New species Joaquinraptor casali described from Patagonia

Paleontologists have described a new species of large predatory dinosaur, Joaquinraptor casali, from central Patagonia whose near-complete skeleton was recovered with the humerus of an extinct crocodyliform pressed between its lower jaws, researchers reported in a study published Sept. 23 in Nature Communications. The specimen, excavated in 2019 from the Lago Colhué Huapi Formation near the headwaters of the Río Chico in Chubut province, Argentina, dates to the latest Cretaceous, about 70 to 66 million years ago.

The fossilized remains are unusually well preserved and partially articulated, including much of the skull, forelimbs, hindlimbs, ribs and vertebrae. Microstructural analysis of the bones indicates the animal was a sexually mature adult, at least 19 years old at death. Researchers estimate Joaquinraptor measured about 7 metres long, roughly 23 feet, and weighed more than one tonne. The new taxon belongs to Megaraptora, a group of large-clawed theropods known for elongated skulls and powerful forearms, and may be one of the geologically youngest members of that group yet discovered.

Lead researcher Lucio Ibiricu of the Patagonian Institute of Geology and Paleontology...