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Post by theropod on Jun 12, 2013 0:21:55 GMT 5
I have checked the information often enough. What I do not understand is why you think wanting to establish them as equals is so unfeasible. A megalodon measuring 16, 17 or 18m clearly is a large individual. we have no reason to suspect the livyatan holotype was a large individual of its species, but that is the assumption megalodon being bigger bases on. When their size ranges, in the case of Livyatan the range of estimates, in the case of megalodon that of specimens, perfectly overlap, that means we are speaking of two animals of very similar size.
Maybe you should also check the information again?
PS: With theropods, what I usually argue is the exact opposite of what you seemingly think. I am using maximum sizes, partly because we are mostly talking about animals with at best few specimens known, and partly because even the maximum sizes of pauciptypic species are easily reaching or exceeding that of the animal usually, and sadly, used for comparison, even tough said animal has more known specimens. What I usually argue about in those taxa is the maximum size each attained. If I went for average sizes in those cases, the difference would be even more marked, but I am not that much interested in their averages since due to scarce remains they are usually not very meaningful anyway. In theropods, my main interest is in the sizes of the largest ones, which are figures we can usually establish relatively conclusively.
Take as an example Spinosaurus. If I assume the only confirmed adult Spinosaurus is significantly bigger than the largest in 31 T. rexes, because all but the lowest, and deliberately low figures suggest so, this is obviously a completely different situation then arguing a monotypic species should best be compared to the average for a polytypic one. The equivalent would be comparing MNSM V4047 to an average T. rex. That is just not necessary and pointless, since we can see it is significantly bigger anyway. Whether it is 2t more or less doesn't really matter in that case.
The animals you probably refer to, which I suggest are at least as large or larger, are actually the ones with the far lower sample size, and yet I am only using maximum.
This is not a debate on maximum size, C. megalodon is probably 18-20m at maximum. It is a debate about whether one animal is larger than the other, which doesn't seem to be the case at the moment, since we don't even have the slightest cluse on the maximum size of Livyatan. Hence I am not taking the only known specimen of Livyatan and comparing it to the largest in thousands of C. megalodons, just to establish C. megalodon as the larger animal.
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Post by Grey on Jun 12, 2013 1:15:14 GMT 5
For now, the maximum size we have of the whale is 17,5 m.
The maximum size of the shark is at around 18 or 20 m, depending the author.
I won't speculate on Livyatan intraspecific variation.
I assume all the published, not refuted sizes/mass figures. Using these, megalodon is slightly-quite larger.
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Post by theropod on Jun 12, 2013 15:59:10 GMT 5
I tought you had understood my point and even agreed with it? Sure, in a sample thousands of Megalodons, the largest specimens will logically be larger than the single specimen known of Livyatan. That is not indicative of a larger animal, therefore I prefer to take them at the same size, considering their ranges center around the same figure.
If we find an extinct hippo, say H. gorgops, and it is larger than an extant hippo, that doesn't equal it exceeding exceptionally large specimens like that 4,8t one. still, H gorgops is considered larger.
Was I too sensationalistic about Livyatan relative to C. megalodon, I would be able to come to completely different conclusions based on sample and animal sizes, which may make Livyatan a fair deal largerr. I do not, because I am not. I merely insist to consideer them equals for now. I think this opinion has its justification.
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Post by Grey on Jun 12, 2013 17:38:27 GMT 5
I've already explained why making these two animals figures by different methodologies at some kind of average is pointless.
Based on the available evidences, megalodon is probably larger, even though due to scanty remains, the datas can change. That's the opinions of different paleontologists I've quoted before.
Saying that only the largest megalodons were larger than Livyatan is total speculation because saying that the Livyatan was commonly 15 m or so on average is total speculation. We don't know at all.
The suggested upper end known in megalodon is slightly above 20 m and there is no reason at now to think that Livyatan reached the same.
Even Bretton Kent, who is cautious and prefers maintain 18 m for the largest ones without conclusive evidences of larger sizes, indicates the shark most likely as the largest marine carnivore known based on extant evidences.
Awaiting more stuff, I'm fine with this.
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Post by creature386 on Jun 12, 2013 18:57:42 GMT 5
Sure, in a sample thousands of Megalodons, the largest specimens will logically be larger than the single specimen known of Livyatan. Thousands? Wow, I thought it were only some hundret. If we find an extinct hippo, say H. gorgops, and it is larger than an extant hippo, that doesn't equal it exceeding exceptionally large specimens like that 4,8t one. still, H gorgops is considered larger. A hippo can't reach a mass of over 4,8 t. 3 t ones are already seen as freaks. |
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Post by theropod on Jun 12, 2013 19:56:36 GMT 5
Sorry, i rechecked and it was 4,5t for the largest. Anyway, the analogy stands either way.
a normal hippo is mere 1,5-2t. A specimen of 3t is a large specimen, 3,6t and more are exceptional. The record holder is 4,5t. Of course an extinct hippo whose only specimen is say 3t is larger than this animal, despite not actually being larger than the record weight.
