Sarcosuchus imperator vs Carcharodontosaurus saharicus

[blaze]

Judging by the length given (86cm, probably in the greatest dimension) it has to be a full grown adult, so in its 40s, though maybe is scaled a little too big, on second thoughts it might be fiction as it looks very weird compared to the record Tomistoma. I'll search for photos of live adults instead.

I am not saying that adult animals have such specialized dentition, but rather that the slender snout and needle-like tooth morphology of tomistoma...

You're saying it doesn't but it does?

On to the next point, well, that's what I mean,

this


is closer to this

4.5m male Tomistoma, it's alive I swear! I don't know why it's injured.

than to this

4.5m saltie

We also have to think of allometry, Sarcosuchus is easily twice as long as any of these crocs and several times heavier, maybe that's how the teeth of Tomistoma will look if it grew that big?

creature386
Exactly, adult Tomistoma catch small terrestrial prey and pretty big ones in the 4.5-5m range can and have been reported to kill people, which is a prey item considerably smaller than themselves but still, that's how I think of Sarcosuchus, it didn't had the adaptations to kill prey in its size range but it could still take on big fish/small dinosaurs by virtue of its giant size alone, judging by the depth of its snout and the size of its teeth, both comparable to ~6m modern salties I think the upper size range of the prey of Sarcosuchus was around 1 tonne.

[theropod]

^Yes, definitely more comparable to the Tomistoma specimen.

btw I think it looks injured because it is, injured rostra are pretty common in crocs.

[theropod]

I have no doubt in my mind that fish made up most of its diet, but claiming it to have not been an opportunist is unreasonable.

IÂ’m sorry, I was unaware "oppurtunist" was an even graver insult than "piscivore"...

The spike-like morphology of spinosaurus' dentition is an indication of
predation on very large and powerful fish; they were well designed for
piercing deeply without many problems and yet were still very thick and
certainly very resistant. The powerful build of both spinosaurus'
dentition and snout is not an implication for generalism but rather a
primary food source revolving around large freshwater fish.

OK, I must say it again; of course it was primarily piscivorous, just like crocodilians are. But what made it suitable for predation on multi ton fish would, as I elaborated, also be somewhat suited for other animals.

Spinosaurus had not problems being a generalist predator because it was
so large, but it was horribly-adapted for taking down large terrestrial
animals (talking close to or exceeding in its own size) as evidenced by
its conical dentition and snout that lacked any sort of exceptional
depth or width present in the snouts of other large theropods like
tyrannosaurus or carcharodontosaurus for example.

Show me again the part were I suggested Spinosaurus preyed on 10-15t Ceratopsians or large sauropods please!

IÂ’m talking about >10t, more likely ~5t animals at most, Ouranosaurus, Aegyptosaurus, Lurdusaurus...

But that doesnÂ’t mean it was less macrophagous than Sarcosuchus. Their jaw robusticity is not much different, and you also have to keep in mind Sarcosuchus would have relied on bite force or riping much more, and therefore imposed much greater stresses on the structures of its cranium when killing. Spinosaurus is better designed to avoid those, and thus has a different rostrum and tooth shape.

And note that this scenario actually uses a very deep skulled, gigantophagous Carcharodontosaur of gigantic size as the crocodilianÂ’s adversary.

As
I have stated before, sarcosuchus' teeth were more-so reminiscent of
thick spikes over anything (regardless of size). The premaxillary teeth
are no exception; they were enlarged by comparison to posterior
dentition and were very well designed for vertical resistance and
crushing (in a way) as evidenced by their lack of exceptional elongation
as seen in spinosaurus for example.

Actually, raptorial crushing teeth tend to be somewhat long-crowned, as for example in Tyrannosaurus. Crushing (at least in macrophagy, thus unlike for example placodonts or Globidens) doesnÂ’t work well without a somewhat effective puncturing component (to simply focus the force and go somewhat deep), and thus carnivores that utilise it to some extend donÂ’t have many, uniform, short teeth, regardless of their robusticity, but fewer, overally larger ones. You can see that in extant crocodilians, or in bone-crushing carnivorans and other mammals, certain theropods...

If we are to expect such high reliance on fish, sarcosuchus' dentition
would most definitely be expected to be more gracile and slender by
appearance as opposed to so broadened and sturdy.

Well, while it appears that broadened and sturdy dentition, while well-designed for increasing the "drag" in tissues when gripping something, would require very large forces in order to effectively cause injuries to a large animal, which is not at all consistent with the morphology of the cranium.

Let's ignore entire snout right now and only talk about the tips. One
major indication of piscivorous reliance in spinosaurus (aside from its
comparably more slender snout and teeth) is the presence of a very
specialized and gracile premaxilla. [...]
In sarcosuchus we rather see the direct opposite; much more robust and
generalized premaxilla that would have been fundamentally better adapted
for resistance.

And the only reason you think that of Sarcosuchus was less gracile is that itÂ’s big but hollow. That of Spinosaurus doesnÂ’t accomodate for a naris (let alone a huge one), and is probably solid or very nearly so. The one of Sarcosuchus is only SUPERFICIALLY robust, but is in fact not a valid argument for increased macrophagous potency.

This region would have been particularly weak by comparison to the more
posterior portions of the snout and would have been damaged quite easily
if it was used in macrophagy.

Given it was used to transmit large forces, which it likely wasnÂ’t. And as you stated previously, those fishes Spinosaurus was so specialized for were quite large, 1-2t to be exact.

One thing that characterizes many slender-snouted animals often regarded
as obligate piscivores is the presence of a very specialized snout tip.
We simply do not see this in sarcosuchus and it as well is studded with
far more broadened and stout dentition better designed for resistance.

Actually we see enlarged narial regions in gharials, false gharials and slender-snouted crocodiles. Those appear more marked than in broad-snouted crocodiles, which have more gently tapering and rounded jaws.

Robust dentition is not necessarily an implication of generalist
feeding, as more mature animals will fundamentally possess far more
heavily-built and less specialized teeth than those belonging to
juvenile animals. I mean, spinosaurus too possessed very spike-like
dentition that was very well designed for resisting the forces brought
upon it by large fish, but its more slender shape by comparison to that
of sarcosuchus tells us that puncturing deeply without much driving
force is not a problem. But with sarcosuchus, we see even far more
robustly-built teeth that are possessive of a less elongate and more
broadened shape implying that they are fundamentally more resistant.

But greater reliance on brute force to power the biting acttion is not evidence for a more effective bite. Even among predators with generally similar jaws and/or teeth, thatÂ’s not the case. For example, wolves are just as macrophagous as hyaenas, if not more so, even though they have a weaker bite less specialized for crushing.

Most piscivorous species tend to have teeth that are more elongate and
slender (better designed for piercing deeply without that much driving
force) than those of sarcosuchus (which are fundamentally more
heavily-structured and are less well designed for piercing deeply and
rely more-so on impressive force to drive them deeply into an animal's
hide).

The point is how much damage the bite causes overall, not how it does that. You just demonstrated how both can be capable of puncturing deeply.

But even still, can you explain to me the
physics piece of it with bending resistance and stuff, because you
clearly know more about that than I do.

well, as you may have noticed IÂ’m certainly not very well-informed about that subject, albeit interested in it. I canÂ’t claim to have more than a very basic understanding of it.

But very roughly, the degree to which a material resists bending in mostly affected by its depth in the direction it is loaded in. In a brittle material, that also translates to its resistance to failure, but the situation is more complicatad with natural materials that are all somewhat elastic and can deform without suffering any significant structural damage. Still, what we see mostly with bone is that is is thickest in the direction it is loaded in, and that limb bones are hollow to increase their stiffness without expending too much material or weighing too much.
Stress is the force per unit area. The higher the force relative to the area resisting it, the higher the stress gets. Of course the higher the force an animal excerts, the higher the stressgets if the jaw stays the same, and the longer an animal holds onto something with its jaws, the greater the probability that it experiences critically high stress gets.

If an animal shakes a prey item, thatÂ’s an application of brute forces in various directions. This requires very high strenght from the jaws. A traditional bite is much more controlled, even though it usually requires at least a moderate time of contact with the prey animal and a moderately large force. A slashing or striking bite will greate (very) large but mostly unidirectional forces, so that a cranium reinforced in that direction does not have to be paticularly resistant in the others.

Spinosaurus wouldnÂ’t need as high a bite force as Sarcosuchus to cause critical damage to an animal, since its teeth are likely much more efficient at puncturing. This will reduce the necessary force and, considering their jaws are similarly robust, the overall amount of stress it will experience when causing the same degree of damage.

I
was talking about robusticity. This does not just incorporate the
width, but both width and depth of the snout. Sarcosuchus and
Spinosaurus both seem to have similarly robust snouts overall, even
tough one is much more robust in depth, and one more in width.Such
impressive depth does not seem very relevant in all honesty for
crocodilians.

