beware the tail

Look: This dinosaur had a natural weapon unlike any other


Mauricio Álvarez

Esther van Hulsen/Stocktrek Images/Stocktrek Images/Getty Images

Ankylosaurs are known for their full-body armor and massive, club-like tails.

Their distant cousins, stegosaurs, were studded with armored plates and had deadly spiked tails called thagomizers.

The late Jurassic and Cretaceous periods were the heydays for these beefy, spiked dinosaurs.

Now, a species new to science, described this month in the journal Nature, pieces together yet more details of their evolution.

Lucas Jaymez.

Dubbed Stegouros elengassen, this little punk was about 6.5 feet long, from head to tail.

Luis Pérez López

Mauricio Álvarez

But what a tail. It had a distinct form of tail weaponry — one that would shame other known ankylosaurs.

Instead of a club, this bad boy had a flat tail, segmented like a leaf.

This 3-D reconstruction shows the segmented tail of S. Elengassen.

José Palma and Joao Francisco Botelho

Sergio Soto and Alexander Vargas

A near-complete skeleton of the dino was discovered in subantarctic Chile — a region where researchers have unearthed very few remains of armored dinosaurs.


Hundreds of millions of years ago, that region was part of the southern half of Pangea, called Gondwana.

Most ankylosaur species have been discovered in the northern half of Pangea, which makes the finding of Stegorous extremely rare.

Stegouros elengassen has elements of both Stegosaurus and Ankylosaurus, but it is more closely related to Ankylosaurs.

Soto-Acuña et. al./Nature

Lucas Jaymez

Yet its closest relatives are other short, stout, armored dinosaurs that once roamed Antarctica and Australia.

Stocktrek Images/Stocktrek Images/Getty Images

Researchers think some of the earliest ankylosaurs lived in Gondwana, and future finds could help us piece together more of these studded punks’ history.

Lucas Jaymez

The study authors hypothesize ankylosaurs branched off into two separate groups after Pangea split into two major parts.

Mauricio Álvarez

“Stegouros illustrate(s) that much still remains unknown about the evolution of armored dinosaurs, especially in Gondwana.”

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