Paleontologists Discovered Dinosaur Remains with Deadly Armored Tail

Paleontologists working in subantarctic Chile have unearthed the bones of a "very strange" ankylosaur with a deadly armored tail, unlike any other known dinosaur, according to the experts.

The Untold Tale About Ankylosaur Evolution

Study co-lead researcher Alexander Vargas, a vertebrate paleontologist at the University of Chile's Department of Biology told Live Science the tail would have appeared like a sword because it's so flat. And it would have looked a little like an Aztec sword, or the macuahuitl also called the Aztec club.

The dinosaur's bones provide a previously unknown story about ankylosaur evolution, in addition to revealing its armored tail, according to Live Science.

During the Jurassic period (201.3 million to 145 million years ago), the supercontinent Pangaea broke apart, resulting in extreme differences between ankylosaurs on the northern supercontinent Laurasia and those on the southern supercontinent Gondwana, such as this newly discovered species, Stegouros elengassen.

The new species was reported in a paper published online in the journal Nature on Wednesday (Dec. 1).

Scientists Believe the Ankylosaur Died by a River

In February 2018, paleontologists discovered S. elengassen in Cretaceous era rocks ranging from 71.7 million to 74.9 million years old. That it's articulated [the bones are in order] from the waist down is remarkable.

Vargas said the skeleton was well-preserved and around 80% complete. He hypothesized that the beast died near a river, maybe in quicksand, explaining its well-preserved bottom half.

According to Vargas, the team only had five days in the field season to unearth the dinosaur bones, resulting in a difficult endeavor that included a damaged ankle, a broken rib, and near-hypothermia among the crew. But their perseverance paid off: the mostly Chilean crew now has a beautiful specimen of a 6.5-foot-long (2-meter) ankylosaur with a fern-frond-like tail.

The Most Distinguishing Characteristic of S. elengassen

The genus name of the dinosaur is drived from the Greek words for "roof" (stego) and "tail" (uros), elengassen refers to an armored beast from the Aónik'enk people's mythology.

S. elengassen is unlike other Laurasian ankylosaurs in that it is very poorly armored with a few rows of osteoderms, or bone plates, and had a quite big skull with a thin, curved beak, which is not typical of ankylosaurs. Its limbs are thin. It possesses rounded, hoof-like claws on both hands and feet, rather than sharp claws.

Furthermore, the pelvis of an ankylosaur is broad and stegosaur-like. The most distinguishing characteristic of S. elengassen is its tail, which is the shortest of any known armored dinosaur. It's made up of seven big, flattened osteoderms in pairs.

They are welded together to make a flat, robust weapon, according to Vargas. Other ankylosaurs possessed spikes or clubs on their tails.

Vargas says it was unclear if Laurasian ankylosaurs had traveled south to colonize Gondwana.

The new research demonstrates that S. elengassen and two other Southern Hemisphere ankylosaurs - Antarctopelta from Antarctica and Kunbarrasaurus from Australia - lack many of the specialized features that the ankylosaurs of the North possessed and that they already had in the mid-Jurassic. He pointed out that it's possible that these roots go back much farther than the mid-Jurassic.

For more news, updates about dinosaurs and similar topics don't forget to follow Nature World News!