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Post by theropod on Dec 7, 2013 15:54:32 GMT 5
Found again the quote from Greg Paul I think where he considers Carcharodontosaurus to be more powerful than Spinosaurus : s6.postimg.org/ho2y1jqg1/Spinosaurus_Greg_Paul.pngThis was mainly what brings my doubts about the claimed superiority of Spinosaurus in sheer strength compared to any other theropod. As in what? Bite force? Skull strength? What? As I said in the Spinosaurus vs Carcharodontosaurus thread, spinosaurus actually likely had denser jaws according to what skull evidence we already have (skull possesses smaller and lesser fenestrae, and their is obviously little emphasis on any sort of depth of width). Now, this does not prove whether or not it had a stronger bite force, but it certainly had a denser skull and thus a greater resistance to lateral forces than carchy. Carcharodontosaurus definitely had the advantage here in the realm of vertical biting (as its skull was very deep in profile), but that does not necessarily state whether or not it had a more powerful bite. I must acknowledge that, given the fact that allosaurs were better off attacking the flanks of a prey animal (again, as evidenced by their jaws and teeth), carchy's bite was probably a lot weaker than many claim. In the event that it tries to damage the spinal cord, it would use its powerful neck muscles, wide gape, and immensely knife-like teeth to perform the hatchet-bite technique, which has zero reliance on bite force and instead only utilizes the animal's top jaw. It's probably a lot stronger than many claim, considering its more likely ~3t than the usually (usually as in "that's what most people seem to believe in") claimed 1-2t. Carcharodontosaurus didn't rely on cervical depressor force as much as Allosaurids (as evidenced by the anatomy of its paroccipital processes). Of course the bulk of force would be pulling and also some depressing, besides the biting action, but that doesn't have to mean the adductors were particularly weak. Also, keep in mind 3t bases directly on the Allosaurus specimen SMA 0005 anyway, so it's conservative. Density alone (as in less extensive sinuses) is not all. The overall cross-section of resistant tissue (ie. bone of comparable strenght) has to be bigger in order to be more resistant. I'm certain Spinosaurus' rostrum isn't a weak structure (let alone its mandible...), but that it must necessarily be stronger than Carcharodontosaurus is speculation. Possible, but we don't know it like you seem to propose, just because the skull is likely less pneumatic. But you are right, Paul isn't very specific here and even if he was, how much of it is based on proper empirical methods, and how much is just guesswork? I find it funny how people consistently distrust Paul in other regards, where he actually uses scientific methodology (eg. his mass estimates), but suddenly trust him as soon as it comes to a single, vague sentence in a Field Guide, that's not even consistent with the rest of the book. Runic: I think some degree of shaking could be within its capabilities, simply because its jaws must have had the strenght to resist a fair deal of stress during its hunting routine, but I doubt it would be efficient in terms of dealing damage. This resistance would rather be employed for holding something, together with the arms. For a bite to do lethal damage to a large and robust (ie 6t+ and not a sauropod or other animal with a slender and vulnerable neck) animal, a throat bite would be its best chance, since it offers a good chance of closing the windpipe, or perhaps even puncturing some big blood vessel. |
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Post by Godzillasaurus on Dec 7, 2013 21:00:33 GMT 5
3 tons is definitely likely for carcharodontosaurus; I never said otherwise. It is just that many people (specificalyl those that are misinformed) always tend to believe that a larger skull and/or larger jaws (whether it be deeper or wider) = a stronger bite overall, which is simply not true. This is evident in the fact that carcharodontosaurus had a very long and deep skull, even proportionally larger than that of tyrannosaurus, yet its skull was still very lighly-built and its bite force paled in comparison to that of the latter animal.
Carcharodontosaurids had very deep skulls in general, which means that they were definitely more resistant to vertical forces than spinosaurus (also evidenced by their hatchet-bite killing style as well). Spinosaurus needed to have a skull that, to make up for the lack of depth and/or width, could withstand intense amounts of pressure from prey, as spinosaurus' jaws and teeth were obviously not designed for slicing or ripping and were an obvious adaptation for piscivory. The gripping function of spinosaurid jaws and teeth signified that it would have killed much larger animals (in the event of course) by biting their neck or back regions and then violently shaking its head side-to-side to increase overall potency and rip out chunks of flesh.
