Learning about science often means learning lots of new words. Don’t worry – you can use the glossary at the end of the story to help you understand them. There, you can also find lots of cool videos and websites that are related to the story, and some fun questions to help you learn more. Happy reading!
Meet Dr Nizar Ibrahim. He’s a German-Moroccan biologist.
Nizar is a palaeontologist (pay-lee-on-toll-oh-jist). That means he’s a special kind of biologist, who studies fossils. Nizar spends his time investigating what life on Earth used to be like a long time ago, and how prehistoric animals, like dinosaurs, used to live.
Many of the dinosaurs we know and love, like the ferocious Tyrannosaurus rex, were discovered in North America. We know lots about the dinosaurs from here, but much less about dinosaurs from other continents. Expedition teams haven’t been everywhere, and many places have never been explored. This is something that Nizar wants to change.
Imagine a barren desert. There’s no life in sight, and the sun blazes down above you. The ground is dusty, and as you walk, your footprints are the first marks on the sand. Water is hard to find and, even though you have sunglasses on, the bright sun hurts your eyes. These are the conditions that Nizar works under, in the Sahara Desert of North Africa.
Going to the Sahara was a risky choice – many other scientists told him that he wouldn’t find anything, or that the expedition would be a waste. Luckily, it turned out to be the opposite.
Nizar and his team found many fossils of predators. Enormous predators, taller than houses; medium-sized predators that would still make you feel tiny, and several crocodile-like predators in what seemed to be an ancient river site.
These fossils weren’t found all at once. Nizar and his team had to work hard on their site, over a number of years. They focussed on a particular area in Morocco, known as the Kem fossil beds. Many fossils from the Cretaceous period have been found in these rocks over the years. Nizar hoped that, because fossils of crocodiles and turtles had been found there, he might discover something amazing – an aquatic dinosaur.
Nizar and his team searched hard, collecting fossils as they went, and eventually they found what they had been looking for – Spinosaurus. This dinosaur was described as a “dragon from deep time”. It was longer than a T-Rex and had an enormous sail across its back.
The story of Spinosaurus has mystified scientists for centuries. Its first fossils were discovered by a German palaeontologist named Ernst Stromer von Reichenbach, in 1912. However, these fossils, along with all of Ernst’s other research, were destroyed during World War 2. All that remained were a few drawings and descriptions.
This remaining evidence fascinated Nizar. When he was a little boy, dreaming of exploring far-away places and discovering dinosaurs, Spinosaurus was the one that he loved the most. Scientists still knew so little about it – but here in the Moroccan deserts, Nizar was sure there were answers.
In 2013, Nizar completed a successful trip to the Kem beds, and returned with enough fossils of Spinosaurus bonesto attempt a reconstruction of its skeleton. When they laid out all the bones, they could see that Spinosaurus was over 15 metres long – that’s about as long as TWO double-decker buses!
Something else about the skeleton really excited Nizar. He noticed that, like the fossils of ancient crocodiles that had been found nearby, Spinosaurus seemed to have a long, narrow skull, and short, stubby limbs. The bones also had thick walls, similar to those of modern-day penguins or manatees.
Nothing about the fossil suggested that Spinosaurus was a similar predator to Tyrannosaurus rex, which ran on strong hind legs and had a strong, broad jaw for crushing its prey. Instead, Nizar thought, the skeleton looked like something new – a dinosaur that could swim and hunt prey in water.
Every significant palaeontologist before Nizar had assumed that dinosaurs didn’t venture into the water. It was assumed that dinosaurs lived on land only, because no one had found any evidence to suggest otherwise.
There were certainly creatures around at the time that lived their whole lives in water, including the early crocodiles and turtles, as well as the famous Ichthyosaur and Plesiosaur. However, animals these were not dinosaurs.
The idea that Nizar had discovered a dinosaur who lived and hunted in water caused strong reactions from other palaeontologists. Some were convinced by his arguments, and excited to find out more – while others challenged him. Nizar didn’t have enough evidence to convince everyone of his ideas.
Palaeontologists like Nizar use the fossils that they find to predict how animals might have looked or acted. They can’t go back to the time of the dinosaurs to see how things really were, so they have to make educated guesses based on the evidence they can find.
One way to work out how a dinosaur might have acted, is to compare its skeleton to that of a living animal, to see what is similar and what is different. Nizar already did this, when he noticed that Spinosaurus’ skull is like a crocodile skull, and that its bones are like those of penguins.
To work out how Spinosaurus might have moved through the water as a swimming dinosaur, Nizar needed to know what its tail looked like. However, this was the one piece of information that he didn’t have.
Dinosaur tails are made of many small bones called vertebrae. Vertebrae are the bones that make up your spine. In dinosaurs, and other vertebrate animals with tails, the spine stretches down into the tail. Without finding every one of these small fossilised bones, Nizar and his team had no way of knowing what the tail really looked like.
They returned to Morocco, determined to find a more complete skeleton.
Despite lots of setbacks – including scorpion stings, broken equipment, and dehydration caused by the punishing heat – the team were driven by their goal: finding the Spinosaurus tail. Their spirits were kept high by chocolate breaks, until one day they found something much sweeter: the first tail vertebrae of a Spinosaurus fossil.
