New Spinosaurus Restoration!

[suspsy]

It is perfectly possible that Spinosaurus' tail did not permit it to swim fast or gracefully, and yet swim it did regardless. There are plenty of extant aquatic animals that are very poor swimmers, but have been able to survive for eons. The megamouth shark's body is soft and flabby and its top swimming speed is only half that of a human walking down the street. On paper, it sounds like an evolutionary failure, doomed to die out from competition or predation by faster, stronger, more vicious sharks or toothed whales. And yet it's still out there swimming in the ocean depths.

[Loon]

H @HD-man This looks spectacular! I saw a Picture with the Forms for the Tail.

But is this the old one? Seems to lack the "new" Tail.

Nope, it's the new 1 (as indicated by the mural).

Ooh, I'd love a model based on that. EoFauna could knock it out of the park.

The 1 in Kapitaenosavrvs' post or my post?

I mean either would be nice. But, I should have been more clear, your post. Also, where was that picture taken?

[HD-man]

I mean either would be nice. But, I should have been more clear, your post. Also, where was that picture taken?

Don't know. I got it from here: https://novataxa.blogspot.com/2020/04/spinosaurus.html

[HD-man]

For those who haven't seen how awesome this new 3D Spino is.

I'm loving the awesome new 3D Spino that's based on Bonadonna's awesome new 2D Spino. Not only does it look great (I especially like the croc-like skin texture & blue coloration), but it seems to match up well w/Naish's reconstruction in terms of having a longer tail & more upright posture.

[Patrx]

I'm really loving all the new art that's already being produced based on this new paper; fantastic stuff. Like Tyto says, there's something sort of immediately believable about this new silhouette, though of course that's mere intuition on my part. There's bound to be (and indeed already has been) some lively discussion in the palaeo-community about this. Ibrahim et. al. seem pretty confident about these processes being a swimming adaptation, but I've already encountered some opinions that seem to land more on the "display" side of things. For example, this Tweet by Mark Witton:


This of course isn't conclusive either, you can click the screencap there to check out a fascinating conversation between Witton and other workers on the matter. I suspect it will be some time before anything even approaching consensus begins to emerge.

"The lengthened digit I and flattened pedal unguals in Spinosaurus suggest that the foot may have been adapted to traversing soft substrates or webbed for paddling."
Also interesting to note in the new paper because of the increased size of the tail they have recalculated a change in the center of mass and illustrate a possible walking/standing pose that has the front limbs raised off of the ground.

Yes! The flat toes were a major part of that 2014 paper, it's odd how many of the "new-Spinosaurus" figures have missed that detail. As to the posture, the newly-weighted bipedal posture makes a lot more sense to me than the "knuckle-walking" or flat-handed quadruped ideas. Again, though, that's primarily intuition on my part.

[stargatedalek]

H @HD-man This looks spectacular! I saw a Picture with the Forms for the Tail.

But is this the old one? Seems to lack the "new" Tail.

Nope, it's the new 1 (as indicated by the matching mural).

The model doesn't match the mural however, the model has a crocodilian inspired tail and the mural looks like the new "newt-like" one. I assume the model was already made before the mural was, or someone vetoed the new tail being included, perhaps to prevent it from being leaked?

[Loon]

I don't know if it's the same model, or a copy, but there is an updated version.

[ITdactyl]

Echoing @stargatedalek 's post: I'm surprised few people are reacting to the seemingly big difference between the spines on the back vs. those on the tail.  The tail may have had its rudder fin, but the back sail seems to be a meatier structure.

Maybe (wild guess) the back sail's main function is primarily mechanical (like a cantilever bridge?) to support its elongated body on dry land; and the spines just got taller due to sexual selection.  As opposed to the spines on the tail, that just started to elongate to support a swimming fin.

[Brocc21]

Echoing @stargatedalek 's post: I'm surprised few people are reacting to the seemingly big difference between the spines on the back vs. those on the tail.  The tail may have had its rudder fin, but the back sail seems to be a meatier structure.

Maybe (wild guess) the back sail's main function is primarily mechanical (like a cantilever bridge?) to support its elongated body on dry land; and the spines just got taller due to sexual selection.  As opposed to the spines on the tail, that just started to elongate to support a swimming fin.

I'd say the sail is primarily for display. If your underwater all the time it's may be the only way to recognize you.

[Dinoguy2]

Echoing @stargatedalek 's post: I'm surprised few people are reacting to the seemingly big difference between the spines on the back vs. those on the tail.  The tail may have had its rudder fin, but the back sail seems to be a meatier structure.

