A Cretaceous crocodile has been found with a newly eaten dinosaur in its stomach. This wasn’t quite the titanic dinner-time duel we might first imagine – the crocodile wasn’t all that large even by modern standards and the dinosaur was chicken-sized. Nevertheless, it's confirmation of something palaeontologists have long suspected, as well as marking the discovery of a new crocodile species and genus.
In 2011 a team of paleontologists and volunteers were digging up some sauropod bones near Winton, Queensland in Australia. Dr Matt White of the University of New England told IFLScience the specimen turned out to be “not a very good one”. Nevertheless, having extracted all they could find with picks and shovels the team called in a front-end loader to scrape successive layers of dirt from the site.
Having dug down a meter with no success the team was just about to send the loader elsewhere but decided to take one more level. On the plus side, they hit a concretion that turned out to include a 93 million-year-old fossil crocodile that would otherwise still be sitting undiscovered beneath the sheep station. Instead, the unusual – for many reasons – find has been described in Gondwana Research. Unfortunately, the machine did considerable damage to the fossil in the process – heavy machinery not being the best way to treat fossils.
Alerted to the crocodile’s presence, White and others dug it up using more appropriate technology and found something remarkable: an unusually complete crocodile skeleton with a small ornithopod dinosaur in its belly. “You make the best discoveries when you break something,” White told IFLScience. Words to live by.
The ornithopod is too incomplete for identification, although White told IFLScience it might be from the same species that made the famous Lark Quarry trackway. The crocodile is a previously unknown genus, now named Confractosuchus sauroktonos, meaning “broken dinosaur killer”.
Modern crocodiles are famously willing to eat anything, and it has long been thought small- to medium-sized dinosaurs made up a large part of at least some species' diet during the Jurassic and Cretaceous. However, the stomach contents of only two extinct crocodile ancestors have been found, one of which was impossible to identify and contained a smaller crocodylomorph.
White told IFLScience the two fossils were too closely intertwined to be able to remove either’s bones without damaging the other. Instead, the team used micro-CT scanners to create 3D models of each bone. From this, they confirmed the ornithopod was indeed the crocodile’s last meal, with one femur snapped in two by a mighty bite, while the other carried the clear imprint of a crocodile tooth.
Digital model of the Confractosuchus skeleton as preserved, along with bones of the small dinosaur found in its stomach region.
The crocodile was around 2.5 meters (8 feet) long – small by Cretaceous standards – while the ornithopod would have weighed 1-1.7 kilograms (2-4 pounds). White described the crocodile to IFLScience as a “subadult” based on the state of its vertebrate but did not think it would have grown much further.
Why the crocodile died so soon after consuming a tasty snack remains a mystery. White noted the tail has not been found, adding “That’s the tastiest part of a crocodile,” so it is possible some larger dinosaur avenged its tiny counterpart.
“While Confractosuchus would not have specialised in eating dinosaurs, it would not have overlooked an easy meal, such as the young ornithopod remains found in its stomach,” White said, explaining to IFLScience that, like its modern counterparts, it was capable of taking down prey larger than itself.