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

[Simon]

Here is part 1 of the discussion (translated from Italian): http://translate.googleusercontent.com/translate_c?depth=1&hl=en&ie=UTF8&langpair=it%7Cen&rurl=translate.google.com&tbb=1&u=http://theropoda.blogspot.it/2016/08/spinosaurus-gambe-corte-o-torace-lungo.html&usg=ALkJrhhGFvZpWKYzeI-Z27qFtipI4t7F_Q

Here is part 2 of the discussion (translated from Italian): http://translate.google.com/translate?u=http%3A//theropoda.blogspot.com/2016/08/il-canyon-la-carrucola-e-lo-spinosauro.html&hl=en&langpair=it|en&tbb=1&ie=UTF-8

[Silvanusaurus]

So... Have I got this right, the suggestion is that Spinosaurus was almost like the anatomical equivalent of a suspension bridge?

[Simon]

I haven't read every word of it, but the hypothesis is that the tall spines over the hips were a necessary development to counterbalance the extra-long front torso - so that the animal could, and in fact, did, walk bipedally. 

Basically, as the front end of the torso got longer due to advantages it gave in terms of feeding - the spines rose in order to provide a counterbalance allowing the animal to continue walking on its hind legs.

Its a brilliant engineering deduction, and solves the mystery of the purpose of the spines, which otherwise simply don't make any sense.

[RobinGoodfellow]

.....well, I read both articles in the original language (I'm italian).
Dr. Andrea Cau first said clearly that we don't have a complete skeleton of the animal so it's a speculative discussion based on logic and similar skeletons of others relative dinosaurs (like Sereno did).
In the 2 post he said:
1) Spinosaurus wasn't quadrupedal (but it doesn't mean that Spinosaurus can walks on two legs...)
2) Spinosaurus was an acquatic animal
3) Spinosaurus wasn't a full bipedal animal on land

He suggest that Spinosaurus (as a semi-marine animal) wasn't quadrupedal but not a full bipedal on land, like a seal.
For him, the Spinosaurus on land could be like this  Luis V. Ray picture:

https://luisvrey.files.wordpress.com/2014/09/spinosaurus-walrusb1.jpg

That is what dr. Cau said in the blog.

[Silvanusaurus]

He suggest that Spinosaurus (as a semi-marine animal) wasn't quadrupedal but not a full bipedal on land, like a seal.
For him, the Spinosaurus on land could be like this  Luis V. Ray picture:

https://luisvrey.files.wordpress.com/2014/09/spinosaurus-walrusb1.jpg

That is what dr. Cau said in the blog.

I think you are mistaken, the Spinosaurus in that Luis V Rey picture is quadrupedal, that's basically what CollectA based their quadrupedal spinosaurus on, you can see that the forelimbs in that image are clearly bearing a lot of the weight of the animal, apparently even more than the hind legs, to the extend that the wrists appear to have broken (which is my big problem with that reconstruction). Rey himself even compared it to the quadrupedal CollectA figure, so there's no doubt about that. 

From what I gathered of the second post linked above, the ultimate conclusion of that particular post, is that it was indeed bipedal, and the 'spines' actually explain how that was possible, and why they would have developed. I agree with Simon, that this theory offers a believable explanation for the spines, which alternative concepts don't. I am probably wildly ignorant, but from what I've seen and read (not just in this article but multiple others, and through consideration of logic), of all the possible forms of locomotion Spinosaurus could have had on land, the quadrupedal option is the least believable of all, simply because of the problem presented by their being no evidence to explain how it's forelimbs could possibly have served this purpose.

If Spinosaurus did indeed have the spines to support bipedalism, would that make it likely to have had more of a hump than a sail?

I wonder whether the tall spines of Becklespinax, assuming it was another megalosauroide, developed for the same reasons?

