Art print by Jakapil kaniukura. Credit: Gabriel Díaz Yantén.
You’ve probably heard of (or at least seen a picture of) Ankylosaurus, a heavily armored four-legged dinosaur with a large club-like protrusion at the end of its tail. These fascinating dinosaurs belonged to the order Thyreophora, which means “shield bearers”, and used to be some of the most extraordinary creatures to roam the Earth. Now, paleontologists have discovered a much more primitive relative of the Ankylosaurus, a small armored Cretaceous dinosaur that lived about 100 million years ago in South America.
The newly discovered thyreophorus was discovered during excavations in Argentina’s Río Negro province in northern Patagonia, and may represent an entirely new lineage of armored dinosaurs that called South America home.
Known as Jakapil kaniukura, this dinosaur ran on two legs and had rows of disc-shaped body armor on its neck, back and tail, quite similar to Ankylosaurus. This bony armor would have offered some protection from predators, and the small Cretaceous dinosaur must have found it useful.
Credit: Gabriel Díaz Yantén.
Measuring about 1.5 meters in length but weighing only 4 to 7 kilograms, Jakapil was in the weight class of a domestic cat. The low weight and erect body of the herbivore probably helped Jakapil to be very agile, but also vulnerable if caught. Fortunately, his armor would have made it difficult for a predator to pierce his flesh.
It probably used its short, but powerful beak to eat tough, woody vegetation. This fantastic CGI animation below gives us a hint of what Jakapil must have looked and sounded like roaming the barren steppes of Patagonia in the Cretaceous.
Excavations at Río Negro were led by internationally renowned paleontologist Sebastian Apesteguia, who found a partial Jakapil skeleton along with 15 tooth fragments with a strange blade shape, similar to iguana teeth. Jakapil is much older than Ankylosaurus or Stegosaurus and represents the only armored dinosaur from South America. Most thyreophores are known from the northern hemisphere.
“It has unusual anatomical features that show that several traits traditionally associated with heavy Cretaceous thyrophorans did not occur universally,” the authors of the new study wrote. “Jakapil also shows that early thyrophorans had a much wider geographic distribution than previously thought.”
The findings were reported in the journal Scientific Reports.