Bizarre Spinosaurus Makes History as the First Known Swimming Dinosaur

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At the end of a dark hallway at Hassan II University in Casablanca, I entered a dusty room containing a remarkable collection of fossils – bones that raise fundamental questions about Spinosaurus aegyptiacus, one of the strangest dinosaurs ever discovered.

Longer than an adult Tyrannosaurus rex, the seven-meter-long predator had a large sail on its back and an elongated snout that resembled the mouth of a crocodile, bristling with conical teeth. For decades, reconstructions of his bulky body ended in a long narrowed tail like those of his numerous theropod cousins.

The brown-red remains deposited in front of me modify this image. These bones assemble into an almost complete tail, the first still found for Spinosaurus. It’s so big, five tables are needed to support its full length, and to my shock, the appendage looks like a giant bone paddle.

Shovels scrape and pickaxes fly as crew members move away from the Zrigat site in Morocco, where paleontologist Nizar Ibrahim and his colleagues dug a Spinosaurus skeleton.

Described today in the newspaper Nature, this tail is the most extreme aquatic adaptation ever seen in a large dinosaur. Its discovery in Morocco allows us to better understand how one of the most dominant groups of terrestrial animals on Earth has lived and prospered.

Delicate struts almost two feet long protrude from numerous vertebrae that make up the tail, giving it the profile of an oar. At the end of the tail, the bony bumps that help interlock the adjacent vertebrae practically disappear, leaving the tip of the tail waving back and forth in a way that would propel the animal through the water. The adaptation probably helped her to move through the vast river ecosystem she called her home – or even to run after the huge fish she probably attacked.

“It was basically a dinosaur trying to build a fishtail,” said Nizar Ibrahim, emerging National Geographic explorer, principal investigator who examines the fossil.

The structure of the bones – as well as advanced robotic tail movement modeling – add new and compelling evidence to an argument that has been raging for years among paleontologists: how long Spinosaurus actually swim and, by implication, how close have large predatory dinosaurs ever come to life in water? In 2014, researchers led by Ibrahim argued that the predator was the first confirmed semi-aquatic dinosaur, a hypothesis that generated a decline in peers who wondered if the Ibrahim fossil team was studying was in fact Spinosaurus, or even a single individual.

Samir Zouhri, paleontologist at Hassan II University, Casablanca, explores a site near Sidi Ali, Morocco, for more fossils from the time of Spinosaurus.

At time Spinosaurus95 to 100 million years ago in the Cretaceous, several groups of reptiles had evolved to live in marine environments, such as dolphin-like ichthyosaurs and long-necked plesiosaurs. But these dinosaur-era sea monsters sit on a different branch of the reptile family tree, while real dinosaurs like Spinosaurus have long been considered land dwellers.

Now, with the newly analyzed tail evidence, there are strong arguments Spinosaurus did not simply flirt with the shore but was capable of fully fledged aquatic movements. Collectively, the results released today suggest that the giant Spinosaurus spent a lot of time underwater, maybe hunting prey like a massive crocodile. “This queue is unambiguous,” said team member Samir Zouhri, a paleontologist at Hassan II University. “This dinosaur was swimming. “

Other scientists who evaluated the new study agree that the tail puts lingering doubts and strengthens the case of a semi-aquatic Spinosaurus.

“It’s certainly a bit of a surprise,” said University of Maryland paleontologist Tom Holtz, who was not involved in the study. ” Spinosaurus is even stranger than we thought. ”

Bones and bombs

The story of Spinosaurus is almost as unusual as the tail found, an adventure that winds through German museums bombarded with Martian sandstone from the Moroccan Sahara.

The remains of this strange animal first appeared over a century ago, thanks to Bavarian paleontologist and aristocrat Ernst Freiherr Stromer von Reichenbach. From 1910 to 1914, Stromer organized a series of expeditions to Egypt that produced dozens of fossils, including pieces of what he would later call Spinosaurus aegyptiacus. In his first published description, Stromer struggled to explain the creature’s anatomy, speculating that his quirk “speaks of some specialization.” He imagined the animal standing on its hind legs as an imbalance T. rex, his long back bristling with thorns. When the fossils were exhibited at the paleontological museum in Munich, they made Stromer famous.

