*FLASH* Andrea Cau Proves that SPINOSAURUS was *BIPEDAL*

[Dobber]

I often wonder if we could see an actual prehistoric Dinosaur like Spinosaurus, T-Rex, ect would we even recognize it as such?

Chris

[Silvanusaurus]

I often wonder if we could see an actual prehistoric Dinosaur like Spinosaurus, T-Rex, ect would we even recognize it as such?

Chris

I imagine it wouldn't look as we'd expect it to, at least in some way, no matter how much we think we may 'know' of it.

I think I might get one of the smaller CollectA spinosaurus' and fiddle around with it. Not with any scientific goal in mind, just for a laugh, and maybe to create a more interesting figure.

[Jose S.M.]

I often wonder if we could see an actual prehistoric Dinosaur like Spinosaurus, T-Rex, ect would we even recognize it as such?

Chris

That an interesting thought.  Even extant animals sometimes look very different in skeleton and in their flesh,  like in elephants,  we probably wouldn't expect the trunk and big ears just by watching their skull

[Silvanusaurus]

It's always disturbed me how much an elephant skull resembles a humanoid face. Supposedly certain ancient folks used to interpret them as the remains of the mythical cyclops, the opening where the trunk was being the single central eye socket.

[RobinGoodfellow]

@ Silvanusaurus: I'm not disputing about the idea that Spinosaurus was bipedal.
The first and the second article tells the same things: for dr. Cau the Spinosaurus was bipedal.
But he's saying that "bipedal" doesn't mean that Spinosaurus can normally walks on two legs.

Quote:

"This question is more complex than the discussed and controversial hypothesis if Spinosaurus was capable of quadrupedal gait. I would like to point out that the problem has been simplified by many observers, estremizzandolo. It should make distinctions: a phenomenon is the acquisition of a horizontal body posture (body axis preferential orientation with respect to the substrate), another phenomenon is the acquisition of a quadruped posture (support of the body part of the four limbs) , another is the acquisition of a quadrupedal locomotion (use of all four limbs in locomotion). For example, a seal has a horizontal posture, but I would be reluctant to call it a quadrupedal posture. A human being can take on a quadrupedal posture, but is unable to maintain an efficient quadrupedal locomotion does not go beyond a few awkward steps hunched. "

An acquatic "bipedal" Spinosaurus (but not fully bipedal on land, like a seal) sounds good to me.
To me, the Spinosaurus was a sort of bipedal crocodile (an animal with a strong marine adaptation).
About the marine enviroment of the Spinosaurus, there is a "proof" (...) that makes sense (I knew about that at the Paul Sereno/National Geographic Exhibit):

" Better evidence for swimming Spinosaurus comes from the structure of the dinosaur's bones. The dinosaur's long bones are solid. This is odd.
Spinosaurus was a theropod – a member of the major lineage that includes dinosaurs such as Tyrannosaurus and Allosaurus – and these dinosaurs typically had relatively light long bones with cavities inside. The dense Spinosaurus bones, by contrast, seem similar to those of some early whales and other semi-aquatic mammals that evolved heavy bones to act as a kind of internal ballast. Based upon what paleontologists have previously discovered about animals that transition from land to the water, the solid leg bones of Spinosaurus are the best evidence that this was a dinosaur that preferred to swim. Trackways have shown that other theropods swam from time to time, but Spinosaurus may have been unique in its dedication to a semi-aquatic lifestyle. "

I hope I was clear enough.

[Dinoguy2]

Yet this still doesn't explain the enormous amount of mass in front of the pelvis. Keep in mind that most of these huge spines were decidedly in front of the hips, which would tip the mass even farther forward. If the neural spines were indeed used for counterbalance, than why would they grow over the torso, rather than closer to the tail, a la Concavenator? Spinosaurus did indeed have a massive tail, heavy with dense bones and muscles, but the front of its body had even more dense bones and even more muscle. There are still too many holes in this argument, and ideas not taken into account, including the aforementioned signs of muscular atrophy on the legs (something I notice most evaluations of the Spinosaurus material ignore).

