Paleontologists have unearthed a remarkable new predatory dinosaur species in Patagonia, Argentina, adding a significant piece to the puzzle of the late Cretaceous period. Dubbed *Joaquinraptor casali*, this megaraptoran offers unprecedented insights into the lives and diets of these fascinating creatures. The exceptionally well-preserved fossils, including a significant portion of the skull, limbs, ribs, and vertebrae, were discovered in the Lago Colhué Huapi Formation. Remarkably, a fossilized crocodile leg bone was found pressed against the dinosaur's lower jaw, providing compelling evidence of its predatory behavior.
*Joaquinraptor casali* belonged to the megaraptoran family of theropods, known for their elongated skulls, powerful forearms, and large claws. While megaraptorans have been found across Asia, Australia, and South America, complete fossils have been rare, hindering a comprehensive understanding of the group. This discovery significantly expands our knowledge. Analysis suggests the specimen was an adult, though not fully mature, estimated to be around 19 years old based on its bone microstructure. Extrapolating from the fossil remains, scientists estimate the dinosaur's length at approximately 23 feet and weight exceeding 2,200 pounds.
The sedimentary evidence points to a humid floodplain environment during the late Cretaceous period, approximately 66 to 70 million years ago. The presence of the crocodile bone strongly suggests *Joaquinraptor casali* was an apex predator in its ecosystem, dominating the food chain. This discovery supports the hypothesis that megaraptorans, including *J. casali*, were the dominant predators of their region, a dominance that ended with the extinction event at the close of the Cretaceous period along with other non-avian dinosaurs.
While this discovery provides remarkable insights, further research is crucial to fully understand *Joaquinraptor casali*'s ecological role and behavior within its environment. This exceptional fossil find promises to significantly advance our understanding of megaraptorans and the biodiversity of the late Cretaceous period in Patagonia.
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Originally published at: https://abcnews.go.com/International/fossils-new-dinosaur-species-found-crocodile-bone-mouth/story?id=125897987
