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Post by theropod on Sept 20, 2013 22:49:55 GMT 5
This is Megalodon size, not Livyatan size. That being said not all adult specimen of a cetacean are or reach the same size (which applies to every animal), even tough mammals stop growth at some point.
Your last point is of course meant as a joke, but accurately it is not "one skeleton" it is "one specimen", which is quite a big difference. Be certain that I already have those facts in mind. It's not as if you never mentioned them before.
It is certainly not unexpected that adults found in a nursery will mainly be females, hence rather on the big side of the population.
And there's only one individual in that location which is that big, the rest are much smaller (which is closer to what can be expected, that smaller individuals will be more numerous because not all make it to each individual's maximum size, of which not all are equally gigantic anyway).
Individuals above 10.5m average 13.3m, so the 17m one is just a big old female that after all also has to reproduce somewhere. Apart from that, I'm certainly not arguing a 17m C. megalodon was all that unusual, but definitely above average.
Animals that grow all their lifes don't always achieve the same potential size. Some, that are lucky, may reach it, the vast majority does not.
Of course C. megalodon didn't completely stop growing. Neither do crocodiles, and yet one hardly refers to a 6m+ giant every time when speaking of a nile, orinoco, saltwater or american crocodile, an Alligator or black caiman. All of these can reportedly reach such sizes, and all of these are usually much smaller. Still, when a lion faces off with a croc, it is rarely if ever a 250kg lion and a 1t suchian.
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Post by Grey on Sept 20, 2013 23:16:42 GMT 5
Not all specimens reach the same size of course but their adult size is more uniform than in sharks and reptiles.
The last point was no joke. That is one unique skeleton specimen. If meg had not been known by teeth before, the logic you used would state this individual was "probably" more in the average specimen, whereas it is obviously not. This simply means that this is not extraordinary to find a potentially large or very large specimen. Keeping in mind the other points, this can be true as well for Livyatan. But I don't suggest Livyatan holotype is a record-breaking specimen, only that it is more likely to be on the upper range than otherwise. Of there was hints of youth traits in the remains, we could without a doubt reasonnably speculate of its maximum size, after all I did it with the MoA.
My point is not to state 17 m was average, my point is that on a few individuals, it is not extraordinary to find a massive individual (if Gottfried is right we talk about a 60 tonnes shark here even though this is debatable as well).
You forget another point : nothing says that the few adults there all represent females. You can notice that the smallest of the adults is in grey zone between juvenile and adult stage and can be as well a young subadult of either gender. The smaller adults could be males at least for some.
You also forget that the classification of lifestages in the paper is directly from Gottfried. The smaller adults do not necessarily correspond in their size to the size range of females in Gottfried. Today you can find adults males sharks in the nurseries as well, though less often than female.
The females could correspond to sexually matures females but not average sized females.
There is a massive gape between sexual maturity, average size and maximum size in lamniforms sharks today. No apply this to meg.
Last point, I recall that depending the regions there seems to be a size variation. I ignore the average size of meg adults teeth from Gatun. Does the 17 m female represents a very large individual in a small-sized population or a not unusually large shark within that population ?
Again, I recall that the tooth representing a 17 m female is, here again, only a tooth lost at one given time, and that the size corresponds to the shark when she lost it, not when she died.
To summarize, megalodon is known by too poor remains and have a too complex and yet misunderstood life story to state that "thus one was above average, this one well above...".
If you want try to establish average sizes, do it by regional and temporal range. This will be always debatable but less complicated.
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Post by Grey on Sept 20, 2013 23:34:39 GMT 5
Theropod, you once said you find more important to state average size.
IMO that's only partially true and hardly predictable for megalodon.
To know its maximum size is more important in the context of macroevolution. Read the mail from Kent earlier, megalodon pushed the size far far above what has been known in macro-predatory sharks earlier. To know its maximum size is important in the trophic implications, biomechanical limits and evolution understanding.
All the meg experts refer to it by sizes of 16, 18 m or more. This is not because this is average, this us because this is representative of its unique evolution, no other shark was ever comparable and it is actually odd that it grew potentially so large.
