Fossil skull belonged to ‘cute’ little croc

Part fossil of Trilophosuchus rackhami skull. (Credit: Jorgo Ristevski)

Researchers have discovered new information about a particularly tiny species of crocodile, Trilophosuchus rackhami, that lived in north-west Queensland approximately 13.5 million years ago.

“By micro-CT scanning the beautifully preserved skull, we were able to digitally separate each bone,” says Jorgo Ristevski, Faculty of Science PhD candidate at the University of Queensland.

“We estimated that at adulthood, Trilophosuchus rackhami would have been between 70 and 90 centimeters long and weigh one to two kilograms, which was very small compared to most present-day crocs. (That’s roughly 28 to 35 inches and almost four and a half pounds.)

“This was a truly unique looking croc, with a short snout and three distinct ridges on the top of its skull.”

Trilophosuchus rackhami means Rackham’s three-crested croc, which was named in 1993 in honor of Alan Rackham, who now manages the Riversleigh Fossil Discovery Centre at Mt Isa.

Ristevski says paleoneurology, a field that studies the brain and nervous system of fossil species, can provide crucial insights into the animal’s evolution, morphology, and even behavior.

“For one of the studies, I digitally reconstructed the brain cavity of Trilophosuchus rackhami and found that it resembles that of some distantly related and potentially terrestrial extinct crocs from Africa and South America,” Ristevski says.

“We were quite surprised to find this because evolutionarily speaking, Trilophosuchus rackhami is more closely related to today’s crocs.

“This may indicate that Trilophosuchus rackhami spent more time on land than most living crocs.”

Ristevski says the findings would be useful in interpreting the evolutionary relationships of extinct crocs, something that will be researched in the future.

Associate professor Steve Salisbury says up until very recently, Australia had an amazing diversity of prehistoric crocs.

Trilophosuchus rackhami was certainly one of the cutest,” he says.

“If we could travel back in time to north Queensland 13 million years ago, not only would you need to watch out for crocodiles at the water’s edge, but you’d also have to make sure you didn’t step on them in the forest.”

The research appears in The Anatomical Record and the Journal of Anatomy.

Source: University of Queensland