In February of 2018, paleontologists discovered the fossil of an unknown species of ankylosaur dinosaur in the Chilean Patagonia. Like other members of the Ankylosauria group of herbivore dinosaurs, this species would’ve been a bulky quadruped. With short, powerful limbs and armor in the form of bony osteoderms. However, unlike other ankylosaurs, this one apparently had a tail a lot like an Aztec sword-club.
Live Science reported on the new species of ankylosaurus, which its discoverers have dubbed Stegouros elengassen. Aside from standing as a new species of ankylosaurus, S. elengassen is also the most complete dinosaur fossil that’s ever appeared in Chile. Indeed, even “a milestone” paleontological discovery for the country.
“It was a great surprise,” Chilean paleontologist, Sergio Soto-Acuña from the University of Chile, told the scientific news agency of the Spanish Foundation for Science and Technology, SINC. Soto-Acuña is the co-lead author on a study outlining S. elengassen published in the journal Nature. He also added that he and his colleagues did not expect to find the remains of an ankylosaur in the southernmost tip of the country.
Its discoverers found the fossil of S. elengassen in Cretaceous period rocks. These rocks date back to somewhere between 71 and 75 million years ago. The fossil remains n good condition, with approximately 80% of the extinct dino’s fossilized bones still intact. However, it’s more intact from the waist down. According to speculation by co-lead Alexander Vargas, this anomaly may have occurred because the dinosaur trapped itself in quicksand. The quicksand may have preserved the bones.
The paleontologists now have the 6.5-foot-long dinosaur pegged as a “transitional” ankylosaur. Soto-Acuña et al. note that the split of Pangea into the northern supercontinent Laurasia and southern supercontinent Gondwana between 201 million and 145 million years ago split Ankylosauria as well. It led to ankylosaurs with paired spikes or clubs on their tails in the north. However, in the south, the extant lineage had more slender limbs, lighter bony armor, and a relatively underdeveloped tail.
Speaking of which, Vargas told Live Science that S. elengassen‘s tail appeared similar to a macuahuitl; that is, a sword-club that Aztec military forces commonly used. Indeed, the new dino species’ tail does look somewhat like a macuahuitl with its large, flat osteoderms. Plus, it seems about the right length too. Which kind of makes us wonder if some other S. elengassen fossils in the region could’ve inspired the weapons? Nature makes for a great muse when it comes to making deadly things, after all.