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Post by spinodontosaurus on Dec 27, 2013 13:33:36 GMT 5
You didn't...
Gripping yes, crushing? I'm not so sure about that. Whether Sarcosuchus was proficient at crushing is one thing, but it's a completely different thing to claiming it's teeth are specifically designed for such a job.
It's width seems impressive only to you.
Not shallow compared to that of Sarcosuchus, which is something Blaze has since addressed better than I could.
I'm not sure what you are trying to prove with that video either. A large Nile croc takes on a 200kg plains zebra, so what? That doesn't address anything. Nile Crocodiles are significantly better adapted for tackling large prey (relative to their size) than Sarcosuchus is - how is a video of one such Nile Croc taking an animal only half its size in anyway supporting the notion that Sarcosuchus could tackle large prey? I recall you doing something similar once on Carnivora, where you brought up a rare account of Tomistoma killing a man (one seventh it's size...) and Freshwater Crocodile completely failing to do anything bar inflicting a few cuts to a 50 year old woman in the water. All of these accounts you use to support yourself actually do the opposite.
For all intents and purposes, how is that any different to what I said?
But they were.
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Post by theropod on Dec 27, 2013 17:33:57 GMT 5
Not significantly. Of course it's very narrow, which also makes for the overall thing being visually less imposing, and potentially for a much weaker bite, but it's much deeper in exchange (what people should recall is how the two compare). This and the different tooth arrangement obviously serve a somewhat different purpose (while those in Sarcosuchus are shorter and stouter, and the largest are in the premaxilla, in Spinosaurus they are more elongate and pointed, longer, with some long ones being in the premaxilla but also on the maxilla). But I strongly presume they had broadly comparable prey and killing potency. but much "thicker laterally" (deeper but narrower) That's your opinion... In fact, I think Sarcosuchus is the one more adapted for gripping, and more reliant on bite force to kill, while Spinosaurus has teeth that would puncture more easily. I don't think so. They are not the same, and not specialized for the same thing. It is wider, but also shallower. And as we know that particularly blunt tip is not necessarily helpful for predation (it's really mostly nasal air sinus, not a huge piece of solid bone), but rather needed to enlarge size of the nares. Actually, becoming wider and/or deeper posteriorly makes sense. After all, the most forceful bite will likely be delivered further back in the jaw, and the greatest forces will be withstood there, not at the tip (which doesn't actually have to be incorporated at all and thus often shows adaptions for different purposes, eg. as a hook, for spearing, or as a cooling system). Becoming more slender in the front gradually reduces weight and friction. But the overall built of that "generalized rostrum" corresponds to a slender-snouted crocodile, not a nile croc or saltie. I acknowledged it could deliver a very powerful bite (and I explained why), but that does not mean it took similarly large prey or that it's skull was so hugely resistant.
They are not that different. Whatever difference you find is far less significant than that to crocodilian specimens with a specialization for macrophagy.
You can compare our known sarcosuchus specimens to adult slender-snouted crocodiles (and please look at it again, and see how robust large Mecistops or Tomistoma are!), perhaps with the exclusion of gharials.
scienceblogs.com/tetrapodzoology/wp-content/blogs.dir/471/files/2012/04/i-cbbdc8a13eea39f677e918307d55ff6b-Pete_Edwards_NHM_crocs_Colin_McHenry_Oct_2008.jpg
Also note how mecistops also has an enlarged bulla. That that in Sarcosuchus is bigger is probably due to the animal's size.
It looks as if you did not read that part. Ii just explained that there isn't a great difference, and you went on and claimed there was one without providing a counterargument. |
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Post by Godzillasaurus on Dec 27, 2013 22:09:27 GMT 5
Actually, the stout and robust morphology of its dentition appears to imply a crushing/gripping of larger animals function. Especially in the premaxilla, its dentition was perfectly designed for clamping down with decent amounts of force and piercing into the hide of a large prey animal, as it is very bulky and pointed simultaneously. If it was a specialized piscivore, we would expect its dentition (and snout in general) to be much more slender and less broadened.
