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 鈥� both of which may have contributed to its ultimate demise.
鈥淚t鈥檚 direct evidence of a violent interaction between members of the same species,鈥� 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鈥� 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. 鈥淗e actually saved the specimen, or large parts of the specimen,鈥� says Bastiaans.
Carlo consists of most of the skull plus a few other bits, so we don鈥檛 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.
鈥淭hey are one of these super-predators that could potentially feed on almost anything,鈥� says Bastiaans.
However, Carlo had major injuries. 鈥淲e see that it鈥檚 missing at least part of the front of its snout,鈥� says Bastiaans. 鈥淭here must have been some bite there that chopped it off.鈥�
The attacker鈥檚 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鈥檚 snout in its jaws.
The injury wasn鈥檛 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.
鈥淢ost likely the animal would have suffered quite a bit, and perhaps this infection would have hampered its ability to feed,鈥� says Bastiaans.
It isn鈥檛 clear what eventually killed Carlo, he says, but the infection and lack of food are obvious possibilities.
Cretaceous Research
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