Indeed not, at least not that much for bite force. Hence I agree sarcosuchus likely had a far stronger bite than Spinosaurus and even Carcharodontosaurus.

The American alligator does not possess a particularly
deep rostrum, but does that make it any less adapted for vertical
resistance than spinosaurus?

It depends on a number of factors. But keep in mind The american alligator has a FAR wider and overally more robust skull than Sarcosuchus does.

Don't get me wrong, spinosaurus' snout was
clearly very resistant vertically due to not only its overall
robusticity but also its possession of a decent depth, but that is still
more an adaptation for resistance purposes in large-scale piscivory as
opposed to generalism.

Actually for mere resistive purposes one would expect a more marked width. While relatively wider than other spinosaurs, Spinosaurus still has a much narrower snout than most non spinosaurid theropods IÂ’m aware of.
That Spinosaurine rostra retained a pretty large depth relative to those of crocodilians (keeping in mind both had ancestors with the classic archosaurian "hatchet head", eg deep and relatively narrow), and that their teeth are so relatively long and pointed, indicates they were built for something different than solely gripping. As I said, probably killing by puncturing, eg. puncturing the spinal medulla of mid-sized terrestrial prey, or, more importantly, gripping but at the same time impaling its large fish prey, to kill it as quickly and economically as possible while minimising the stress on the skull.

Again, what we should instead see in
sarcosuchus is any lack of such a broadened premaxilla and any lack of
adaptations for opportunist feeding if it was such a specialized
piscivore.

But we already explained why that broadened premaxilla is not indicative of generalist feeding exceeding that of extant spender-snouted crocodilians.

For example, this region is more specialized animals is
considerably more specific and gracile, and they anchor far more
elongate dentition.

ThatÂ’s just because the animals you compare it too are immatures AND orders of magnitude smaller in absolute terms.

Unlike the false
gharial or spinosaurus, they were better designed for gripping with
large crushing force as opposed to piercing deep into a prey animal's
hide so easily (they were not very slender but rather very widened at
the base).

But that morphology is observed in Spinosaurus for a different reason to, and is not the same as in Tomistoma, and just that Sarcosuchus had thicker (and smaller!) teeth does not mean it had a more dangerous bite than the latter, or that it could not be explained by normal allometry in relation to the former.

[blaze]

I meant what caused it, I've only seen that kind of injuries on crocs killed by people but I guess is just me not being exposed to many croc photos, I'll change the sentence to avoid further confusion.

[theropod]

Oh, sorry, I meant to add a


But how come that kind of injury would be on a croc killed by people? The pathologies look more like it engaged in skull-biting behaviour with another crocodile. Had humans killed it, wouldnÂ’t it simply have a bullet in its body, or perhaps a few stabbing wounds? For sure humans wouldnÂ’t be dumb enough to go for the skull of a crocodile in order to subdue it.

[blaze]

I was probably only thinking in this example when I said that
www.orangutan.org.uk/blog/2009/01/23/endangered-crocodile-species-kills-local-man/

[Godzillasaurus]

Jan 9, 2014 19:57:25 GMT 5 creature386 said:

Jan 9, 2014 19:16:26 GMT 5 Godzillasaurus said:

How old was that animal in the picture you posted a couple weeks ago? I am not saying that adult animals have such specialized detition, but rather that the slender snout and needle-like tooth morphology of tomistoma indicates a primary diet of fish. Still, its teeth are nowhere near comparable to those belonging to sarcosuchus.

Well, according to wikipedia, the diet of the false gharial is much more varied than previously thought, so I don't really believe this is accurate. The crocodile bite force paper seems to agree with it:

All other crocodilian ecomorphs (molluscivores, terrestrial foragers, broad-snouted generalists, and the slender-snouted generalists – such as Tomistoma schlegelii and the American crocodile – Crocodylus acutus [1], [7]) show similar values to each other that are relatively lower.

www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031781

I never said that slender-snouted species were not generalists, in fact pretty much every living crocodilian species is a generalist feeder with the exception of the Indian gharial.

You're saying it doesn't but it does?

On to the next point, well, that's what I mean,

Exactly, adult Tomistoma catch small terrestrial prey and pretty big ones in the 4.5-5m range can and have been reported to kill people, which is a prey item considerably smaller than themselves but still, that's how I think of Sarcosuchus, it didn't had the adaptations to kill prey in its size range but it could still take on big fish/small dinosaurs by virtue of its giant size alone, judging by the depth of its snout and the size of its teeth, both comparable to ~6m modern salties I think the upper size range of the prey of Sarcosuchus was around 1 tonne.

And so I'm guessing that makes spinosaurus well adapted for taking down large dinosaur because it has long teeth and a comparably deeper snout...

btw I think it looks injured because it is, injured rostra are pretty common in crocs.

Or it appears to just be very old, judging by the condition of its teeth.

IÂ’m sorry, I was unaware "oppurtunist" was an even graver insult than "piscivore"...

Say what?

But that doesnÂ’t mean it was less macrophagous than Sarcosuchus. Their jaw robusticity is not much different, and you also have to keep in mind Sarcosuchus would have relied on bite force or riping much more, and therefore imposed much greater stresses on the structures of its cranium when killing. Spinosaurus is better designed to avoid those, and thus has a different rostrum and tooth shape.

Unless animals have a considerably similar snout width and morphology (such as the false gharial and spinosaurus for example), depth seems to be quite irrelevant. I say again, the depth present in the rostrum of spinosaurus is an adaptation for increased resistance vertically, not necessarily making for a more robust rostrum overall. The ability for sarcosuchus to effectively bite a prey animal with such intense force (and dentition that would have faired perfectly for it) implies that vertical resistance is likely not an issue even given its lack of any reasonable depth. You must remember that crocodilians as a whole do not possess very deep rostra and instead only seem to possess it with very old age. Its snout was relatively shallow, but obviously its higher reliance on such impressive forces makes resistance of any kind a tiny issue.

Even the premaxilla too was likely much stronger than you are implying; its overall morphology is an implication that it was perfectly adapted to have been used in predation on large animals; it was actually particularly robust, it was the deepest region of the snout, it was most likely very resistant, and it anchored vaguely hook-like dentition that was very robust and spike-like in build that would be expected to have been far more elongate and slender if it was not used in macrophagy. There is no proper reason to believe that the entire snout was weak both vertically and laterally, and this applies to the bulla as well. For it to have been weak is not only preposterous to believe but also completely illogical given its morphology in not only that region but the entire snout as well.

And note that this scenario actually uses a very deep skulled, gigantophagous Carcharodontosaur of gigantic size as the crocodilianÂ’s adversary

Carcharodontosaurus was designed to feed on animals that were not heavily armored; it was horribly adapted for crushing and penetrating deeply (especially into thick structures such as its opposer's osteoderms). Unless it can very precisely and very slowly (this would be a bad thing, you have to remember that) try to sever any important tissue and/or musculature in the crocodylomorph's neck or flanks, it does not really have any other way to effectively damage its spinal cord and kill it.

And carcharodontosaurus is a horrible example for a "robust-snouted species". It possessed a very deep snout, but nothing more. Its snout was still very narrow and very lightly-constructed unlike both spinosaurus and sarcosuchus which possessed snouts that would have faired much better in gripping.

Actually, raptorial crushing teeth tend to be somewhat long-crowned, as for example in Tyrannosaurus. Crushing (at least in macrophagy, thus unlike for example placodonts or Globidens) doesnÂ’t work well without a somewhat effective puncturing component (to simply focus the force and go somewhat deep), and thus carnivores that utilise it to some extend donÂ’t have many, uniform, short teeth, regardless of their robusticity, but fewer, overally larger ones. You can see that in extant crocodilians, or in bone-crushing carnivorans and other mammals, certain theropods...

Many crocodilian species possess very robust but yet not very long-crowned teeth and obvious adaptations for crushing such as very wide and heavily-built snouts: American alligator, Chinese alligator, deinosuchus, and purussaurus. In sarcosuchus we see less adaptations for bone crushing and/or the damage of hard-shelled animals (such as turtles and shellfish) but rather adaptations for clamping down with such impressive force and allowing its generally stout teeth to effectively impale the hide of a larger prey animal deeply (although bone damage can still be done) and further allow for a strong grip (not to say the listed species did not possess these traits, sarcosuchus just appears to possess them solely). When I am claiming sarcosuchus to have been decent at crushing, I am rather talking about its ability to bite down with extreme force and allow its conical teeth to pierce into the hide of a prey animal without them or its snout breaking. Both its snout and teeth appear to have been very well adapted for resistance.

And in tyrannosaurus, its teeth seem perfectly adapted for creating deep and forceful puncture wounds on skeletal structures such as the spinal cord for example.

Well, while it appears that broadened and sturdy dentition, while well-designed for increasing the "drag" in tissues when gripping something, would require very large forces in order to effectively cause injuries to a large animal, which is not at all consistent with the morphology of the cranium.

