Fossilized remains have led to the identification of new dinosaur species, along with evidence of the last meal, according to a new study released on September 23.
It seems the predator ate crocodiles, given that a leg bone was found right in its fossilized mouth.
The new dinosaur, named Joaquinraptor casali, was about 23 feet (7 meters) long and weighed over 1,000 kilograms (2,200 pounds).
The meat-eating creature lived 70 to 66 million years ago, and the fossil provides a rare snapshot of its life.
The Patagonian Institute of Geology and Paleontology unearthed the remains from the Lago Colhué Huapi rock formation in Patagonia, Argentina.
One of the most complete fossils
During the Cretaceous Era (about 143 to 66 million years ago), a diverse group of large predatory theropod dinosaurs called megaraptorans lived across Asia, Australia, and South America.
Long skulls, powerful forearms, and large claws characterized megaraptorans.
Despite their wide distribution and millions of years of evolution, the family’s evolutionary history remains poorly understood because the fossil record consists mainly of incomplete and isolated remains.
This made it difficult to see how megaraptorans fit into the broader evolutionary timeline.
“Many important aspects of megaraptoran morphology and evolution remain poorly understood, due in large part to the fragmentary nature of most fossils of these theropods,” the study noted.
This new fossil contains parts of a skull, along with arm, leg, and tail bones, making it one of the most complete fossils ever found for this group.
The analysis revealed previously unknown features in the bones, which pointed towards it being a new species.
As per the study, the dinosaur was likely a “minimum of 19 years old” at the time of its death, though the cause of death remains unknown.
The dinosaur’s death scene held a surprising detail: the skeleton remains preserved a front leg bone (humerus) wedged against the dinosaur’s lower jaws.
Reportedly, the researchers acknowledge that the crocodile bone could have been deposited there in other ways, such as being washed into the mouth of the already-dead dinosaur.
However, the presence of tooth marks on the bone suggests a direct interaction, such as eating or a fight over food.
The fossil’s surrounding sediments suggest the dinosaur lived in a hot, damp floodplain environment.
Dominant hunter
It was likely a dominant hunter on the humid flood plains.
In the southern continents of South America and Australia, raptors evolved to become the top predators, filling the ecological niche that was occupied by large tyrannosaurs in the northern landmasses.
“Megaraptorids appear to have been the apex predators in central and southern Patagonian palaeoecosystems approaching the end of the Cretaceous, in contrast to more northerly areas of South America where these niches were occupied by other non-avian theropod groups,” the study noted.
The species was named to honor the son of the study’s lead author, Lucio M. Ibiricu, and the Valle Joaquín locality where the fossil was found.
The dinosaur‘s reign as a top predator came to an end with the catastrophic Chicxulub event, which caused a mass extinction 66 million years ago.
The discovery of the new megaraptoran species helps to fill a major gap in scientific knowledge about this group of dinosaurs. However, more research is needed to understand its behavior and role within its ecosystem fully.
The findings were published in the journal Nature Communications.