Megalodon vs. Livyatan melvillei

[elosha11]

Feel free to continue the discussion, both of you! I'm just saying you should get more directly into the conflict as opposed to their specific anatomical features. For instance, I need to finish up a long post I started awhile back about each animal's possible advantages/disadvantages in a fight. I think the conflict goes beyond total size and comparative bites, although those are admittedly primary factors.

[theropod]

No, I don't think that would be a good idea at the moment. We need to calm down, hence thank you for intersecting the debate which would otherwise have continued on and on...

[stomatopod]

I have problems with a few statements by theropod:

First, his notion about GWS size. Females start to mature at around 4.5 meter. Now I could take a human population mostly composed of children an call the 1.70/70 kg adults exceptional specimens.

I also have a problem with the statement about Meg not being as abled to "crush" bones dut to him being a "slicer" the case of the latter one could argue not but this is due to brittleness)
Of course there are tradeoffs, like additional weight and being more prone to damage than conical teeth.
It´s like I would make an analogy and say that there cannot be car that has the same acceleration and top speed as another car but with different tires and motor.

Please do not take this as an offence, theropod.

I hope we can at least agree on the first point.

On the second point you would have to clarify what you undestand as "crushing".

[elosha11]

Grey - I think the museum Siversson is talking about is in Aurora, NC. Here's the website. www.aurorafossilmuseum.com/. Big emphasis on Megalodon and prehistoric whales. When I have time, I'll try to contact them and see if they can identify the baleen whale centra in question.

[theropod]

Jun 18, 2013 20:12:08 GMT 5 stomatopod said:

I have problems with a few statements by theropod:

First, his notion about GWS size. Females start to mature at around 4.5 meter. Now I could take a human population mostly composed of children an call the 1.70/70 kg adults exceptional specimens.

I also have a problem with the statement about Meg not being as abled to "crush" bones dut to him being a "slicer" the case of the latter one could argue not but this is due to brittleness)
Of course there are tradeoffs, like additional weight and being more prone to damage than conical teeth.
It´s like I would make an analogy and say that there cannot be car that has the same acceleration and top speed as another car but with different tires and motor.

Please do not take this as an offence, theropod.

I hope we can at least agree on the first point.

On the second point you would have to clarify what you undestand as "crushing".

None taken.

My point on great whites was mainly about comparative tooth/bone size (human femur or tibia vs great white tooth), noting great whites saw through those bones commonly in the (of course rare) attacks. I was probably not right about the weight, but it was a rough figure.
It seems tooth bone contact and subsequent bone damage is present in many animals, the presence of ghashes alone is not indicative of particular killing style. Not containing any definite statement about the killing style of C. megalodon, merely that we need a bit more precise data and for now it seems it basically does what a great white can do too, it is just more specialized in it.

I define Crusher as an animal using blunt force, and slicer as an animal relying on cutting ability. All existing anyimals have a bit of both, that's were the tradeoff is figured in. In a car, the variable factor is the amount of fuel. It does not have to worry about brittleness of teeth, while in this case, a teeth that is more robust is also less well suited to slice or the reverse. That's why I do not think you can say one can be just as good at one thing and better at the other thing. The equivalent to the fuel in the car for the damage done by a bite would simply be size in the animal kingdom. I hope I didn't express it in an overly confusing manner...

[Grey]

Jun 18, 2013 20:16:21 GMT 5 elosha11 said:

Grey - I think the museum Siversson is talking about is in Aurora, NC. Here's the website. www.aurorafossilmuseum.com/. Big emphasis on Megalodon and prehistoric whales. When I have time, I'll try to contact them and see if they can identify the baleen whale centra in question.

Excellent, yes, I've checked the mail and he precised it was in NC.

If you don't have time I'm going to do it if you want.

I will start again to try reaching Dr Hubbell in the meantime.

By the way, is it certain that the large Hubbell's meg tooth is an upper anterior ?