Another example would be bovines. The largest cattle ever weighed was 2t, while Gaur reach 1,5t. Since the sample size in the Gaur is smaller and the conditions are generally less in favour of attaining freak weights, the gauri, not the cattle is the species considered larger.
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Post by theropod on Jun 12, 2013 20:00:50 GMT 5
I've already explained why making these two animals figures by different methodologies at some kind of average is pointless. Based on the available evidences, megalodon is probably larger, even though due to scanty remains, the datas can change. That's the opinions of different paleontologists I've quoted before. Saying that only the largest megalodons were larger than Livyatan is total speculation because saying that the Livyatan was commonly 15 m or so on average is total speculation. We don't know at all. The suggested upper end known in megalodon is slightly above 20 m and there is no reason at now to think that Livyatan reached the same. Even Bretton Kent, who is cautious and prefers maintain 18 m for the largest ones without conclusive evidences of larger sizes, indicates the shark most likely as the largest marine carnivore known based on extant evidences. Awaiting more stuff, I'm fine with this. Yes, based on the largest ones found probably. We haven't yet found such specimens of Livyatan, and we do not know whether we will or how large exactly they will be. Why should we compare maximum sizes in this case, when that is clearly biased? Do not confuse opinions with evidences. The total speculation is assuming it was not average, but it was objective to compare the holotype to the largest specimens of C. megalodon. Average is the most objective. As you yourself listed them their respective ranges have the exact same mean values. |
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Post by Grey on Jun 12, 2013 23:11:12 GMT 5
I've already explained why making these two animals figures by different methodologies at some kind of average is pointless. Based on the available evidences, megalodon is probably larger, even though due to scanty remains, the datas can change. That's the opinions of different paleontologists I've quoted before. Saying that only the largest megalodons were larger than Livyatan is total speculation because saying that the Livyatan was commonly 15 m or so on average is total speculation. We don't know at all. The suggested upper end known in megalodon is slightly above 20 m and there is no reason at now to think that Livyatan reached the same. Even Bretton Kent, who is cautious and prefers maintain 18 m for the largest ones without conclusive evidences of larger sizes, indicates the shark most likely as the largest marine carnivore known based on extant evidences. Awaiting more stuff, I'm fine with this. Yes, based on the largest ones found probably. We haven't yet found such specimens of Livyatan, and we do not know whether we will or how large exactly they will be. Why should we compare maximum sizes in this case, when that is clearly biased? Do not confuse opinions with evidences. The total speculation is assuming it was not average, but it was objective to compare the holotype to the largest specimens of C. megalodon. Average is the most objective. As you yourself listed them their respective ranges have the exact same mean values. You basically don't know that. Nobody knows the intraspecific variation size into this species. Perhaps we'll never found another individual or another larger individual. And even in species known by a number of individuals we don't know the absolute upper size. There are 31 Rex individuals but there are still possibilities of larger ones than Sue. We have numerous meg teeth but teeth are used with different methodologies giving different results. Some estimates reach 70 feet. There are also reports of 20 cm meg teeth from Chile and Peru, by Dr Kent by example. We can speculate of larger individuals at length with any species, even in extant taxa. I'm not interested in that. We do with what we have. Can you pay attention to the quotes please ? Bretton Kent actually argues "based on the available evidences". That's not an opinion, that's what he actually argues, based on actual evidences. He's opened to any new evidences that could change that. I am too. You, I or scientists don't know the exact average in both of these species. Megalodon's average size could be lower than the average size in Livyatan but the largest megalodons specimens could still have exceeded any Livyatan. The intraspecific variations are different between selacians and odontocetes. Sharks grow all their whole life, even if slower at adulthood. Sperm whales individuals don't get larger once fully grown (only their teeth still grow). We can speculate at length with that. I'm not interested into such speculations. Perhaps we'll never found a larger Livyatan or in short, another individual. We do with what we have, we don't establish some average that we virtually don't know, nor on some maximum size that we don't know in one or the other. We use the available data. |
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Post by theropod on Jun 13, 2013 1:24:33 GMT 5
Grey: That's the very reason it is wisest to assume them to be similar in size, considering their size ranges point out to that and we don't have precise data, particularly in Livyatan. What we cannot say at now is that one was larger than the other. "Could", that's the point. What you are doing is entirely speculation, you are speculating that even tough what we have suggest a similar size, C. megalodon was larger, because the largest remains in a sample larger by orders of magnitude are. That's not scientific. And this statement is not contradicting the quote, Kent argues the largest remains are larger. The rest is opinion. If you find a single, saltwater crocodile, it is very likely smaller than a record-sized bull shark or mako. This does by no means mean the species in general is smaller, or the maximum size is. We simply cannot argue something like this without at least having a small sample of Livyatan individuals. Until then they are of approximately equal size, and I think it is not a sign of particular maturity that you are constantly claiming I was not paying attention because I do not agree with you here. Why is it so hard to agree to disagree on this, if you cannot agree with what I say? PS: Exactly. There is the possibility of larger T. rex specimens than Sue. However the probability to find a larger Giganotosaurus is even bigger, since the sample sizes we are talking about are 31 vs 2. These two specimens are at least as large or larger than 31 specimens of T. rex, at both average and maximum. Even if in 31 T. rexes the largest was larger, that won't make it the larger species in general (and that's not the case) if the average is the same and the sample size of one is lower in a way that makes it likely comparable individuals were simply not found.