[RobinGoodfellow]

The picture from Luis Rey is the best I found; probably this is better:

http://bestinslot.wikia.com/wiki/Spinosaurus?file=SpinosaurusSizeNew.png

About the article, I'm not a paleontologist so I just can't say if it's right or wrong.
But what dr. Cau said is :

"  Inoltre, fintanto che non avremo elementi del cinto pettorale, è del tutto immotivato pensare che Spinosaurus fosse capace di muovere alternativamente le braccia in una locomozione quadrupede. Ciò implicherebbe una radicale modifica della regione pettorale

Pertanto, questo modello predice che un animale "iper-allungato" rispetto alla gamba, come Spinosaurus , dovrà evolvere delle spine neurali molto alte per aumentare l'efficacia dei legamenti che tengono sospesa la testa.


Questa interpretazione quindi indica che le spine neurali di Spinosaurus non sono un "vezzo" o "optional" della sua anatomia, ma una necessaria conseguenza biomeccanica delle sue inusuali proporzioni corporee. Le spine neurali iper-elevate di Spinosaurus si sono evolute come ancoraggio di legamenti epiassiali necessari per bilanciare una leva corporea molto "sbilanciata" in avanti.

Sulla base di queste considerazioni, penso che l'ipotesi di una postura orizzontale strisciante, da "foca" o, per restare in Theropoda, da "pinguino che striscia sul ventre", possa essere la chiave per comprendere Spinosaurus fuori dall'acqua. Ovvero, estendendo il ragionamento di D. Nash, penso che un animale a postura orizzontale obbligatoriamente a contatto con il substrato, corti arti posteriori capaci comunque di generare una marcata spinta locomotoria (il quarto trocantere del femore è enorme) sia in acqua che su un substrato fangoso, possa essere la soluzione delle anomalie proporzionali di Spinosaurus , senza dover ricorrere ad una postura quadrupede che, fino a prova contraria, non ha alcuna evidenza morfologica a suo favore "

Using Google Translator:

Furthermore, until we have elements of the pectoral girdle, it is totally unjustified to think that Spinosaurus was able to alternately move his arms in a quadrupedal locomotion. This would imply a radical change in the pectoral region

Therefore, this model predicts that an animal "over-stretched" compared to the leg, such as Spinosaurus, will have to evolve very tall neural spines to increase the efficiency of the ligaments holding the head suspended.


This interpretation thus indicates that neural spines of Spinosaurus is not a "quirk" or "optional" of his anatomy, but a necessary consequence of its biomechanics unusual body proportions. The hyper-high neural spines of Spinosaurus have evolved as an anchor of epiassiali ligaments needed to balance a lever body very "unbalanced" forward.

Based on these considerations, I think that the hypothesis of a creeping horizontal posture, to "seal" or, to remain in Theropoda, from "Penguin crawling on his belly", can be the key to understanding Spinosaurus out of the water. Namely, by extending the reasoning of D. Nash, I think that a horizontal posture animal compulsorily in contact with the substrate, Short hind limbs still capable of generating a strong thrust locomotor (the fourth trochanter of the femur is huge) both in water and on a muddy substrate, can be the solution of the anomalies proportional Spinosaurus  without having to resort to a quadrupedal posture that, until proven otherwise, has no morphological evidence in his favor. "

Sorry, I don't want to be rough, but I think I can understand my own language better than Google Translator.

From both articles, the idea of dr. Cau is that Spinosaurus wasn't quadrupedal but even not totally bipedal on land.
Again, I don't know if he is right or wrong...

All the Best

[Dinoguy2]

I think Cau would be the first to tell you that this "proves" nothing and that even the notion of "proof" in science is actually anti-science. This is pretty a compelling idea that next needs to be peer reviewed, published, and tested before it can even qualify as a hypothesis.

[sauroid]

if Spinosaurus bipedalism isnt conclusive, then the recent CollectA figures are still valid. (YAY)

[tyrantqueen]

I know you're not supposed to get attached to ideas but I still prefer the idea of a bipedal Spinosaurus.