This seems to correlate perfectly with its skull morphology, actually. As I said above, the ability for sarcosuchus to "crush" rather relies on its ability to withstand stress on both its snout and teeth alike and be able to effectively transmit enough force with its bite without breaking occurring at all. Its snout doesn't have to been well adapted for crushing the shells of animals, but it was still very strong and would have had no problems exerting such biting force on a large animal. Both its snout and tooth morphology actually seems to correlate perfectly.

And the only reason you think that of Sarcosuchus was less gracile is that itÂ’s big but hollow. That of Spinosaurus doesnÂ’t accomodate for a naris (let alone a huge one), and is probably solid or very nearly so. The one of Sarcosuchus is only SUPERFICIALLY robust, but is in fact not a valid argument for increased macrophagous potency.

So it has a big hole in it; that doesn't necessarily make it any more or less robust necessarily. You must still realize that it wasn't at all very specialized or gracile by any means and was instead very broad and, aside from the huge hole (which was only there to house the sinus system), perfectly designed for generalist feeding and very strong/resistant. There is no reason to believe that it was no good in use for generalist feeding, as it instead was actually very sturdy and it let alone anchored perfectly-designed dentition for resistance purposes.

Actually we see enlarged narial regions in gharials, false gharials and slender-snouted crocodiles. Those appear more marked than in broad-snouted crocodiles, which have more gently tapering and rounded jaws.

But those belonging to such specialized feeders are nonetheless far more gracile in morphology; ill-adapted for generalist feeding. Much different from that of sarcosuchus which was so much broader and more robust by comparison. In sarcosuchus, the premaxilla would have had no problems with resistance or generalism.

The point is how much damage the bite causes overall, not how it does that. You just demonstrated how both can be capable of puncturing deeply

Not necessarily. What I said was that the dentition belonging to sarcosuchus are much less elongate and specialized (again, far better designed for downward resistance), and were, fundamentally, far less adept at puncturing deeply into a prey's hide without much driving force. Those in spinosaurus were strong, but much more slender and were better adapted for impaling without as much immense driving force.

Actually for mere resistive purposes one would expect a more marked width. While relatively wider than other spinosaurs, Spinosaurus still has a much narrower snout than most non spinosaurid theropods IÂ’m aware of.

Again, I am very bad with physics (such as beam theory), but spinosaurus in no way possessed a weak snout, as it was perfectly adapted for gripping very large and powerful fish.

But we already explained why that broadened premaxilla is not indicative of generalist feeding exceeding that of extant spender-snouted crocodilians.

And I explained why the hole doesn't really mean much in terms of robusticity and resistance.

ThatÂ’s just because the animals you compare it too are immatures AND orders of magnitude smaller in absolute terms.

Reread my last post; I compared sarcosuchus to a reasonable tomistoma specimen, and yet it was still far more robust in terms of rostral width.

Actually for mere resistive purposes one would expect a more marked width. While relatively wider than other spinosaurs, Spinosaurus still has a much narrower snout than most non spinosaurid theropods IÂ’m aware of.

Mm, I wouldn't be so confident about that... Its snout was, first and foremost, designed for resistance against forces exerted by large and powerful fish; it was very slender but yet heavily-constructed at the same time (even compared to more generalist predators like carcharodontosaurus, as we have already talked about). Its snout was in no way monstrously strong, but it was definitely very strong.

That Spinosaurine rostra retained a pretty large depth relative to those of crocodilians (keeping in mind both had ancestors with the classic archosaurian "hatchet head", eg deep and relatively narrow), and that their teeth are so relatively long and pointed, indicates they were built for something different than solely gripping. As I said, probably killing by puncturing, eg. puncturing the spinal medulla of mid-sized terrestrial prey, or, more importantly, gripping but at the same time impaling its large fish prey, to kill it as quickly and economically as possible while minimising the stress on the skull.

You seem to be comparing spinosaurine rostra to allosaur rostra; they did not compare and they were fundamentally designed for completely different purposes. Spinosaurus posessed a much more slender and specialized rostrum (that was much thinner both laterally and dorsally) designed for reducing drag in water, but allosaurs possessed deeper rostra that was clearly designed to be used vertically as opposed to laterally and/or for gripping purposes. I must add that spinosaurines possessed far more heavily-constructed rostra by comparison (given their lack of such large fenestrae, being more-so a solid and dense piece of bone) where non-vertical resistance was much more of a necessity.

And while spinosaurus' teeth were very well structured to pierce deeply with much ease (as that is what they were fundamentally designed for in the first place), there is no true evidence that they were actually used to impale the spinal cord or windpipe; that remains entirely hypothetical based on its dental morphology. I am not in any way saying that spinosaurus' teeth could not kill with spinal or throat impaction, but they were best designed to pierce deeply into the hide of a large fish without much driving force (again, unlike sarcosuchus) and retain a strong grip.

[spinodontosaurus]

Oh dear...

Sarcosuchus does not have a robustly built premaxilla. It is filled with air and only lightly joined to the maxilla. This has been pointed out to you before, stop bringing it up. You also criticised me elsewhere for saying Carcharodontosaurus had a more robust rostrum than Spinosaurus because of Carcharodontosaurus' fenestrae - I latter amended my claim to specify more voluminous as a result of this. Most of Sarcosuchus' supposedly robust premaxilla was taken up by sinuses; am I the only one who finds your two claims rather conflicting as a result of this?

Sarcosuchus does not have exceptional dentition even in absolute terms. Blaze already pointed out how the teeth are barely any bigger than those of Lolong, and compared to the length of the skull the teeth are positively small. The teeth are clearly no bigger relative to the skull than those of slender-snouted crocodilians either (such as Tomistoma), the pictures in this thread as well as any decent Google search (i.e. stop looking at juveniles) will show this. To claim Sacosuchus had some massive advantage in the dentition department over Tomistoma and friends is completely false, as was the case in snout construction.

I also feel you have completely missed the mark with Theropod's remark that "this scenario actually uses a very deep skulled, gigantophagous Carcharodontosaur of gigantic size as the crocodilianÂ’s adversary."
I very much interpret it along this lines of "it's all well and good comparing Sarcosuchus and Spinosaurus to modern-day small prey specialists (or 'generalists' if you like), and hypothesising that they hunted fish in the region of 1-2 tonnes, but this matchup pits the former against an 8 tonne predatory theropod with a very deep skull that is very, very well adapted for hunting and therefore killing large animals".

In the end nitpicking about which exact crocodilian is the best analogue is rather irrelevant (I personally see it as a complete no brainer, with tooth and jaw morphology clearly indicating species such as Tomistoma and Crocodylus johnsoni are close to the mark), because even those with enormously robust dentition and rostra are still not known for their hunting or combat ability versus animals of equivalent size. In the face of an adversary equally large, but with far greater freedom of movement and a far superior bite in terms of inflicting injuries, Sarcosuchus is out of it's depth here, regardless of which seemingly customisable snout you put on it.

[blaze]

Godzillasaurus
GIF
That was my expression when you wrote this: "I am not saying that adult animals have such specialized dentition, but rather that the slender snout and needle-like tooth morphology of tomistoma..."

I can't think of another interpretation other than: "I don't claim adult (tomistoma) have needle-like teeth but rather that their slender snout and needle-like teeth..."

It reads like a contradiction,

the "On to the next point, well, that's what I mean" is in response to you not finding any overlap between the croc in your avatar and Sarcosuchus but I just got the idea that the shape of their teeth was the only thing you got from that comparison.

And so I'm guessing that makes spinosaurus well adapted for taking down large dinosaur because it has long teeth and a comparably deeper snout...

Different snout morphologies (platyrostral vs oreinirostral), likely different ways of killing (head vs head+arms) come wit a whole suite of variables to account for, to simplify everything to be the work of only two, specially when one of them is a given considering the different morphology of their snout, is misleading and I never did so.

but in case you're interested, I don't think Spinosaurus was able to kill large dinosaurs with only its head and by large dinosaurs I mean several tonnes.

[theropod]

And so I'm guessing that makes spinosaurus well adapted for taking down large dinosaur because it has long teeth and a comparably deeper snout...

Neither was blaze ever talking about Spinosaurus, nor did his post imply that.

Or it appears to just be very old, judging by the condition of its teeth.

Since when do old crocodiles have missing teeth and scarred rostra if not by virtue of injuries?

Unless animals have a considerably similar snout width and morphology (such as the false gharial and spinosaurus for example), depth seems to be quite irrelevant.

From what functional princeple do you deduce this?

I say again, the depth present in the rostrum of spinosaurus is an adaptation for increased resistance vertically, not necessarily making for a more robust rostrum overall.

How does increase resistance not contribute to the overall robusticity of the structure, and, most importantly, how is it not relevant to this comparison? And didnÂ’t you even acknowledge they had similarly robust rostra overall?