The team went on to uncover over 30 fossils of tail vertebrae, which they now could match up with the original skeleton Nizar found. The fossils also looked similar to the ones Nizar had seen in drawings all those years ago – another great sign that the team were on the right track.
In the past, palaeontologists who, like Nizar, came from America or Europe, would often assume ownership of the fossils they found in other parts of the world, taking them when they returned to their home countries. However, Nizar and his team agreed that Spinosaurus should stay exactly where it belonged. They found a home for it at the Moroccan University of Casablanca.
But before Spinosaurus could be displayed, Nizar and his team needed to put the fossils together to form something incredible: the most complete Spinosaurus skeleton ever found. They worked hard in the lab to achieve this, and excited by their success, Nizar set straight to work with testing the tail, to see if it could have helped Spinosaurus swim.
This task was too big for Nizar to do alone, so he contacted two other biologists, Stephanie Pierce and George Lauder, and asked for their help. George is a fish biologist, and the trio decided that his lab would be the perfect place to test out Spinosaurus’ swimming abilities.
There was no way that Nizar was going to use the real Spinosaurus fossils in these experiments. They were far too precious!
Instead, Nizar’s team made a replica of Spinosaurus’ tail. By taking careful measurements of each fossilised bone, they were able to work out what the tail’s outline would have looked like. Then, they drew the outline onto stiff, thick plastic and cut it out.
They made the plastic tail much smaller than the real Spinosaurus’ tail, so that it would fit into the water tanks in George’s lab. At full size, the tail would have been far too difficult to move and use in experiments!
Now that the team had a replica Spinosaurus tail, they wanted to compare it to the tails of other animals, to see whether its shape would have allowed Spinosaurus to swim well. They made similar plastic tail replicas for four different animals: the dinosaurs Coelophysis and Allosaurus, a modern crocodile, and an amphibian, the crested newt.
Coelophysis and Allosaurus were both dinosaurs that spent all their time on land, and had long, narrow tails. If Spinosaurus’ tail acted similarly to theirs in water, Nizar could assume that Spinosaurus too spent most of its time on land.
On the other hand, crocodiles and crested newts spend almost most of their time in the water. If Spinosaurus’ tail acted like theirs did in the water, Nizar would have evidence that Spinosaurus also used its tail to swim. This would be the final piece of evidence he needed to prove that Spinosaurus is the first known aquatic dinosaur!
To test the tails, Nizar and his team attached them to a robotic controller, which made them move from side to side in the water, like a crocodile. A sensor attached to the tail recorded how efficient the tail was at moving through the water, and the amount of force it generated to push the animal forward (this is called thrust).
Nizar was so excited to receive the results. If Spinosaurus’ tail showed similar characteristics to swimming organisms, he would know for certain that his theories were correct!
The results from the experiment were in. Nizar looked nervously at the computer, and was immediately overjoyed. Spinosaurus’ tail generated far more power than the tails of the other two dinosaurs! Its broad shape, more similar to a newt’s tail than that of an Allosaurus, would have allowed it to swim fast and aggressively through the water.
This was the final piece of evidence needed to support Nizar’s theory that Spinosaurus was a totally new kind of dinosaur: a swimming predator that didn’t just wander into the water every so often, but actually lived there. He was so pleased!
Nizar’s results not only confirm a theory that he has worked hard all his life to defend, but also have an impact on the world of palaeontology as a whole.
When something as new and important as this is discovered, it forces scientists to change their assumptions. People always assumed that dinosaurs couldn’t swim, but now, because of Nizar, they know differently. What’s more, it opens up even more ideas for new discoveries.
Now that Nizar has shown that swimming dinosaurs existed, scientists wonder whether prehistoric waters may have been much fuller than we once thought – because where there’s one dinosaur, there are likely to be many more.
Thank you for reading!
This story was written as part of a Masters in Science Communication project, investigating whether storytelling is an effective way to teach children about science and scientists. As a result, I would really appreciate some feedback, which you can give by answering a short survey. The survey takes less than 5 minutes to complete, and I will use the results to develop even better science stories in the future. To help, just click on the button below.
Nizar’s research paper: Ibrahim, N., Maganuco, S., Dal Sasso, C., Fabbri, M., Auditore, M., Bindellini, G., Martill, D., Zouhri, S., Mattarelli, D., Unwin, D., Wiemann, J., Bonadonna, D., Amane, A., Jakubczak, J., Joger, U., Lauder, G., Pierce, S. (2020). Tail-propelled aquatic locomotion in a theropod dinosaur. Nature. 581: 67-70
More information about Nizar and his dinosaur discoveries:
More information about fossils:
More information about dinosaurs:
The research was produced not just by Dr Nizar Ibrahim, but also by the other members of his research team: Simone Maganuco; Cristiano Dal Sasso; Matteo Fabbri; Marco Auditore; Gabriele Bindellini; David Martill; Samir Zouhri; Diego Mattarelli; David Unwin; Jasmina Wiemann; Davide Bonadonna; Ayoub Amane; Juliana Jakubczak; Ulrich Joger; George Lauder, and Stephanie Pierce. They too deserve credit for this discovery – good science is often best done as a team.
This story would not be nearly so good without its illustrations by the wonderful Alice Chen, and the advice and support of Dr. Nicola Hemmings.