Carcharodontosaurus simply did not need to have dense or powerful jaws, as its skull's impressive depth would already allow for functional resistance to vertical forces. Spinosaurus was simply better adapted for gripping as evident in a multitude of ways.
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Post by theropod on Dec 7, 2013 22:10:36 GMT 5
I don't think people do that actually, most people suffer from nonontyrannosaurinecanhaveastrongbite-syndrom and will just generally claim them to be weak, regardless of their structure.
While there is a pretty good correlation with skull width, depth, at least in dinosaurs, doesn't really tell us much about bite force (our best example is Allosaurus, with a very deep skull but comparatively little adaptions for a strong bite).
Of course T. rex undoutedly had the strongest bite of these theropods we are discussing (not necessarily strongly related to the strenght of its skull). Carcharodontosaurus would have a skull much more adapted for killing large stuff, and accordingly deepened and built to deliver large forces perpendicular to its transverse axis. Spinosaurus' is built to grip and secure something.
This would mean a much more even distribution of stresses and accordingly reinforcement, with less emphasis on the strenght of the rostrum since the mandible is just as important here, and probably not a built made to deliver large forces, but to withstand and absorb them.
There's no definitely here, but that's certainly highly likely.
it isn't really "making up" if you say it makes up for a disadvantageous shape for handling stresses by being highly resistant to stress...
I think whether it really killed via back-bite and ripping out flesh is very doubtful. I think all the potential larger terrestrial prey (comparable to Aegyptosaurus or Ouranosaurus) could be dispatched by a neck bite that would suffice to puncture their spinal canal or suffocate them, or overcome by sheer mass and power. Of course it must have had the ability to tear flesh for feeding, but I doubt efficient enough to use it for killing. Crocodilians today need immense forces to do it, so it would probably create immense loads on the skull to rip flesh with that dentition, if not used very carefully.
Surely they couldn't be weak, but that doesn't mean they have to be strong for dinosaur standarts.
Carcharodontosaurus likely had a strong skull, that's basically what you are saying as well. Whether Spinosaurus could match it in this regard, we can't tell.
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Post by Godzillasaurus on Dec 7, 2013 23:35:30 GMT 5
That is what I said
The majority of my plight was attributed to lateral resistance, not vertical resistance. Despite having a denser skull overall, the ability for spinosaurid jaws to withstand high-degree vertical stress pales in comparison to that ability in allosauroids.
I don't get it...
Spinosaurus damaging the spinal cord that way is probably not likely, as its teeth and jaws did not work in the same way as those of carnivorans, which normally kill with throat bites. The long and thin shape of their jaws and their conical dentition were not designed for killing with a single bite and would have instead been better off being used as clamps so that further damage can be done (ie. shaking its head from side-to-side or up and down), as they were fundamentally designed for gripping and puncturing deeply, but not fatally (in general). As I said, its snout was more-than-capable of withstanding decent side forces, as it was very robust.
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Post by theropod on Dec 8, 2013 1:38:41 GMT 5
As I wrote there's no "definitely" here.
As per your own arguments regarding the lateral resistance, the internal builts are not well-documented enough. I agree that is extremely likely.
You don't make up for being bad at activity A by being good at activity A, you make up for it by being good at something different.
Eg. you don't make up for having a weak skull by having a strong skull.
A carnosaur makes up for its modest bite force by its sharp, sawlike dentition, pulling and depressor forces and a big gape
A spinosaur makes up for its gracile jaws (regardless of their internal built their strenght is limited compared to more voluminous ones) by the ability to quickly snatch something in the water
We don't know whether it could really withstand this kind of force, neither do we know how much it would take to effectively rip out something with those jaws.
Spinosaurus has some very long, straight teeth in its mouth. A use for puncturing a vital structure is fully conceivable, so is clamping down on a windpipe (tough it would take some maneuvering), which is actually quite easily applicable by any kind of non-ziphodont because it doesn't take a lot of force or especially adapted teeth.
Compare its jaws to crocodilians, which have mushc shorter teeth (even more adapted for holding), and a wider, but often shallower skull, and you get what I mean.
They were even less designed for ripping out chunks of flesh. In fact long, conical teeth are well suited for inflicting penetrating injuries, but not well designed for ripping out things at all.
I cannot see a lot of evidence for that.
