Amazing dino discoveries

Is T. Rex actually three different species? 

For more than a million years, Tyrannosaurus rex ruled what’s now western North America, from Canada to New Mexico. But a few scientists think that some of the fossils that we call T. rex are actually two new species of tyrannosaur.

These paleontologists looked at 37 skeletons labeled T. rex. They found that the oldest skeletons had stockier femurs, or thighbones, and two pairs of chisel-like incisor teeth on their lower jaw. They suggested naming this species T. imperator, the Latin word for “emperor.”

A group of younger fossils that have a single pair of the incisor teeth and narrower femurs should be another species, T. regina, the Latin word for “queen.” The only fossils considered to be the species T. rex  would be younger fossils with one pair of incisors and thicker femurs.

But other paleontologists disagree: They say the difference between the thighbone thickness could be because the dinosaurs were different ages when they died. Another explanation could be simply that different dinos were different sizes, just like how people can be short or tall. Plus, another paleontologist who studied 1,850 T. rex skeletons didn’t find the same results.

The study shows that even when it comes to the world’s most famous dinosaur, we’ve still got a lot to learn!

TEXT ADAPTED FROM A FEBRUARY 2022 NATIONAL GEOGRAPHIC ONLINE ARTICLE

Spiky-ribbed ankylosaur 

Between 168 million and 164 million years ago, a strange reptile walked through what’s now northern Morocco—a creature with large spikes attached to its ribs that sometimes even grew out of its skin!

Paleontologists think that this new species belongs to a type of armored dinosaur called an ankylosaur. Base on the one fossil they found—a piece of a rib bone about 10.5 inches long—scientists named the dinosaur Spicomellus afer. That comes from the Latin words for “spike,” “collar,” and “inhabitant of Africa.”

This new dino is the oldest known ankylosaur and the first to be found in Africa. Even more amazing, scientists don’t know of any other animal with such strange ribs.

“If you feel your own ribs, there’s muscles over the top of them that allow your arms to move,” says Susannah Maidment, the paleontologist at London’s Natural History Museum who led the research on Spicomellus. “What were they doing with their muscles when their ribs clearly had spikes above the skin?”

TEXT ADAPTED FROM A DECEMBER 2021 NATIONAL GEOGRAPHIC ONLINE ARTICLE

Australia’s biggest dinosaur 

In the Australian outback, sheep and cattle ranchers stumbled on an ancient bone bed—and uncovered Australia’s biggest known dinosaur.

For 10 years, scientists have been running tests on the fossils from the 95-million-year-old animal—which they nicknamed “Cooper” after a nearby creek. But now they’re sure that this dino is a new species, which they named Australotitan cooperensis.

Australotitan is a member of the sauropod family, a group of long-necked, plant-eating dinosaurs that include the biggest animals that ever walked on land. (Brachiosaurus is also a member of this group.) Australotitan is the largest dinosaur ever discovered in Australia: Its upper leg bones were at least 6.2 feet long, and the animal is estimated to have weighed between 26 and 82 tons. (That means it might’ve weighed more than three loaded garbage trucks!)

TEXT ADAPTED FROM A DECEMBER 2021 NATIONAL GEOGRAPHIC ONLINE ARTICLE

Herbivore with comma-shaped crest 

A team of Mexican paleontologists excavated the remains of a new species of dinosaur that lived about 72 million years ago. Scientists named the species Tlatolophus galorum for the crest on its skull that looks like the tlahtolli, a comma-like symbol in Aztec art. (The Aztecs were people who lived in what's now central Mexico from 1345 to 1521.)

Plant-eating Tlatolophus probably stretched about 26 feet from snout to tail and stood about 6.5 feet tall at the hip. Based on its well-preserved skull, scientists think that the animal was a close cousin of Parasaurolophus, which also has a fancy crest. Experts think the crest of Tlatolophus affected the sound of their calls and were therefore used to help them communicate.

TEXT ADAPTED FROM A DECEMBER 2021 NATIONAL GEOGRAPHIC ONLINE ARTICLE

Croc-faced dinos

Fossils found on the Isle of Wight in the United Kingdom revealed two new dinosaur species with crocodile-like skulls. (Although today it’s an island, this spot was a savanna-like, river-filled valley 125 million years ago.)

Both dinos are types of spinosaurid, a group of large predatory dinosaurs that includes Spinosaurus. Each dinosaur was probably about 26 feet long and roughly 6.6 feet tall at the hip.

Because spinosaurids were likely riverbank hunters like today’s herons, one of the new species is named Ceratosuchops inferodios, which comes from the words for “horned crocodile-faced fiery heron.” The other species is named Riparovenator milnerae; that translates to “Milner’s riverbank hunter” in honor of a British spinosaurid expert.

TEXT ADAPTED FROM A DECEMBER 2021 NATIONAL GEOGRAPHIC ONLINE ARTICLE

Dinosaur with blade-like tail 

More than 72 million years ago in what’s now Chile, a tough little dinosaur wielded a unique weapon: Its tail was a mass of fused bone resembling a jagged paddle. Alexander Vargas, a paleontologist at the University of Chile, says that the tail is something they’ve never seen before.

The new species is called Stegouros elengassen. (Stegoros means “roof tail” in Greek, and the word elengassen comes from a beast in the mythology of the Indigenous people who lived where the fossils were found.) Scientists even gave its tail a unique word—macuahuitl—named after a bladed club wielded by the Aztec people.

Paleontologists are a bit puzzled by this dino. Its skull, teeth, and club-like tail make it seem like an armored ankylosaur. But the dinosaur’s slender limb bones and pelvis look more like those of a stegosaur, which had been extinct for tens of millions of years by the time Stegouros elengassen emerged. 

TEXT ADAPTED FROM A DECEMBER 2021 NATIONAL GEOGRAPHIC ONLINE ARTICLE