The ability for sarcosuchus to effectively bite a prey animal with such intense force (and dentition that would have faired perfectly for it) implies that vertical resistance is likely not an issue even given its lack of any reasonable depth.

Hello? That very lack of depth DOES imply its jaws were prone to experiencing such stresses!

You must remember that crocodilians as a whole do not possess very deep rostra and instead only seem to possess it with very old age.

But extant macrophagous crocodilians do have considerably deeper rostra than Sarcosuchus.

Its snout was relatively shallow, but obviously its higher reliance on such impressive forces makes resistance of any kind a tiny issue.

How will resistance to force it has to excert somehow ever be "a tiny issue"?

The very inference that it was capable of relying on "such impressive forces" merely bases on the assumption that it was capable of withstanding them!

Even the premaxilla too was likely much stronger than you are implying; its overall morphology is an implication that it was perfectly adapted to have been used in predation on large animals; it was actually particularly robust, it was the deepest region of the snout, it was most likely very resistant, and it anchored vaguely hook-like dentition that was very robust and spike-like in build that would be expected to have been far more elongate and slender if it was not used in macrophagy. There is no proper reason to believe that the entire snout was weak both vertically and laterally, and this applies to the bulla as well. For it to have been weak is not only preposterous to believe but also completely illogical given its morphology in not only that region but the entire snout as well.

Ok, now its enough. You keep repeating the same claims, no matter how often the very reasonable doubts are explained to you, without ever adressing any of the arguments.

You keep claiming its "overall morphology" implied it was very robust, even "perfectly adapted to have been used in predation on large animals". Others including me have told you it does not, and why it doesnÂ’t, but you just repeat the same phrase!

Carcharodontosaurus was designed to feed on animals that were not heavily armored; it was horribly adapted for crushing and penetrating deeply (especially into thick structures such as its opposer's osteoderms).

Correction, it was very well adapted for penetrating and slicing deeply. It shows no particular adaption towards armour-breaking, but that will hardly even be necessary here. A bite to the neck or the abdomen will eviscerate the crocodilian.

Unless it can very precisely and very slowly (this would be a bad thing, you have to remember that) try to sever any important tissue and/or musculature in the crocodylomorph's neck or flanks, it does not really have any other way to effectively damage its spinal cord and kill it.

It doesnÂ’t have to sever the spinal cord to kill it, you have to realise that. Only certain types of animals actually do that, and neither crocodilians nor Carnosaurs are/were among them.

For sure, the killing process in this case would be quite a slow one, owing to the crocodilianÂ’s durability. But the Carcharodontosaurus has the tools and a way to use them to allow it to eventually suceed.

And carcharodontosaurus is a horrible example for a "robust-snouted species". It possessed a very deep snout, but nothing more. Its snout was still very narrow and very lightly-constructed unlike both spinosaurus and sarcosuchus which possessed snouts that would have faired much better in gripping.

Firstly that and your definition of "robust" is beside the point. Carcharodontosaurus had a skull and dentition very well designed for causing wounds to, and subduing large animals, despite, even especially, because it did not rely on an exceptionally powerful bite and could avoid high stresses that might cause its skull to fail. If a Sarcosuchus tried to kill a Paralititan, well, you know those photographs of crocodiles lacking parts of their jaws...

SarcosuchusÂ’ jaws are built in a way that both requires a great deal of bite force, and is not exceptionally resistant. You see this in slender snouted crocodilians; they have strong bite forces too, but their skulls have lower savety factors and thus are at a higher risk when using their bite to kill large animals, ergo they confine themselves to prey that poses a lower risk because its easier to kill and eat.

An additional problem is that Sarcosuchus, in gripping, killing, and immobilising prey, would have entirely relied on its jaws. Given it attacked a large animal, it didnÂ’t just have to place a quick bite (relatively low risk), but hold onto it and actually grapple with it using its dentition. It doesnÂ’t take a high level of physical expertise to see that this is a strategy that could cause serious harm to a structure not well-designed for handling such forces.
In the cases of our terrestrial analogies tough (Spinosaurus, used for comparison and, more relevant, Carcharodontosaurus), they have no such restriction, because all they have to do is place quick bites. They can follow their prey if it is terrestrial, are much closer to its height, and will hopefully manage to have pulled it onto land if itÂ’s aquatic.

Oh, and SarcosuchusÂ’ rostrum isnÂ’t that much broader than CarcharodontosaurusÂ’ actually.

Many crocodilian species possess very robust but yet not very long-crowned teeth and obvious adaptations for crushing such as very wide and heavily-built snouts: American alligator, Chinese alligator, deinosuchus, and purussaurus.

What you have to remember is that the primary purpose of all those teeth is not crushing, its gripping. In an animal perhaps more reliant on a puncture & crush biting mode, Kaprosuchus, we see longer, larger and fewer teeth. We also see large teeth and deep skulls in forms like Barinasuchus, or triassic rauisuchians. By comparison, flattened skulls and shorter conical teeth are an adaption towards gripping, and we usually observe that the more they specialize towards gripping, the shorter and more uniform they get.

In sarcosuchus we see less adaptations for bone crushing and/or the damage of hard-shelled animals (such as turtles and shellfish) but rather adaptations for clamping down with such impressive force and allowing its generally stout teeth to effectively impale the hide of a larger prey animal deeply (although bone damage can still be done) and further allow for a strong grip (not to say the listed species did not possess these traits, sarcosuchus just appears to possess them solely). When I am claiming sarcosuchus to have been decent at crushing, I am rather talking about its ability to bite down with extreme force and allow its conical teeth to pierce into the hide of a prey animal without them or its snout breaking.

But crushing usually does not imply sinking its teeth into the hide to get a firm grip. Whether an animal good at gripping is also good at crushing depends on how effectively its dentition will damage deeper structures, especially bones.

This seems to correlate perfectly with its skull morphology, actually. As I said above, the ability for sarcosuchus to "crush" rather relies on its ability to withstand stress on both its snout and teeth alike and be able to effectively transmit enough force with its bite without breaking occurring at all. Its snout doesn't have to been well adapted for crushing the shells of animals, but it was still very strong and would have had no problems exerting such biting force on a large animal. Both its snout and tooth morphology actually seems to correlate perfectly.

No, they do not. The tooth morphology does not suggest efficiency at crushing, just at gripping. the skull morphology, while not necessarily contradicting a strong bite force, does not suggest it was particularly resistant, certainly not more so than extant crocodilians such as salties, even though the latter have teeth that would likely have a higher efficiency at crushing. All those features are reminiscent of slender-snotued crocodilians whose main goal is to grip small-to-mis-sized animals and either kill them instantly or drown them.

So it has a big hole in it; that doesn't necessarily make it any more or less robust necessarily. You must still realize that it wasn't at all very specialized or gracile by any means and was instead very broad and, aside from the huge hole (which was only there to house the sinus system), perfectly designed for generalist feeding and very strong/resistant. There is no reason to believe that it was no good in use for generalist feeding, as it instead was actually very sturdy and it let alone anchored perfectly-designed dentition for resistance purposes.

Again, you managed to fabricate a fact ("very strong/resistant"), and repeat the same thing three times without adressing my argument properly.

It makes a huge difference whether a structure is more or less exclusively composed of cortical bone, or whether its more or less exclusively composed of air sinus.

Also, did you by any means rethink your use of the word "generalist"? Not too long ago I saw you arguing how "generalised" this rostrum was...

But those belonging to such specialized feeders are nonetheless far more gracile in morphology

And you were already given a metabolic explanation for that, and shown that it isnÂ’t that relevant for the strenght of that region.

Much different from that of sarcosuchus which was so much broader and more robust by comparison. In sarcosuchus, the premaxilla would have had no problems with resistance or generalism.

You simply cannot say that as if it was a fact. Of course it wasnÂ’t tested properly anywhere, but that its broad does not equal it being strong when we know this is probably just because it had to accomodate for an air sinus. Actually, assuming that would be very premature.

All this, it shows us Sarcosuchus had no monstrously robust skull, designed for predation and crushing of large prey. Its skull and tooth morphology are all consistent with the gripping and crushing or drowning of smaller animals, perhaps a few tons at most, how many exactly I cannot say, but smaller than itself. For reasons explained earlier macrophagous behaviour would pose some serious difficulties to it, because of both its cranial and postcranial morphology.

Not necessarily. What I said was that the dentition belonging to sarcosuchus are much less elongate and specialized (again, far better designed for downward resistance), and were, fundamentally, far less adept at puncturing deeply into a prey's hide without much driving force. Those in spinosaurus were strong, but much more slender and were better adapted for impaling without as much immense driving force.

Exactly! So how exactly is that a disadvantage for the Spinosaurus?

Again, I am very bad with physics (such as beam theory), but spinosaurus in no way possessed a weak snout, as it was perfectly adapted for gripping very large and powerful fish.

