Functional Morphology of Animal Feeding Apparata

[Infinity Blade]

No, is there any reason it didn’t? As you know, older, larger crocodiles (which take relatively large tetrapod prey) become increasingly rare, and I’ll wager that the skulls of relatively young individuals are more common in collections. But this is just a possibility that has been left unaccounted for, I’m not implying that it’s necessarily the case.

A reasonable premise, but I'm not really betting that a particularly old crocodile specimen with an exceptionally robust skull was used, just a plain old average adult. And if RVC AN1 really is a young specimen, wouldn't you think Foffa et al. would have bothered to mention this considering how (needless to say) a young crocodile's skull would be significantly weaker than an adult's (even proportionately), thus warranting an important caveat regarding the study's results?

Yes, certainly. And its also noteworthy that alligators or caimans don’t seem to take proportionately larger prey than nile crocodiles (if anything the reverse is true), so prey availability is probably the deciding factor rather than for extant crocodilians. I presume the same may hold true for pliosaurs, especially considering that for something the size of a large Killer Whale the majority of potential prey would be smaller than its own size anyway.

Agreed.

I too find that limit strange, and it isn’t really explained where they got it from. As I mentioned above, if the abundance of available prey is taken into account, it is reasonable to assume that most of its prey would have been less than half its body length, but I don’t really see why that should be the upper limit either.

Once again, I agree.

Hell, Darren Naish even once mentioned plesiosaur-induced bite marks on Leedsichthys fins (and I'm pretty sure he wasn't referring to long-necked plesiosaurs). I know you and Grey discussed this too (incidentally also questioning Foffa et al.'s prey size limits for pliosaurs), and you said that it was unlikely to have been a scavenging event.

[Infinity Blade]

Would anyone like to create a comparison between the skulls of Pliosaurus and C. niloticus (not to scale, duh)?

[Ceratodromeus]

Rudimentary, but eh

[Grey]

antediluviansalad.blogspot.fr/2016/01/the-disservice-of-tyrannomania-taking.html

theropod you might like this article.

[theropod]

Of course, don’t you?

I don’t really agree with his conclusion that "blade toothed theropods were eating more bones than tyrannosaurids" or even that they were necessarily consuming them in particularly great quantity, imo those are the sorts of conclusions that one gets with insufficient sample sizes and a lack of quantitative analysis. But he’s certainly right on many accounts imo.

Some of it I already posted→, there’s some very interesting new stuff in there too, for example I had never head of that giant score mark.

[Grey]

Yes I like most of Nash articles, this one is pretty good.

I guess that at the end he's rather sending a wild suggestion rather than a conclusion, but an interesting one.

I also ignored this giant coprolithe filled with bones.

[Infinity Blade]

Unrelated to the purpose of the thread, but from the link:

"Amazing post as always. We seriously need more attention on the massively diverse lineages of non Tyrannosaurid Theropods. Like seriously, just look at how "diverse" Tyrannosaurids are. You basically just have Tyrannosaurs rex kind of forms that just have giant robust jaws with tiny arms, and then you have little dainty forms like Alioramus that have long teeth and long snouts; although they still have about the same body plan. There are some forms in between but that's about it. But look at literally any other Theropod group. Bull horned Abelisaurs, pack hunting uber mega sauropod/stegosaur hunting Carnosaurs, small sized basal Neotheropods that (possibly) used mob/hoard tactics to viscerate large sized prey, near sabertoothed Herrerasaurids and Ceratosaurs, giant crocodile mimic Megalosaurids (although Spinosaurus is WAY too over hyped), giant scythe armed Megaraptorids, nocturnal Troodontids that were essentially ground dwelling owls with the attitude of a pissed of [sic] Cassowary and giant and even semi-volant Dromaeosauirds [sic] were all stalking and eviscerating the multitude of prey items in their habitats. Well, enough with my long ramble, you get the gist of it. You're doing a great service to the paleontological community by focusing on Theropods that were utterly destroying flesh. I look forward to your next post!"

This guy does realize he's comparing the diversity of ONE FAMILY to that of A BUNCH OF OTHERS COMBINED (some of which would form whole clades, i.e. Carnosauria), right?

Of course a family will appear comparatively monotonous in its members' bauplans. A family is a comparatively small taxonomic ranking and is where taxa really start to resemble each other. To compare, again, ONE FAMILY to A BUNCH OF THEM? How does that make for fair comparison? Try comparing Tyrannosauridae to only say, Megalosauridae; neither appear particularly diverse on their own, do they?

