A juvenile Spinosaurus beside a basketball court (Photo by Linda Crampton)

Spinosaurus is a large and intriguing dinosaur that ate fish and may have been semi-aquatic. Spinosaurus fossils have been found in Egypt and Morocco. They date from around 95 million years ago and give us tantalizing suggestions about the animal’s life. Many questions about the reptile remain unanswered, but what is known is very interesting.

Every year in the last two weeks of August, the Pacific National Exhibition in Vancouver holds a popular fair. One of the exhibits at the 2019 fair was called Dinosaur Stomp. It contained animated dinosaur models with features that scientists believe the real animals possessed. The Spinosaurus shown in the photo above was one of the models. The creators were careful to say that the animal was a juvenile. In real life, an adult Spinosaurus is believed to have been as big or bigger than a Tyrannosaurus rex.

The dinosaur models had a small sensor in front of them that detected the movement of a visitor and triggered the animation sequence. The animated animal shown in the video below was made by the same company that created the PNE exhibit.

The complete remains of a particular Spinosaurus haven’t been found. Different parts of the body have been found in different areas, however, allowing an overall picture of the dinosaur to be created.

An adult Spinosaurus is thought to have been around 50 feet long, which would make it longer than an adult T. rex. It was a large animal that may have weighed 7.5 tons. It’s often assumed to have been bipedal because its back legs were longer and more muscular than its front ones.

Spinosaurus had long spines on its back. Its name means “spine lizard”. Researchers suspect that the spines were covered by skin, forming a sail-like structure. The sail may have been used for social displays or for species recognition. These are the most popular ideas. Some researchers have suggested that the sail was used for temperature regulation, however. Others have suggested that it was actually a hump that stored fat and water.

A reconstructed Spinosaurus skeleton in Japan (Photo by Kumiko, CC BY-SA 2.0 license)

Spinosaurus was a predator. It caught and ate fish (and perhaps other animals) and had a number of adaptations for this lifestyle. It was likely a paddler and even a swimmer. It had a long head and long jaws. Its nostrils were located on the top of its head instead of at the end, which would have allowed it to breathe when most of its body was submerged. Its head looked somewhat like a crocodile’s. Its teeth were conical and well-adapted for catching fish.

The animal had a long head and neck. These features may have moved its centre of mass forward compared to that in other bipedal dinosaurs, causing it to have a more horizontal and less upright posture on land.

Despite being larger than its front legs, the animal’s back legs appear to have been proportionally smaller than those in other predatory and bipedal dinosaurs. Spinosaurus may not have been a great mover on land. Some researchers suspect that it may even have been quadrupedal.

Unfortunately, the earliest known fossils of Spinosaurus have been destroyed. They were discovered in Egypt in 1912 and described in 1915 by a German paleontologist named Ernst Stromer. He sent them to a Munich museum, where they were destroyed by allied bombing in 1944.

Stromer’s illustrations and photos of the fossils have survived and are useful. The fossils themselves could have been examined by new techniques and given researchers a better idea of what the animal was like, though. Every discovery is important when we’re dealing with ancient life with hidden and perhaps uncommon remains.

Reproduction_of_Stromer's_Spinosaurus_Display

Reproduction of some of Stromer’s fossils (Photo by Ryan Somma, CC BY 2.0 license)

As always in paleontology, our ideas about a particular dinosaur may change as more fossils are discovered. Some criticisms have been directed at researchers who have combined fossils of different body parts together in order to create an overall picture of Spinosaurus. The different fossils might have come from different species. Disagreement about interpretations of fossils known to have come from Spinosaurus have also arisen, such as the animal’s ability as a swimmer, its capabilities on land, and even its posture.

To get to the bottom of the Egyptian giant, everybody is going to have to keep digging. (Asher Albein, The Atlantic)

As the writer of the article in The Atlantic says, the only way to solve the disagreements at the moment seems to be to keep digging in the hope of finding new fossils. I hope new evidence about the body structure and life of Spinosaurus is found. It’s a fascinating animal.