The darned things made no sense as a display mechanism for a semi-aquatic animal, their sheer size and mass indicates that they MUST have had some actual function.  Once you see them the way he sees them, they kind of fit in with the rest of the bizarre body shape....

What about a sailfish? They are completely aquatic animals, yet they have a massive sail very similar in shape to that of a Spinosaurus that it uses to effectively herd its prey. There are more functions to bizarre physical anomalies than you might think.

Cau's idea has zero to do with counter balance. He's saying the body hung from the vertebrae like a suspension bridge (like an extreme version of a diplodocid neck). Mechanically it seems legitimate, though I'm not an engineer - let's see what peer reviewers think.

If this argument pans out, we will need to re-evaluate the sails of things like Concavenator in this light. Cau's hypothesis seems like it would predict spine heightening to start over the hip and extend along the spine as the fore body gets longer. So early spinosaurids would be expected to have longer hip spines, and then longer spines further along the back as they evolved longer torsos. That's what his line diagram is showing. And in fact, more basal spinosaurids like Suchominus with only moderately long torsos do seem to have the longest spines over the hips.

One way to test his hypothesis is to calculate the trunk to hindlimb ratio of Concavenator. If Cau is right, it should have a longer than average torso, if the sail is serving the same purpose. The "shark fin" is actually an anchor point for ligaments holding the body in the air like the cables of the Brooklyn Bridge. The side effect of all this that he doesn't mention us that the "sails" would look quite different than anybody has ever drawn them. If this is correct there needs to be massive amounts of soft tissue connecting the sail to the neck. Think Greg Paul hadrosaur silhouette style.

(I think a big construction crane might be a better analogy than a bridge actually, for a biped. Think of the base of the crane as the legs, the top as the hip, the arm as the vertebrae, the cable as the neural spine ligaments, and the cargo as the head.) A longer stronger tail doesn't get you balance-you don't need balance. What you need is leverage to haul the front load upward off the ground. That's where a big tail with big neural spines would help.

[Silvanusaurus]

Cau's idea has zero to do with counter balance. He's saying the body hung from the vertebrae like a suspension bridge (like an extreme version of a diplodocid neck). Mechanically it seems legitimate, though I'm not an engineer - let's see what peer reviewers think.

If this argument pans out, we will need to re-evaluate the sails of things like Concavenator in this light. Cau's hypothesis seems like it would predict spine heightening to start over the hip and extend along the spine as the fore body gets longer. So early spinosaurids would be expected to have longer hip spines, and then longer spines further along the back as they evolved longer torsos. That's what his line diagram is showing. And in fact, more basal spinosaurids like Suchominus with only moderately long torsos do seem to have the longest spines over the hips.
One way to test his hypothesis is to calculate the trunk to hindlimb ratio of Concavenator. If Cau is right, it should have a longer than average torso, if the sail is serving the same purpose. The "shark fin" is actually an anchor point for ligaments holding the body in the air like the cables of the Brooklyn Bridge. The side effect of all this that he doesn't mention us that the "sails" would look quite different than anybody has ever drawn them. If this is correct there needs to be massive amounts of soft tissue connecting the sail to the neck. Think Greg Paul hadrosaur silhouette style.

I'm glad somebody else hit on the suspension bridge comparison. That was my first thought as I was reading the post.

[CarnegieCollector]

Personally, I like the idea of a spinosaurus being both a quadruped and a biped. I like both interpretations, four legged and two legged, but I prefer the look of the typical biped spino. Just my opinion.

[Megalosaurus]

Its amazing how any spinosaurus news make us start such hot discussions about it. Thank you Mr. Spinosaurus. 
Well, I have never been convinced of cuadrupedal locomotion of spinosaurus for the same reasons that Silvanusaurus pointed in the first page.
I must confese that I bought the little Swimming CollectA one. I choosed that one because is the only one that doesn't have "broken wrists".
But as some of you did, I've readed every article & paper on spinosaurus since the controverse started (and the Scott Hartman topics too). I'm not Paleontologist. I'm not convinced yet of the cuadrupedal stance and the body proportions of the new chimeric spinosaurus reconstruction. And I use the word chimeric in literal sense, not in offensive way.

