New species of dinosaur with armored tail discovered in Chile

December 3, 2021

A new species of armored dinosaur discovered in Chile had a weaponized tail not seen before in any other dinosaur.

Roughly 2 meters (6.5 feet) in size, the small armored dinosaur called an ankylosaur dates from the late Cretaceous period, around 71.7 million to 74.9 million years ago. Its largely complete fossilized skeleton was found in Magallanes province in Patagonia, Chile's southernmost region.

The dinosaur, named Stegouros elengassen, had evolved a large tail weapon unlike those seen in other armored dinosaurs such as the paired spikes of Stegosaurus and the club-like tail of Ankylosaurus.

While its skull had features in common with other ankylosaurs, its tail weaponry was "bizarre," according to the study, which was published in the journal Nature on Wednesday. The dinosaur's tail had seven pairs of flattened, bony deposits fused together in a frond-like structure.

"The tail is extremely strange, as it is short for a dinosaur and the posterior half is encased in dermal bones (bones that grow in the skin) forming a unique (tail) weapon," said Sergio Soto Acuña, main author of the study and a doctoral student at the Universidad de Chile, via email.

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