Paleontologist Cristiano Dal Sasso delicately holds the fourth vertebra at the base of Spinosaurus’S tail, one of the most complete vertebrae the team has recovered.

During World War II, Allied bombing prompted Stromer – a critic of the Nazi regime – to beg the museum director to move the fossils to safety. The Nazi director refused and the bombing destroyed the fossils in 1944. Drawings, photos and descriptions in newspaper articles were all that remained to prove Spinosaurus fossils never existed.

In the decades that followed, Spinosaurus took on a certain myth, as generations of paleontologists found more of their close relatives around the world, from Brazil to Thailand, and tried to understand how they lived. Discovered on four continents, these additional “spinosaurids” almost certainly ate fish because of their skull anatomy, their dental structures and, in one case, fish scales that were found preserved in a rib cage of spinosaurids.

Early 20e century, paleontologists played with the notions of aquatic dinosaurs, including an idea that large plant-eating dinosaurs lived in lagoons to help support their immense weight. But decades of anatomical research now show that dinosaurs of all shapes and sizes, even the titans among them, thrived on terra firma. The anatomy of the hind limbs of other spinosaurids strongly suggests that they too have walked on earth.

Without news Spinosaurus skeleton to be examined, the species seemed destined to remain ambiguous.

Spinosaurus animation

In this animation, a Spinosaurus aegyptiacus uses its paddle tail to propel itself through the water.

MODELING: DAVIDE BONADONNA AND FABIO MANUCCI; ANIMATION AND TEXTURATION: FABIO MANUCCI; COLOR DESIGN: DAVIDE BONADONNA, DI.MA. DINO MAKERS SCIENTIFIC SUPERVISION; SIMONE MAGANUCO AND MARCO AUDITORE; RECONSTRUCTION BASED ON: NIZAR IBRAHIM EA,
NATURE, 2020.

When Stromer tried to rebuild Spinosaurus in the 1930s, he filled in details with other theropod dinosaurs and gave him an now obsolete posture. Since 2014, a team led by Nizar Ibrahim has supported Spinosaurus was a seimaquatic predator, an idea that the new tail reinforces.

JASON TREATMENT, NG STAFF; MESA SCHUMACHER

(See how paleontologists used the new Spinosaurus fossils to rebuild a gigantic aquatic predator.)

Lost and found

Clarity would come decades later from south-eastern Morocco, where thousands of artisanal miners have scoured the region’s rocks and found fossils that cover hundreds of millions of years of Earth history. Hoping to find dinosaur remains in particular, some diggers have focused their energies on the beds of Kem Kem, a 95-100 million year old sandstone formation that begins 200 miles east of Marrakech and stretches 150 miles to the southwest. The rocks retain traces of what used to be a vast river system where car-sized fish once swam. If you spot an exposed plate of red sandstone from the Kem Kem beds on the side of a mound, you may find the mouth of a tunnel too short to stand, carved by local miners with a piece of bar sharpened frame.

When miners come across fossils, they usually sell the bones to a network of wholesalers and exporters. This fossil mining industry provides vital income to thousands of people in this region, although it operates in a legal and ethical gray area. Locals dig all year round, making them almost certain to find more scientifically valuable specimens than university paleontologists, who only dig a few weeks a year.

This is why paleontologists get to know the local diggers and frequently check their features. An assistant professor at the University of Detroit Mercy, Ibrahim, who is of German and Moroccan descent, travels from village to village each time he visits Morocco, discussing the latest finds from locals in Darija, the local Arabic dialect, above steaming glasses of fresh mint tea.

During one of these visits to a village outside the city of Erfoud in 2008, Ibrahim – then a specialist in Kem Kem beds – met a man who had found bones of which the scientist realized by following that it belonged to a Spinosaurus. The meeting might as well have been fate. Ibrahim had liked Spinosaurus since he was a young boy who grew up in Berlin.

Ibrahim’s research partners at the Milan Natural History Museum alerted him to even more bones from the same local miner in Italy and helped secure their return to Morocco. A second trip from Ibrahim, Zouhri and paleontologist David Martill from the University of Portsmouth in 2013 finally led the team to the outcrop of Kem Kem where the fossils originate, and they began to find more fragments of ‘bone.