And the only real way I can see a Spinosaurus inflicting serious damage to a large animal's spine is via a well-placed, puncturing neck bite, that focuses the force of its bite on a few tooth-tips to pierce or separate vertebrae and sever the spinal chord that way.
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Post by Godzillasaurus on Dec 8, 2013 5:53:37 GMT 5
A spinosaurid would make up for its slender and specialized jaws with a high skull density and robusticity; thin jaws are an adaptation for catching swift aquatic animals, so spinosaurids would need to have very strong jaws to be able to withstand the forces exerted by various Cretaceous fish (some of which being huge). This is not only logical to believe but also entirely evident as well.
Conical teeth are perfect for piercing, but that doesn't always mean they would be used for killing, at least directly. All (f not, most) spinosaurines had this kind of dentition, but it was used for gripping, not creating deadly puncture wounds. Don't get me wrong, spinosaurus could easily cause a good amount of deep tissue damage with a single bite, but its teeth were still designed for gripping solely. Spinosaurus could have caused a good degree of spinal damage with a single vertical bite, but the damage done would not have been as severe as if carcharodontosaurus did so.
Crocodilians, too, need to use rolling or head-shaking methods to dispatch large terrestrial prey, yet generalist species are much better adapted to attack larger prey than spinosaurus.
Yes, but in primarily piscivorous animals (ie. Indian gharial), conical teeth are used mostly for gripping. Now, they would need to be able to easily pierce an animal's hide to do so, but that does not necessarily translate into causing deep puncture wounds
The pierce wounds given by the theropod's teeth would surely create a good amount of deep pentration damage on their own, but spinosaurus would need to use the shaking technique that I described to "separate" vertebrae or to sever the actual spinal cord as its teeth were horribly-adapted for doing so. In fact, this would probably not end in either of those events, but would instead help in ripping the prey's hide apart (which crocodiles do in similar ways).
The teeth themselves would be very deadly nonetheless in that they would be perfect for penetrating deeply into a prey's hide, but that would not necessarily be fatal in itself (in that case, the spinosaurus would need to sit there and wait for the animal to die while its teeth were embedded within the neck or back).
Oh yea, and this has actually been theorized on Monsters Resurrected. Yes, I know, I know; a lot of dinosaur fans refute that show's claims due to its overrating of various animals (specifically spinosaurus itself), but this argument is actually quite valid, as the similarities between crocodiles and spinosaurids are actually quite prominent.
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Post by theropod on Dec 8, 2013 14:34:03 GMT 5
That is probably true.
Just have a look at the differences between Spinosaurines, baryonychines and crocodiles. You see Spinosaurines have pretty large, robust teeth. Those would be it's best chance for killing something big with a bite, not using some kind of ripping movement when its teeth and skull weren't well-suited for that.
Gripping involves puncturing, and puncturing is what I presume it would have resorted to for killing, not flesh-tearing.
I never suggested Spinosaurus' bite would be anywhere near as potent as the one of an animal designed for dealing immense amounts of tissue damage. But Carcharodontosaurus was in no way built for damaging the spine of its prey, T. rex is the one with the bone-crushing bite.
--and crocodilians in fact do not have the same kind of dentition. they are similar in that they are conical, but both the jaw-layout and tooth sizes.
And Spinosaurus obviously cannot deathroll.
As I wrote, gripping requires them to also puncture what they grip. And, there are obvious differences between Spinosaurus and Indian gharial
That is primarily dependant on tooth lenght and bite force in an animal with conical teeth. Obviously, spinosaurus has much longer teeth, and a much more robust mandible (and a more robust rostrum too in fact) than a gharial, thus it could drive its teeth deeper.
On they other hand, they would be just as ill-suited, if not more so, for ripping anything, because the larger teeth are more deeply and firmly anchored in the tissues (which is certaily advantageous if you want to get a hold of a big, struggling fish) and will accordingly take even greater forces to rip free of them.
Extant cats have canines very similar (at least more so than to any other theropod I'm aware of) to Spinosaurus' teeth, and in fact one of their main purposes is puncturing the spinal medulla (by puncturing or sliding in between vertebrae).
But crocodiles, due to various reasons, are no ideal analogy for the biting-mechanics of Spinosaurus.