I do not know what to say about the whole "proportionally small teeth argument", as tooth size is, again, a poor indicator of diet. What matters more is tooth morphology. Take spinosaurus for example, its premaxillary, central maxillary, and tip of dentary teeth are very slender by comparison and yet are much longer in proportion to snout length. They are clearly designed for puncturing deeply, but yet are designed for gripping fish (this is evident in its much more slender and specialized snout by comparison) and not causing fatal damage to large animals (although, as Theropod said in the Spinosaurus Bite Force thread, spinal damage can be done with decent precision). Sarcosuchus in general appears to be ill-adapted for snatching quick fish from the water, as not only would its impressively broadened rostrum create too much drag, but its teeth were not designed for puncturing deeply (they were designed for piercing and crushing, but not necessarily DEEP penetration unlike spinosaurus, as their stout shape implies it).
If sarcosuchus was a specialized piscivore, it would be almost imperative that it had a: very slender snout that lacked in exceptional width, less robust dentition, pointed tip, and lack of any obvious adaptations for crushing and resisting stress. Its snout was not slender at all (in general) and was in fact, as I said, very broad and robust in its own regard. Depth is a poor indicator of this as well, as bathe American alligator does not possess a very deep snout either, and it was clearly very well adapted for transmitting immense force (crushing). Spinosaurus had a much proportionally deeper rostrum than sarcosuchus, and, based on its morphological snout and tooth features, it was much better adapted for specialized piscivory. Sarcosuchus was so much more generalized than the freshwater and slender-snouted crocodile, as its snout was simply so much broader and more heavily built in adulthood and its teeth were so much bulkier and and much less slender and elongate by comparison. Oh yea, and sarcosuchus had an overbite, not an underbite.
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Post by Godzillasaurus on Dec 27, 2013 22:58:43 GMT 5
Aside from being conical and pointed, sarcosuchus' dentition was, again, very thick and robust; it appears to have been perfectly designed for causing forceful perpendicular damage, even the premaxillary dentition. The very broadened shape of its teeth is no more than an adaptation for the delivery and resistance of force, as they were not built like those of spinosaurus for example; they were poorly-adapted for puncturing very deeply as evidenced by their lack of any especial elongation.
Along with this, its rostrum was also very broadened in mature animals (for an animal that is designed for trasmitting decent amounts of force, a wide snout is impreative. A deeper snout is not as necessary). In general, sarcosuchus appears to have been very well adapted for crushing, contrary to popular belief, as evidenced by its robust rostrum and dentition alike. And even without those factors into consideration, its mandible was still relatively slender but still much less so than in modern slender-snouted crocodilians.
Why shouldn't it be?
You should not base robusticity on elongation alone...
In sarcosuchus, we see a very constant and impressive width throughout. What this implies is that its jaws were more more capable of delivering an exceptionally powerful bite and generalist feeding behavior. The depth present in spinosaurus' rostrum is not an adaptation for delivering force but rather being reinforced in that direction for predation on such large fish. The dentition present in spinosaurus' jaws is designed for piscivory and is perfectly designed for piercing deeply without much driving force, meaning such a large bite force is, again, unnecessary.
That does not make for a more robust rostrum, however.
That is basically what I said... Spinosaurus simply does not need such a powerful bite because it is mostly reliant on large fish as part of its diet and its teeth are structured to easily puncture flesh deeply. Whereas in sarcosuchus, the were more-so reinforced and more robust to cope with such powerful perpendicular forces.
Spinosaurus' rostrum, despite obviously being very robust in its own regard, simply pales in comparison. It was so much narrower and was not designed for exerting monstrous force but rather resisting it. If sarcosuchus was as specialized of a piscivore, its snout would be most likely much more slender and would be very well designed for reducing drag. With such a wide rostrum, a diet consisting primarily of fish is unlikely.
But what it does imply is less reliance on smaller aquatic animals as part of its diet. In general, the bulla seems particularly resistant and, while hollow, is certainly not weak. In the event that sarcosuchus would manage to use that area as a hook, it would most likely be very strong.