[Dinoguy2]

I still like the CollectA figures, for the record - even if they turn out to be wrong. All dinosaur reconstructions are hypotheses, and it's cool to have past hypotheses as figures. Though this is also the reason I only bought the swimming version so far, odds that the quadruped thing would last more than a year or two before getting shot down were always pretty low.

[stargatedalek]

the new chimeric spinosaurus reconstruction. And I use the word chimeric in literal sense, not in offensive way.

Only the neck is chimeric.

[Megalosaurus]

According to Ibrahim this reconstruction is composed of olotype + neotype + isolated remains + other spinosaurids + inferred. The mixture affects most segments of the  body. This can be seen in the supplemental figure S3 of the paper.

[stargatedalek]

But it doesn't affect the legs or hip. The reconstructions chimeric nature is in no way indicative of any locomotion methods, nor is there particularly much room for error given how closely related these species really are and how straight forward most of the inferred regions are.

[Silvanusaurus]

It's still very doubtful that this offers us a definitive or totally accurate reconstruction of the animal, and it will continue to be doubtful until a much more complete specimen is discovered. We try to force the scant bits and pieces that we have to make sense, to gratify our need for certainty, creating images of strange animals and then struggling to explain how they could possibly have existed, rather than accepting that the reason they are so difficult to explain may simply be because they never did exist. It's fine to not know, and until we know more, it's reasonable to feel uncomfortable or suspicious of any reconstruction we make.
With an animal that is this unusual, I think people are jumping the gun in trying to nail down exactly how it functioned as a fully fleshed out creature, before there is even something approaching a complete picture of it's underlying skeleton. I believe this is truly beyond us at this time, and so my mind remains completely open to the possibilities. Though ultimately, this also goes for any prehistoric dinosaur species. 

[Megalosaurus]

Lets just relax a little moment.
Who doesn't like especulative reconstructions of spinosaurus?

Do you know whats wrong with this spinosaurus reconstruction?

?
?
?
?
Yes, the tail it too short. 

[stargatedalek]

It's still very doubtful that this offers us a definitive or totally accurate reconstruction of the animal, and it will continue to be doubtful until a much more complete specimen is discovered. We try to force the scant bits and pieces that we have to make sense, to gratify our need for certainty, creating images of strange animals and then struggling to explain how they could possibly have existed, rather than accepting that the reason they are so difficult to explain may simply be because they never did exist. It's fine to not know, and until we know more, it's reasonable to feel uncomfortable or suspicious of any reconstruction we make.
With an animal that is this unusual, I think people are jumping the gun in trying to nail down exactly how it functioned as a fully fleshed out creature, before there is even something approaching a complete picture of it's underlying skeleton. I believe this is truly beyond us at this time, and so my mind remains completely open to the possibilities. Though ultimately, this also goes for any prehistoric dinosaur species.

Not completely accurate no, but ignoring the inferred and chimeric areas we know what its legs and hips looked like, what its shoulder girdle and upper arms looked like, what its skull looked like, what its "sail" looked like, and we know the neck and tail are very long even if the exact proportions are estimates. And that's still a fairly complete picture of a skeleton, especially considering the animal is so far removed from its closest better preserved relatives.

[tyrantqueen]

Lets just relax a little moment.
Who doesn't like especulative reconstructions of spinosaurus?

Do you know whats wrong with this spinosaurus reconstruction?

?
?
?
?
Yes, the tail it too short. 

Cutest Spinosaurus ever

[Dobber]

Lets just relax a little moment.
Who doesn't like especulative reconstructions of spinosaurus?

Do you know whats wrong with this spinosaurus reconstruction?

?
?
?
?
Yes, the tail it too short. 

Lol! That is do awesome! 

Chris

[Jose S.M.]

Lets just relax a little moment.
Who doesn't like especulative reconstructions of spinosaurus?

Do you know whats wrong with this spinosaurus reconstruction?

?
?
?
?
Yes, the tail it too short. 

Now we need some company to make a figure of this reconstruction

[Silvanusaurus]

Everything has changed.