They are analogous in that both have relatively elongate jaws, well-suited to snatch and hold things. But in the way they would have killed, they are different.
An animal doesn't die from mere penetration of its hide, but I also don't presume 10cm teeth would merely embed themselves into the skin, they'd go deeper and in some animals (of course not something as large and robust-necked as another big theropod, but a mid-sized ornithopod or small sauropod) could actually puncture deep enough to threaten the spinal chord.
We consider that show crappy not because of overrating, but simply because of terribly bad science in its portrayals of those animals.
regardless of whether it overrated it or not, it portrayed Spinosaurus as a sail-backed killing machine that could outrun and snatch whole Rugopses in its jaws, that would use its forelimbs to swipe like a bear to kill Carcharodontosaurus or tear them across a Sarcosuchus to disembowel it completely.
Whatever stuff they noted, it was not due to scientific methodology but feeling, sensationalism and superficial resemblance.
I'm not arguing Spinosaurid jaws had no partial resemblance to crocodilians, but it is being far overrated and by now people presume spinosaurus was a giant Gharial on two legs and with a sail on its back, while in fact it is a giant mixture of bear (lifestyle, diet, part of dentition), eagle (claws), heron (stance), chameleon (ridge, tail) and false gharial (skull proportions, part of dentition, habitat, diet). It is simply a much more complicated animal than given credit for, and cannot be expected to be modeled accurately with just a single analogy.
That doesn't mean I argue it was somehow weak, in fact the opposite is the case. But I do not think it relied on killing strategies that were very similar to extant crocodilians, because the similarity between these two is limited and only perpetuated because of superficial resemblances.
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Post by Godzillasaurus on Dec 9, 2013 3:55:06 GMT 5
Spinosaurine teeth were horribly adapted for both creating fatal puncture wounds (as in deep enough to impact vital organs. They were well adapted for deep penetration, but this is rather an adaptation for predation on such large fish for the most part) AND ripping. But different killing styles (such as the head-shaking) can be used to increase the overall potency and would more often than not rip out a good deal of flesh while possibly impacting the spinal cord. Remember, spinosaurus had very thin yet very dense jaws, so resistance here would most likely not be an issue. I already said that  The puncturing adaptation of spinosaurine teeth was, fundamentally, used for gripping, as they were piscivorous animals. I am fully aware that slicing is not what they were designed for, but that does not mean that flesh cannot be ripped out after grabbing a hold of a prey animal and utilizing various ripping techniques. I realize that; I was talking only about the spinal cord (which allosauroids could have very easily damaged with a hatchet-bite), not the actual vertebrae making up the entire spine. Proportionally, spinosaurus had much longer teeth than those of modern crocodiles. But that does not necessarily mean that spinosaurus would have been able to kill larger animals with a single bite (as in creating fatal puncture wounds) as easily as you are implying. Much more emphasis on overall potency itself would need to be put into effect for spinosaurus to kill a large terrestrial animal than just simple perpendicular biting. Ripping =/= slicing. Once a spinosaurine would grab a hold of a large prey animal, it would need to rip it apart so that it can be consumed (it would not fit in its maw or throat if it was too big). Of course both its teeth and jaws were horribly-adapted for slicing, but that does not mean that it cannot rip out flesh using varied methods. Caniniforme crocodilian dentition is also (somewhat) similar to the canine teeth of felids, but are they designed for the same thing? No. Big cats will often kill animals much larger than themselves, while spinosaurus, while not being exclusively piscivorous, would have been restricted to preying on animals smaller than itself due to its piscivorous charscteristics. I realize that, but the mere penetration itself would allow for the spinosaurus to get a good grip on that said animal and further allow it to, yes, rip out chunks of flesh and kill it in the process. Well now that I think about it more, spinal damage from a spinosaurine bite does seem much more likely than I have previously implied, as their teeth were perfectly-shaped and designed for piercing deeply, but it was merely a possible killing technique, not necessarily probable. Spinosaurid teeth and jaws were designed and used for gripping smaller animals as opposed to creating deadly spinal wounds, and the jaws of spinosaurids were not characterized by particularly powerful bites and/or especially wide gapes, so the actual damage done to the spine itself would probably be quite superficial in this event (although it was still very well possible). I think the main thing to remember is that spinosaurus was mainly piscivorous by nature, so a killing style revolving around deep puncture damage is, for the most part, much less likely than you are implying, yet spinosaurus COULD have still killed larger animals this way. |
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Post by theropod on Dec 9, 2013 18:01:38 GMT 5
They were horribly adapted for ripping. They were very well adapted for puncturing, even tough their jaws may have lacked the strenght to be very effective at it. But that also applies to ripping.
