Dog-sized Jakapil kaniukura dinosaur discovered in Argentina


A species of dinosaur recently discovered in Argentina had an armored back, a distinctive jaw and tiny arms – and was about the size of a dog.

Fossils dated to the Upper Cretaceous Wet Period — nearly 100 million years ago — suggest that the Jakapil kaniukura walked on two feet, unlike most other dinosaurs in its family. The herbivorous creature had armored plates to protect it from predators and weighed about as much as a Boston terrier, according to a study published last week in the journal Scientific Reports.

The discovery of the jakapil sheds light on a previously unknown lineage of dinosaurs in the family Thyreophora, which includes the much larger Stegosaurus, in the Southern Hemisphere.

“For Argentines, Jakapil complete, in a vast succession of discoveries, the missing letter of our dinosaur alphabet, and we can, for the first time, show an alphabet of dinosaurs that lived in Argentina,” researcher Sebastián Apesteguía said in a statement.

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The jakapil’s name comes from the ridge on the lower part of the dinosaur’s jaw, the function of which is unknown. “Kaniukura” means “stone ridge” in the language of the indigenous Mapuche people, the researchers said.

The jakapil’s teeth were also unusual. While most herbivorous dinosaurs had similar leaf-shaped teeth in both jaws, the newly discovered dinosaur’s teeth had a different shape in each jaw. Its teeth also appear worn, which researchers say indicates it processes food more efficiently than other members of its family.

The path to reconstructing the dinosaur’s body began in 2012, when Apesteguía visited the paleontological area of ​​La Buitrera – where other dinosaurs have been discovered – and found two small bones that he could not identify. Two years later, he and other scientists discovered a skeleton with unusual teeth and a block-like jaw.

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A researcher recognized the fossil as a type of armored dinosaur and continued collecting bones until 2020 when he finished reconstructing the structure of the species. The desert region is uninhabitable for many species, so it tends to have fossils of a few animals, Apesteguía said in the statement.

“Jakapil is a very rare little dinosaur, and obviously he liked to travel in desert environments,” Apesteguía said.

Scientists shared a video reconstruction of the species on Twitter. In it, two jakapils walk along a desert landscape, stretch upwards and emit soft throaty growls.

Dinosaur finds are somewhat common; paleontologists identify dozens of species each year. In 2021, Australian scientists announced the discovery of a dinosaur the size of a basketball court.

But many dinosaurs would not have been fossilized, which means we will almost certainly never discover all the types that existed, Gizmodo reported. The fact that a dinosaur must have died under the right circumstances for its remains to be found makes every discovery a notable event.