95 million years ago, Spinosaurus had a scimitar-shaped head crest and walked the rivers of the Sahara like a ‘hell’s heron’

About 95 million years ago, a spinosaurus dinosaur with a tall blade-like crest on its head and a large sail on its back lived in what is now Niger, a new study has found.

The newly discovered species, which researchers named Spinosaurus mirabilis (Latin for “amazing spinosaurus”), lived far inland along rivers — a finding that could hold the key to resolving the debate over whether the dinosaur and its relatives were swimmers, the researchers reported Thursday in the journal Science.

“There is simply no way to discover an essentially aquatic animal buried in river sediment hundreds of miles from the coastline,” Paul Sereno, a paleontologist at the University of Chicago who was the study’s lead author and led the fossil discovery team, told Live Science.

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Sereno’s team made the discovery in 2019 thanks to a Tuareg guide, a member of a local nomadic tribe living in the Sahara desert. The guide led them to the remote location on a several-hour trek in 2019. Paleontologists who looked at the fossil noticed something unusual. It turns out that the bones were black because the concentration of phosphate in them increased. Sereno said that in his 25 years of field work, he had never seen colored fossils in the Sahara Desert.

The coat of arms indicates a new species

At first, Sereno and his team couldn’t understand how some of the bones fit into the rest of the skeleton. “We didn’t recognize the coat of arms,” ​​Sereno said. [and] It’s asymmetrical. ”

When a large team visited the same site in 2022 and discovered a skull with a partial emblem on it, everything clicked. After performing CT scans of the fossil and using computer models, the researchers found numerous fossilized blood vessels inside, as well as a surface texture that suggested the bone was actually covered by a sheath of keratin. This would have given it a peak height of up to 20 inches (0.5 meters).

In a paper describing their discovery, the researchers called it the tallest crest known among carnivorous dinosaurs and argued that it served a decorative role, perhaps allowing the animal to identify potential mates or rivals as it walked along riverbanks.

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Paleontologist Dan Vidal has collected a variety of black bones, including jaw pieces and crest fragments from Spinosaurus mirabilis.

Close-up of the crown of Spinosaurus mirabilis. It is estimated to be about 2 feet long.

Skull model of Spinosaurus mirabilis, a new species of Scimitatosaurus dinosaur

Paleontologist Paul Sereno poses with a Spinosaurus mirabilis skull model.

Observing the open jaws of a newly discovered dinosaur species, Spinosaurus mirabilis

About 95 million years ago, two Spinosaurus mirabilis dinosaurs fight over the carcass of a Coelacanth mausonia on a forested riverbank in the Sahara Desert in what is now Niger.

Spinosaurus mirabilis devoured prey during the Cretaceous period 95 million years ago.

New head and neck rendering of Scimitar-crested Spinosaurus mirabilis skull and neck bones

So…was Spinosaurus a swimmer?

In recent years, some researchers have proposed that Spinosaurus (the genus that includes S. mirabilis and its relative S. aegyptiacus) was a marine hunter, chasing prey underwater. For example, the researchers reported that S. mirabilis has the iconic teeth of a fish hunter, with teeth on the lower jaw that stick out and sit neatly between the sharp teeth on the upper jaw.

However, based on the fossil’s location (it was buried next to two long-necked sauropods in a riverbed) and its body shape, Professor Sereno believes that this dinosaur was a kind of ‘hell’s heron’ that could easily walk up to 2 meters on strong legs. [6.5 feet] “Although the water was deep, we probably spent most of our time searching for shallow traps, targeting many of the big fish that day,” he said in a statement.

The rear sail would have added so much weight to Spinosaurus’ body that it would have had difficulty moving, Sereno noted. Therefore, it is unlikely that members of this genus swam, he said. “To do that… we sacrifice the agility aspect, which is an important feature,” Serrano told Live Science.

In the paper, the researchers compared S. mirabilis’ body shape to other living and extinct predators, placing it between semi-aquatic waders like herons and aquatic divers like penguins.

“This shows how science evaluates evidence and new evidence emerges,” Sereno said.

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