A giant marine reptile from the dinosaur era had part of its face bitten off, probably by another member of its species. The huge predator survived the attack, but it lost part of its jaw and developed a severe infection – both of which may have contributed to its ultimate demise.
“It’s direct evidence of a violent interaction between members of the same species,” says Dylan Bastiaans at the University of Zurich in Switzerland.
The animal was a mosasaur, one of several groups of reptiles that lived in the sea during the dinosaur era. Mosasaurs looked like whales with the heads of crocodiles, and towards the end of the dinosaurs’ reign, they became the top marine predators.
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Bastiaans and his colleagues studied a mosasaur fossil that was discovered in 2012. The specimen is nicknamed Carlo, after Carlo Brauer, an excavator operator who spotted it in a limestone quarry in the Netherlands. “He actually saved the specimen, or large parts of the specimen,” says Bastiaans.
Carlo consists of most of the skull plus a few other bits, so we don’t know if it was male or female. The team has tentatively identified it as Prognathodon sectorius. Prognathodon species were some of the largest mosasaurs, reaching lengths of around 10 metres. They had powerful, crushing jaws and some species are thought to have eaten large sea turtles.
“They are one of these super-predators that could potentially feed on almost anything,” says Bastiaans.
However, Carlo had major injuries. “We see that it’s missing at least part of the front of its snout,” says Bastiaans. “There must have been some bite there that chopped it off.”
The attacker’s teeth left marks: based on their shape and size, the researchers believe they were made by another Prognathodon. Bastiaans says the other mosasaur probably approached from below, as sharks do, and grabbed Carlo’s snout in its jaws.
The injury wasn’t immediately fatal, as new bone was deposited around the injury, a process that takes months. Carlo also developed a severe infection that spread through its jawbones.
“Most likely the animal would have suffered quite a bit, and perhaps this infection would have hampered its ability to feed,” says Bastiaans.
It isn’t clear what eventually killed Carlo, he says, but the infection and lack of food are obvious possibilities.
Cretaceous Research
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