Well that is true... But again, why was spinosaurus' snout so well adapted for piscivory? Because it was very slender and was designed to reduce drag (however, it was, again, still very strong and heavily-built. It just pales in comparison). The enlarged bulla in sarcosuchus was most likely an adaptation for resistance in that region (again, in the event that it utilizes that area as a hook).
THAT I agree with. But that still does not completely denote the fact that its rostrum, in general, was so much more robust and, yes, generalized than mecistops.
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Post by theropod on Dec 27, 2013 23:22:25 GMT 5
Again, what's that supposedly huge width you are talking about? It wasn't a gharial (for reasons already explained), but it's snout clearly is less wide, deep and robust than that of extant broader snouted forms, and much more comparable to slender snouted ones therein. It's snout would have little trouble whipping through water (as I already explained, it's by no means less well adapted for that than that of Spinosaurus. The difference results from the fact that crocodilians, due to their hight and locomotory system, will grip fish in a lateral motion, while Spinosaurus will do it from above, so both are well suited. Extant crocodilians, even those with much thicker snouts, also don't have problems snatching fish, and the ones we are talking about here are huge, as in "buffalo-sized"). Tooth size is part of tooth morphology. In taxa with functional differences (eg. Smilodon-lion or Spinosaurus-crocodile), tooth size does not matter, because different morphologies are to be expected. But it seems like you suggest Sarcosuchus killed just like modern crocodiles, by gripping, crushing and ripping, which you believe was supported by the teeth and snout. In that case, one would also expect a comparable tooth morphology, including tooth size. that it has smaller teeth likely means that its dietary preferences were different. Actually, the stout and robust morphology of its dentition appears to imply a crushing/gripping of larger animals function. Especially in the premaxilla, its dentition was perfectly designed for clamping down with decent amounts of force and piercing into the hide of a large prey animal, as it is very bulky and pointed simultaneously. If it was a specialized piscivore, we would expect its dentition (and snout in general) to be much more slender and less broadened. I do not know what to say about the whole "proportionally small teeth argument", as tooth size is, again, a poor indicator of diet. What matters more is tooth morphology. Take spinosaurus for example, its premaxillary, central maxillary, and tip of dentary teeth are very slender by comparison and yet are much longer in proportion to snout length. They are clearly designed for puncturing deeply, but yet are designed for gripping fish (this is evident in its much more slender and specialized snout by comparison) and not causing fatal damage to large animals (although, as Theropod said in the Spinosaurus Bite Force thread, spinal damage can be done with decent precision). Sarcosuchus in general appears to be ill-adapted for snatching quick fish from the water, as not only would its impressively broadened rostrum create too much drag, but its teeth were not designed for puncturing deeply (they were designed for piercing and crushing, but not necessarily DEEP penetration unlike spinosaurus, as their stout shape implies it). If sarcosuchus was a specialized piscivore, it would be almost imperative that it had a: very slender snout that lacked in exceptional width, less robust dentition, pointed tip, and lack of any obvious adaptations for crushing and resisting stress. Its snout was not slender at all (in general) and was in fact, as I said, very broad and robust in its own regard. Depth is a poor indicator of this as well, as bathe American alligator does not possess a very deep snout either, and it was clearly very well adapted for transmitting immense force (crushing). Spinosaurus had a much proportionally deeper rostrum than sarcosuchus, and, based on its morphological snout and tooth features, it was much better adapted for specialized piscivory. Sarcosuchus was so much more generalized than the freshwater and slender-snouted crocodile, as its snout was simply so much broader and more heavily built in adulthood and its teeth were so much bulkier and and much less slender and elongate by comparison. Oh yea, and sarcosuchus had an overbite, not an underbite. I'm sorry to say so (and I really am), but even tough it may sound mean, you seem to be imagining all that "super broadened and robust snout-stuff". Its snout simply is not that broad. Again, more robust than a gharial, but not more so than several slender-snouted, piscivorous crocodilians. You seem to built your whole standpoint around this argument, the supposedly robust snout, but it's not very wide at all. It's premaxillae are voluminous, and blaze has explained why and why that does not mean they were hugely robust (naris and nasal air sinuses). The largest part of its snout is really shallow (which alone does not denote a powerful bite, but nevertheless will make it more prone to bending and breaking in the case of a large, struggling prey being gripped, which is the reason large, macropredatory crocodilians tend to have very wide but also increasingly deepened skulls), and not particularly wide. It would not be particularly robust. It's tooth morphology seems to resemble large specimens of Mecistops, in any case much more so than crocodylus niloticus or porosus |
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Post by theropod on Dec 27, 2013 23:34:46 GMT 5
How does it not?