IÂ’ve not argued it was weak, IÂ’ve argued it was not specialized for carring massive multidirectional loads. IÂ’ve also explained ways how I think Spinosaurus would most effectively use its jaws while reducing those as far as possible.

And I explained why the hole doesn't really mean much in terms of robusticity and resistance.

It does, it means that isnÂ’t a solid or near-solid bloc of bone in the front of the jaw, designed to reinforce the structure and handle large forces. Its a hollow bulla designed to enlarge naris size and control the body temperature. Its the width that under these circumstances does not mean much.

Reread my last post; I compared sarcosuchus to a reasonable tomistoma specimen, and yet it was still far more robust in terms of rostral width.

Take that Tomistoma, add an enlarged, pneumatic, narial bulla in the front, and youÂ’ve pretty much got a Sarcosuchus in terms of proportions. No seriously, SarcosuchusÂ’ rostrum is more uniform in width along its lenght, more like mecistops, and the skull expands at a steeper angle in the orbital region.

Take a close look and youÂ’ll find many similarities between Sarcosuchus and large specimens of these slender-snouted crocodilians. If youÂ’d see them in flesh, itÂ’d be fairly difficult to distinguish between the head of a large Mecistops and that of a Sarcosuchus (omitting size differences of course). YouÂ’ll immediately group S. imperator with M. cataphractus or T. schlegelii, or perhaps (abeit seemingly more different in terms of geometry, albeit not robusticity) slender-snouted and small members of Crocodylus in terms of jaw morphology, not with Crocodylus pororus or Alligator. And it is that very functional morphology that also suggests a more comparable predatory ecology to the former than to the latter.

You know that those are not exclusively piscivores, but generalists. They just donÂ’t incorporate large animals, as in "as large as themselves" in their diet as more brevi- and latirostrine forms do. They predate on animals they can subdue without too much of a struggle and without too much stress on their jaws, eg. up to human size or slightly bigger for Tomistoma.

Mm, I wouldn't be so confident about that... Its snout was, first and foremost, designed for resistance against forces exerted by large and powerful fish; it was very slender but yet heavily-constructed at the same time (even compared to more generalist predators like carcharodontosaurus, as we have already talked about). Its snout was in no way monstrously strong, but it was definitely very strong.

Strong enough, no more.

You seem to be comparing spinosaurine rostra to allosaur rostra

No, crocodilians rostra

; they did not compare and they were fundamentally designed for completely different purposes.

ThatÂ’s what IÂ’m arguing, in allosaurs, but even in crocodilians to a good extent.

And while spinosaurus' teeth were very well structured to pierce deeply with much ease (as that is what they were fundamentally designed for in the first place), there is no true evidence that they were actually used to impale the spinal cord or windpipe; that remains entirely hypothetical based on its dental morphology.

Yes, but it is the best available hypothesis. We relie on the correlation between form and function. It is not 100% accurate, but its the best we can do.
You on the other hand are hypothetising stuff about Sarcosuchus without any unequivocal morphological correlates.

[coherentsheaf]

ou also criticised me elsewhere for saying Carcharodontosaurus had a more robust rostrum than Spinosaurus because of Carcharodontosaurus' fenestrae - I latter amended my claim to specify more voluminous as a result of this.

Note that at least to my eyes the skull of Carcharodontosaurus looks far more resistant to vertical bending. Note that this resistance is not only based o material used but also on the configuration, wide structures being more resistant.

[Godzillasaurus]

Sarcosuchus does not have a robustly built premaxilla. It is filled with air and only lightly joined to the maxilla. This has been pointed out to you before, stop bringing it up.

And I say again, having a hole in that area does not make it any more or less robust necessarily; the bulla was still very broad and relatively deep in general (talking in adult animals of course), so there is practically no reason to believe that it would have been weak at all. Based on its morphology, it would have likely been very strong and would have likely been used as a "hook" of large animals if anything, contrary to what you are claiming. It was not slender, it was not specialized, it was likely very strong (so what if it had a big hole used for sinus purposes? Want a good idea of scary holes? Look up trypophobia on Google images...), and it anchored very heavily-built dentition that was clearly in need of very powerful forces to be driven deeply into the hide of large animals (as it was not very elongate). Compare that to the premaxillae of the Indian gharial, false gharial, and spinosaurus...

And I have realized that for a long time now; there is no reason to believe that it was lightly-built. The main problem with you is that you bring up a point that I am refuting for good reason and then you simply claim that I am wrong when the evidence is apparently right there in front of me. That is the beauty of debating, bro... People don't give in that easily.

Sarcosuchus does not have exceptional dentition even in absolute terms. Blaze already pointed out how the teeth are barely any bigger than those of Lolong, and compared to the length of the skull the teeth are positively small. The teeth are clearly no bigger relative to the skull than those of slender-snouted crocodilians either (such as Tomistoma), the pictures in this thread as well as any decent Google search (i.e. stop looking at juveniles) will show this. To claim Sacosuchus had some massive advantage in the dentition department over Tomistoma and friends is completely false, as was the case in snout construction.

And so long and slender teeth are apparently common morphologies found in obligate macropredators? Even when spinosaurus had much longer teeth than carcharodontosaurus? And if you actually read one of my last posts, I actually compared sarcosuchus to a particularly large tomistoma specimen.

I very much interpret it along this lines of "it's all well and good comparing Sarcosuchus and Spinosaurus to modern-day small prey specialists (or 'generalists' if you like), and hypothesising that they hunted fish in the region of 1-2 tonnes, but this matchup pits the former against an 8 tonne predatory theropod with a very deep skull that is very, very well adapted for hunting and therefore killing large animals".

And I say again (from the Primal Carnage forum), carcharodontosaurus in no way possessed a very robust snout or a very robust tooth structure. Its ability to kill large animals comes from its possession of a very deep rostrum (just as spinosaurus' ability to do so comes from sheer size advantage in most cases), not because it had a robust snout... Allosaurs were best designed for attacking the flanks or dorsum of a terrestrial (note, I did not say "squat" or "semi-aquatic") prey animal by utilizing their maxillary teeth in conjunction with their wide gape, deep rostra, and powerful necks; it would simply not be able to attack sarcosuchus this way. And even if it did, it would most likely not cause enough vertical damage to begin with due to the specialization of its teeth being in cutting and ripping, not necessarily piercing as seen in an animal like spinosaurus.

That was my expression when you wrote this: "I am not saying that adult animals have such specialized dentition, but rather that the slender snout and needle-like tooth morphology of tomistoma..."

I was a little bit confused when I said that, or maybe you just misunderstood me. I dunno... I will go edit that when I finish this post, m'kay?

but in case you're interested, I don't think Spinosaurus was able to kill large dinosaurs with only its head and by large dinosaurs I mean several tonnes.

Sure it would, with enough precision it could have. Theropod convinced me of that after he (sort of) reasoned with me about the beam theory and how it plays a role in spinosaurus' ability to effectively shake prey animals to dismember them (I knew spinosaurus had very strong jaws obviously as an adaptation for such large-scale piscivory, but I know practically nothing about physics. Sooo, yea)

Since when do old crocodiles have missing teeth and scarred rostra if not by virtue of injuries?

Missing teeth is often a condition found in very old crocodilians. That or just having very blunt and rotten (as in taken over by bacteria) teeth. The crocodile in that picture does not appear to be in its prime one bit.

From what functional princeple do you deduce this?

Compare carcharodontosaurus to spinosaurus or sarcosuchus. You will see what I am talking about. Of course its snout was far less prone to bending vertically than spinosaurus, but it was still very sparse and gracile.

How does increase resistance not contribute to the overall robusticity of the structure, and, most importantly, how is it not relevant to this comparison? And didnÂ’t you even acknowledge they had similarly robust rostra overall?

Again, compare carcharodontosaurus to spinosaurus. The former is in possession of a much deeper snout but it is yet far less heavily-constructed and was not designed for gripping in the same way as spinosaurus.

The very inference that it was capable of relying on "such impressive forces" merely bases on the assumption that it was capable of withstanding them!

Not entirely; if it was much less reliant on such powerful biting forces in predation we would most likely expect far more elongate and slender dentition (being designed for piercing deeply into a prey animal without much driving force) as opposed to being in possession of such broad and robust dentition that obviously lacked the morphology needed to do so with such ease. The perfect example of this is its premaxillary dentition; one would expect them to have been much more similar to the premaxillary teeth of spinosaurus to indicate piscivory if anything (such as having a much more elongate and less powerfully-built design).

Hello? That very lack of depth DOES imply its jaws were prone to experiencing such stresses!

And that is assuming that the American alligator as well is in possession of such an exceptionally deep snout, which it was not. I say again, this actually seems to pertain to all average-sized modern crocodilians.

But extant macrophagous crocodilians do have considerably deeper rostra than Sarcosuchus.

So does spinosaurus (even in comparison to modern macrophagous crocodilians)

Ok, now its enough. You keep repeating the same claims, no matter how often the very reasonable doubts are explained to you, without ever adressing any of the arguments.



