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An artist's reconstruction of Joaquinraptor, with its crocodile meal. (Andrew McAfee, Carnegie Museum of Natural History)
Paleontologists person discovered a caller taxon of megaraptor dinosaur successful Argentina, on with a startling hint astir what it ate. Named Joaquinraptor casali, the apex predator seemingly ate crocodiles, judging by the limb bony recovered successful its mouth.
As the sanction suggests, megaraptors were a clade of carnivorous dinosaurs that looked similar elephantine versions of the raptors made celebrated successful Jurassic Park. In this case, the researchers estimation that Joaquinraptor was much than 7 meters (23 feet) long, chemoreceptor to tail, and weighed implicit 1,000 kilograms (2,200 pounds).
With nary tyrannosaurs astir successful that portion of the world, Joaquinraptor would apt person enjoyed beingness astatine the apical of the nutrient chain. This fossil find includes immoderate of the astir nonstop grounds of a megaraptor fare truthful far, which seemed to see the past ancestors of crocodiles.
Related: Giant 'Death Shadow' Dinosaur Found successful Argentina Is Largest Megaraptor On Record
"Interestingly, we recovered a humerus, betwixt the little jaw bones of Joaquinraptor, suggesting – though not proving – that the caller megaraptor whitethorn person been eating the crocodyliform erstwhile it died," Lucio Ibiricu, a paleontologist astatine the Patagonian Institute of Geology and Paleontology (IPGP), told ScienceAlert.
The researchers admit that the limb bony could person gotten determination immoderate different way, possibly washed into the submerged rima of the already-dead megaraptor. But fixed that the bony is not lone touching immoderate of the predator's teeth, but features bony marks arsenic well, immoderate benignant of enactment seems likely. The 2 creatures mightiness besides person been warring implicit different nutrient sources.
Perhaps Joaquinraptor was simply balancing the scoreboard for each the crocodilians suspected to person chowed down connected dinosaurs.
The crocodyliform limb bony and the megaraptor jaw arsenic they were primitively found. (Ibiricu et al., Nat. Commun. 2025)The researchers estimated the property of this peculiar idiosyncratic erstwhile it died by studying the microstructure of its bones. This Joaquinraptor seems to person been sexually mature, but not yet afloat grown.
"Mainly based connected the microstructure of a fragment of tibia of Joaquinraptor and the disposition of the LAGs (lines of arrested growth) recovered there, and assuming that LAGs correspond to annually deposited structures (like histrion rings), a minimum property of 19 years is inferred for this Joaquinraptor specimen," Ibiricu told ScienceAlert.
Although paleontologists lone recovered pieces of its jaws, skull, forelimbs, legs, and a fewer process vertebrae, this is 1 of the astir implicit megaraptor specimens discovered truthful far. So, on with adding a caller taxon to the roster of dinosaurs that lived successful past Patagonia, Joaquinraptor could assistance scientists capable successful immoderate gaps successful this little-understood clade.
While bluish landmasses were dominated by huge tyrannosaurs, their lack successful the southbound meant that raptors evolved to fill the apex predator role successful what are present South America and Australia.
And it seems that these animals could person filled that niche close up to the end-Cretaceous extinction event. The remains of Joaquinraptor were dated backmost astir 68 cardinal years, making it 1 of the youngest-known megaraptors, whose reign whitethorn person continued were it not for cosmic intervention.
Paleontologist Marcelo Luna holds a megaraptor claw. (Marcelo Luna)During their time, megaraptors seemed to instrumentality improvement successful a antithetic direction: alternatively than going for size and earthy power, they kept their swift stature and grew big, beardown hands that enactment T. rex's puny arms to shame.
"Megaraptorids, among different aspects, are characterized by powerfully developed forelimbs equipped with hypertrophied claws connected the archetypal and 2nd digits," Ibiricu said.
"So its claws whitethorn person played an important ecological role. For example, megaraptorids whitethorn person utilized these claws … to entree brushed tissues and/or to assistance successful prey seizure and manipulation."
The inevitable Jurassic Park 8 mightiness person conscionable recovered its cleanable villain.
The probe was published successful the diary Nature Communications.
