Megalodon vs. Livyatan melvillei

[elosha11]

This is a revealing picture of just how much thinner Livytan's lower jaws are than are than even the most conservative Meg jaws models. Here an adult man with arms on both sides of the holotype model's lower jaws while he bends his arms at around 90 degrees. While the upper jaws are larger than the bottom they are meant to interlock with the lower fitting into the upper jaw. Most of the upper jaw, other than the base, doesn't appear to be all that much wider than the lower jaws.

Obviously, Livytan's jaws are somewhat longer than Megalodon's but the difference doesn't seem nearly as pronounced as the difference in their width. So whenever I see someone's diligent models, I appreciate it, but it's pictures like these that make me highly skeptical that Livyatan's overall mouth volume was as big as Megalodon's. And just based on sperm whales, I also have my doubts that the whale's gape was as great as the shark's, which is another factor that plays into overall bite size. But there's as of yet no study of Livyatan's gape, so that's simply speculation.



BTW, while size of the bite is an important factor in a conflict scenario or size comparison, it's certainly not the only one. No one factor could be decisive in determining who would hypothetically win this contest.

[elosha11]

More illustrations. Again, while absolutely enormous in relative terms, I just can't see how anyone could think these jaws are larger than Megalodon's. Dimensionally speaking, it looks like Livyatan could likely swallow a man whole, but not without some difficulty. But I don't think that would be even a remote challenge for an adult Megalodon.

[jhg]

That’s still seriously freaky jaws. And to think no full body of Livyatan has been discovered...

[sam1]

That's a great picture, thanks.
But it's not about the volume..when said "jaw damage output alone", I was taking the whole picture.
The teeth of livyatan are simply dwarfing megalodon's teeth. That's the point.
Also, I don't see it having any difficulty in swallowing a man whole. The lower jaw is relatively narrow but it is just the protrusion of the mouth..the base was wide enough to easily gulp a man down.

[Grey]

The Yorktown is no less an individual potentially in the average adult size range than the Livyatan holotype, just like a 14 or a 16 m male Physeter is variably seen as an average size specimen.

Regarding the jaws reconstructions, most of them are actually poorly reconstructed, even if the dental formula and proportions are good enough, the structure of the jaws is at best speculative and likely incorrect given the suggestions by Gottfried of a heavy structure in order to operate the dentition.

This is thus an interesting reconstruction but far from written into the stone.

And I still find far more impartial to compare the Livyatan holotype to any Carcharocles associated dentition for which we can make a size estimate.

[theropod]

... And I have already done that, I compared it to jaws scaled to the size of the yorktown specimen way before scaling them down to represent average-sized jaws.

We need to make a decision on whether we want to take into account isolated teeth or not, but stop ignoring them or including them at will when it fits our narrative. Either we acknowledge giant isolated teeth, but also that the average size implied by isolated teeth is smaller, or we ignore both.

The average size is actually a lot more reliable than the sizes of the owners of individual tooth specimens, as the large sample compensates for the impact of individual variation far better than the far smaller sample of exceptionately large teeth would. Yet you had no problem to remark repeatedly about the size of some isolated teeth (with which I agree, as I wrote the largest teeth in the dataset are 25% bigger than Yorktown), so you can not find it inappropriate or irrelevant to note the average size indicated by those same teeth.

And that is what the comparison shows. There is one with a yorktown-sized individual as well. I am considering both at the moment.

Based on isolated teeth, Yorktown is not the largest specimen, but clearly large compared to the average. Based on dentitions, our sample is small, so Yorktown is not that much larger than the average, but still the largest dentition.

So what jaw model or depiction with known dimensions and jaw perimeter would be best to use? There needs to be some reliable way to scale it, but I am fine with using any model here, I simply used that one as it was the one Life used before.

14 and 16 m male Physeter are not "variably seen" as average adults, they are averages of two different sections of the population. 14 m is (approximately) the average for adults, whereas 16 m is the average for fully grown individuals, only a relatively small part of the population. As I recall McClain et al. noted that 95% of all Physeter individuals in their data were below 15 m.


sam1 tooth size isn't relevant when comparing animals of such vastly different tooth functions and morphologies.
In fact most conclusions drawn from these size comparisons (not the comparisons themselves) about the subject at hand are merely subjective impressions, nothing more, although certainly it is better to at least draw that from a comparison based on solid data.

