Spinosaurus' relatives... Or Just other spinosauruses: The Semi-Aquatic Giants and Drifting Continents

 Spinosaurids are really diverse .Like, they spread from West Europe to Africa, and then they went from Africa to South America, and from Europe to Asia. That really makes studying spinosaurids feel like studying a black hole. Seeing that they range from the UK to Egypt and Morroco makes sence, since these three places were geographically close back then. But seeing them reach Laos and Australia? That is weird. It once kept me up at night. The even weirder part is that all spinosaurids have a very similar anatomy: Long snout, Sharp claws in the front arm, a sail or hump like structure (except most baryonichids) and possibly webbed feet. The fact that these creatures went on so many places and didn't change is just weird. Most creatures change a lot when they change enviroments. Spinosauridae's success of going in so many different places and mostly not changing reminds me of crocodiliformes. Sadly, we can't do much to explain how they diversified. But I tried my best. 

Yes, I made this in microsoft paint, but that isn't our problem right now. Here we see my possible speculations of spinosaurids diversified. They originated in the UK, then went on Morroco, from Morroco to Egypt, From Morroco and Egypt to South America (and also from the UK, since there are also some baryonichids in South America I think) and then from either UK or Morroco to Laos. Now, I personally believe that oxalaia isn't actually spinosaurus. I think that the similarities between these two creatures are an example of convergent evolution (two unrelated animals evolving similar characterestics because of similar problems/enviroments). Unlike Oxalaia though, sigilmassasaurus is completely impossible. Its fossils are just some neck vertebrae, which can be anything really. You might be wondering, where is Australia in the diagram? Well, I didn't include it. Why? Because it is really questionable.

Above this text there is a map of the late Jurassic. We see that Europe is really close to Africa, while Africa is united with South America and Antarctica, which in turn is United with Australia (and India, but we don't care about India now). It really is weird that spinosaurids just travelled from Europe to Asia and Africa, and from Asia to South America and Australia so quick. They really were successful. Not because they were some sort of really strong predators, but because they adapted really quickly. They evolved webbed feet (or as I and my friends call them, "duck feet") to swim in the water, they evolved dense bones just like those of crocodiliformes, and a long snout for catching fish. You might say that these are aquatic adaptations;and that's

right. Spinosaurids lived everywhere on earth that there is water, especially swamps. And there is lots of such places. With these places come open niches, so spinosaurids filled them. In chance there was no open niche, they just took one by outcompeting. 

   The Australian Spinosaur

Artwork By FabrizioDeRossi on DeviantArt

At first I had no idea of the Australian Spinosaurid. I thought it should be some irritator-like creature. But guess what: I was wrong. It seems like it actually is a baryonichid. Doing more research I saw something shocking: Not only is it a baryonichid, but it resembles Baryonyx walkeri itself, which if you don't know, comes from the UK. The bones are from the Early Cretaceous Period, which helps us add more depth to our diagram. So, Spinosauridae first appeared in the UK, then went into Africa, and the from Africa they went to South America, and from South America they went to Australia. But now I'm going to be honest. How far away is modern day Australia from South America?

Why Oxalaia Is Not Spinosaurus

Oxalaia is, as I said in my last blog post about spinosaurus, very questionable. Paleontologists from all over the world have been redirecting it to Spinosaurus. But wait a second, is this possible? Well, as we said in the start, Spinosaurids had made their way to South America in the Late Jurassic, and that because that's the only time in geological history that Africa and South America where united, that they existed at of course (don't forget about pangea). But oxalaia and spinosaurus appeared in the cenomanian stage of the cretaceous (late cretaceous), spinosaurus lasted a bit longer (until the turonian). At that time Africa was pulled completely away from South America, making it almost impossible for oxalaia to be a spinosaurus. But what have we found of it? As I said in the last post, only parts of its pelvis and skull are found. So, we can't have a sure idea of what it looked like. 

Life Reconstruction Of oxalaia by PaleoGeeok

So what about Sigilmassasaurus or S.maroccanus? Well, they most likely are both doomed by the curse of invalidility (overdramatisation). 

That was it! So until now we have covered the spinosauridae family tree, the three questionable specimens of spinosaurus, three spinosaurids usually beeing redirected to Spinosaurus aegyptiacus, and now we covered how they diversified into almost all continents. Just make sure to know, the timeline of diversification along with the paths took both evolutionary and by walking are kind of speculation. Especially the one that talks about them going into Antarctica is just an idea. Thank you for reading this far! See you tommorow! Oh, forgot to say, the Spinosaurus' relatives posts are going to be posted a bit later so they won't fill the blog, and also so I can post other stuff. Bye!