Armored dinosaur discovered in Chile had “bizarre tail” as weapon

A new species of armored dinosaur, discovered in Chile, had a tail like a weapon never seen before in any other dinosaur. At approximately 2 meters, the small armored dinosaur – called ankylosaurus – dates from the late Cretaceous period, about 71.7 million to 74.9 million years ago.

Its fossilized skeleton, largely complete, was found in the province of Magallanes, in Patagonia, the southernmost region of Chile.

The dinosaur, called Stegouros elengassen, had developed a large-tailed weapon unlike those seen in other armored dinosaurs, such as the paired tips of Stegosaurus and the club-shaped tail of Ankylosaurus.

Although its skull had features in common with other ankylosaurus, its tail armament was “bizarre”, according to the study, which was published in the journal Nature on Wednesday (1). The dinosaur’s tail had seven pairs of flat, bony deposits fused into a foliage-like structure.

“The tail is extremely strange, as it is short for a dinosaur and the back half is wrapped in dermal bones (bones that grow in the skin) forming a unique weapon (tail),” said Sergio Soto Acuña, lead author of the study and doctoral student at University of Chile.

Chilean paleontologist Sergio Soto was the lead author of the study / Courtesy Sergio Soto He said it looked like the tail of a rattlesnake or spiny-tailed lizard. But unlike these creatures, the dinosaur had real bones under its scales. The most similar feature would be the tail of a giant armadillo, but they are also extinct, he added.

Stegouros, meaning “covered tail” in Greek and “elenggassen”, comes from Aonikenk, the language of the original inhabitants of Patagonia, and refers to a mythological beast in armor. The fossil was found in 2018.

The study noted that few ankylosaurs were found in southern Gondwana – the lower part of the ancient supercontinent Pangea.

“Unlike the northern hemisphere ankylosaurus, our new dinosaur has light armor, slender legs and a smaller size,” he said.

Fossilized plants discovered in the same region indicate that the climate was warmer when this dinosaur inhabited the site – very different from the current cold climate prevailing in Patagonia.

(Text translated, read original in English here)