctica and Australia," Ristevski tells ABC News. "But now we have proved that tomistomines were here as well."

Tomistomines are called “false gharials” because they have a skinny set of jaws that resembles the fish-catching chompers of the gharial. This group has many extinct members but only one living representative, the Malaysian false gharial. The tominstomines appeared some 50 million years ago, according to the Conversation. Their range was very widespread, with remains found on every continent except Antarctica.

It’s unclear what caused this lineage to go extinct in Australia, but Salisbury tells the Guardian that “it’s very likely related to the gradual drying of the Australian continent over the last few million years, and in particular over the last few 100,000 years. The big river systems that once supported crocs like this have long since dried up from south-east Queensland, and with them so have the crocs.”