I wouldn't be surprised if the average megalodon still has a significantly bigger bite volume than the Livyatan holotype (though we should attempt to quantify that), due to its roughly semicircular shape. But I've already explained why I don't find that very important, and I don't think this can be translated into the overall power or potential for dealing damage of these two vastly different jaw apparata.

[Grey]

I don't ignore anything, I recommand to use any good meg specimen with any Livyatan specimen or size figure as long as numerous specimens in both taxa with good TL predictions are absent.

We can't elude the possibility as well that, due to biology specifics, one taxa could be on average smaller in size but able to reach a maximum size than another taxa.


And guess what, I don't have any problem with the possibility to use the reported 40 cm teeth in order to suggest some plausible potential upper size for the giant KSW.

[theropod]

Where is the problem then? Using the average, as in my comparison, represents the middle ground when considering all adult meg specimens and comparing them to Livyatan, anything between a 10.5 m male that just matured to a giant 20 m female.

Of course if you prefer, I can make a comparison comparing Livyatan’s jaws to both the largest and smallest adult megalodons, I just don’t think that would be more informative.

We can't elude the possibility as well that, due to biology specifics, one taxa could be on average smaller in size but able to reach a maximum size than another taxa.

Yes, but we don’t know which one, so what you are pointing out is correct, but I don’t see the relevance.

1. Large Megalodon would be far lower in number than juvenile Megalodon whose teeth are easily accessible from formerly shallow water environments or supposedly nursery locations.

Had not addressed that one yet, at least not recently.

But firstly, the megalodon fossils come from the same localities as those of Livyatan. If you really want to consider a 15 m megalodon to be a juvenile based on its occurrence in coastal regions, then you must consider the possibility that a 15 m Livyatan might be as well, as absurd as that would be.

Secondly, much of megalodon’s preferred prey comes from those same formations, so I see no reason at all to presume adult megalodons where not typical inhabitants of those localities, same goes for Livyatan.

And thirdly yes there are nurseries, see my post on the meg profile discussion thread to find me fully acknowledge and even suggest that myself, but we are only considering adults here, so they are irrelevant. Obviously the mean of the entire tooth record would include many immature individuals, just like the mean of the entire record of great white sharks includes many juveniles, we are already excluding those (that’s why this is the average adult size, the average of the whole sample is just 75% of that).

Take for example the Gatun or Calvert formations, which are or at least may be nurseries:


compared to the Yorktown formation, which likely is not:

[sam1]

Theropod, I think I made it clear numerous times that I don't even question the volume of the bite is easily in favor of the megalodon.
As for noticing one teeth being much larger than the other, there's nothing subjective about it. It's a statement of a fact.
And it isn't irrelevant at all..bigger teeth do more damage than smaller teeth, all else being equal. Bigger jaw does more damage than smaller jaw, all else being equal..obviously.
What I'm saying is that livyatan jaw looks like being able to do massive damage provided it gets a full bite.
If that thing clamped around a fin, spine, it would puncture deeply, crush and tear specifically because of the massive teeth volume combined with likely enormous bite force.

[theropod]

Yes it is a statement of fact. It just isn’t that relevant, because all else is not equal. Megalodon’s teeth have cutting edges. Livyatan’s don’t. So much is obvious. The damage done by a Livyatan tooth and the damage done by a megalodon tooth are simply two entirely different things to begin with, the teeth don’t necessarily need to be the same size (by whatever measurement we are determining that) to do similar amounts of damage.

And agreed, Livyatan’s jaw does look like being able to do massive damage with a full bite. Absolutely. I’ve never doubted that. The sheer power and crushing ability of those jaws must have been enormous, quite scary to imagine really what would happen to something those jaws clamped down on.

