Spinosaurus aegypticus

Spinosaurus sp. is one of the few dinosaurs to hold its own if we held a dino popularity contest. If you go to the store and buy a pack of the less exciting plastic toys, you are almost guaranteed to get a T-rex, a Triceratops, a Velociraptor... and a Spinosaurus.

The Discovery

Paleontologist Freiherr Ernst Stromer set out in 1910 for the Egyptian desert alongside Richard Markgraf, an Austrian Fossil enthusiast. The looming threat of what would become World War I, and a devastating outbreak of cholera on Stromer's ship was not enough to alter their course.

 

 

Freiherr Ernst Stromer (Left) & Richard Markgraf (Right)

 

After reaching the Cretaceous layer of sediment during their hunting, the two of them eventually stumbled upon fossil remains that would change how we view the world of dinosaurs forever. They discovered the partial skeleton of a large unknown species of dinosaur. Some of the most notable features of these finding included a 15 foot jaw section, many large teeth that were conical in shape, and enormous spinal segments standing 5 feet tall.

This discovery took place in 1912 but Stromer did not official describe that finding until 1915, settling on Spinosaurus aegypticis, translating to "Egyptian Spine Lizard." Unfortunately, the fossilized remains of the initial discovery were kept in the Bavarian Nation Museum in Munich, Germany. During the Second World War, the specimen was lost to an Allied bomb raid in 1944. Tragedy stayed with Stromer as time went on. He lost two sons to the war with another being taken as prisoner of war. He died in 1952, leaving only sketches and photographs of the originals discovery.

There are officially two different species of Spinosaurus described today, the second being Spinosaurus maroccanus. This species was described in 1965 by Dale Russell, an American-Canadian Geologist and Paleontologist. There is much, much speculation surrounding this second species. Its naming was based on the length of its neck vertebrae. Because the original fossils of S. aegypticus were destroyed, there is no way to accurately compare the two finds. Some scientists accept the new species without much hesitation while others believe S. maroccanus may as well serve as a synonym for the original species, even though was found on the opposite side of North Africa. 

 

Barvarian National Museum - Munich, Germany

 

For many years Spinosaurus remained a mystery. Only small fragments were found here and there over the years. During the late 2000s, Nizar Ibrahim, a paleontologist also from Germany, was conducting research in Kem-Kem Beds on the boarder of Morocco and Algeria. It was during this time he was shown fossil specimens from another fossil hunter. These pieces were house in a distinctive purple-yellow sediment. The next year Ibrahim was working with a newly discover skeleton. The specimen he was prepping had very similar matrix to the ones he had seem the year prior.

He was eventually able to make contact with the fossil hunter many years later. Because of this he was able to find the exact location where they were originally found, leading to deductions not possible before. He concluded the areas which Spinosaurus had lived use to be plains full of rivers during the Early and Late Cretaceous periods.

 

Nizar Ibrahim on Spinosaurus - TED Website ALL RIGHTS RESERVED

 

With all of the newly presented information, Ibrahim created a detailed reconstruction of what Spinosaurus may have looked like. What they found was not only interesting, but may have led to what is the only semi-aquatic dinosaur discovered to this day. Let's dig into what made this dinosaur not only the largest land predatory to ever walk the Earth, but possibly the most unique dinosaur as well...

The Facts

Living during Late Cretaceous Period, about 95 million years ago, Spinosaurus is considered the largest land predatory for a few reasons. For many years it confused scientist exactly how Spinosaurus could live alongside other large carnivorous dinosaurs such as Bahariasaurus and Carcharodontosaurus, the mighty "African T-rex." How could all three of these top predators live alongside each other? How was there enough food to sustain their populations? Ibrahim help solve the puzzle. Based on his research and a visit to the location of newly discovered fossils, he was able to concluded that Spinosaurus spent much of its time in the rivers that use to cover its hunting grounds. While these other therapods where hunting on land for their food, this spinosaurid evolved its way back to the water in search for fish. 

Spinosaurus could reach almost 55 feet (~17 meters) in length from its snout to the tip of its tail, potentially weighing in 17000 pounds. When looking at all of the recent discoveries revolving around this particular dinosaur, we continuously see waterborne adaptations. Spinosaurus had conical teeth that acted like fish hooks, grabbing onto its prey quickly and securely as opposed to tearing chunks out with thin, heavily serrated teeth. Spinosaurus also had a long, narrow skull, similar to that seen in modern-day crocodiles. This skull had small nostrils located directly in the middle of its skull. This would have allowed Spinosaurus to breathe while its body remained submerged under water. Its skeleton possessed neural spines reaching nearly 5.5 feet upward. It is suggested these spines may have acted as a "sail-like" structure. Other researchers suggest the spines formed a hump that contained fat storage, similar to that of a camel. The bone structure of its tail was "loose." The placement of bones in its tail allowed a wide-angle of flexion when moving through water. This could have been used to help proper the dinosaur forward just as boney fish do today. Lastly, it is speculated that Spinosaurus may have had webbed feet, allowing it to easily traverse the muddy water banks where its remains have been found.

 

 Rendering of Spinosaurus Skeleton - Genya Masukawa

Even with everything we have learned from the fossil record. Many scientists agree that Spinosaurus sp. likely hunted both on and off the land. Semiaquatic would be the best term for this dinosaur. Given its size and its bone structure, it is doubtful it was agile and quick enough to chase prey through water. While this dinosaur might not have the fame of a T-Rex or Velociraptor, it still struck fear into the eyes of its prey and likely its competition.

 

 

References

Paul Sereno Paleontologist - Spinosaurus

Smithsonian Magazine - Discovering Spinosaurus, the Lost Dinosaur

Spinosaurus - Wikipedia