Australia may be known for its tourist-frightening myth of the “drop bear,” but researchers have now uncovered the remains of a real-life “drop croc” that hunted the ancient forests Down Under millions of years ago.
Before Australia became the continent it is today, it was joined to a much larger landmass, connecting it to Antarctica and South America. One of Australia’s oldest fossil sites, also a remnant of this era, was the location of the recent discovery made by an international team led by the Institut Català de Paleontologia Miquel Crusafont (ICP), revealed in the Journal of Vertebrate Paleontology.
Finding Egg Shells
Located outside the town of Murgon at Tingamarra, the discovery consisted of eggshell fragments of a mekosuchine crocodile, Wakkaoolithus godthelpi, which lived in the area 55 million years ago—well before modern freshwater crocodiles arrived in Australia 3.8 million years ago.
“These eggshells have given us a glimpse of the intimate life history of mekosuchines,” said lead author Xavier Panadès i Blas. “We can now investigate not only the strange anatomy of these crocs, but also how they reproduced and adapted to changing environments.”
Since 1983, Prof. Archer has been working in the Murgon area, even going door to door in search of new finds.
“That year, UNSW colleague Henk Godhelp and I drove to Murgon, parked the car on the side of the road, grabbed our shovels, knocked on the door, and asked if we could dig up their backyard,” Prof. Archer says. “After explaining the prehistoric treasures that might lay under their sheep paddock and that fossil turtle shells had already been found in the area, they grinned and said ‘of course!’.
“From subsequent excavations, that’s where the eggshell pieces came from,” he added. “And, quite clearly, from the many fascinating animals that we’ve already found in this deposit since 1983, we know that with more digging there will be a lot more surprises to come.”
Drop Croc
Mekosuchine fossils evidence that the creatures lived much different lives from crocodiles today. Instead of making their homes primarily in fresh or saltwater, they stalked the forests of ancient Australia and grew to lengths of up to 5 meters.
“It’s a bizarre idea,” says co-author Professor Michael Archer. “But some of them appear to have been terrestrial hunters in the forests.”
“Some were also apparently at least partly semi-arboreal ‘drop crocs’,” he says. “They were perhaps hunting like leopards – dropping out of trees on any unsuspecting thing they fancied for dinner.”
Professor Archer first encountered Mekosuchine fossils earlier in his career, when he found an unusual crocodile jaw in southeastern Queensland in 1975, shocking American reptile specialist Professor Max Hecht.
“When he saw it, Max nearly dropped his coffee cup,” Prof. Archer says. “It closely resembled another kind of extinct croc with dinosaur-type teeth that had been found in South America. That was the first realisation that crocodiles with teeth like this were also part of the older record in Australia.”
Reading the Shells
According to the researchers, paleontologists typically fail to utilize eggshells for the wealth of insights they can provide.
“They preserve microstructural and geochemical signals that tell us not only what kinds of animals laid them, but also where they nested and how they bred,” Blas said. “Our study shows just how powerful these fragments can be. Eggshells should be a routine, standard component of palaeontological research – collected, curated and analysed alongside bones and teeth.”
The team closely examined the shell fragments on multiple levels, employing both optical and electron microscopes. From these observations, the researchers believe that the Mekosuchines laid their eggs at the edges of a lake, surrounded by a lush forest, a strategy used to mitigate the territorial changes experienced as Australia’s waterways shrank and large prey disappeared.
Prof. Archer says that the team’s work in understanding how these reptiles responded to a changing environment is not just of theoretical interest, but can be applied to managing today’s changing climate. Presently, he is engaged with the Burramys Project, an effort to save the Mountain Pygmy-possum from extinction.
“The Burramys Project is a demonstration that, at least in some cases, we can develop strategies to save endangered species,” Prof. Archer explained. “Clues from fossil records matter. Not just to understand the past, but also to help secure the future.”
The paper, “Australia’s Oldest Crocodylian Eggshell: Insights into the Reproductive Paleoecology of Mekosuchines,” appeared in Journal of Vertebrate Paleontology on November 11, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.