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Post by Deleted on Sept 20, 2013 23:44:12 GMT 5
Does the 17 m female represents a very large individual in a small-sized population or a not unusually large shark within that population ? Again, I recall that the tooth representing a 17 m female is, here again, only a tooth lost at one given time, and that the size corresponds to the shark when she lost it, not when she died. How do you find out the gender of a shark through it's teeth. |
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Post by Grey on Sept 20, 2013 23:51:18 GMT 5
Does the 17 m female represents a very large individual in a small-sized population or a not unusually large shark within that population ? Again, I recall that the tooth representing a 17 m female is, here again, only a tooth lost at one given time, and that the size corresponds to the shark when she lost it, not when she died. How do you find out the gender of a shark through it's teeth. That's tricky but basically the largest teeth belong normally to females (but in some cases can come from males, see the GWS Apache). In nurseries, you can expect that most of the adults teeth are from females, but not all since males also frequent these areas. Except of these assumptions, this is impossible to know for sure. |
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Post by Deleted on Sept 20, 2013 23:56:27 GMT 5
How do you find out the gender of a shark through it's teeth. That's tricky but basically the largest teeth belong normally to females (but in some cases can come from males, see the GWS Apache). In nurseries, you can expect that most of the adults teeth are from females, but not all since males also frequent these areas. Except of these assumptions, this is impossible to know for sure. So based on only presumptions based on holocene sharks then? Since this is impossible to really prove and very large teeth can also come from males, then the safest way would be to not attach any presumed gender to any megalodon specimen, unless proven otherwise. |
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Post by Grey on Sept 21, 2013 0:16:54 GMT 5
That's a matter of probability, in all sharks females are larger so...
But old males rivaling some females exist.
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Post by theropod on Sept 21, 2013 0:22:00 GMT 5
Not all specimens will reach the same size in sharks or reptiles either, even if you let them grow until they die of old age.
Of course variation among mature individuals is greater in a species that does not stop growing. But the average size will still give a better idea of a species' comparative size than the maximum, since the maximum is almost certainly a very big specimen. I'm not saying maximum sizes, or limits which were likely exceeded by it, are not important as well.
I'm saying this for the objectivity of interspecific comparisons. Of course I'd far prefer to have better data, and I won't simplistically rely on some approximate figure that is the likely average of the population considered adult, for comparisons.
The problem this causes is, that you cannot properly compare this species to others with different ontogenies. To come back to the point you adressed earlier, you thus cannot say it was bigger than, for example, Livyatan, that is likely well within the size range of adults. How are we going to compare it? In cases of doubt, we have to remain doubtful (i.e. we have to consider all possibilities created by their similar sizes), instead of making a statement about it.
Do you have any data how much of the variation in mature C. megalodon is growth-related, and how much just individual variation? The second usually has very big impact by itself, and in many species it could already account for the degree of variation
Without such data, we can only speak in probabilities. It is relatively certain not every megalodon would have reached 17m had it grown to it' s absolute maximum. It is quite certain every one would have exceeded 11.5m-to what extend is not clear and it's going to be variable, but truly big specimens are gonna be increasingly uncommon.
We can only say the population's mean will probably reflect the species' average better than it's maximum will.
Yes, but fact is, we do have many other specimens to see this happens to be a large one.
The example of Alamosaurus impressively demonstrates how first specimens can as well be particularly small and produce tremendous underestimates. The best is to assume the middle ground between those extremes.
That's not what I suggest. Nevertheless the probability is greater that such a specimen is an average one, and the most objective assumption is that it is neither a particularly large nor a particularly small one.
But by the same logic it could be true just as well that it was a small specimen (variation among adult physeter for example is still considerable, VERY considerable.)
What I cannot see is why this should be the case. It can jsut as well be at the lower end as at the upper end, neither is more likely than the other.
I did too and more and more I think that was just as pointless.
No not that extraordinary, there's a rough 1/6 chance in the sample from the nursery. That's not at all in disagreement with what I'm saying.
Do you mean UF 245852? we can exclude it if you want, but the result will not be massively different. An 11m individual would probably rather be there to give birth than because it hadn't left yet.