You keep claiming its "overall morphology" implied it was very robust, even "perfectly adapted to have been used in predation on large animals". Others including me have told you it does not, and why it doesnÂ’t, but you just repeat the same phrase!

You guys are guilty of the exact same thing... Specifically with sarcosuchus having a weak premaxilla that was apparently "perfectly designed for piscivory"

Correction, it was very well adapted for penetrating and slicing deeply. It shows no particular adaption towards armour-breaking, but that will hardly even be necessary here. A bite to the neck or the abdomen will eviscerate the crocodilian.

Depending on where exactly its teeth come into contact with its opponent of course. It again lacked a very powerful biting force, so this would rather rely on the ability of its teeth to slice efficiently. And even then, all of the powerful driving force in predation from allosaurs rather comes from its powerful neck and ability to both exert and withstand vertical force. It would simply not be able to pull this off when fighting a semi-aquatic crocodylomorph.

And a deep penetration morphology is definitely not present.

It doesnÂ’t have to sever the spinal cord to kill it, you have to realise that. Only certain types of animals actually do that, and neither crocodilians nor Carnosaurs are/were among them.

While spinal damage is not a necessity, carcharodontosaurus was more than capable of pulling off such a feat for reasons that you should already know.

Firstly that and your definition of "robust" is beside the point. Carcharodontosaurus had a skull and dentition very well designed for causing wounds to, and subduing large animals, despite, even especially, because it did not rely on an exceptionally powerful bite and could avoid high stresses that might cause its skull to fail. If a Sarcosuchus tried to kill a Paralititan, well, you know those photographs of crocodiles lacking parts of their jaws...

Did I ever say that sarcosuchus had to be able to effectively take down an animal as large as paralititan? Or very large sauropods for that matter? Sarcosuchus still clearly had a much more resistant snout in terms of ability to effectively maintain a strong grip on something without breaking.

SarcosuchusÂ’ jaws are built in a way that both requires a great deal of bite force, and is not exceptionally resistant. You see this in slender snouted crocodilians; they have strong bite forces too, but their skulls have lower savety factors and thus are at a higher risk when using their bite to kill large animals, ergo they confine themselves to prey that poses a lower risk because its easier to kill and eat.

And so ignoring the particularly irrelevant Yellowstone Caldera situated within sarcosuchus' bulla, there is no reason to believe that sarcosuchus would have been irrestant in terms of snout strength the least bit. The greater reliance on exerting crushing forces makes a more resistant snout a necessity (let alone being perfectly 100% evident...).

An additional problem is that Sarcosuchus, in gripping, killing, and immobilising prey, would have entirely relied on its jaws. Given it attacked a large animal, it didnÂ’t just have to place a quick bite (relatively low risk), but hold onto it and actually grapple with it using its dentition. It doesnÂ’t take a high level of physical expertise to see that this is a strategy that could cause serious harm to a structure not well-designed for handling such forces.

As I have said before, there is no reason to believe that its snout was weak but rather the polar opposite. Gracile snouts (even though the possession of one in sarcosuchus is debatable, with me being on the opposite side of the debate) in general do not necessarily imply weak jaws; just take spinosaurus for example.

Oh, and SarcosuchusÂ’ rostrum isnÂ’t that much broader than CarcharodontosaurusÂ’ actually.

But again, it was far more heavily-constructed and was clearly much better adapted for exerting powerful crushing forces on large animals and retaining a stable grip on such animals, so there is practically no reason to believe that it was weaker or more gracile the least bit.

What you have to remember is that the primary purpose of all those teeth is not crushing, its gripping. In an animal perhaps more reliant on a puncture & crush biting mode, Kaprosuchus, we see longer, larger and fewer teeth. We also see large teeth and deep skulls in forms like Barinasuchus, or triassic rauisuchians. By comparison, flattened skulls and shorter conical teeth are an adaption towards gripping, and we usually observe that the more they specialize towards gripping, the shorter and more uniform they get.

Crushing can mean a few things. When I refer to it as a capability possessed by sarcosuchus I am rather referring to its ability to exert such crushing forces, retain a stable grip, and not have its snout or teeth broken in the process. Such broad and conical dentition as we see in sarcosuchus is an adaptation for vertical resistance with such powerful forces acting against it and piercing alike, not the same thing as we see in more specialized animals.

But crushing usually does not imply sinking its teeth into the hide to get a firm grip. Whether an animal good at gripping is also good at crushing depends on how effectively its dentition will damage deeper structures, especially bones.

With enough driving force and precision, bone breaking is definitely possible if bitten by such a powerful animal even if its teeth indicate better gripping adaptations. Leg, ankle, and foot damage is definitely a possibility here. Such robust, conical teeth are perfectly designed (but not necessarily being evolved to do) for creating broader and more localized bone damage through the use of intense forces and ability to pierce alike; they are perfectly structured for piercing and yet retain exceptional vertical resistance. There is no reason to believe that leg damage is completely out the question here, especially when the tooth morphology of sarcosuchus indicates it as a direct possibility.

No, they do not. The tooth morphology does not suggest efficiency at crushing, just at gripping. the skull morphology, while not necessarily contradicting a strong bite force, does not suggest it was particularly resistant, certainly not more so than extant crocodilians such as salties, even though the latter have teeth that would likely have a higher efficiency at crushing. All those features are reminiscent of slender-snotued crocodilians whose main goal is to grip small-to-mis-sized animals and either kill them instantly or drown them.

Deeper skeletal damage is unlikely, but the sheer ability of its teeth to withstand immense force while being in possession of a very robust build and and a pointed tip (for piercing functions, obviously) indicates that bone damage is definitely possible. Sarcosuchus' teeth were not very well designed for piercing deeply and/or piercing into a hide with much ease but they rather again correlate directly with a high biting force.

You simply cannot say that as if it was a fact. Of course it wasnÂ’t tested properly anywhere, but that its broad does not equal it being strong when we know this is probably just because it had to accomodate for an air sinus. Actually, assuming that would be very premature.

And so claiming sarcosuchus to have been a very weak piscivore because its snout was relatively elongate isn't? I am using inference and observation; that is not immature at all but rather the direct opposite. Now if I were to claim sarcosuchus to be a very powerful animal just because it was closely related to crocodiles, that would be very immature.

Exactly! So how exactly is that a disadvantage for the Spinosaurus?

It is not a disadvantage, but rather seems to indicate that it was a far more specialized animal. Its teeth, being so much less broadened and robust than in sarcosuchus, were very elongate and slender and were more-than-capable of puncturing deeply without much, if any, driving force. In sarcosuchus we again see far broader dentition that was far less adapted for such a similar piercing-of-fish function and was instead far more resistant in terms of ability to withstand vertical stress (again indicating that larger forces were likely present; it would have had no problems causing bone damage with enough precision given its morphology.

It does, it means that isnÂ’t a solid or near-solid bloc of bone in the front of the jaw, designed to reinforce the structure and handle large forces. Its a hollow bulla designed to enlarge naris size and control the body temperature. Its the width that under these circumstances does not mean much.

And so modern broad-snouted crocodilians do not have a similar hole within their premaxillae?:

You on the other hand are hypothetising stuff about Sarcosuchus without any unequivocal morphological correlates.

Oh really? What have I been doing for the past few pages? Would you care to elaborate on that a bit?

[theropod]

And I say again, having a hole in that area does not make it any more or less robust necessarily

It does. A structure with the same dimensions is of course less resistant if it is hollow than if it is solid.

And I have realized that for a long time now; there is no reason to
believe that it was lightly-built. The main problem with you is that you
bring up a point that I am refuting for good reason and then you simply
claim that I am wrong when the evidence is apparently right there in
front of me.

Well, you are not refuting it. You just keep repeating "you are wrong, it was obviously very robust", but you donÂ’t give any valid argument as to why a pneumatic premaxilla would be tremendously strong just because it is somewhat broadened.

In fact, that this part is so much broader and deeper than the rest of the jaw, even tough it is in the very front, should make you sceptical of whether this was really an adaption towards resistance, and as it turns out thatÂ’s likely not the purpose of this structure.

And so long and slender teeth are apparently common morphologies found
in obligate macropredators? Even when spinosaurus had much longer teeth
than carcharodontosaurus? And if you actually read one of my last posts,
I actually compared sarcosuchus to a particularly large tomistoma
specimen.

More so than short and blunt ones, yes. Why you cannot compare a ziphodont animal with sharp, recurved teeth to one with conical straight ones should be self explanatory, regardless of how macrophagous they were. One of course utilised cutting power, and doesnÂ’t rely that much on downward-directed forces but on pulling. Ergo it biting deep is not as much a result of long teeth and bite force than of slashing and tearing motions, and ergo its teeth are also different in shape. But you indeed wonÂ’t find a Carcharodontosaurus with 1cm teeth.