One of its side is almost 2 cm shorter than the other, and I remember Life wondering it was perhaps more likely a lateral one, suggesting in that case that the actual possessor of that tooth may have had larger anteriors and thus the prediction by Jeremiah by tooth width would make the 19 m TL estimate conservative...

Where that tooth would be placed ? A strict UA or an UL ?




EDIT : I've overlooked that the shorter measurement is the perpendicular height of the tooth, not the side length.

Still, where would be placed the specimen ?

[stomatopod]

Well I think you comparision is a bit confusing,(though this might be due to my own analogy being confusing itself) look, the are other possible tradeoffs than having to be badder at crushing when you cut better. A dAne axe is as likey to destroy you skull as is sledgehammer, the former is still better at cutting wood. But its more prone to get dull or get damamged. this is trade off. Or in the metalurgy of ferrous metals, you can either have very hard, brittle material which you can sharpen very finely without it getting dull fast, or softer and more flexible steel which does not hold an edge as well.
But you can selectively harden steel or forge a three layered blade. And of course yo can have steel that is soft and brittle.hich it could quickly regain, but at a price, as it does not grow from nothing.

[Grey]

stomatopod,

Was that with you that we discussed that the metabolism of an active hypercarnivorous mammalian predator such as Livyatan would not allow it to reach as efficiently the same large sizes than an active hypercarnivorous selacian predator such as Carcharocles ?

[theropod]

Jun 18, 2013 20:53:17 GMT 5 stomatopod said:

Well I think you comparision is a bit confusing,(though this might be due to my own analogy being confusing itself) look, the are other possible tradeoffs than having to be badder at crushing when you cut better. A dAne axe is as likey to destroy you skull as is sledgehammer, the former is still better at cutting wood. But its more prone to get dull or get damamged. this is trade off. Or in the metalurgy of ferrous metals, you can either have very hard, brittle material which you can sharpen very finely without it getting dull fast, or softer and more flexible steel which does not hold an edge as well.
But you can selectively harden steel or forge a three layered blade. And of course yo can have steel that is soft and brittle.hich it could quickly regain, but at a price, as it does not grow from nothing.

Yes, but all top predators achieve a similar degree of optimisation for their respective tasks, there arent some ones with structurally greatly superior weapons, and unlike a human with a tool, animals usually do not afford having tools that get dulled quickly by the task they do.
Your analogy is that of two tools that both do not have any difficulty withstanding the purpose. This is like a great white slicing through your leg or a hyaena crushing it, not a problem for either. But if you want to accomplish a more challenging task in either direction, eg. take both to break down a wall or in the case of animals crack a proportionally really large bone, you may see a greater difference. Animal teeth are not made of steel, but dentine and enamel, they are more prone to breaking because these materials are much closer to cast iron (see gray's anatomy of the human body) Maybe stone tools can offer the better analogy since their properties are closer to teeth.

If I have a really short, thick flint blade, it is much less likely to crack on impact than a long clovis point, because it has a smaller lever arm compared to a greater cross-section, hence better suited for hard material and the stresses excerted while cutting/crushing it but less well suited for effective cutting due to the greater efford it takes to pull it through soft tissues. There is a basic payoff between sturdyness and sharpness in animal teeth, that's the reason for different tooth morphologies. In steel, this often simply doesn't matter much, but of course it basically applies to all materials.

[Grey]

A glimpse on the perhaps dentition of a large megalodon.



The teeth are really thick and robust, the most robust teeth a predatory shark ever had.





Some are casts yeah, but based on actual specimens. Just like the Livyatan skull reconstruction.

The teeth have the structure reminescent of an axe, more than flat blade.

[theropod]

Fitting the ones of C. megalodon above, some shots of the Livyatan holotype. Clearly a completely different set of adaptions and a different purpose in terms of the teeth, but also very robust in both the teeth and the jaws department.

