Functional Morphology of Animal Feeding Apparata

[Infinity Blade]

Does anyone know of any good pictures of Koolasuchus' teeth? Or even any studies into bite force, gape, etc. perchance? The only pictures of its jaws and teeth I can find are from Poropat et al. (2018), but the teeth have obviously suffered postmortem damage and distortion (Koolasuchus material below is A-C).

[Infinity Blade]

Another cranial kinesis paper on Tyrannosaurus rex. But this time its findings suggest that the skull of Tyrannosaurus was functionally akinetic.

onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24219

[Grey]

Bite forces studies are quite various and complex. I need to know if this is correct.

It is often argued that the highest bite force estimated anywhere in science as of 2019 (awaiting for some data from gigantic killer sperm whales material) at around 100 000-180 000 N of posterior bite force. Ryce 2016 using another method found figures almost twice higher for anterior bite forces.

But I need to be clarified on Dunkleosteus.
This source indicate it could have about 80 000 pounds at the tip of its fangs with a bite pressure in itself of 11 000 pounds.

But other sources indicate different numbers with an estimated maximal bite force of over 4400 N at the jaw tip and more than 5300 N at the rear dental plates (Anderson 2007).

What is the actual hardest data here ?

Same thing regarding Tyrannosaurus. The 2017 study by Erickson indicates for this one 8 000 pounds of bite pressure but 430 000 pounds per square inch at the tip of some of its teeth.

So, if C. megalodon has the highest bite pressure, is it actually Tyrannosaurus (or Dunkleosteus) that has the highest tooth pressure on record ?

Can we expect this very high tooth pressure to have been similar or larger in other gigantic animals with high bite forces estimates (Deinosuchus, C. megalodon, some pliosaurs) or is it only made possible because of Tyrannosaurus particular biting anatomy ?

Also, isn't the highest bite force known to science actually still from Tyrannosaurus itself with Meers 2003 suggesting up to 53 000 pounds of bite pressure ?

With all of that , isn't possible for Tyrannosaurus to actually have had the nastiest, deepest bite in history, despite being rivaled or outclassed in sheer size by a very few some aquatic/marine predators ?

theropod

[dinosauria101]

Grey
Correct me if I'm wrong or I've missed something, but don't some studies call Dunkle's bite inferior to a great white's, let alone a T Rex's?

[Grey]

That is what I had in mind but I remember these claims of 36 tonnes of pressure at the tip of its fangs.
But I certainly doubt it.
The extremely high figures for Tyrannosaurus are more insisting.

[Grey]

Basically I wonder if the capability of T. rex to pulverize bones due to the extreme pressure at the tip of its teeth and their design makes it unique among strong biters in history.

Is their any other multi-tons predator that literally pulverize large bones with its bite ?

[dinosauria101]

Maybe Tarbosaurus and Ekrixnatosaurus? They're both comparable to T rex in size at about 6 tons each, and they have bone crushing bites as well

[Grey]

Both are much lower in body mass compared to any Tyrannosaurus, the largest abelisaurids are 9 m, including Ekrixinatosaurus and Tarbosaurus was in the 5 tonnes range compared to the 8 tonnes of Tyrannosaurus. Its jaws were much less robust.

Actually, the only reptiles that may rival it are the large pliosaurs and the giant crocodilians.

[dinosauria101]

Jul 3, 2019 17:42:22 GMT 5 Grey said:

Both are much lower in body mass compared to any Tyrannosaurus, the largest abelisaurids are 9 m, including Ekrixinatosaurus and Tarbosaurus was in the 5 tonnes range compared to the 8 tonnes of Tyrannosaurus. Its jaws were much less robust.

Umm.....Was Ekrixnatosaurus downsized? And about Tarbosaurus, isn't 5-7 tons comparable to 5-8 tons for T rex? 

That being said, you have a point. Tarbo's skull is thinner than Rex's by a fair margin

[theropod]

OK, I had written a more lengthy reply to Grey, but when I clicked on "post" the forum went into maintenance mode and I lost it

I have no time to write it all again, but here’s the important bits:

Are you talking about force, or pressure?

36 tonnes is force, not pressure. But Dunkleosteus certainly didn’t generate 36 tonnes of force either, anywhere in its jaws. The only estimates are those by Anderson & Westneat (2006, 2009), who estimated about 5.3 kN at the tips of the fangs, and 7.5 kN in the back, for the largest specimen. So 0.75 t at most.