I know that THAT was not what I said.
I was NOT implying Spinosaurus was any more or less piscivorous.
What I said was that with the same prey, and the same damage done to it, the animal with longer, more slender and pointed teeth will certainly require less force to do that damage.
When and where did it do that?
How do you know that (not that I even denied that, but it's completely unknown and completely beside the point)?
and how about it's very low drag in lateral movements, due to the very low depth.
But what it does imply is less reliance on smaller aquatic animals as part of its diet. In general, the bulla seems particularly resistant and, while hollow, is certainly not weak. In the event that sarcosuchus would manage to use that area as a hook, it would most likely be very strong.
Perhaps it wasn't (that is, not any more so than Mecistops or Sarcosuchus) As was Sarcosuchus'
No, and no
More likely, an adaption for easy breathing when submerged, and to cool the animal down with increase evapouration.
Did you just agree and disagree with me, all in one line?
And how is a killing strategy not a way of delivering (or at the very least withstanding) force? A knife blade cannot be made of paper just because My intend is not to deliver force with it, but rather to use it for killing!
We also see "impressive depth" in Spinosaurus, and we only not have it "constant" or "throughout" (that is, because the premaxilla is more slender), because
A the anteriormost region was not as pneumatic as it certainly is in Sarcosuchus
and B because it was not likely to encounter great stresses, since great forces would be delivered posterior to it.
Did you mean to write unnecessary in the last sentence?
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Post by Runic on Dec 28, 2013 2:22:02 GMT 5
I posted a video of a Nile crocodile attacking a larger wildebeest from the water. The crocodile eventually got bored and left but still the wildebeest died from its wounds. So indirectly crocodile have killed larger prey before.
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blaze
Paleo-artist 
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Post by blaze on Dec 28, 2013 3:27:14 GMT 5
 What kind of superlatives does C. thorbjarnarsoni deserve? Look at how wide and deep that snout is. Forget comparisons with juvenile salties, big satlties have skulls as impressive as C. thorbjarnarsoni.  As do big Nile crocodiles  Tooth shape alone is not as important for prey selection as you imply, there's no discernible ecomorph in the tooth pressure performance (which will be dictated by its shape) of the molariform teeth in extant crocodilians (Erickson et al. 2012), molluscivores, terrestrial foragers, broad-snouted generalists, slender-snouted generalist, piscivorous and semi-piscivorous, they all have similar molariform teeth. Erickson et al. (2012) did found that certain species, the gharial, freshwater crocodile and the Orinoco crocodile generate relatively higher tooth pressure in their caniniform teeth which yes, implies their caniniform teeth are longer and or slender than in other taxa but not all "piscivorous" species were like this, the false gharial performed like all the other ecomorphs. Sarcosuchus has "normal" crocodilian teeth but its arrangement is like that of a piscivore, the general shape of the snout is like that of a piscivore, a relatively slender snout of uniform depth through out its length filled with small and numerous teeth. It couldn't be more different from the snouts of salties and nile crocodiles which have deep snouts, specially in the places where the big teeth are, to the extent that their snouts are shaped by them, their teeth are also much bigger. btw here you can see how big of a hole the bulla is  |
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Post by Godzillasaurus on Dec 28, 2013 6:19:58 GMT 5
Its impressive width was not monstrous, but it was still clearly present, especially in comparison to modern slender-snouted crocodile species. Sure, it was elongate, but it was still very broad and was clearly designed for generalist feeding behavior. That is because modern broad-snouted crocodiles will commonly catch fish... That does not prove anything but rather proves more against the idea that sarcosuchus was a full-on piscivore. Spinosaurus was even more-so comparable to slender-snouted crocodilians in terms of tooth morphology (as it had relatively slender and elongate teeth that were perfectly designed for piercing) than sarcosuchus. It was a much more specialized piscivore, but yet its teeth still retained proportionally greater lengths than both sarcosuchus and generalist crocodilians. If sarcosuchus was such a specialized piscivore, one would expect it to be much more similar to