Ibrahim used these fresh fossils, previously found bones, and Stromer’s articles to attempt a new reconstruction of Spinosaurus. Their work, published in Science in 2014, said Moroccan fossils to replace those of Egyptian origin lost during the bombings of World War II. Their reconstruction revealed that the creature was 50 feet long in adulthood, longer than an adult T. rex.

The study also argued that Spinosaurus had a slender torso, truncated hind limbs, a fish-eating crocodile-shaped skull and thick-walled bones similar to those of penguins and manatees – characteristics that indicated a sort of semi-aquatic lifestyle.

Samir Zouhri examines a large Spinosaurus tooth at a villager’s house in Taouz, Morocco. Paleontologists in the region are building relationships with locals to ensure that scientifically significant fossils reach public trust.

The study polarized paleontologists. Some reacted positively, convinced by the new data SpinosaurusThick-walled bones. “It really sealed the deal for me,” said Lindsay Zanno, a paleontologist from the North Carolina Museum of Natural Sciences who was not part of Ibrahim’s research team. “Bone has memory,” she adds, noting that the microstructure of bone is different in land animals, flying animals, or animals that spend most of their time in water.

For other paleontologists, however, the evidence presented in 2014 did not support the conclusion of active swimming Spinosaurus. These researchers thought that Spinosaurus, like other spinosaurids, ate fish while wading in shallow waters like grizzly bears and herons. But on the basis of incomplete Moroccan remains, could the researchers now say with certainty that the prehistoric predator did more than his relatives and quickly swam after aquatic prey? If so, how did it move through the water?

Others still doubted that Moroccan bones belong to a Spinosaurus. While the Moroccan bones found were clearly spinosaurids, the number of spinosaurid species in North Africa has been and remains a subject of scientific debate. Did the fossil anatomy exactly match the lost Egyptian creature of Stromer? Or did they rather belong to a close but separate relative? “No one was particularly sure how many species or genera we have [in North Africa], and quite where one is in time and space, “said Dave Hone, a paleontologist at Queen Mary University in London and a specialist in spinosaurids.

Seeking to put an end to the controversy, Ibrahim and his colleagues returned to the Moroccan site, with the support of the National Geographic Society, to search for more bones in September 2018. The clock was ticking: he had heard of local contacts fossils were digging tunnels in the nearby hills to find bones. Ibrahim could not risk leaving the rest of what he believed to be the only known in the world Spinosaurus skeleton disappears in collectors ‘collectors’ cabinets.

Mohand Ihmadi, owner of the Ihmadi Trilobites Center in Alnif, Morocco, is preparing a Spinosaurus tooth for sale. For years, Ihmadi saved the rarest fossils that cross his shop in the hopes of founding a museum. “It is important that we preserve our past,” he says. “If we lose it, we will never get it back. “

Fossil bonanza

The 2018 excavation started suddenly. To clear tons of sandstone, the crew purchased the only jackhammer in the area. It broke in a few minutes. The days were so exhausting that several members of the team were hospitalized after returning home. But the promise of discovery kept them, as did the Nutella breaks that temporarily diverted their minds from the work of punishment. Finally, they began to find one tail vertebra after the other from the tail of the animal, sometimes a few minutes and a few inches apart. The team was so dizzy about the windfall, they beat musical rhythms with their rock hammers and started to sing, humming, “This is another tail!” to the rhythm of the “Final countdown” in Europe.

I tasted the challenges of the site and the rush for discovery when I joined the team in July 2019 for a return expedition. The heat of 117 degrees and the arid winds absorbed liters of water from my body as we made our way through a marbled outcrop like bacon. Fanned along the outcrop below, Ibrahim students in Detroit Mercy transported rocks in buckets made from recycled tires and scoured debris for even the smallest bone spots.

By the end of the next day, we had found several Spinosaurus fossils, including the bones of the foot and two delicate caudal vertebrae which would have formed the tip of the dinosaur’s tail. When the fruits of all this work were finally placed on tables in the Casablanca laboratory, Ibrahim and his colleagues knew that they had something truly remarkable.