Missing teeth is often a condition found in very old crocodilians. That
or just having very blunt and rotten (as in taken over by bacteria)
teeth. The crocodile in that picture does not appear to be in its prime
one bit.

Do old crocodilians loose their polyphyodonty then?

Compare carcharodontosaurus to spinosaurus or sarcosuchus. You will see
what I am talking about. Of course its snout was far less prone to
bending vertically than spinosaurus, but it was still very sparse and
gracile.

Again, you can go on from claiming how tremendously robust snouts of animals like Spinosaurus or Sarcosuchus were, to saying how "un-robust" those of Carcharodontosaurus are, even tough the latter has a much more robust one than the former two.

What do you call robust? If you say robust, are you exclusively referring to width? Because almost every time you use this term it is in conjunction with something being very shallowly built, but yet very robust, or something being very deep, and yet much less so.

The depth of the snout of course also plays a part in its overall robusticity. An animal like Carcharodontosaurus is by no means specialized for holding struggling prey or crushing it, and it didnÂ’t need to. but its skull displays adaptions for resisting large dorsoventral and pulling forces, which is just as relevant to this.

Again, compare carcharodontosaurus to spinosaurus. The former is in
possession of a much deeper snout but it is yet far less
heavily-constructed and was not designed for gripping in the same way as
spinosaurus.

No, you should phrase it like this: its snout is less compact, but is also far larger in all dimensions but lenght. It being not made for gripping is a consequence of its tooth design, in exchange much better for tearing flesh and causing wound to large game, and its different mandibular morphology. That does not mean its rostrum wouldnÂ’t have been as resistant as SpinosaurusÂ’ or more so, considering SpinosaurusÂ’ snout did not necessarily endure huge loads, which to avoid there are several possibilities.

Not entirely; if it was much less reliant on such powerful biting forces
in predation we would most likely expect far more elongate and slender
dentition (being designed for piercing deeply into a prey animal without
much driving force) as opposed to being in possession of such broad and
robust dentition that obviously lacked the morphology needed to do so
with such ease. The perfect example of this is its premaxillary
dentition; one would expect them to have been much more similar to the
premaxillary teeth of spinosaurus to indicate piscivory if anything
(such as having a much more elongate and less powerfully-built design).

I think you got me wrong. It is not realistic that it would have bitten with a greater force than its skull could withstand, regardless of its tooth design. Its tooth design is made to grip and avoid breaking or dislodging, but that does by no means indicate it was designed for crushing or controlling large prey animals, it is simply a result of its overall size. Its bite force would not have been much stronger than that of extant animals with analogous morphology when corrected for size, which should by any means be astronimic enough a figure to content you, and it was probably used as to reduce stresses on the skull, in sharp contrast to the vigorous shaking and torsion used by Crocodylus niloticus or porosus in conjunction with the strong bite AND a dentition that would puncture deeply more effectively.

And that is assuming that the American alligator as well is in
possession of such an exceptionally deep snout, which it was not. I say
again, this actually seems to pertain to all average-sized modern
crocodilians.

So does spinosaurus (even in comparison to modern macrophagous crocodilians)

Not compared to reasonably-sized specimens of Crocodylus or similarly robust taxa. Compared to slender snouted crocodilians, yes, but in exchange its also narrower.

And as I already suggested, Spinosaurus and Sarcosuchus have similarly robust snouts, both being not particularly robust, one being deeper while the other is wider.

You guys are guilty of the exact same thing... Specifically with
sarcosuchus having a weak premaxilla that was apparently "perfectly
designed for piscivory"

Well, thatÂ’s because we actually have proper arguments as to why that premaxilla wasnÂ’t as robust as you claim, and because we are aware of how extant crocodilians feed and what requirements those feeding techniques pose to their anatomy, while you simply havenÂ’t given an argument why you thought it was so robust!

Depending on where exactly its teeth come into contact with its opponent
of course. It again lacked a very powerful biting force, so this would
rather rely on the ability of its teeth to slice efficiently. And even
then, all of the powerful driving force in predation from allosaurs
rather comes from its powerful neck and ability to both exert and
withstand vertical force. It would simply not be able to pull this off
when fighting a semi-aquatic crocodylomorph.

And a deep penetration morphology is definitely not present.

If you want to insist, not penetrating, but slicing. The latter does more extensive damage anyway. No, it did not crush. But that does not mean the crocodilian would be impervious from its attacks, especially considering itÂ’s hopelessly inferior in terms of mobility.

I honestly cannot see how the highlighted part is in any way disadvantageous.

While spinal damage is not a necessity, carcharodontosaurus was more
than capable of pulling off such a feat for reasons that you should
already know.

That was neither in the typical repertoire it would use against a large or robust animal, nor in for that matter would it use it against a crocodilian. Of course on a smaller prey animal , such a a mid-sized ornithopod or small sauropod, a bite as massive as that of carcharodontosaurus would, by virtue of the sheer impact and pulling forces, realistically cause a spinal shock.

But it was neither built for nor reliant on this strategy for killing its prey. It could simply rip out the carotid or cut open the abdomen and wait for its victim to die (from very quickly to quite slowly), or disable its locomotory system if necessery.

Did I ever say that sarcosuchus had to be able to effectively take down
an animal as large as paralititan? Or very large sauropods for that
matter? Sarcosuchus still clearly had a much more resistant snout in
terms of ability to effectively maintain a strong grip on something
without breaking.

No you didnÂ’t. But this example illustrates you the problems Sarcosuchus has with macrophagy, while at the same time Carcharodontosaurus was well-equipped for it.

The part about robusticity is quite questionable and remains to be proven by you, but it is not relevant to this matter. How deadly an animalÂ’s bite is does not depend on how good a vice it would make.

And so ignoring the particularly irrelevant Yellowstone Caldera situated
within sarcosuchus' bulla, there is no reason to believe that
sarcosuchus would have been irrestant in terms of snout strength the
least bit. The greater reliance on exerting crushing forces makes a more
resistant snout a necessity (let alone being perfectly 100%
evident...).

It is not in the least bit "irrelevant" whether the structure about whose robusticity we are arguing has a huge hole in it and is largely hollow.
You have to start conceiving that adductor force is just one of the forces acting on a jaw when killing, and that the degree to which a jaw is well-suited for killing large animals does not just depend on how strong it is, but also on how much strenght it even required to do the job.

As I have said before, there is no reason to believe that its snout was
weak but rather the polar opposite. Gracile snouts (even though the
possession of one in sarcosuchus is debatable, with me being on the
opposite side of the debate) in general do not necessarily imply weak
jaws; just take spinosaurus for example.

IÂ’m by no means suggesting SpinosaurusÂ’ was built to kill large prey, let alone utilising only its jaws. But its partly terrestrial mode of locomotion, its height and the posession of 2m arms with 30+cm claws put it at a natural advantage here, and allow it to reduce the stress its jaws had by biting precisely and largely delegating the grappling job to its forelimbs. Thus I think it was likely quite capable of killing small sauropod-sized prey, using the above advantages and its sheer size, without the need for a particularly strong skull.

But again, it was far more heavily-constructed and was clearly much
better adapted for exerting powerful crushing forces on large animals
and retaining a stable grip on such animals, so there is practically no
reason to believe that it was weaker or more gracile the least bit.

It is more gracile. Have a look at dorsal and lateral views of both of them please!

And the difference lies in how much force they actually had to withstand to accomplish the same amount of damage. In Sarcosuchus, that figure will be astronomically higher.

With enough driving force and precision, bone breaking is definitely
possible if bitten by such a powerful animal even if its teeth indicate
better gripping adaptations. Leg, ankle, and foot damage is definitely a
possibility here.

If you go back a few pages, youÂ’ll see I already proposed and acknowledged that earlier.

And so claiming sarcosuchus to have been a very weak piscivore because
its snout was relatively elongate isn't? I am using inference and
observation; that is not immature at all but rather the direct opposite.
Now if I were to claim sarcosuchus to be a very powerful animal just
because it was closely related to crocodiles, that would be very
immature.

Premature?immature

You are overdramatising everything IÂ’m saying. What IÂ’m suggesting is that Sarcosuchus was not well designed to kill animals in its own size range (basing on inference and observation; modern crocodilians that somewhat routinely do that have far more robust jaw structure and tooth morphology more consistent with killing large animals, and those with comparable jaw robusticity and tooth design to Sarcosuchus donÂ’t do it). Not that it was "a weak piscivore" out of some Spinosaurus-haterÂ’s dreams. It was instead a very large crocodilian, but with a relatively gracile snout that suggests the prey it killed was relatively smaller than in robust-snouted Crocodylus or alligatorids.

[Godzillasaurus]

It does. A structure with the same dimensions is of course less resistant if it is hollow than if it is solid.

And so that makes carcharodontosaurus far less prone to lateral stress than animals like spinosaurus because it had a wider snout?

