Spinosaurus

Spinosaurus was a large meat-eating dinosaur from Africa. Scientists think it may have lived a semi-aquatic lifestyle.

Our understanding of Spinosaurus has changed in recent years. For over 100 years we only had very incomplete remains of this dinosaur. Plus, the few bones from the first discovery in 1912 were accidentally destroyed during the Second World War.

For most of the last century scientists reconstructed Spinosaurus as a completely land-based animal with long hind legs, like Tyrannosaurus and Allosaurus.

We now know that Spinosaurus had quite short legs and may have spent a lot of its time living in and around water. It also had a wide, paddle-like tail.

It isn't clear whether this dinosaur swam a lot, or mostly lived on the shoreline.

We know from the shape of the dinosaur's jaws that it fed on fish, although it may have eaten other dinosaurs too.

Like other members of the spinosaur group, Spinosaurus had a narrow snout and a distinctive notch near the front of its jaws. This would have been very effective at trapping fish.

There are several theories about the impressive 1.5-metre-high sail on Spinosaurus' back.

It may have helped to regulate the animal's body temperature or been part of an elaborate mating display.

The sail may even have helped to propel the dinosaur through water.

Some scientists have speculated that Spinosaurus had a thick, fleshy hump rather than a thin sail. But the latest research suggests that a thin sail is most likely.

Spinosaurus lived between 99 and 93.5 million years ago in the Late Cretaceous Period. At that time, its North African habitat consisted of tidal flats (muddy or marshy areas that get covered by the sea) and mangrove forests.

The hottest time of year would bring long droughts, which would cause many lakes and rivers to dry up. This may have forced Spinosaurus to sometimes act as a land predator.

At 14 metres (46 feet) long from nose to tail, Spinosaurus was longer than any other carnivorous dinosaur known to science. But we don't have any complete skeletons, so the full length is just an estimate.

However, Spinosaurus' short hind legs meant that T. rex stood taller at the hips.

Our understanding of how Spinosaurus walked has changed over the years.

Some reconstructions of Spinosaurus show it walking on all fours, while many scientists today believe that it was able to walk on two legs. It's still not clear who is right, and we may need to wait for new discoveries or studies to find out more.