Functional Morphology of Animal Feeding Apparata

[Grey]

The lateral teeth in lamniforms are often wider than the upper.
Brett Kent owns a lateral meg tooth which is 14,5 cm high and 13,5 cm wide.

[theropod]

You mean wider than the anterior ones? Do you have a picture of an anterior and lateral Carcharodon tooth?

Meg is a different story, it is adapted primarily for very robust prey items, that´s why its teeth are thicker. Ecologically, it is like T. rex compared to Carcharodontosaurus, even tough anatomically it resembles neither and functionally it is more like a more robust-toothed carnosaur because shark teeth simply lack the root and peg-like shape to crush something the way T. rex did. That´s why it instead utilised a slicing motion, comparable to Galeocerdo. The bulkier a prey item is, the bulkier the teeth have to get because they are more likely to encounter bone. Carcharodontosaur teeth are somewhere in between. Definitely not adapted for damaging skeletal structures as a main purpose, however robust enough to bite whatever they want.

[Grey]

That's not restricted to megalodon, have a look at these great white jaws :




The lateral are very wide, some more than the upper.

I wouldn't apply the term of "robust" to the carcharodontosaurs teeth. I recall the statement of Rodolfo Coria :

These teeth are sharp, very, very flat and very sharp so they were just like knifes, just like we use knifes when we are eating a steak, so at the same time these teeth are very weak, they are never strong, as strong like Tyrannosaurus rex teeth.



What we see in Giganotosaurus is a mechanism for the animal to come in basically take a big goushe in the side of the prey by slicing with its teeth inside of the flesh, avoiding the bone and then moving back as fast as it can for avoiding to get hit or turned on by the animal that it's going after, awaiting to see the effects and coming again, and again until its prey weakened affalse.



www.youtube.com/watch?feature=player_embedded&v=wGlCzJmLslU

Of course, they are not dramatically fragile, but not robust, that's a whole kind of different purpose of killing and feeding apparatus. I dont think these are more robust than the teeth of a white shark, simply comparable.

[theropod]

We have to keep in mind the comparison he uses there (T. rex). Of course these teeth are by no means comparable to those of this taxon in terms of strenght, morphology or function. But among animaly whose teeth are primarily meant to slice, Carcharodontosaur teeth are moderately robust.

Some Carcharodontosaur teeth are also shorter and broader than others:
compare these (all are not much shorter rostrocaudally and probably thicker labiolingually than in Carcharodon)
www.buriedtreasurefossils.com/images_Morocco/images_Dinosaurs/M1202-R.jpg
www.buriedtreasurefossils.com/images_Morocco/images_Dinosaurs2/M1214.-F.jpg
www.buriedtreasurefossils.com/images_Morocco/images_Dinosaurs2/M1216-F2.jpg

from here: www.buriedtreasurefossils.com/moroccan_dinosaurs.htm

I suppose if Carcharodon can ram-feed, carnosaurs could also target regions like the ribcage, face or limbs (for comparison, komodo dragons don't seem to avoid such regions either during attack and feeding).

[Grey]

Hm no, these teeth are thicker and broader at parity but they are not as wide as the larger in the jaws of the carcharodontosaurs.

Fair enough for the rest. Beside that if Komodos attack any region, they don't target bony parts.

[theropod]

The lateral teeth in sharks are not as large as the anterior ones either, you yourself posted the comparisons proving that. I think at this point we agree.

No, komodo dragons don't target bones, their aim is not to damage them. They pretty much ignore them, however they often target bony regions like the metatarsals of bovines or cervids (a place were there's hardly any flesh to rip but only tendons to cut). That apparently poses no problem to them.

In the case of a theropod like Allosaurus placing a bite to the ribcage of another animal of similar size, I think the mere power of the head depressors and/or momentum of the skull and the transmittal of this energy onto the relatively narrow surface of the upper jaw could potentially break the ribs of all but the really robust forms (eg. ceratopsians or ankylosaurs which they mostly didn't coexist with).

[Grey]

I did not say the lateral teeth are as large, they are as wide or wider than the upper ones despite being smaller. Check the pics. That's not the case in carnosaurs where teeth become narrower as well as smaller with decreasing.



Are there evidences of allosaurs breaking large ribs ? That needs support.

Edit : regarding what says Coria in the video about the teeth, that's not relative to Tyrannosaurus, he ony alluded to it, but he describes the teeth with no comparison.

[theropod]

Do they? To me the Shark teeth also seem to become significantly smaller, and actually the pictures I showed were all of isolated teeth, neither seem we to have precise data on their relative sizes.