[coherentsheaf]

Jun 18, 2013 20:12:08 GMT 5 stomatopod said:

I have problems with a few statements by theropod:

First, his notion about GWS size. Females start to mature at around 4.5 meter. Now I could take a human population mostly composed of children an call the 1.70/70 kg adults exceptional specimens.

I also have a problem with the statement about Meg not being as abled to "crush" bones dut to him being a "slicer" the case of the latter one could argue not but this is due to brittleness)
Of course there are tradeoffs, like additional weight and being more prone to damage than conical teeth.
It´s like I would make an analogy and say that there cannot be car that has the same acceleration and top speed as another car but with different tires and motor.

Please do not take this as an offence, theropod.

I hope we can at least agree on the first point.

On the second point you would have to clarify what you undestand as "crushing".

Ithink the 4.5m average size claim is pretty much up to debate. There is a paper claiming this size, but it has a small sample size and simply dismisses smaller sizes as outliers - something you should never do quickly. Most great white populations do not contain many animals in this size range and since lamnids are k-strategists this should surprise us (maybe it can be explained by very slow growth) if they actually mature that late. In most K strategist average sizes are much closer to sizes of grown individuals than in R strategists, since the latter have a far higher number of offspring and therefore the juveniles outnumber the grown individuals.

[Grey]

theropod

I've seen your post on the CF.

Can you frankly stop to suggest Livyatan delphinid-like bodied when nothing even hints this ?

I don't say that the idea has to be ridiculoused, we can discuss it, but you act like if it was a real likely possibility.

Raptorial sperm whales are not delphinids bodied as I know and probably even less at larger scales.

That's again your overenthusiasm to envision the most spectacular size based on an unlikely possibility... By the way an idea that was first suggested by Sam1, more or less as unbiased, objective and honest as Taipan... Sam1, the guy who spent his time to draw and establish factual 30 m sperm whales all the time or agued that orcas were more intelligent than H. sapiens...

Am I suggesting necessarily Carcharocles with the proportions of its teeth/body as a tiger shark (which would make it very long) or in its bulk as a porbeagle (which would make it bulkier than a white shark as model) ?

All the large marine active macrophagous predators have evolved a similar thunniform basic body plan but the ration head/body depends of the phylogenetic.

Regarding its size, you can trust me, I've mailed Lambert, De Muizon, Salas and Reumer (it only lacks Post and Bianucci), mails filled with enthusiasmitic questions, no one has even slightly hinted on that.

Nor the paper, nor the supplementary information.


I know you don't consider the great physeteroid as such, but I argue that you give too much credential to this. Or I will also suggest for Livyatan a ratio skull/body as in ichthyosaurs, pliosaurs, mosasaurs...hey, they also occupied a similar niche and lifestyle.

There are others more valid arguments in the defense of Livyatan that I wouldn't reject.

[theropod]

I think you have to stop interpreting too much about my posts, at least if you meant this one:

A 3,8m false killer whale is smaller than an average adult great white, and at parity not even near as large-skulled (consequently well armed) as Livyatan (unless you give Livyatan a large size advantage basing on delphinid head-body proportions)

This is no suggestion of Delphinid body proportions, I was stating the fact that at lenght parity a Livyatan is either much more large skulled than animals SUPPOSEDLY dominated by great whites, or it would necessarily have to have a size advantage.

I have not even hinted any delphinid proportions since a long time.
The tiger shark is a terrible analogy since its teeth are not even remotely similar in proportions.

This is the same problem we had in our last debate if you ask me. No offense, you have a tendency to misinterpret/exagerate my posts and overreact because of that. Lots of the things you accuse(d) me of claiming I have not actually claimed since many months, if at all.

I've never seen those claims sam1 alledgedly made.

[Grey]

Okay, I may have misinterpreted indeed, but not so long ago in the thread you hinted on this so makes sense I recalled you.

Sam1 suggestion was in the old carnivora version before you join.