Well, you are not refuting it. You just keep repeating "you are wrong, it was obviously very robust", but you donÂ’t give any valid argument as to why a pneumatic premaxilla would be tremendously strong just because it is somewhat broadened.

Again, I state the fact that the teeth in this region were nowhere close to specialized and are instead very resistant and heavily-structured, let alone this area being more broadened than the premaxillae in more obligate piscivores. They are well designed for piercing, but not necessarily very deeply as we see in spinosaurus but rather being very well adapted to compensate for the immense forces that would be fundamentally brought upon them. I say again, its tooth morphology seems to correlate perfectly with its snout morphology:



In mature animals, what we see instead of a sheer "specialization" in either realm is rather a direct relationship between impressive snout width (again, more elongate than most broad-snouted species but still there is no reason to believe it to be gracile) that is an indicator of strong resistance and ability to withstand strong biting forces, and the sheer ability of these teeth to withstand such pressures as well. But in something like spinosaurus we rather see a far more gracile and slender snout and sharper and more elongate dentition obviously as adaptations for piscivory.

In fact, that this part is so much broader and deeper than the rest of the jaw, even tough it is in the very front, should make you sceptical of whether this was really an adaption towards resistance, and as it turns out thatÂ’s likely not the purpose of this structure.

What other reasons do you have to back this up? I have explained to you why this region was particularly generalized and would have no problem doing so.

Ergo it biting deep is not as much a result of long teeth and bite force than of slashing and tearing motions, and ergo its teeth are also different in shape. But you indeed wonÂ’t find a Carcharodontosaurus with 1cm teeth.

A deep penetration ability is not only much more evident in spinosaurus' teeth than those belonging to both carcharodontosaurus and sarcosuchus, but it is far more necessary. Spinosaurus did not need such an impressive bite force or slashing ability, as its diet is fundamentally taken over mostly by very large and powerful fish. The ability of its teeth to sink in deeply without much driving force and yet still be strong enough to retain a sturdy grip is the direct effect of its piscivorous nature. Again, its tooth shape correlates strongly with that of its snout, just as with the case of the latter two animals. 

Again, you can go on from claiming how tremendously robust snouts of animals like Spinosaurus or Sarcosuchus were, to saying how "un-robust" those of Carcharodontosaurus are, even tough the latter has a much more robust one than the former two.

Umm, how so? I have explained to you why this is not the case. Sarcosuchus was much more reliant on a strong bite force than carcharodontosaurus, as evidenced by its comparably wider rostrum in relation to depth and far more robust dentition that obviously correlates with such an ability to exert such forces. Spinosaurus was in possession of a snout morphology that obviously indicates large-scale piscivory; a more resistant snout is much more of a necessity in this case. Let alone the two former animals having far more heavily-constructed snouts...

What do you call robust? If you say robust, are you exclusively referring to width? Because almost every time you use this term it is in conjunction with something being very shallowly built, but yet very robust, or something being very deep, and yet much less so.

I am referring to build in general; carcharodontosaurus had a very deep snout that was poorly adapted for gripping and lateral resistance as evidenced by its possession of a very gracile build. But the other two animals possess far denser and more compact snouts that are far better adapted for gripping functions.

The depth of the snout of course also plays a part in its overall robusticity. An animal like Carcharodontosaurus is by no means specialized for holding struggling prey or crushing it, and it didnÂ’t need to. but its skull displays adaptions for resisting large dorsoventral and pulling forces, which is just as relevant to this.

Its depth is what makes it dorsally and ventrally strong in the first place. The ability to withstand pulling and dorsoventral forces correlates perfectly with its serrated and knife-like dentition that was poorly adapted for lateral resistance and gripping but rather downward and pulling functions. The other two animals, again, possess snout and tooth morphologies that indicate much more reliance on gripping for killing, and even crushing ability in one of them.

That does not mean its rostrum wouldnÂ’t have been as resistant as SpinosaurusÂ’ or more so, considering SpinosaurusÂ’ snout did not necessarily endure huge loads, which to avoid there are several possibilities.

The presence of impressive density in spinosaurus' snout is a direct result of its piscivorous morphology (slender and specialized snout for reducing drag as much as possible in an aquatic environment) and need to withstand large amounts of stress. There is no reason to believe that an animal well adapted for hunting and killing large and powerful fish would not experience any sort of large stresses and rather possesses a morphology well designed to withstand them (heavily-constructed snout and resistant dentition).

It is not realistic that it would have bitten with a greater force than its skull could withstand, regardless of its tooth design. Its tooth design is made to grip and avoid breaking or dislodging, but that does by no means indicate it was designed for crushing or controlling large prey animals, it is simply a result of its overall size.

Again, by "crushing" I am not referring to its ability to crush bone (even though such an event is still a possibility). The ability of its teeth to resist downward stress is a direct result of their robust morphology; they again indicate heavy correlation with strong biting forces to drive them deeply into a prey animals hide and still be able to resist those pressures. They seem quite similar in build to the frontal teeth present in deinosuchus actually: they are very robust as a direct result of the animal's bite force and snout morphology, and they are yet still conical and pointed, indicating that they were well designed for piercing. There actually appear to be decent parallels between sarcosuchus and deinosuchus, an animal that was obviously very well adapted for crushing.

Not compared to reasonably-sized specimens of Crocodylus or similarly robust taxa. Compared to slender snouted crocodilians, yes, but in exchange its also narrower.

Umm, no. Spinosaurus did not have a narrower snout than all slender-snouted crocodilians.

And as I already suggested, Spinosaurus and Sarcosuchus have similarly robust snouts, both being not particularly robust, one being deeper while the other is wider.

I remember you saying before how spinosaurus actually did possess a particularly robust snout, a multitude of times. There is in fact no reason to believe that either were very fragile and weak but rather the direct opposite. 

Well, thatÂ’s because we actually have proper arguments as to why that premaxilla wasnÂ’t as robust as you claim,

ONE argument; you guys gave me one argument.

and because we are aware of how extant crocodilians feed and what requirements those feeding techniques pose to their anatomy,

I am aware of that too, and yet I still do not think that sarcosuchus would have as many problems as you guys are implying with such feeding.

while you simply havenÂ’t given an argument why you thought it was so robust!

Oh, but I have. I explained to you why it was not very specialized and was in fact far more robust than the premaxillae of far more piscivorous animals.

If you want to insist, not penetrating, but slicing. The latter does more extensive damage anyway.

I thought you said that it possessed an imperative morphology for piercing deeply...

I honestly cannot see how the highlighted part is in any way disadvantageous.

Carcharodontosaurus- well adapted for killing much larger and taller animals than the crocodylomorph

Sarcosuchus- too low to the ground for the theropod to effectively utilize the same killing strategies as it can with larger terrestrial animals

No you didnÂ’t. But this example illustrates you the problems Sarcosuchus has with macrophagy, while at the same time Carcharodontosaurus was well-equipped for it.

Sarcosuchus being poorly-adapted for macropredation as a whole is a major overstatement. Nile crocodiles today are very well equipped for taking down antelope, zebras, and wildebeest but yet have major problems taking down animals as large and powerful as buffalo. It is evident here:





In both cases, the crocodile got incidentally pulled onto land; out of its element. With particularly smaller and less powerful animals, such an event is far more unlikely to happen.

Thus I think it was likely quite capable of killing small sauropod-sized prey, using the above advantages and its sheer size, without the need for a particularly strong skull.

But it did have a strong skull... Even though you had previously reasoned with me about beam theory and how such vigorous forces would likely be too much for it (because, I admit, I know practically nothing about beam theory or physics in general for that matter), but its snout was very well adapted for taking down very large fish and was obviously designed for gripping purposes.

It is more gracile. Have a look at dorsal and lateral views of both of them please!

Again, carcharodontosaurus was horribly adapted for withstanding the forces exerted by gripping large animals and pales in comparison to that ability in spinosaurus and sarcosuchus, which possessed far more robust rostra as evidenced by their possession of a more heavily-constructed one! Dimensions don't mean much all of the time.

Premature?immature

Then what was apparently "occurring or done before the usual or proper time; too early."?

Do old crocodilians loose their polyphyodonty then?

No, but out of inference and observation, it just appears to me at least that older animals tend to possess uglier and lesser teeth than younger and more healthy ones. I think I even read that somewhere once.

[creature386]

Jan 11, 2014 21:59:48 GMT 5 Godzillasaurus said:

It does. A structure with the same dimensions is of course less resistant if it is hollow than if it is solid.

And so that makes carcharodontosaurus far less prone to lateral stress than animals like spinosaurus because it had a wider snout?

I don't quite understand the context of your comment. Theropod was talking of structures with the same dimensions (width is a dimension too), but one is hollow (= has some holes) and the other is not.

Jan 11, 2014 21:59:48 GMT 5 Godzillasaurus said:

Premature?immature

Then what was apparently "occurring or done before the usual or proper time; too early."?

The word you are searching for is premature.