Some may have been males (how big is the percentage of males in nurseries of lamniforms? above 17%), this is not important. It is about the approximate size. Perhaps the 17m one was a freakish male, perhaps a 9m one was a freakish dwarf of one.
In the end, the Nursery probably won't be very useful for proving anything.
Of course you could also simply apply the rations seen in Great whites, but that includes the problematic that maximum sizes among the two are not compatible...
We cannot tell, but it isn't wise to rely on one single sample for all our conclusions anyway.
Yes, probably. But the teeth we find represent the population of sharks you would encounter back then, those of individuals >10m will probably represent ecologically adult specimens.
Well, then take this as the approximate average size thus far known from the regions examined.
Nobody is denying maximum size can be relevant, but without concrete data on it, and with even less on it in most others, average can be more relevant for comparisons. Nowhere am I saying you should not use maximum size when making clear what it is, and to make clear what sizes a species is known to reach. You just cannot put that figure on one step with that of various other animals, depending on the amount of known specimens.
The points you make about the extraordinary maximum size in C. megalodon can also be applied to it's extraordinary average size, which after all probably well exceeded 40t and thus dwarfs any extant Selachian even at it's maximum size.
btw I just noticed there's a regression equation for Great whites on page 15 of the most recent paper I posted on the standard-works-thread (that GWS Symposium you already know). You might wanna check it out, if I did it correctly it gives very Siverssonesque figures. The weight thing is very diffifult.
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Post by Grey on Sept 21, 2013 2:38:23 GMT 5
I don't know if you don't understand or ignore my posts but I get REALLY tired of repeat myself.
For the first part, again, in two species in which we don't know average sizes and we cannot reasonably know, in two species were average size means something different, one species being more uniform than the other, in two species with a complex and unknown life history, you cannot expect to get a reasonable idea of average size.
Megalodon and Livyatan : perhaps the former was on average smaller but in absolute terms the shark could reach larger sizes (as suggested by fossil records to now).
So in absolute terms, I give the upper hand to the largest known.
But we don't KNOW the average size of megalodon for all the reasons I've reported earlier. And we don't even know the exact size of the Livyatan holotype.
So move on. You can compare megs individuals with Livyatan holotype, you can loosely try to make regional and temporal average size range for meg then compare with Livyatan holotype (and its uncertain size). But that's all. Everything else is speculative hogwash.
Without such data, we can only speak in probabilities. It is relatively certain not every megalodon would have reached 17m had it grown to it' s absolute maximum. It is quite certain every one would have exceeded 11.5m-to what extend is not clear and it's going to be variable, but truly big specimens are gonna be increasingly uncommon.
Like in any species but AGAIN in some regions, megs appear larger than in others so your statement has a limited reach.
One explanation also is that Miocene and Pliocene seas were potentially dangerous even for a 10-15 m megatooth, hence fewer specimens got old and larger.
We can only say the population's mean will probably reflect the species' average better than it's maximum will.
You've ignored my very last mail...or you have no consideration for my posts, specialists infos and research, as always I must say.
That's not what I suggest. Nevertheless the probability is greater that such a specimen is an average one, and the most objective assumption is that it is neither a particularly large nor a particularly small one
Ignoring again all the points mentioned above which explains why Livyatan type is potentially a large one. But you don't want to accept that. You're absolutely unable to at least accept these probabilities.
Yes, but fact is, we do have many other specimens to see this happens to be a large one.
But if we have not, this just shows your logic has limited value, a first specimen can be on the upper end.
The first Stegosaurus were very larger than the more recently found. There's no certainty in what you argue.
Liv type can be an average but there's nothing indicating this and the few points I've listed suggest it could be a quite large specimen.
The example of Alamosaurus impressively demonstrates how first specimens can as well be particularly small and produce tremendous underestimates. The best is to assume the middle ground between those extremes.
No the best is to avoid crappy speculations and check real and reliable facts on a rational basis, not assumptions.
But by the same logic it could be true just as well that it was a small specimen (variation among adult physeter for example is still considerable, VERY considerable.)
Among full grown specimens ? No, there is variation but they are far more uniform in size than sharks. You have in mind the sizes datas of killed sperm whales.