In terms of pressure, 430 000 psi equals about 2965 MPa. Basically such a figure is totally irrelevant, because tooth enamel fails at a compressive stress of less than 400 MPa. It is physically impossible to use a tooth to apply a pressure that high (newton’s third law: there must be an equal and opposite force), because the tooth will break once its failure stress is reached. But of course if you assume very high bite forces applied over a few teeth or a single tooth, you can easily calculate such figures when you assume sufficiently small areas, such as tooth tips. They just can never really exist in nature, because no biological material could withstand them. Bone will fail at less than 200MPa.
Lots of carnivores can generate pressures sufficient to crush bone, and the pressure necessary for "pulverizing" bone is scale-independent, so T. rex is very far from unique in that regard.

I’ve discussed this with Infinity Blade previously, including some calculations for a T. rex tooth: theworldofanimals.proboards.com/post/32476/thread

Meers’ bite force estimate for T. rex is extremely unreliable, and hardly relevant when compared to more recent estimates that actually looked at the morphology and capabilities of T. rex’ jaw apparatus. You could just as well use their regression of bite force against body mass to estimate the bite force of Megalodon.

Anderson, P.S.L.. and Westneat, M.W. 2007. Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator. Biology Letters 3 (1): 76–79.
Anderson, P.S.L. and Westneat, M.W. 2009. A biomechanical model of feeding kinematics for Dunkleosteus terrelli (Arthrodira, Placodermi). Paleobiology 35 (2): 251–269.
Meers, M.B. 2002. Maximum bite force and prey size of Tyrannosaurus rex and their relationships to the inference of feeding behavior. Historical Biology 16 (1): 1–12.

[elosha11]

FYI, theropod, I've also had lengthy posts lost on WoA before or during sending them. Even if you accidentally highlight something and a portion or all of your post gets deleted, there's no way to get it back, no undo button. So do one of two things. At a minimum, when you're writing a lengthy post, highlight and copy it right before sending so if the server goes down or any other error occurs you can repost and send. But the better solution is to write and save your lengthy posts on Word, Google docs, or some other preserved record and then just copy and paste in WoA. That way you don't accidentally delete it right in the middle of the post with no way of recovering it.

[theropod]

Yes, I usually do this with long posts, but sometimes posts get longer than I anticipated and then I forget to switch over to a text editor.

[Grey]

That said, excluding C. megalodon, which is a particular case, and in the absence of an actual Livyatan bite analysis, what taxa has the real highest bite force determined in the fossil record, even including theoretical figures for larger specimens ?

Would the Harvard Kronosaurus estimated at 11 000 kg or Sachicasaurus (the most impressive skulled pliosaurs I know of) bite harder than say a Sue or Scotty-sized T. rex ? How Deinosuchus and Purussaurus compare as well ?

[theropod]

The large pliosaurids might have been biting marginally harder.
McHenry estimated very similar bite force figures for the largest T. rex and a relatively modest-sized Kronosaurus queenslandicus with a 1.85m skull (26.1 vs 27.7 kN). This is probably the best comparison we can make, as he used the same method to estimate both, and the Pliosaur turned out to bite marginally harder (despite not being the max size for its species, or even close to it). If we scaled that up to the largest known Kronosaurus skull at 2.36m, we’d get 45.1 kN. Keeping in mind, of course, that the method produced underestimates by a factor of two compared to living crocodilians, and assuming (for lack of other evidence) that this would equally apply to all animals, this would suggest the largest pliosaurs bit quite a bit harder than T. rex (in this case, maybe realistically 9t vs 5t).

Using midline skull-length of Sachicasaurus, it is 2.25/2.00=1.125 times the size of P. kevani (a specimen estimated to be approaching a large T. rex in terms of bite force, but with slightly different methodology). Scaling up the estimated (upper) posterior bite force of 48.7 kN up to that skull length gives us 6.2t. Bates & Falkingham’s upper estimate for Stan was 57.2kN (Stan is a large T. rex and the skull as restored is quite close in size to sue’s), which is quite consistent with what one would expect based on McHenry’s estimate and the inherent underestimate he noted, so this might be a realistic absolute figure.
The difference could be a bit on the low end, because Foffa et al.’s estimates were relatively more in line with McHenry’s than were Bates & Falkingham’s, even though they approach and overlap those for the T. rex. It is entirely possible both are still underestimates, although the pliosaur probably more so than the theropod.

Overall this is not an easy question to answer, but I’d more likely than not give an edge to the pliosaurs based on the only comparable estimates that we have.

Comparison with the crocodilians is even more difficult, because they tend to base on different methodology that leads to a systematic bias (crocodilians having in-vivo bite forces available).

[Grey]

Yeah, this was already my thinking years ago.

How about Tyrannosaurus bite force vs Deinosuchus and Purussaurus ?