Different guy:
"Also, screw tyrannosaurs. They can't kill anything bigger than themselves (though they definitely were not small-prey specialists) for Carcharodontosaurus's sake!"

This sounds a helluva lot like something acepredator would say.

But seriously, how the hell are people arriving at this idiotic premise? Extant macropredators that utilize powerful bite forces in conjunction with raptorial teeth are more than capable of killing prey items larger than themselves (I mean, hello, carnivorans anyone?). What's there to suggest tyrannosaurids could not do the same? Well, other than a mythical, magical aura surrounding them that, because of the massive popularity they garner from exceptionally intelligent primates that evolved millions of years after they went extinct, would render them unable to do so.

Might I frankly add that, in any case, that's a very biased way to look at these animals (in a fanboy/hater way). I mean, just look at the damn comment!

I of course am agitated by the excessive embellishment of certain things (tyrannosaurids in this case). But when it comes to taking hype down a notch, some people really do go a foot when given an inch. I don't know which I hate more.

[Infinity Blade]

Okay, something that has to do with the thread.

Terrestrial-style feeding in a very early aquatic tetrapod is supported by evidence from experimental analysis of suture morphology
Molly J. Markey and Charles R. Marshall, 2007

There is no consensus on when in the fish-tetrapod transition suction feeding, the primary method of prey capture in the aquatic realm, evolved into the direct biting on prey typical of terrestrial animals. Here, we show that differences in the morphology of selected cranial sutures between species that span the fish–tetrapod transition (the Devonian osteolepiform fish Eusthenopteron, the aquatic Devonian tetrapod Acanthostega, and the Permian terrestrial tetrapod Phonerpeton) can be used to infer when terrestrial feeding first appeared. Our approach consists of defining a sutural morphospace, assigning functional fields to that morphospace based on our previous measurements of suture function made during feeding in the living fish Polypterus, inferring the functions of the fossil sutures based on where they fall in the morphospace, and then using the correlation between feeding mode and the patterns of inferred suture function across the skull roof in taxa where feeding mode is unambiguous to infer the feeding mode practiced by Acanthostega. Using this procedure, we find that the suture morphologies of Acanthostega are inconsistent with the hypothesis that it captured prey primarily by means of suction, which suggests that it may have bitten directly on prey at or near the water's edge. Thus, our data strongly support the hypothesis that the terrestrial mode of feeding first emerged in aquatic taxa.

Link

[creature386]

I wonder if we should include some sort of index in the OP, as the thread grew quite long and that would make it a nice compendium of scientific works on feeding apparata (I tend to forget quickly what I read about the feeding strategies of an animal). Maybe I add such an index once I find the patience.

EDIT: Looks like I got support, I'll try to add one.

Anyway, on topic, this study on Majungasaurus is not exactly new, but I wanted to post it here, as I recently forgot about it and needed to search for it:

Thus, they argued, Majungasaurus likewise was a hunter of large prey and delivered slashing bites capable of removing sizeable portions of flesh. Moreover, their mechanical analyses suggested that Majungasaurus could deliver high bite forces (and that Carnotaurus could bite even harder, in contrast to the findings of Mazzetta et al. [2000]).

www.ohio.edu/people/witmerl/Downloads/2007_Sampson_&_Witmer_Majungasaurus_skull.pdf

[creature386]

Added an index.

[Infinity Blade]

So I guess Majungasaurus really could bite down hard.

[Infinity Blade]

While I was doing research on Dilophosaurus, I also came across some info on the similar-looking Sinosaurus. This caught my eye:

Sinosaurus had a deep notch at the suture between premaxillary and maxillary bones. This notch was very powerfully built, possibly to anchor muscles that would produce a powerful bite. Sinosaurus might have been either a scavenger or a predator. The premaxilla was probably covered with the narrow, hooked beak used to tear skins and abdominal walls of poor victims. A crested crown, which is sometimes fan-shaped, may have been helpful to keep the abdominal wall open while devouring. The feet of Sinosaurus were similar to those of Himalayan vultures, and had become adapted to eating the corpses of large animals, such as prosauropods.

link

[Infinity Blade]

I've heard at least once the idea that theropods (or at least certain groups thereof) could have charged at prey and driven their teeth into them at high velocities; the first quote is that at least one time.