By the end of 2018 alone, the excavation team had discovered more than 30 Spinosaurus caudal vertebrae. Above all, some of the tail bones perfectly match the more fragmentary spinosaurid tail vertebrae illustrations that Stromer published in 1934, reinforcing the case that a species of spinosaurid living in the Cretaceous in North Africa went from Morocco to Egypt. . In addition, Ibrahim and his team did not find any duplicate bones on the Moroccan site – a clear sign that the fossils belong to a single individual, which is extremely unusual in the rugged river beds of the Kem Kem beds.

Designed for water

With the almost complete tail of the creature now in hand, Ibrahim and his colleagues are more convinced than ever that Spinosaurus was a swimmer – an assertion that they began to test in the laboratory.

In February 2019, Ibrahim contacted Stephanie Pierce, curator of vertebrate paleontology at the Harvard’s Museum of Comparative Zoology, with a question: could she help him test the thrust that a dinosaur tail would generate in water? Although numerical modeling of animal movement is one of his specialties, Pierce knew that to answer the question, dynamic and real experiences were required. She and her colleague George Lauder, a fish biologist, have agreed to join the team.

Almost six months after the Harvard duo joined Ibrahim’s team, I entered Lauder’s laboratory, a buzzing ventilation room and overworked computer fans. Lauder, seated at a workbench, reached for an orange sheet of plastic – the laser-cut outline of a Spinosaurus tail and tied it to a metal rod. He then walked through the laboratory to what looked like a carefully constructed aquarium and mounted his tail inside a tangle of metal beams hanging from the ceiling.

With new bones come new models: Guzun Ion from DI.MA. Dino Makers, a museum sculpture company in Fossalta di Piave, Italy, molds an updated version of the tail for a full size Spinosaurus sculpture.

The device is a robot called “Flapper”, which hangs under a water channel whose Lauder flow speed can control with exquisite precision. Dotted with lights, cameras and sensors, the set can accurately track the aquatic movements of a swimming animal or swimming robot and the forces they transmit as they move.

As I watched, Lauder lowered the valve into the water and the plastic model Spinosaurus the tail attached to it came to life with a movement intended to imitate a swimming alligator. With each shutter, a shadow crossed the tail and the data was transmitted to Lauder’s computers. The Flapper recorded the forces transmitted by the tail, reflecting how much it would have propelled Spinosaurus through the water.

The results of Pierce and Lauder, which are included in the Nature paper, show that the tail of Spinosaurus provides more than eight times the forward thrust in water than the tail of non-spinosaurid theropods Coelophysis and Allosaurus“And does it twice as effectively. The discovery suggests that the giant Spinosaurus spent a lot of time submerged, perhaps sailing the rivers like a modern crocodile but on a large scale.

This conclusion establishes Spinosaurus apart from other aquatic dinosaurs described since 2014, including species that may have lived like geese or turtles. The more Lauder talks about a paddle in the back of a predator up to 50 feet long, the more his eyes widen at the unprecedented nature of the discovery. ” It’s incredible! ” he says.

In future experiments, Pierce and Lauder say a modified version of the Flapper tests could test a 3D model of the tail, or even a full body model of the update Spinosaurus, which would help clarify how the dinosaur’s six-foot-high dorsal sail affected its swimming. To realize this dream, however, Ibrahim wants to incorporate every last bit of bone he can, which is why his team returned to the desert at the height of summer 2019 for more excavations.

Some of the fossils I saw them on this expedition will soon help test another aquatic characteristic of Spinosaurus: his feet possibly webbed. With more bones in hand, researchers can finally rebuild the entire foot of the dinosaur to help test Spinosaurus spread out his toes.

Crucially for Ibrahim, all of the fossils the team finds remain in Morocco, expanding the collection that Zouhri, the paleontologist at Hassan II University, oversees in his laboratory in Casablanca. The hope is that one day these bones and the scientists who will study them will seed Morocco’s first national museum of natural history – and inspire people across North Africa to dream of the lost worlds beneath their feet.

“What I want to do is build a house for Spinosaurus», Ibrahim explains. “It will become a symbol – an icon – of African paleontology. “

Paolo Verzone is a member of Agence VU and has received three World Press Photo honors. His story on
the hunt for ancient biblical manuscripts was in the December 2018 issue of
National Geographic magazine. See more of his work on his
website and
Instagram.

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