Paleontologists have discovered a new species of megaraptor dinosaur in Argentina, along with a startling clue about what it ate. Named Joaquinraptor casali, the apex predator apparently ate crocodiles, judging by the leg bone found in its mouth.
As the name suggests, megaraptors were a clade of carnivorous dinosaurs that looked like giant versions of the raptors made famous in Jurassic Park. In this case, the researchers estimate that Joaquinraptor was more than 7 meters (23 feet) long, nose to tail, and weighed over 1,000 kilograms (2,200 pounds).
With no tyrannosaurs around in that part of the world, Joaquinraptor would likely have enjoyed life at the top of the food chain. This fossil find includes some of the most direct evidence of a megaraptor diet so far, which seemed to include the ancient ancestors of crocodiles.
Related: Giant ‘Death Shadow’ Dinosaur Found in Argentina Is Largest Megaraptor On Record
“Interestingly, we recovered a humerus, between the lower jaw bones of Joaquinraptor, suggesting – though not proving – that the new megaraptor may have been eating the crocodyliform when it died,” Lucio Ibiricu, a paleontologist at the Patagonian Institute of Geology and Paleontology (IPGP), told ScienceAlert.
The researchers admit that the leg bone could have gotten there some other way, perhaps washed into the submerged mouth of the already-dead megaraptor. But given that the bone is not only touching some of the predator’s teeth, but features tooth marks as well, some kind of interaction seems likely. The two creatures might also have been fighting over other food sources.
Perhaps Joaquinraptor was simply balancing the scoreboard for all the crocodilians suspected to have chowed down on dinosaurs.
The researchers estimated the age of this particular individual when it died by studying the microstructure of its bones. This Joaquinraptor seems to have been sexually mature, but not yet fully grown.
“Mainly based on the microstructure of a fragment of tibia of Joaquinraptor and the disposition of the LAGs (lines of arrested growth) found there, and assuming that LAGs correspond to annually deposited structures (like tree rings), a minimum age of 19 years is inferred for this Joaquinraptor specimen,” Ibiricu told ScienceAlert.
Although paleontologists only found pieces of its jaws, skull, forelimbs, legs, and a few tail vertebrae, this is one of the most complete megaraptor specimens discovered so far. So, along with adding a new species to the roster of dinosaurs that lived in ancient Patagonia, Joaquinraptor could help scientists fill in some gaps in this little-understood clade.
While northern landmasses were dominated by huge tyrannosaurs, their absence in the south meant that raptors evolved to fill the apex predator role in what are now South America and Australia.
And it seems that these animals could have filled that niche right up to the end-Cretaceous extinction event. The remains of Joaquinraptor were dated back roughly 68 million years, making it one of the youngest-known megaraptors, whose reign may have continued were it not for cosmic intervention.
During their time, megaraptors seemed to take evolution in a different direction: rather than going for size and raw power, they kept their swift stature and grew big, strong hands that put T. rex‘s puny arms to shame.
“Megaraptorids, among other aspects, are characterized by powerfully developed forelimbs equipped with hypertrophied claws on the first and second digits,” Ibiricu said.
“So its claws may have played an important ecological role. For example, megaraptorids may have used these claws … to access soft tissues and/or to aid in prey capture and manipulation.”
The inevitable Jurassic Park 8 might have just found its perfect villain.
The research was published in the journal Nature Communications.
