Though only 20 percent of the Joaquinraptor casali fossil was recovered, it's one of the most complete skeletons of its kind ever found.
Andrew McAfee/Carnegie MuseumThe Joaquinraptor casali roamed what is now central Patagonia between 66 million and 70 million years ago.
Paleontologists in Argentina have uncovered one of the most complete megaraptor fossils ever found — from a newly identified species.
The fossil of the new megaraptor species, Joaquinraptor casali, was first spotted in 2019, but it took years for experts to fully excavate the prehistoric remains. Notably, the specimen in question was still holding the leg bone of a crocodilian, a large crocodile relative, in its mouth.
In total, paleontologists unearthed approximately 20 percent of the entire Joaquinraptor casali skeleton, which is more than most other megaraptor skeletons that have previously been found. According to a new study published in Nature Communications, the fossil includes remains of the apex predator’s skull, jaws, limbs, ribs, and tail vertebrae.
The Joaquinraptor Casali Roamed Modern-Day Argentina About 67 Million Years Ago
Marcelo LunaThe Joaquinraptor casali fossil was first spotted in 2019.
Before it fossilized, the Joaquinraptor casali specimen measured about 23 feet long and weighed more than 2,200 pounds. It prowled modern-day Argentina about 67 million years ago (the species as a whole lived between 66 million and 70 million years ago, during the Cretaceous period).
In its fossilized jaws were the remains of a crocodilian’s leg, which was probably the dinosaur’s last meal. This find not only provides insight into the megaraptor’s diet, but further proves the creature was a powerful predator, as the crocodilian was a fierce predator in its own right.
Ironically, the megaraptor’s ferociousness may have led to its death, as experts believe it might have choked while gnawing down on the crocodilian.
The Joaquinraptor casali fossil was first spotted in 2019 at the headwaters of the Rio Chico near the shore of Lago Colhué Huapi in Argentina. But it took years for experts to fully excavate and study the specimen.
Though many of the remains were fragmented, paleontologists still unearthed a lot more of that skeleton than they have for other megaraptors.
“It is among the most complete megaraptoran skeletons yet known to science,” paleontologist and study co-author Matt Lamanna told Reuters.
The jaws featured curved teeth that, while perfectly sharp for a meat-eating dinosaur, were small for a dinosaur its size. The Joaquinraptor casali was about 19 years old when it died, and it was probably not fully grown.
How This New Discovery Helps Paleontologists Learn More About Megaraptors
Marcelo LunaThe jaw remains of the Joaquinraptor casali, which was named after the study lead author’s son Joaquin.
The Joaquinraptor casali is just one type of megaraptor, a carnivorous group of dinosaurs that lived throughout prehistoric South America, Asia, and Australia. Megaraptors first emerged nearly 130 million years ago, but the Joaquinraptor casali shows that they survived up until the asteroid that ended the reign of non-avian dinosaurs hit Earth 66 million years ago.
“Megaraptorans are among the least understood dinosaurs of all,” study lead author and paleontologist Lucio Ibiricu told Reuters.
The newly uncovered Joaquinraptor casali fossil is one of the most complete fossils of its kind to have been discovered so far. The fossil has allowed paleontologists to learn a lot about the Joaquinraptor casali’s lifestyle, like how it probably preyed upon several different plant-eating dinosaurs, such as long-necked titanosaurs and duck-billed hadrosaurs.
Though Joaquinraptor casali would’ve walked the Earth at the same time as North America’s Tyrannosaurus rex, the two dinosaurs had a few notable differences, including that the Joaquinraptor casali boasted longer and stronger arms. Megaraptors likely used their arms to catch their prey.
“This suggests that these two predatory dinosaur lineages evolved different adaptations to accomplish basically the same thing — that is, to capture, subdue, kill and eat other animals such as other dinosaurs,” Lamanna explained. “Precisely why these groups evolved along these different evolutionary pathways remains a mystery, but it shows that, during the Cretaceous, there was more than one way to be a top predator.”
Next, learn about how researchers just directly dated dinosaur eggs for the first time. Then, take a look at how the dinosaurs went extinct.