[Derek.McManus]

It's an interesting idea with a ring of truth about it I think.

[sauroid]

also, this means that previous bipedal Spinosaurus representation in figures/models isnt accurate either.

[Jose S.M.]

From what I understand,  it refutes both Collecta like quadrupedal movement  and traditional bipedal movement,  but still calls the theorized  penguin like sliding as bipedal movement  because it propulses with it's hindlimbs.

[Dobber]

From what I understand,  it refutes both Collecta like quadrupedal movement  and traditional bipedal movement,  but still calls the theorized  penguin like sliding as bipedal movement  because it propulses with it's hindlimbs.

I agree. Also if the theory is correct the Spines would give the animal the option/ability to "rear up" on its hind legs for possibly limited times. Maybe to strike or threaten. It really makes the animal very fascinating. Personally I'm viewing the Spinosaurus as the dinosaur equivalent of the Crocodile with it's own adaptations like limited Bipedal locomotion.

Chris

[stargatedalek]

I purposed a similar idea a few months ago based on the width rather than height of the spines, suggesting that the ones over the hip supported a hump to aid in balance. However, after bringing it to Duane Nash he explained more exactly how the legs themselves are atrophied to where they would have simply buckled under the animals weight, regardless of their length or of any counterbalances in place.

That being said, just because Spinosaurus wouldn't have been able to walk bipedally doesn't mean it was incapable of standing bipedally or perhaps even briefly staggering, like a ferret or woodchuck (or the go-to comparison loons themselves for that matter).

Also interesting to hear the sliding movement described as itself being bipedal. I hadn't really thought of it that way but I suppose it would still be bipedal movement technically. Otherwise loons would be the first official vertebrate tripods.

[Simon]

Obviously the word "proves" was used in the title by me as a "hook". 

(There can be no conclusive "proof" since the animal is no longer around to be observed.)

Having said that, Cau is definitely on to something - finally someone started looking at the sails from a mechanical standpoint, and *voila* - a purpose for their existence can be hypothesized, and backed up, by engineering mechanics.

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....

I'll repeat something I've said before - even a front-heavy animal can walk bipedally so long as it shifts the center of balance backwards by rising upwards from a strictly horizontal posture.  The massive ligaments connecting to the sails over the hips would be the mechanism for just such an action, and provide stability.

Spino was no sprinter, and probably looked a bit off walking around, but on dry land I am more convinced than ever that walk it did ..

[Silvanusaurus]

This interpretation thus indicates that neural spines of Spinosaurus is not a "quirk" or "optional" of his anatomy, but a necessary consequence of its biomechanics unusual body proportions. The hyper-high neural spines of Spinosaurus have evolved as an anchor of epiassiali ligaments needed to balance a lever body very "unbalanced" forward.

...

Sorry, I don't want to be rough, but I think I can understand my own language better than Google Translator.

From both articles, the idea of dr. Cau is that Spinosaurus wasn't quadrupedal but even not totally bipedal on land.
Again, I don't know if he is right or wrong...

All the Best

If the content is radically different in it's original language, fair enough, but I fail to see how it would make any sense at all, let alone enough for me to glean this information, if the translation process was that faulty.

The quote above which I have highlighted in bold, includes this sentence, which you omitted:

No minor detail, this model implies that all the weight forces of Spinosaurus apply back on the limb, so that it is a biped.

I'm not sure what you are disputing; as it literally states there at the end: "it is a biped".
Note that I am talking of the second post which is linked to. These are two seperate pieces of writing, but you've quoted them in a muddled up order, which confuses the content.