such animals than just half-ass snout similarities and great dental differences. You think so?:  Once again, what makes it so "specialized"  Clearly, its rostrum was not only much more broadened than animals like the false gharial or freshwater crocodile, but it was also so much less specialized, specifically at the premaxilla area. One would expect it to be more "specific" and gracile in that area, as opposed to so generalized and broad; something like we see in spinosaurus, which would have used the front region of its rostrum mainly in catching fish, as the teeth in that area were not only very long and relatively slender but also radiated outward to a certain degree. In spinosaurus' case, its frontal "cleft" in both is premaxilla and dentary is an obvious adaptation for catching fish, as it was very gracile and its teeth were perfectly designed and positioned in that area; but in sarcosuchus, we should more-so expect that area to have similar features as opposed to being so much more robust and possessing very thick and generalized dentition. It is quite obvious in terms of visible morphological features that its snout was NOT weak or specialized by any means... Again, if it was so "specialized" in catching fish, then it would be expected that its snout and premaxilla alike be more narrow. Yea, its premaxilla was not solid, but it actually appeared to have been a perfect adaptation for gripping large terrestrial animals, as it was, again, very broad and clearly very heavily-constructed; it also forms a "hook-like" formation. Not to mention how the teeth in that region were particularly large and very heavily-structured at the same time. As I said above, the bulla appears to have been very well adapted for macrophagy, at least in comparison to its adaptations (or lack thereof) for piscivory. So that is assuming that mecistops (at maturity) has dentition that is not only very robust, but also is an obvious adaptation for generalist feeding. Broad-snouted crocodilians are very well adapted for both gripping and crushing alike, and their dentition is so much more robust and spike-like itself, much more similar to that of sarcosuchus. In mecistops, the tip of its snout as well was nowhere near as heavily-constructed and robust as that belonging to sarcosuchus.
 We went over this before... Spinosaurus did not have a weak rostrum at all (as its post-premaxillary rostrum was actually quite robust in general and generalized by comparison to that of modern slender snouted crocodilians), but it was still very specialized in piscivory; it was still very thin. And it was, yes, much more gracile in build than that of sarcosuchus, which possessed a much broader and less specialized rostrum overall:  Again, the mere fact that spinosaurus had a relatively deep snout overall (it was not especially deep as in animals like allosaurus or carcharodontosaurus) does not at all imply a very forcefu l and crushing bite. Whereas sarcosuchus had a much more broadened rostrum, it clearly had a much more powerful bite overall and was much better adapted for crushing (spinosaurus would have killed, as we talked about, with precise biting or POSSIBLE shaking, as both techniques do not require such crushing capabilities and instead put the deep-penetration  adaptation of spinosaurus' conical and slender dentition to good use. The depth in spinosaurus' rostrum is rather for increased vertical resistance, not crushing.The false gharial has dentition that is still very specialized and slender in shape:  But what the tests show is an "adeptness" for generalism. Spinosaurus is basically the same thing (figuratively), as both its snout and its dentition indicate reliance primarily on fish as part of its diet (its snout was very specialized and thin similarly, and its teeth were built similarly to slender spikes), but it still exercised generalist behavior. BTW, I'm sorry for sounding angry, I am just feeling irritated. It's not you, it's me. |
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blaze
Paleo-artist
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Post by blaze on Dec 28, 2013 7:33:48 GMT 5
Why you insist on drawing your conclusions from juveniles? that skull is only 25cm long, probably total length, not the standard DCL, its owner would be about 1.5m long, it's what I've been saying, if you want to compare make sure the skull is from a full grown adult. Do you see those slender teeth in this adult skull from the same page?  It even shares with Sarcosuchus two enlarged premaxillary teeth and an enlarged maxillary teeth at the middle of the snout. It looks weird though... |
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Post by theropod on Dec 28, 2013 20:46:51 GMT 5
I fear the rest of us has big trouble seeing that.