Tyrannosaurs, on the other hand, seem suited to ambush attacks, literally ramming their jaws into the flanks or whatever into the animal...

link

Work suggests that allosaurs (and Giganotosaurus is in many ways a giant allosaur) had a relatively weak bite and relied on the impact of the momentum of the animal to deliver power to a bite (i.e. hitting the prey with the mouth open) wheras the derived tyrannosaurs quite simply had power delived from the actual muscles of the head to make the bite strong.

link; could possibly be referring to the hatchet bite

And here, theropod seems to make a comparison between allosaurids and great whites:

Great white sharks (Carcharodon carcharias) are more similar in body size, hypothetisized speed and they have similar bite forces (Wroe et al. 2008) to allosaurids. These predators make use of their velocity to drive their teeth into prey when ramming them from below.

link

Not that I find this improbable, but is there anything to suggest they would have done this?

[theropod]

Do note that I do not mean to imply allosaurids (or any theropod) rammed their prey with their whole body the way sharks do, so if that’s what you mean, I don’t think it’s suggested by, or consistent with any evidence.
Chondrichthyans don’t have flexible necks, with all the advantages and drawbacks that has, and that makes them function very differently. What I do think is common to both is that there is a high-velocity impact component in their bites.

Imo Bakker (1998) argued convincingly for the presence of such a mechanism on qualitative grounds, and his hypothesis was quantitatively corroborated on all accounts by a number of more recent studies.
The neck musculature allows high levels of ventroflexive acceleration (Snively et al. 2013), bite force is comparable to a great white shark of similar body mass (Bates & Falkingham 2012), the skull is dorsoventrally reinforced (Rayfield et al. 2001) and the jaw joint permits very large gape angles (Lautenschlager et al. 2015), the teeth are relatively low-crowned but retain a CBR characteristic for slicing teeth (Smith et al. 2005). This combination is best explained by striking motions akin to the samoan war club Bakker suggested as an analogy, followed by subsequent pulling and tearing.
Individually these features don’t mean much, but taken together I’d have serious trouble explaining all of them otherwise (especially the combination weak bite–strong skull–high acceleration).

For the record, I think ramming a large prey item at high speed would potentially be suicide for a large theropod (basically the same situation as with theropod headbutting), the neck and cranial articulation wouldn’t be equipped or properly positioned to withstand that sort of stress. Animals that do this have their jaws or whatever they ram their opponent with very close to the main axis of the body and the axis of movement, so that the stress is mainly compression.
An s-shaped theropod neck articulating with the posterior surfact of the skull wouldn’t fare well if it had a couple of tons of accelerated theropod ramming that skull into something large (whether it’s the oral margin in a ram-feeding scenario, or the skull roof in a headbutting scenario).


––Refs:
Bakker, Robert T. (1998): Brontosaur killers: Late Jurassic allosaurids as sabre-tooth cat analogues. Gaia 15 pp. 145-158.
Bates, Karl T.; Falkingham, Peter L. (2012): Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics. Biology Letters 8 (4) pp. 660-664.
Lautenschlager, Stephan (2015): Estimating cranial musculoskeletal constraints in theropod dinosaurs. Royal Society Open Science 2 (11): 150495.
Rayfield, Emily J.; Norman, David B.; Horner, Celeste C.; Horner, John R.; Smith, Paula M.; Thomason, Jeffrey J.; Upchurch, Paul (2001): Cranial design and function in a large theropod dinosaur. Nature 409 (6823) pp. 1033-1037.
Smith, Joshua B.; Vann, David R.; Dodson, Peter (2005): Dental Morphology and Variation in Theropod Dinosaurs: Implications for the Taxonomic Identification of Isolated Teeth. The Anatomical Record 285 (A) pp. 699-736.
Snively, Eric; Cotton, John R.; Ridgely, Ryan; Witmer, Lawrence M. (2013): Multibody dynamics model of head and neck function in Allosaurus (Dinosauria, Theropoda). Palaeontologia Electronica 16 (2) pp. 1-29.

[Infinity Blade]

Looking into Greg Paul's Predatory Dinosaurs of the World, I noticed something that kind of puzzled me. In regards to soft tissue damage, Paul claims that a typical theropod bite would have produced slash marks, which is of course reasonable. But then he says the following about Carcharodontosaurus.

"The type of C. saharicus is some distinctively straight-shafted teeth and some heavy-set advanced allosaurian skull bones bear such teeth. These vaguely sharklike teeth hint that Carcharodontosaurus had independently developed a unique way of cutting out wounds, rather than slicing the victim." (p. 317)

In fact, he rather clearly makes a distinction between simple slicing and "cutting out wounds" for these big game hunting, head hunter theropods.

I don't get it. Isn't it kind of the idea that typical bladed-toothed theropods would be adept at "cutting out wounds" (i.e. biting out big chunks of flesh), more than just creating horrific lacerations?