Larger than a t-rex and able to catch fish the  size of bison. This ferocious predator from the  

cretaceous is one of the most mysterious  and controversial dinosaurs to ever live.  

Its secrets are only starting to be  uncovered. This is the spinosaurus.

Hi I’m Danielle Dufault and you’re watching  Paleologic. Today we’re delving into dangerous  

Cretaceous waters and discussing one of the  biggest bones of contention in the Dino world.  

What did spinosaurus actually look like?

The story of Spinosaurus starts in 1915 when  a German paleontologist named Ernst Stromer  

discovered the fossils of a theropod  with very narrow 1.6 meters long  

lower jaws and long spines  coming out of its backbone.

Wanting to be as descriptive as possible, he  named it spinosaurus and sent the fossils to  

the Bavarian State Collection of Paleontology in  Munich, where it was estimated to be about 97 myo.

But during World War 2, the fossils were  destroyed during a bombing of the city.

For decades, illustrations of  these few bones were all we had,  

so paleoartists imagined it as a 16-meter long  t-rex with a croc-like face, and a back sail.

Basically the coolest dino of all  the time. This was the last time we  

had a unified vision of this dino  and everyone was happy. But then  

more fossils started popping up, and the  paleo community started forming factions.

In the 1980s, a new similar species was  discovered. It was called the baryonyx,  

it had huge claws, and showed that these  were part of a family of dinosaurs,  

which was then named the spinosauridae.

These related species helped scientists  piece together what spinos looked like  

a little better and cemented its place  as the largest theropod ever known.

The long snout suggested a fish-heavy diet,  

and the huge claws would have helped  it grab prey close to the shore.

Fortunately, or maybe unfortunately, we kept  

finding fossils, which contradicted  our early perceptions of spinos.  

Its like reading a book in reverse and  understanding less and less as the pages turn.

First of all, their hind legs  were revealed to be extremely  

short compared to other theropods  like T-rex. They would make spinos  

awkward and slow walkers, but might have  been an adaptation for life in the water.

They could have helped it swim like a crocodilian,  

and since they already had a  croc-like face and likely ate fish,  

it would have made sense to spend more time in  the water than other dinos. And the bones were  

also more dense than in other theropods, which  in other animals is used for buoyancy control.

This is a bigger deal than it sounds like. Up  until that point there had been no indications  

of aquatic dinosaurs. Other aquatic creatures  of the time like the plesiosaurs and mosasaurs  

are technically not dinosaurs. It was  weird! But then, tail vertebrae were found.

The tail was revealed to be long, narrow,  and flat, like the tail of an axolotl  

which would have helped spinosaurus  propel itself in the water.

Long and strong toe bones, similar  to those found in modern shorebirds,  

suggested they have the ability  to walk in muddy or silty soil.  

They could have even been webbed, but  unfortunately we have no evidence of that.

There is also evidence that they had pressure  receptors along the snout, much like crocodilians.

And then, the discovery of a large number  of teeth in river environments suggested  

they could have spent a lot of time,  maybe all of their time in the water.

Of course, that would have been way  too easy a conclusion to this debate.  

Evidence for a more land-based  lifestyle also started mounting.

Body reconstructions suggested it  couldn’t really stand upright in  

the water without tipping over  unless it was moving forward.  

The tail also seemed too weak to be used for  propulsion as effectively as a crocodilian does.

It would also have been too massive and too  awkward a swimmer to pursue prey underwater.

The sail and tail may not have been for  balance and propulsion respectively,  

but rather, a display for sexual selection, like a  peacock’s tail. Or it could have been a structure  

for a thermoregulatory organ like elephant ears,  or maybe even fat deposits, like a bison’s hump.

So depending on how you see it, it  could have been an aquatic predator  

behaviourally similar to a croc, or a  wading predator, like a grizzly bear,  

who specialized in fish but could venture to land  and eat carrion or catch prey opportunistically.

The whole issue is complicated by the fact  that only 6 specimens have ever been found,  

and they all have been incomplete  and of different ages and sizes.

Making an accurate model has been  

difficult, kinda like solving a 1000 piece  jigsaw puzzle, but you only have 6 pieces.

Every sail vertebra ever found  is broken and we don’t even know  

how long they were or if they created an arc or  an M-shaped structure or what its purpose was.  

We don’t know how powerful  and propulsive the tail was.

We don’t know if when it walked on land it  moved like a bear with the ability to stand  

on its hind legs, or more like a pangolin, using  its tail to balance while walking on two feet.

We don’t know how good of a swimmer it was.

But we do know it liked to eat fish, and  spend a lot of time near the water fishing.  

We know it was huge and, more importantly, that  it was one of the coolest animals to ever live.

So please, if you’re out there looking for  fossils in the deserts of northern Africa,  

we need you to help us get closer to solving  this puzzle! Until then, it will continue to  

cause fights on paleo-subreddits, provoke academic  beefs and break up families of paleontologists. 

What do YOU think it looked  like based on the evidence?  

My favourite thing about it, is there’s  still so much room for interpretation.

Let us know in the comments below and don’t forget  

to subscribe for new episodes every  week. Thanks for watching. See ya!