That proves that even crocodilians with much more robust jaws than Sarcosuchus rely on fish as a major part of their diet (AND have no problem catching them). That a more slender-snouted form like Sarcosuchus would primarily be reliant on and capable of preying on such prey is most logical.
Nope, because it's toothrow and jaw geometry show considerable differences. Extant slender-snouted crocodilians have more uniform and smaller teeth, more comparable to baryonychines (even tough those also have certain differences). Spinosaurus' dentition is a mixture of features of piscivorous and macrophagous crocodiles and felines in a jaw that's elongate like that of a piscovorous crocodile but much more so in it's width than it's depth.
It's teeth did not "retain" their great lenght. They evolved them. The plesiomorphic condition for spinosaurs is more similar to baryonychines, bearing many and small, slightly recurved teeth. The large, conical, straight teeth are an autapomorphy of Spinosaurids.
Nothing, it's not necessarily specialised to mainly target small prey. In fact, the macrophagous taxa tend to be the most specialized ones. Crocodilians alltogether are generalist feeders, but that doesn't mean all of them take large prey relative to their body size.
How except for the greater width does "so much less specialized" show itself?
The contrary is the case. The premaxilla is specialized to accomodate a hypertrophied naris. That does not necessarily affect its predatory capacities (not saying that definitely wasn't the case, but we have no evidence).
No, because as I pointed out those two have different morphologies and fulfilled different functions (for reasons as simply as their stance). I did not deny Sarcosuchus relied much more on bite force than Spinosaurus did, and that for various reasons it's snout was broader. But that does not automatically imply a greater degree of macrophagous specialization.
Take raptors as an example. The macrophagous forms tend to have inferior grip strenght, but longer claws with better puncturing capacity.
As I said above, the bulla appears to have been very well adapted for macrophagy, at least in comparison to its adaptations (or lack thereof) for piscivory.Because of what? Just because its teeth are not that slender? As already noted, large Mecistops or Tomistoma can also have robust dentition in this area, and you must recall we are talking about thick-scaled, giant fish it had to bite, and a really huge bite force it excerted. That it's teeth won't be needle-like is obvious. The size distribution of the teeth, the snouth shape (up to even the presence of the bulla!) resemble Mecistops.
Again, as previously with the bulla; apart from being "very robust", what's that "obvious adaptation for generalist feeding"?
And again, I do not deny it was a generalist, but I think the maximum size of it's prey was not as large as in something like a saltie or Nile croc, and closer to aforementioned taxa.
These taxa actually tend to have larger and also longer teeth (meaning greater efficiency at deeper puncturing and causing of internal damage with a crushing bite vs just holding), with the largest ones on a different area. They have thicker snouts and mandibles in general, with a lack of overbites or pronounced narial bullae.
Shaking would require even greater and more generalized resistance to stresses and would rather be expected from a much more robust-snouted form.
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.
Please show me where I denied that Sarcosuchus would have had the more powerful bite! I never did that. But bite force alone is not indicative of macrophagous potency without regard to tooth and snout morphology and the various influences postcranial forces have. The analogy with raptors that I gave earlier also applies here.