Do you mean UF 245852? we can exclude it if you want, but the result will not be massively different. An 11m individual would probably rather be there to give birth than because it hadn't left yet.
Oh, you know the exact biology and sexual history of megalodon now ? No we don't know, it can be a sexually mature individual still living in the area or a very small just mature female. We don't know.
Well, then take this as the approximate average size thus far known from the regions examined.
No you do, you're the one thinking he can establish average sizes in extinct species.
I'm fairly or more, less agreed with the parts I've not quoted.
For the last part, I rely on the largest sizes we know a species to have reached, period. Average cannot be precisely known in the huge absence of determining datas like those I've listed. So to quote Siversson, it is likely but not demonstrated beyond all doubt that megalodon grew larger than Livyatan. Nothing to add.
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Post by theropod on Sept 21, 2013 16:57:27 GMT 5
Just what is it that makes you think we knew the maximum sizes any better? Also, where is the evidence for lamniforms being more variable than Physeteroids? Physeter males are typically about 30-50% longer than females, and the males themself show huge variation, the largest, as in all species, being rare. Up to now the fossil record does not suggest anything like this, we simply cannot know. Based on great white sharks, a specimen maturing at 10.5m would be fully grown at about 13.5m, with a big deal of variation of course. No, not all in our sample will have already attained maximum size, and some smaller ones that already have may not have been included, but even sharks that have will still loose teeth (and if they do, do so over a relatively long period of time), and individual variation accounts for a large part of the variation. Are you suggesting the sample from here reflects small megalodons? All those points are points in favour of it being an ADULT one, but adult sperm whales can vary from ~12 to ~20m. I accept them as possibilities, not probabilities. You aren't able to accept the probabilities I give you, so why are you telling me that? Just like it can be on the lower. All considerations have limited value, including (especially) using maximum size. Have I claimed anything in that direction? Few things un palaeontology are certainties, many are hypotheses, theories or probabilities. The rule we have to stick to is to always take the best we have. You cannot even tell whether it's a male, that's merely the more probable at it's upper end of estimates because if it was a female this would either suggest atypical sexual dimorphism or males perhaps too titanic to be probable. It's an adult, that's all, we have neither reason to suspect it was particularly small nor that it was particularly large. Which is what I'm doing, the crappy speculation is that any single specimen should be assumed to represent the upper size limit. I do. But you act as if you did, instead of assuming what's more probable. Because we can unless a species has too few fossils known, and even when there are prolems we cannot just ignore it and treat maximum like average. I've got something to add. You basically repeated this point over and over again. Without demonstrating why it should be likely beyond the point of being a possibility just like the other way around. You have to understand my point, a single individual is not representative of a species maximum size. A single caught orca will likely not be 10m in lenght, a single caught sperm whale not 18m, and a single caught great white not 6m-that's not probable, albeit not completely impossible, and that applies to every species of course. You see, I've got absolutely no problem accepting C. megalodon is a bigger species than Genus X species y, but this has to be demonstrated based on objective data, not concluded from the fact that in a sample of thousands there are individuals larger than a single specimen. This single specimen for now has the probability 1/1, while a 16m+ C. megalodon definitely doesn't. Future findings may change this in either direction, which one remains to be seen. Perhaps our single specimen of Livyatan turns out to be a large one, perhaps it turns out to be a small one. No data exist that favour either. The same for C. megalodon. Perhaps what we can assume about it's size range and mean size turns out to be too low, or too high. |
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Post by Grey on Sept 21, 2013 20:58:30 GMT 5
Because research has for now only focused on :
-maximum size in the species
-individual sizes
Both results are subject to uncertainties, but average is even more complicated.
No mention or test to predict average size. Perhaps because that's impossible to know at now like I repeat since months.
Regarding sperm whales , I OF COURSE separate males and females. In lamniforms I separate too genders. Yes, lamniforms appear less uniform than mammals at adult size just looking at datas.
Megalodon was probably, not certainly, larger than Livyatan at maximum modern ranges. I've posted enough support about that.
At first, don't forget that's "based on great white sharks" Gottfried works. But we do know that meg was no great white or lamnid. So that's already very doubtful.
