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Spinosaurus aegyptiacus: A swimming dinosaur bigger than an adult T. rex.

Can dinosaurs swim? It is a question that has puzzled palaeontologists for over a decade. Much of the fossil record suggests Spinosaurus, a theropod (three-toed) dinosaur, lived around water and fed on fish. But when Ibrahim, a researcher suggested that the 50-foot-long Spinosaurus aegyptiacus lived a life aquatic in a paper published in Science in 2014, Palaeontologists were not convinced. But a new study published in the journal, Nature provide a strong evidence that Spinosaurus dinosaur indeed lived in the water and were an excellent swimmer.

Spinosaurus dinosaurs, a swimming dinosur is thought to have lived in the present-day North Africa during the Cretaceous period about 112 to 95 million years ago. They are a unique dinosaur with staggering sizes- up to 50 feet (15 meters) long and seven tons. Most people are not aware of the name Spinosaurus. Many people who are aware are either a palaeontologist or people who came to learn about the Spinosaurus when it was featured in the 2001 movie “Jurassic Park III,” Spinosaurus dinosaurs is the only swimming dinosaurs recorded till today.

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Stromer and Spinosaurus aegyptiacus

The story of Spinosaurus is nearly as unusual as the newfound tail, an adventure that winds from bombed-out German museums to the Martian-like sandstone of the Moroccan Sahara.

The existence of Spinosaurus was not known until a century ago when a Bavarian paleontologist Ernst Freiherr Stromer von Reichenbach uncover Spinosaurus aegyptiacus fossils during one of his expeditions to Egypt. At first, he could not give proper explanation of the fossil he had discovered. In his first published description, Stromer speculates that its oddness “speaks for a certain specialization.” He envisioned the animal standing on its hind limbs like an off-balance T. rex, its long back bristling with spines. The fossil was displayed in Munich’s Paleontological Museum. However, the fossil in Munich museum did not last as expected.

During World War II, Germany was at war with the allied forces. There were constant bombings on buildings by allied forces. Knowing the danger and possibility of the fossil getting destroyed by bombing, Stromer begged the museum director to move the fossils to safety. Unfortunately, the Nazi director refused, and bombing destroyed the fossils in 1944. Every piece of the fossil was crushed. Drawings, photos, and descriptions in journal articles were all that remained to prove Stromer’s Spinosaurus fossils ever existed.

Plate I in Stromer (1915) showing S. aegyptiacus holotype elements
Credit: Stromer
Plate I in Stromer (1915) showing S. aegyptiacus holotype elements
Credit: Stromer

In the decades that followed, Spinosaurus took on a certain mythos. Many theories were proposed on how they lived. It was believed they ate fish. There was also an idea that large plant-eating dinosaurs lived in lagoons to help support their immense weight. Theories were put forward but without a new Spinosaurus skeleton to examine, the species seemed destined to remain ambiguous or rather a mystery.

Ibrahim and his journey to uncover the fossils of the swimming dinosaur, Spinosaurus aegyptiacus.

Clarity would come decades later from south-eastern Morocco, in a place called Kem Kem Beds, a sandstone formation between 95 and 100 million years old, period Spinosaurus lived.

In 2008, Ibrahim, an assistant professor at the University of Detroit Mercy, who is of German and Moroccan descent, went to Kem Kem and met a man who had found bones which might belong to a Spinosaurus. It was indeed the first fossil of Spinosaurus discovered in 60 years after the previous one was destroyed in WWII. A second trip by Ibrahim was organized to return to Kem Kem in 2013. On his return, they started finding more bone fragments. Ibrahim used these fresh fossils, previously found bones, and Stromer’s articles to attempt a fresh reconstruction of Spinosaurus. Their work which was published in Science in 2014, declared the Moroccan fossils as a replacement for the original Egyptian ones lost in World War II bombings. Their reconstruction revealed the creature was 50 feet long when fully grown, longer than an adult T. rex.

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The study divides paleontologists. Some reacted positively, convinced by the new data on Spinosaurus’s thick-walled bones. For other paleontologists, however, the evidence presented in 2014 were not strong enough to claim the case of actively swimming Spinosaurus. Those researchers believed that Spinosaurus, like other spinosaurids, ate fish by wading into the shallows like grizzly bears and herons.  Still others expressed doubt whether Moroccan bones belonged to a Spinosaurus. Did the fossil’s anatomy exactly match Stromer’s lost Egyptian creature? Or did they instead belong to a close, but distinct, relative? were some of the question raised.

Ibrahim’s return to Kem Kem

Seeking to put the controversy to rest, Ibrahim and his colleagues returned to the Moroccan site, with the support of the National Geographic Society, to check for more bones in September 2018. They started digging and found several Spinosaurus fossils, including foot bones and two dainty caudal vertebrae that would have formed the tip of the dinosaur’s tail. By the end of 2018, the dig team uncovered more than 30 Spinosaurus tail vertebrae. Crucially, some of the tail bones neatly match up with illustrations of more fragmentary spinosaurid tail vertebrae that Stromer published in 1934, bolstering the case that a spinosaurid species living in Cretaceous North Africa ranged from Morocco to Egypt. In addition, Ibrahim and his team haven’t found any duplicate bones at the Moroccan site—a clear sign that the fossils belong to just one individual, an extremely unusual occurrence in the Kem Kem beds’ rough-and-tumble riverbeds.

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Computer simulation study

With the creature’s nearly complete tail now in hand, Ibrahim and his colleagues are more confident than ever that Spinosaurus was a swimmer and they started testing in the lab. In February 2019, Ibrahim collaborated with Pierce, a fish biologist and Lauder, curator of vertebrate Palaeontology at Harvard’s Museum of Comparative Zoology. They compare the tail of the Spinosaurus dinosaurs with the tails of two extinct land-dwelling dinosaurs and two modern-day semi-aquatic species, the Nile crocodile and the crested newt, by creating 2D models they tested in the water. Using computer modelling they showed that the tail of Spinosaurus delivers more than eight times the forward thrust in water than the tails of the non-spinosaurid theropods Coelophysis and Allosaurus—and does so twice as efficiently.

The finding suggests the giant Spinosaurus spent plenty of time submerged, possibly navigating rivers like a modern crocodile but on a massive scale. This indicates Spinosaurus terrorized rivers and riverbanks as a semi-aquatic animal, not merely wading into the water waiting for fish to swim by. It may have eaten huge fish, including sharks. That conclusion sets Spinosaurus apart from other water-loving dinosaurs described since 2014, including species that may have lived like geese or turtles.

A swimming dinoaur, Spinosaurus aegyptiacus reconstruction Artwork by Joschua Knüppe
Spinosaurus aegyptiacus reconstruction Artwork by Joschua Knüppe

Ibrahim has a hope that someday these bones and the scientists studying 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.

References:

Nature, Science, ABC News, CNET, National Geographic

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