Rare toothless dinosaur is an oddity among its carnivorous cousins
Today, a piece of land in the state of Paraná, in southern Brazil, is called the Pterosaur Cemetery because of the hundreds of fossilized pterosaur bones found in the ancient basin. So when paleontologists working there unearthed a new fossil creature with a horny parrot-like beak, they first assumed it was another flying reptile.
Instead, the researchers were shocked to learn that they had found a whole new species of toothless dinosaur. Stranger still, the animal belongs to a group called ceratosaurs, almost all carnivores.
“The fact that we now have this toothless dinosaur means that we have to rethink the evolutionary loss of teeth for all the dinosaurs in this group,” says Alexander Kellner, paleontologist on the team that found the fossil and director of the National Museum of Brazil . “It’s a discovery that will change the way we think and what we know about these animals.”
The fossilized skeleton, described in the review Scientific reports, belongs to a new species called Berthasaura leopoldinae who lived between 80 and 70 million years ago in the Cretaceous. The official name is a nod to Bertha Lutz, a prominent Brazilian scientist who defended women’s suffrage, and Maria Leopoldina, an Austrian who became Empress of Brazil and advocate for the natural sciences.
The nickname makes Berthasaura one of the few dinosaurs to pay homage to women of a newly named gender.
“This is an important message that could inspire new women scientists to join these fields, and in particular the study of dinosaurs”, explains Aline Ghilardi, paleontologist at the Federal University of Rio Grande do Norte who was not part of the study team.
She also notes the value of the skeleton being almost complete and extremely well preserved. Between 2011 and 2014, researchers from the National Museum of Brazil and the Paleontological Center of the University of Contestado collected parts of his skull and jaw, spine, pectoral and pelvic bones, as well as his front and rear limbs.
“This is something that is always welcomed in paleontology,” says Ghilardi, “because it helps us better understand the relationships between species. “
When the researchers who found Berthasaura leopoldinae realized that the dinosaur in front of them had no teeth, they immediately thought of Limusaurus inextricabilis, a toothless theropod found in northwest China. Limusaurus lived between 161 million and 156 million years ago, during the Jurassic period. Based on fossils of adults and juveniles of the same species, scientists know that this ceratosaurian dinosaur lost its teeth as a teenager and did not grow from another set.
Berthasaura, on the other hand, never had any teeth at all.
The skeleton found at Paraná is that of a young animal, and “on the upper arch [of the mouth] it was clear that there were no teeth, ”Kellner says. “There was a plate of bone where you would expect teeth. But we wondered if there were teeth on the lower arch? So we isolated that part of the material and used a CT scan to confirm that this animal really never had teeth. “