Then it would be even less of an issue for puncturing. For the kind of shaking are mean, not just a big deal of resistance, but also a big deal of bite and neck force would be needed.
That is irrelevant, it remains an adaption for puncturing.
I already conceded that, but it doesn´t mean it would be an effective killing strategy.
The spinal chord is largely protected by the vertebrae, which would naturally make a crushing bite better-suited for damaging it. Of course that doesn´t mean it is invulnerable, especially if the spine was relatively gracile.
I was not implying that. In fact I think most crocodilians have much more potent bites for macrophagy. But I don´t think they worked in the same manner. If Spinosaurus used its jaws to kill, it would not have done this by applying heavy lateral or torsional loads to rip the victim to pieces.
But they work by the same principle; the less sharp and the longer the teeth are, the more force is needed for it: Spinosaurus has the worst combination possible for employing this killing strategy, because it has long, conical teeth.
But on a dead, immobile prey item, under very controlled curcumstances. Not on a living and struggling creature.
Every carnivore can rip out flesh, which does not necessarily make that it´s preferred killing style.
But I just gave you tons of reasons why Spinosaurus dentition would not be used analogous to that of a crocodile.
That´s not what I´m arguing about. Of course Spinosaurus would be more restricted in the size of its prey than an animal with a strong specialization for preying on large herbivores. But that doesn´t change the most likely way the bite worked.
A cat doesn´t kill a small prey item like a monkex by ripping out flesh, but by puncturing its spine or skull.
The ability to grip and the ability to rib are virtually complete opposites. The very fdeatures that make it good at gripping would make it a very ineffective ripper.
All those are reasons why flesh ripping is even less likely for it.
Just give me a reason why any other killing style should be more likely please.
For a grip, shake and rip strategy, a strong bite force as well as massive cranial resistance to torsional and laterwal loads, and well developed lateral neck musculature are necessary-and teeth that have carinae are advantageous. Spinosaurus has a built that would make this technique very difficult For puncturing, it merely has to deliver a decent amount of force, further supported by the good penetrating ability of the long conical teeth.
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Post by Godzillasaurus on Dec 9, 2013 23:16:17 GMT 5
Spinosaurus dentition and jaws were designed for puncturing flesh, but not necessarily creating FATAL puncture wounds. I need evidence that their primary killing style was spinal impaction. You must remember that, in this case, conical teeth were an adaptation for piscivory and not the killing of other dinosaurs. The gripping and ripping killin style is, as of now, more likely due to the fact that, above all, the similarities between spinosaurids and crocodilians are quite vivid (although there are still obvious differences). Crocodilians bear the greatest resemblance to spinosaurids than any other dinosaur (let alone theropods), so we can at least expect that their relatively small conical teeth would do much less damage to any musculoskeletal structure than creating immensely damaging puncture wounds to a certain area.
As for the actual ripping technique itself, it does not actually require that powerful of a bite in itself, and instead would utilize the theropod's overall resistance to outside forces (in this case, lateral forces), which, as I already stated, spinosaurus surely did not lack due to its very dense skull. Remember, the teeth themselves do not have to be adept at slicing for a ripping maneuver to be put into effect, you just need to have a very strong grip. Just look at modern broad-snouted crocodiles; they are much better adapted for killing larger terrestrial animals than spinosaurus, yet their teeth retain the same general conical and non-serrated morphology to the dentition of spinosaurus.
I am not stating that spinosaurus could not kill with powerful perpendicular biting, just that I feel more evidence needs to be provided for it to be a more likely killin strategy than the gripping and ripping technique.
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Post by theropod on Dec 10, 2013 0:41:41 GMT 5
I didn't claim they were, just that they'd rather be suited for creating fatal puncture wounds than for killing by ripping something apart via inertial dismemberment.
I need evidence they they had such a think as a primary killing style that involved their jaws. My theory is that they wouldn't need to do much killing work in the majority of cases. If it wanted to cause immense damage to tissues of its prey, it could much more easily accomplish that by simply stepping on its head and crushing it beneath a clawed foot and 12t body.