This:
"These teeth are sharp, very, very flat and very sharp so they were just like knifes, just like we use knifes when we are eating a steak, so at the same time these teeth are very weak, they are never strong, as strong like Tyrannosaurus rex teeth."
...sounds very much like a comparison with an animal of different tooth-design.
Apart from that that doesn't base on functional analyses, he is only stating rhe obvious in his comparison with T. rex. That's basically just guess and comparison with extant animals does not support the "very weak teeth".
Being from a video, it might also just have the credentials of Matt Wedel's "second brain in the pelvic region of sauropods".

[Grey]

No he only alludes about T. rex at the end of the sentence, the rest is an objective description of the teeth.

This doc has no criticism to be taken, the words by Coria are not taken out of their context, such statements are known from elsewhere. That's not CoD.

Have a look at the lateral teeth width in the shark jaws. You can measure it yourself. The upper anterior are the longest but not the widest teeth in these sharks genera.

[theropod]

The others at least aren't significantly wider, and msot are smaller overall. It isn't said that in Carcharodontosaurus that wasn't the case too, noone made statements about that.
Documentaries are never credible sources, they seduce people to be sensationalistic, to exagerate, and to make poorly researched statements. There is little to backup Coria's claim, given it is not just in comparison to T. rex as I would interpret the sentence.

Let me guess, is from one of those old documentaries made after the discovery of Giganotosaurus? Maybe Beyond "T. rex" or that strange paleoworld episode? I remember one were they made some sort of boxing match, and in between the attacks of their fighters bombarded each other with mostly wrong or speculative claims. I would be cautious about taking anything from documentaries at face value, especially if there is no metod given whatsoever.

[Grey]

No, take the measurements on the pics and interess yourelf in sharks dentition, the lateral are wider than the upper.

Because some docs are bad science, it does not mean that all are. That line from Coria was clear and not taken out of the context. He just alludes to tyrannosaur's teeth at the end, the whole sentence is not a comparison between Giga and Rex teeth.

Now if you want carnosaurs having teeth robust enough to puncture some bones, more powerful teeth than white sharks at parity, do so....

[theropod]

Well, to me that definitely is either a guess, with no scientific methodology behind, or it is a comparison with T. rex, in which case it would be valid.
If Coria's claim is not relative to T. rex, it is contradicted by the functional anatomy of extant analogies such as monitor lizards and sharks, and by bite marks evidently left by carnosaur dentitions.

I am absolutely not talking about puncturing bones, just they would have had no problem biting a victim violently and would not be restricted to soft regions or "bite and retreat" due to insufficiently fast killing bite (the latter only holds true on much larger prey animals).

The common opinion on carnosaurs appears to be "weak slicing teeth and very slow killers that placed a bite, fled and waited for the prey to bleed to death". This is only applicable to gigantic (sauropod) prey items. A similar-sized animal would be killed quickly by the bite of a carnosaur, and such a bite would not be a weak sratching but a pretty brutal attack, involving strong forces.


You don't have to believe me, but it would be wise. I do not just make this up, lateral GWS-teeth may be proportionally broader, but that doesn't mean they are overally the same size. It is not necessary to measure them to see that.
There is no evidence either for Carcharodontosaur teeth of broader shapes just being smaller, that is merely your assumption.
In Allosaurus, I noted quite a prominent variance in tooth shapes and sizes. The premaxillary teeth were significantly thicker than the lateral ones, some had serrations on both sides, some only on one, some seem almost triangular in cross-sections etc.

[creature386]

Not just Coria, but also Wroe claimed the teeth to be relatively gracile:

A number of other taxa that are known or thought to take relatively large prey that are also characterized by sharp, relatively gracile teeth, also appear to generate relatively weak bite forces, for example, allosauroid dinosaurs (Rayfield et al., 2001) and some monitor lizards (Moreno et al., 2008).

www.bio-nica.info/Biblioteca/Wroe2008GreatWhiteSharkBiteForce.pdf

[theropod]

Precisely, "relatively" implies it being relative to something. What Coria claims about the teeth of carcharodontosaurs is either relative, likely to T. rex, or, if that was supposed to be an absolute statement, he suggests the teeth to be "very weak" in absolute terms which doesn't hold up to a comparison with extant analogies and their respective tooth strenghts.

Sharks have no problems ramming prey and shaking it violently, and occasionally attacking big, robust animals. Monitor lizards are biting bony parts of their prey all the time without problems.
This doesn't fit absolutely "very weak" teeth. it was statements liek this, or their interpretation, that my original analogy was aimed against.

[Grey]

I stay on my position of the scientifical observations made regarding these carnosaurs teeth, Coria whole statement was not based on a comparison with Rex and you can found others similar statements elsewhere. Carnosaurs were not brutish feeders.

The comparison with sharks does not change anything, the great white is justly acknowledged to be a cautious attacker and feeder.