Maybe (wild guess) the back sail's main function is primarily mechanical (like a cantilever bridge?) to support its elongated body on dry land; and the spines just got taller due to sexual selection.  As opposed to the spines on the tail, that just started to elongate to support a swimming fin.

If, as some people are suggesting in reply to Witton's Twitter post, the spines on the tail could have been at least somewhat flexible, that could explain the weird variance compared to the spines on the back. Maybe they became thinner and more widely spaced as the tail became used more and more for propulsion (or whatever it was doing). This might actually be an argument against the display hypothesis - why the extreme difference in neural spine anatomy? Simply extending the normal blade-like neural spines, like what happened on the back, would serve the display function and probably provide an even better counter-balance. Hadrosaur neural spines, which also tend to have a "sail"-like configuration similar to but less extreme than Spinosaurus, look pretty much the same as the ones on the back and only really get narrower as they get smaller towards the end of the tail.

[suspsy]

Mark Witton has written up a very good blog post on Spinosaurus. Well worth a read:

https://markwitton-com.blogspot.com/2020/05/spinosaurus-2020-thoughts-for-artists.html?m=1

[ITdactyl]

I wonder if Carcharodontosaurus and Spinosaurus had a similar relationship as today's jaguar and caiman, with big individuals (male carch?) Actively hunting unwary smallish Spinosaurs.

[Concavenator]

I wonder if Carcharodontosaurus and Spinosaurus had a similar relationship as today's jaguar and caiman, with big individuals (male carch?) Actively hunting unwary smallish Spinosaurs.

I remember having posted something similar some time ago. Indeed, I think that's very likely, specially having in mind how (possibly) clumsy Spinosaurus was on land. In that case, the biggest theropod ever could have been the prey of a smaller theropod!

[SidB]

Mark Witton has written up a very good blog post on Spinosaurus. Well worth a read:

https://markwitton-com.blogspot.com/2020/05/spinosaurus-2020-thoughts-for-artists.html?m=1

I appreciated the cautionary notes that he sprinkles throughout. I always find it refreshing when an analysis refuses to become prematurely doctrinaire.

[Dilopho]

Spinosaurus just gets more and more fascinating.
I wonder what else it has in store to just knock us all off our feet.  I can't wait until 2030, when it's discovered that Spinosaurus didn't even have a sail, and the backbones were just to disguise itself as a bunch of old logs sticking out of the river. 

[suspsy]

Interesting discussion on lips in Witton's essay as well. I see Tyrannosaurus rex, Allosaurus, Carnotaurus, and other land theropods as having lips just like lions, leopards, and cheetahs, but I still think of crocodilians and their exposed dentition whenever I imagine Spinosaurus.

But what I really wonder about these days is not so much how it swam, but what its gait was like when it moved on land. Did it walk with a measured, steady pace, or was it more awkward and clumsy and clearly out of its element? In any case, I think it was a strong candidate for the slowest of all theropods, with even some sauropods being able to outpace it. If I were forced to pick one huge theropod to chase after me down the street, it would be Spinosaurus.

[Concavenator]

But what I really wonder about these days is not so much how it swam, but what its gait was like when it moved on land.

Yeah, in my opinion, ever since this concept of the new Spinosaurus that came all the way from 2014 and now 2020, how it moved on land (or if it moved on land at all) has always been the thing that intrigues me the most as well.

[Dinoxels]

https://www.youtube.com/watch?v=De1VJ1UpjhM
A really good video about the new Spinosaurus. I recommend you check it out.

[Libraraptor]

That tail shadows everything we´ve ever known as a tail in a non-sauropod land living animal. Wow!

[stargatedalek]

I rather doubt adult Spinosaurus were preyed on by Carcharodontosaurus. Jaguars are better swimmers than Carcharodontosaurus likely was (at very least faster swimmers relative to their size), and they tend to catch caimans by targeting them off guard while they're in shallow water, the jaguars advantage being their footing on the bottom while the caiman is left struggling against water.

Carcharodontosaurus certainly wouldn't have been capable of ambushing the way a jaguar is, and being a biped it also wouldn't have that stability and bulk that is so essential to the jaguars method of hunting caimans.

Spinosaurus itself was also far more aquatic than crocodilians, hunting aquatic prey rather than ambushing shore dwellers in the shallows. So it was probably a lot less vulnerable to terrestrial predators. More like a jaguar hunting a river dolphin.

And that's assuming Spinosaurus wasn't marine, which considering most of the fossils are of young (including several very young) animals and they come from coast adjacent mangrove swamps I think is extremely likely. Adults probably lived in the ocean, returning to shore to leave the young in protected estuaries. More like sharks or puffins than crocodiles.

I wouldn't even be that surprised if they gave live birth like sharks and only used land travel when young to explore additional area.