I suggest a precise puncturing bite is the killing style most likely resorted to if the oppurtunity and the need arises, ie. something out of the norm.
I'm well aware of that, I'm not the one who is doubting that.
But you were arguing it must have killed large animal in a way similar to a crocodile or tyrannosaur, by massive mechanical damage. I argued if it killed such prey, it likely delivered a precise puncturing bite or a throat hold.
Which one is in better agreement with the animal's morphology and lifestyle?
I already gave you the reasons why this is not wise to assume.
That doesn't mean much. As I already stated, Spinosaurus teeth are not the same as a crocodile's, and their morphology makes such a killing style pretty unlikely.
Perhaps this is more realistic for baryonychines, which have smaller teeth with serrations that would be more effective at tearing.
The skull strenght as of now remains entirely hypothetical. FEA resulted in Spinosaurus being closest to the gharial (compared to Mecistops cataphractus and Alligator missisipiensis), however only the rostrum was figured.
It is not prudent to assume it employed violent shaking, especially since shaking implies not just the ability to resist the force, but also to produce it itself. Since its dentition would have an extremely low efficiency in this regard, this means it needs
A: a very strong skull
B: very strong jaw muscles to hold onto what it's shaking
C: a very strong neck
All at once, in order to effectively kill a decent-sized prey item by the method you are proposing.
On the other hand, assuming it relied on a relatively static puncturing bite, it merely needs a moderate bite force (undoubtedly realistic) and skull resistance, enough to drive the teeth into the prey. This is what those teeth are very well-suited for. Since the force would be concentrated on so small an area (the tooth tips of a few pairs of pretty pointed teeth), the pressure may be sufficient to break bones (and surely to puncture through muscles).
This would not cause a lot of tissue damage, just like extant carnivoran bites, but it could be used sucessfully for killing.
The less efficient the teeth are, the greater the force that has to be applied. That means, in Spinosaurus an IMMENSE force would have to be applied, which would put extreme stresses of various directions at the cranium, and require a huge amount of muscle mass.
You know the forces crocodiles need to produce to employ such behaviour, and that in Spinosaurus would have to be even greater. You also know Spinosaurus likely had a bite force not stronger than the largest extant crocodilians, and a skull that is not exceptionally resistant, not to mention it's obviously unable of performing some of the maneuvers crocodiles are capable of.
put two and two together
As I explained to you, things are not that simple.
The problem: your "grip and rip"-hypothesis would also require the ability to produce high adductor forces. Crocodiles need them, Tyrannosaurs do. If Spinosaurus employed a killing strategy similar to those two, one would have to expect analogous developement. Instead, we see elongation of teeth to be effective at impaling and holding, developement of elongate snouts to snatch things quickly, and pretty moderate bite and resistive forces. Something that's caught on the teeth wouldn't escape easily, which of course includes ripping the teeth out of its tissues.
And holding a big animal is not the same thing as shaking it, in terms of the needed adaptions for resisting and applying forces. When merely holding (and perhaps moving in a simple linear direction, like pulling backwards or pushing forwards), much more of the force can be absorbed by its own cranial and postcranial movements.
All this makes much more sense if, when they killed large land-based animals, they did not resort to the same strategies as aforementioned taxa. And I proposed a good explanation what they could have looked like.
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Post by Godzillasaurus on Dec 10, 2013 0:59:21 GMT 5
I am on an iphone, so I can't quote efficiently. I will try to reply as best as I can:
For one, the resemblance between spinosaurid jaws and those of the Indian gharial is very subtle, as spinosaurids had much deeper and wider jaws, much more morphologically similar to the jaws of the false gharial or slender-snouted crocodile. Not just that, but spinosaurid teeth were also much thicker and more robust than those of the Indian gharial, and they were much longer in proportion to jaw size. So the relevance of the Indian gharial argument is very small here.