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Post by Godzillasaurus on Jan 9, 2014 8:27:34 GMT 5
 I may be imagining things as a result of my recently taken LSD, but this guy looks pretty decently-built. And do you see any sort of needle-like morphology in sarcosuchus' dentition, specifically those located within the premaxilla which apparently imply a piscivorous diet? All modern crocodiles possess one enlarged maxillary tooth and relatively long "fore teeth", so there really aren't that many parallels associated with sarcosuchus in this regard that are not present in broad-snouted species. Again, similar tooth arrangement may be visible, but tooth morphology is completely different with those belonging to sarcosuchus being far more heavily-structured and particularly better designed for forceful downward resistance than any primarily piscivorous animals that possess far more elongate and specialized dentition. The overall build of the premaxillary and foremost dentary teeth present in sarcosuchus imply that their resistance to downward force would be quite high and they were very well designed to have been used for decent crushing-related purposes (not necessarily in the cracking of turtle shells for example, but rather the possible damage of bones with enough precision and force). Compare the premaxillary dentition to that of spinosaurus or tomistoma, and then tell me any parallels present. And even then, the so-called specialized morphology of any of sarcosuchus' dentition is merely due to size. And even then, this seems to be a far more accurate representation of sarcosuchus (of course, this is even an actual fossil):  Guess it's time for an optometrist appointment, then... For you guys of course 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. 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. 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. 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. 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. 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. 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. In sarcosuchus we rather see the direct opposite; much more robust and generalized premaxilla that would have been fundamentally better adapted for resistance. 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. 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. 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). Ignore my OCD, I had to say that. 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. Such impressive depth does not seem very relevant in all honesty for crocodilians. The American alligator does not possess a particularly deep rostrum, but does that make it any less adapted for vertical resistance than spinosaurus? 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. Quote: Again, as previously with the bulla; apart from being "very robust", what's that "obvious adaptation for generalist feeding"? 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. For example, this region is more specialized animals is considerably more specific and gracile, and they anchor far more elongate dentition. What we see in sarcosuchus is a considerably more robust and broadened premaxilla (much less vulnerable to breaking and better designed for transmitting large force) that anchors very thick and broad teeth that vaguely resemble stout spikes. 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) |
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blaze
Paleo-artist
Posts: 766
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Post by blaze on Jan 9, 2014 9:13:21 GMT 5
I was talking abut the dentition, I have never argued for the width of the snout of Sarcosuchus being similar to Tomistoma so I don't see the relevance of showing that image, which doesn't show the dentition and is not the image you showed while claiming Tomistoma still has slender, specialized dentition, you have yet to prove that adult Tomistama have needle like teeth, I can't see how you are seeing needle like teeth in the adult Tomistoma I showed. Yes, in the broad sense all crocodiles have those features but when it comes to specifics Tomistoma is so much more closer to Sarcosuchus than animals like the nile crocodile or the saltie, look at the croc in your own avatar, does its dentition look anything like Sarcosuchus? btw what so called specialized morphology? you are the only one saying its dentition is not average for a crocodilian. Let's agree to disagree, I don't get your reasoning and you don't get mine. edit: btw the rostrum in the American alligator does get noticeably deep in adults, ever more so than a crocodilian you've argued has a deep rostrum tinyurl.com/m98pnef |
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Post by Godzillasaurus on Jan 9, 2014 19:16:26 GMT 5
Quote: which doesn't show the dentition and is not the image you showed while claiming Tomistoma still has slender, specialized dentition, you have yet to prove that adult Tomistama have needle like teeth, I can't see how you are seeing needle like teeth in the adult Tomistoma I showed. 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. Quote: Yes, in the broad sense all crocodiles have those features but when it comes to specifics Tomistoma is so much more closer to Sarcosuchus than animals like the nile crocodile or the saltie, look at the croc in your own avatar, does its dentition look anything like Sarcosuchus? No, its tooth design is only more slender by comparison, especially when considering sarcosuchus' premaxillary teeth: img.4plebs.org/boards/tg/image/1365/46/1365468172966.jpgI don't see many overlaps there |
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Post by creature386 on Jan 9, 2014 19:57:25 GMT 5
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: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031781 |
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Clearly, its rostrum was not only much more broadened than animals like the false gharial or freshwater crocodile, but it was also so much less specialized, specifically at the premaxilla area. One would expect it to be more "specific" and gracile in that area, as opposed to so generalized and broad; something like we see in spinosaurus, which would have used the front region of its rostrum mainly in catching fish, as the teeth in that area were not only very long and relatively slender but also radiated outward to a certain degree. In spinosaurus' case, its frontal "cleft" in both is premaxilla and dentary is an obvious adaptation for catching fish, as it was very gracile and its teeth were perfectly designed and positioned in that area; but in sarcosuchus, we should more-so expect that area to have similar features as opposed to being so much more robust and possessing very thick and generalized dentition.