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Post by Grey on Jun 13, 2013 1:55:20 GMT 5
Based on the available evidences, meg's probably the largest. Kent's words. Mines. Period.
I let you respectfully speculate on anything you want until more stuff (will?) comes.
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Post by elosha11 on Jun 13, 2013 1:57:25 GMT 5
I'm not sure whether it has been mentioned that other physeter teeth have been found that appear similar to those of the Livyatan holotype. Most are mentioned to be significantly smaller than the 36 cm Livyatan holotype teeth, although some alleged 40 centimeter ones do exist. There's really nothing but speculation from these teeth, as we don't know if they all belong to Livyatan species or perhaps to another smaller toothed whale. Likewise, even if they do belong to Livyatan, we don't necessarily know if the smaller ones belonged to average size adults or to juveniles. Likewise, even if the 40 cm teeth exist, we don't know if they necessarily come from a larger, rather than just an older whale than the holotype.
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Post by theropod on Jun 13, 2013 2:03:50 GMT 5
Based on the available evidences, meg's probably the largest OK There is no contradiction here, as I said. The largest remains referred to Carcharocles megalodon are probably indicative of a larger animal than the largest (and only) remains of Livyatan melvillei. As I said, the largest cattle even was also heavier than the largest gaur. @elosha: Yeah, they have been, here and elsewhere. Some time ago i included them, in order to get a higher sample size for livyatan and make comparisons of maximum sizes more objective, btu grey urged me not to do so. I can understand his reasons. therefore I now resort to mean sizes. |
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Post by Grey on Jun 13, 2013 3:00:14 GMT 5
About the 40 cm teeth, you may have missed the recent explanations I had from Lambert on carnivora, why these are not indicative of larger sizes in sperm whales.
Rest my case, to date, as we know, meg was probably larger. I hope more material is published.
And I keep in mind Siversson's suggestions about predatory dominance through time.
Regarding meg's teeth, they are described as more robust than those of the great white, but still with the cutting power. That's actually a combinaison of force and sharpness. This guy can do what a great white cannot respectively with its teeth. There's no point to talk about some compromise. It could slice large balaenopterids dorsal vertebras and caudal vertebras. I never understood this tendency of you to undermine megalodon predatory power in that field. You just have to understand that this is more brutal than a scaled-up white shark. Able to puncture even the thickest bones, with sharp serrations and could be replaced indefinitely, megalodons teeth are not those in great white and carcharodontosaurs.
Livyatan on the other hand of course seems to be a total bone-crusher given the robustness of the jaws and the temporal fossa. Still strange that no evidences of feeding behavior is reported or at least certified.
My whole point is that both can without a problem attack any bones. Only, meg jaws seems (to me) quite more voluminous so able to inflict larger damages, with massive exsanguination.
Can somebody found others pictures of Livyatan's predatory apparatus size compared to men ? I'm not on my PC these days so cannot perform long research.
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Post by theropod on Jun 13, 2013 15:37:55 GMT 5
I am not undermining a creature because I do not think it is an all in one killing machine that excells at everything. This is just not possible for a creature, there is a payoff.
If a tooth could be more robust and retain the same cutting power at the same time, every animal would have the exact same tooth design, since it would be excellent at everything.
I never wrote it was just an upscaled GWS or the same as an aquatic carcharodontosaur. There jsut isn´t anything that suggests it was some sort of bone-crusher and slicer at the same time. It was simply a huge shark with robust theeth whose combined size and slicing power enabled it to target bony regions, and it is wrong to say in this regard it is radically different from other slicers, it merely has a jaw design allowing to slice through most bones effectively. The function is indeed comparable, that doesn´t mean the exact degree of robusticity and efficiency at different tasks is, but as said this is a payoff.
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Post by Grey on Jun 13, 2013 20:06:38 GMT 5
White sharks, large monitors and carnosaurs did not bite through the whole skeleton, skull or vertebral column of large preys. Meg did it. That's the differences. That's why I think you don't pay attention to the informations about it.
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