I admit that the ripping argument seems illogical in some cases, but that is still assuming that spinosaurus was incapable of resisting massive forces, which obviously is not true. You know, we really do not have much evidence for either, but we can clearly infer both of them based on the spinosaurus' skull and tooth structure. Its teeth were conical and designed for piercing, but not necessarily being fatal to a prey animal. Plus, its jaws, despite being powerful, were simply not designed for exerting massive amounts of perpendicular force, so that is another factor to remember here. Spinosaurus was simply ill-adapted for both, as its conical teeth were adapted to act as grippers as opposed to fatal Impalers, and its jaws were vey thin. Man, this is one difficult topic to discuss, as both of us are basically repeating ourselves
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Post by theropod on Dec 10, 2013 2:13:37 GMT 5
I'm not basing this on some superficial resemblance, it's what Cuff & Rayfield stated based on a FE analysis.
That doesn't mean I claim Gavialis gangeticus to be the best analogy for Spinosaurus, since I'm not entirely sure of the relevance of their results, that based on mere anterior rostral fragments (that of Spinosaurus being less robust than MNSN V4047), just that the skull is not as exceptionally powerful as you claim.
That it could handle the stresses induced by crocodile-like feeding habits seems to be quite a stretch.
See? There you have it. Larger, more robust but especially generally larger teeth. Compared to all extant crocodiles actually.
We have nothing to suggest it could resist and apply as massive and direct a force at would be excerted if it killed the way you are proposing.
They were even less designed for excerting massive amounts of non-perpendicular force. As I just explained, they wouldn't need to excert massive forces this way, but would need to both excert and resist immense ones with the other explanation. Their structure makes this unlikely, since it is unlikely their bending resistance was comparable to taxa that employ this kind of bite.
Not too long ago I read you stating they were extremely strong due to them being so extremely dense. Now it seems you use the opposite argument.
But this is all more consistent with what I propose. All the problems it has apply to your ripping-hypothesis as well, yes, even more so, plus there are additional issues.
You hypothetise lots of stuff without an actual reason, and at the same time you seem to miss the important traits I am listing to you.
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Post by creature386 on Dec 10, 2013 2:23:23 GMT 5
I'm not basing this on some superficial resemblance, it's what Cuff & Rayfield stated based on a FE analysis. That doesn't mean I claim Gavialis gangeticus to be the best analogy for Spinosaurus, since I'm not entirely sure of the relevance of their results, that based on mere anterior rostral fragments (that of Spinosaurus being less robust than MNSN V4047), just that the skull is not as exceptionally powerful as you claim. That it could handle the stresses induced by crocodile-like feeding habits seems to be quite a stretch. This is a bit off topic, but if they used MSNM V4047 as a basis for reconstructing an even more fragmentary specimen, won't it be better to directly use MSNM V4047 for their study or am I getting something wrong? |
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Post by Godzillasaurus on Dec 10, 2013 2:42:43 GMT 5
The spinosaurus does not have to rip the flesh itself; its conical teeth and vice-like grip would hold a prey animal in place and they would try to get away and could potentially rip the flesh themselves.
There jaws were still very powerful and dense, so resistance as a whole is, again, probably not going to be a problem here. Their jaws being thin is one story, but their jaws being strong is an entirely different subject. We know that their teeth would also need to be capable to withstanding large amounts of lateral pressure too, as teeth designed for puncturing and gripping powerful animals would require it, regardless of robusticity (which spinosaurine teeth had, but not exceptionally).
This time I was not talking about skull density, but rather the adaptation (or lack thereof) for for such thin jaws to rip flesh when they do not have a good grip on a prey animal. But still, spinosaurus having a good grip on the neck of a prey animal could definitely end in ripped musculature, as the conical teeth would then allow for ripping and tearing to commence. As of now, fatal impalations to the spinal cord do seem much morel likely and effective (for spinosaurus at least), but ripping should still not stay out of the question completely.
I do not necessarily hypothesize without reason. It is just that some stuff may be misunderstood
Their teeth were still somewhat resistant to side forces, however, as their conical shape would need to be adept at withstanding immense pressure from the prey that it caught.
What should the final consensus be now that we just keep repeating ourselves? I did not support your "fatal puncturing" argument earlier due to the piscivorous morphology of spinosaurus (relatively small conical teeth and a moderate bite force), but now it does seem much more likely than the ripping hypothesis because its skull strength (which was quite high) did not seem as relevant for vertical biting than it did with lateral movements due to its skull being much deeper than it was wide. Now I just feel stupid for not thinking about any of that in the first place, which I totally knew the whole time.
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