I recall the age-old comparison I made showing the skull of Livyatan with that of T. rex superimposed on it:

As for the apparently all-important people-swallowing capacity (though a large python can do that as well, so again I don’t think this is so relevant here), we generally agree a large T. rex, like depicted here could have swallowed a person…

[elosha11]

Oct 23, 2019 16:30:18 GMT 5 sam1 said:

Theropod, I think I made it clear numerous times that I don't even question the volume of the bite is easily in favor of the megalodon.
As for noticing one teeth being much larger than the other, there's nothing subjective about it. It's a statement of a fact.
And it isn't irrelevant at all..bigger teeth do more damage than smaller teeth, all else being equal. Bigger jaw does more damage than smaller jaw, all else being equal..obviously.
What I'm saying is that livyatan jaw looks like being able to do massive damage provided it gets a full bite.
If that thing clamped around a fin, spine, it would puncture deeply, crush and tear specifically because of the massive teeth volume combined with likely enormous bite force.

Sure. And what happens when a great white, mako, tiger or bull bites a dolphin, even ones similar in size to the shark? If the shark lands a good bite, it cuts through the cetacean's blubber like butter and mortally wounds it. So imagine what Megalodon's massive mouth, (which you admit is the largest) serrated teeth and presumably very large gape would do if it landed on Livytan. Both animals would do extensive damage with their bites. I think Megalodon would take an overall substantially larger bite, but no question that Livyatan's bite would be very harmful. I still wonder if the whale could open its jaws wide enough to get a "full body" bite on a full grown Megalodon, based on what I've seen as to how relatively narrow sperm whale's gapes appear to be. But perhaps Livyatan had a wider gape than modern sperm whales.

[Grey]

I remember an article by a US paleontologist where he said T. rex could have swallowed a medium-sized person I think but not an obese.
Anyway, Livyatan can certainly swallow at least one guy.
I think elosha simply suggests something like Livyatan would maybe not swallow a human as easily as a meg.

[theropod]

elosha11 That depends, do you think a 5 m orca would have trouble biting <4.6 m white shark? That’s about what the relative size of megalodon’s and Livyatan’s jaws would suggest as the most optimistic estimate of the shark’s size compared to the whale’s jaws. If the shark has positively allometric jaw size, or is a smaller individual than the Yorktown dentition, it ends up smaller than that. If we take the average adult size of the tooth sample, then the comparison is more like that between a 4 m shark and the jaws of a 5 m orca.
An estimated 4.7-5.3 m orca has been recorded biting and holding an estimated 3-4 m great white in its jaws…

And I don’t think sam1 was disagreeing that a shark bite would do massive damage to a similar-sized animal, we seem to all be pretty much agreed on that. But I’ve read suggestions here claiming the Livyatan jaws would be able to cause substantially less damage, so it’s fair to question that on the basis of how the two sets of jaws compare…

[sam1]

Elosha - Well here's a surprise for you then..sperm whales actually have an extreme bite angle - almost 90° - easily the highest of cetaceans to my knowledge.
So if the modern sperm whale is anything to go by, livyatan's bite could've been quite large, to say the least.
That said, I'm pretty sure it couldn't take a full bite on the very side of the megalodon. Otoh, megalodon probably would have no issues doing the same to Livyatan.
But biting the side of megalodon would be the last thing on Livyatan's mind. The first thing to do from that angle would be (again, I'm talking only that specific angle scenario) to try ramming/flipping the shark and then follow that up with a bite that can be fully utilized. Livyatan would probably manage to land a full bite onto anything less round and wide(the underside, the fin, the lower body).
Keep in mind that the side of the shark is very vulnerable. It is basically 10+ tons of liver protected only by muscle and skin. No ribcage, no fat layer.
Getting hit there with the force of a loaded semi truck at 30km/h would be bad enough, but being bitten afterwards would likely be lethal.

Of course, megalodon landing a full bite on the side of Livyatan would be devastating too. I never questioned that.

[theropod]

Elosha - Well here's a surprise for you then..sperm whales actually have an extreme bite angle - almost 90° - easily the highest of cetaceans to my knowledge.

Do you have a source for that? I’ve searched extensively for this kind of information on cetaceans, sadly without results.