Dinosaur found with a crocodile in its jaws named as new species

The excavation of what might be one of the most formidable predators of the Cretaceous has taken place in South America, where the remains of a dinosaur—complete with an extinct crocodile’s leg in its jaws—were unearthed.

The newly identified dinosaur, named Joaquinraptor casali, a member of the megaraptor family, was discovered in the Rio Chico river headwaters in Patagonia, Argentina, in 2019. Researchers believe it thrived shortly before the mass extinction that wiped out non-avian dinosaurs 66 million years ago.

In a detailed study conducted by Lucio Ibiricu from the National Scientific and Technical Research Council in Chubut, Argentina, the fossil was meticulously analyzed, revealing unexpected findings within the near-complete skull.

“The humerus—essentially the leg bone—of an extinct crocodile relative was lodged between the jaws of Joaquinraptor, in direct contact with its teeth,” explains Ibiricu. “This discovery hints, though it does not conclusively prove, that the new megaraptor may have been consuming the crocodyliform when it met its demise.”

Researchers are currently examining the crocodile’s humerus to gauge its size, but initial assessments indicate it was quite large, according to Ibiricu.

Besides recovering the majority of the dinosaur’s skull, the research team also excavated its vertebral column, feet, two claws, along with an arm, leg, and hand. The thumb claw, comparable in size to a human forearm, would have been effective in tearing open the flesh of its prey, according to Ibiricu.

Previously discovered megaraptoran fossils have been found across Asia, Australia, and other parts of South America, but J. casali stands out as it is the first identified species from close to the end of the Cretaceous period and is notably one of the most complete specimens ever found.

Research indicates that the dinosaur had reached at least 19 years of age at the time of its death, based on analyses of the tibia’s microstructure. It is estimated to have been around 7 meters in length and weighed no less than a tonne.

While Tyrannosaurus rex was larger and featured a bigger skull, J. casali boasted more muscular arms, as stated by Ibiricu. Both dinosaurs likely occupied the apex predator role within their respective ecosystems.