The key point in that second article, which presents a different angle than the first, is the explanation that is offered suggesting that the spines exist to serve the function of supporting a bipedal stance. If this were to be correct (and I'm not saying it is), then it would also suggest that the spines would serve no purpose if the animal was supported only by sliding on it's stomach/chest, or on four legs. The diagram that supports that second article:


Is clearly based around the assumption that the red horizontal line is the suspended 'body' in question, which in order to be suspended at an extended length, and thus in order for the theory to have any meaning, that body must be held up by a vertical structure (i.e. hind legs), represented by the vertical red line on the left. This entire second article is based around the concept of Spinosaurus holding it's body off the ground with it's hind legs. If one assumes that the neural spines were indeed to help suspend it's body from the ground, but it spent it's time on land just supporting itself on it's stomach, rather than with it's legs, why would it need the spines in the first place?

In short, the theory here is this: The spines developed as a way of allowing Spinosaurus to hold it's elongated body up on it's two hind legs.

This isn't just another 'spinosaurus moved like a penguin, or an absolute loon' piece, there's been lots of them before. This gives an explanation for the neural spines that is reliant on bipedalism. If the spines developed to such a relatively freakish extent, just in order to maintain bipedalism in spite of it's lengthened bodily proportions, then surely that would imply that bipedalism was a pretty significant part of it's lifestyle, and not something it just did now and then?

Whether or not you agree about the bipedalism or not, and whether or not this theory is valid, the content of the text and the conclusions made within it are fairly clear to me, and they make a lot more sense than the quadrupedal interpretation, which seems to rely on the invention of a totally new form of hand for it's forelimbs, and offers no explanation for the spines themselves.

[Dobber]

I get what you are saying Silvanusaurus, it's a good argument, but using that argument too...IF the animal needed to be bipedal so much that it evolved the long neural spines to allow an otherwise unsuitable body to accomplish the task, then wouldn't other changes like longer stronger legs or a shortened body also accomplished the same thing? It just seems like an extreme adaptation when nature has shown other such evolutionary adaptations that seem to make more sense. This *seems* more like "mans" quick fix to a problem rather than nature gradually doing it over millions of years. I am by no means an expert and think it's a cool idea, and it very well may be accurate...it just seems..... strange is all. Spinosaurus is TRUELY a fascinating animal.

Chris

[stargatedalek]

It also fails to explain why ancestors as far back as Baryonyx are displaying enlarged neural spines relative to other theropods. However the idea of the sail(s) beings a hydrodynamic structure explains perfectly both it's evolutionary path and also why it's so prevalent on Spinosaurus itself compared to Baryonyx and Suchomimus. That's not to say it couldn't have aided in balance, but to suggest it evolved specifically for balance is frankly ludicrous given the overwhelming evidence we have that this feature was a very gradual evolutionary trait.

It also yet again fails to address the leg muscles themselves. Balance is completely meaningless unless you have the muscles to actually lock your joints in place and support any weight at all, and these are what's atrophied in Spinosaurus. The weight bearing muscles, not the locomotion related ones.

[Silvanusaurus]

I'm not saying the idea is totally solid, like I said; the extent to which the spines developed for whatever reason they did, appears freakish to say the least. And it certainly would seem to be a ridiculous adaptation simply to suspend an abnormally long body. Like you say, there would be much simpler ways of achieving this goal. I am just trying to explain why the conclusion of Andrea Cau's post was a bipedal interpretation, which Robin Goodfellows was disputing. Whether that conclusion is likely or even possible, I can't really say, but the conclusion is definitely suggesting bipedalism. I don't think it's likely that it offers a fuller explanation of the animal, but I do think from a perspective of 'mechanical' logic, it is more convincing than the quadrupedal idea. I still believe there is no truly solid conclusion to be drawn about it until a much more complete specimen is found, until then all we can do is fumble around in the dark, creating strange chimaeras and mutants that may all be eventually proven foolish.

It reminds me of how in european medieval bestiaries, the artists would sometimes re-create genuine animals as strange, fantastical creatures bearing little resemblance to reality, because those artists had only vague, exaggerated descriptions to rely upon, usually related by people who didn't know much about them in the first place. We look at them now and think they are naive and amusingly ignorant, but time may yet make fools of us all.

[The Atroxious]

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.