Fully grown at 13.5 m ? Fully grown means that does not grow anymore or almost. Don't understand the remaining of the sentence.
I talk about full grown sperm whales in separate gender, not adults sperm whales above sexual maturity. Livyatan is not a sperm whale that is dead prematuraly killed by a whaleship, it achieved its life. These points are valid. And I'm gonna to confirm this.
I accept your possibilites, I talk about possible probabilities. You really consider yourself the authority around to exchange my terms with yours ! Really, that's very antipathic.
No argument here, you just say the contrary of me.
All my listed points VS your speculation ("the first is an average that's sure !").
So you are telling yourself it's a male but reproach to me to suggest it's a male.
Or it could be a 14-15 m old female, and that in Livyatan sexual dimorphism could be less pronounced than in Physeter, so males would be larger but not as much as in Physeter. I recall you that this dimorphism is unique to Physeter.
But yeah, that's more likely a male. BUT that's speculation at now, based on assumptions, which does not interest me a lot. I like datas, not speculations contrary to you.
Any single specimen should be assumed to represent the upper known size limit. Known data.
And you're wrong because datas sizes of killed sperm whales do not correspond to a Livyatan that had achieved its total size and was probably not dead prematurely. A 12 m male Physeter is obviously not full grown. Livyatan was full grown.
No I don't claim I know it ! That's even my main argument since a while, WE DON'T KNOW MEG EXACT BIOLOGY. We don't know the exact variations, the exact size, the exact growth curve.... You're always ignoring these important factors, you oversimplify.
What I suggest is more probable.
No you absolutely can't, paleontologists can't. You have really lacked of modesty as a wannabe paleo. Like you said, there are few definitive facts in paleontology so stop you speculations and think you can do things nobody else can do. No one here treats maximum like average.
Your last part is, contrary to the rest of your post, interesting. What you say is right, only, the result of this, based on what we know at now, is that megalodon (I repeat, based on what we know at now) is probably larger (with no absolute certainty) than Livyatan. I mean I have enough discussions with authorities that support this likelihood.
Now you have to understand that you're unable to convince me and you certainly won't convince me, I just totally dislike your view of paleontology. Let's agreed to disagree. If you want that Livyatan was at 13.5-17.5 m more likely an average and that megalodon was 13.5 m on average, then believe it but don't even come discuss with me on these matters. I recall that my post was originally destinated coherentsheaf.
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Post by theropod on Sept 21, 2013 22:33:22 GMT 5
I disagree. Research has focused only on individual sizes, which of course includes the sizes of the biggest known individuals.
Btw specialists can also speak about average sizes in a certain context, how else can you explain Zhuchengtyrannus (Hone et al., 2011) is considered
When it is only 75% the linear dimensions of FMNH PR 2081 (!=9m), and even when based on the small-skulled CM at best 92%? Not really in any way comparable to the maximum known size of T. rex, is it?
I don't see what that has to do with what I wrote.
So far, I haven't seen those data.
That works in either direction. You use the "very doubful" point as if it only strenghtened your point, but it does not. In fact, it doesn't change anything. There are no facts here, and not being a fact does not make a conclusion worthless.
Yes, assuming the shark matures and grows like a great white, a shark that matures at 10,5m should stop growing at 13.5m, of course with a huge scope of variation.
So the sperm whales you see reported are all imamture?
There is a difference between possible and probable. It's possible there were 30m Megalodon or Livyatan specimens. Does that make it probable?
It is probable a monotypic species is known rather by it's average size than it's maximum or minimum size. It is possible that is not the case sometimes.
If you don't comprehend my posts, I cannot help you.
No, you are willingly not considering the logic. Your claim is that it was probable it was a large specimen. Based on what? based on indications that it was an adult. But an adult specimen can be either female or male, and of either either a large or a small specimen. You happen not to know which is the case, but automatically assume something as the most probable, while obviously the most probable is that it is an average-sized specimen.
Not necessarily. one could argue that at 16-17,5m it's probably a not a female if males were significantly larger than females. Exactly. But previously, you have been acting as if there were data suggesting it was a large specimen...
The upper known size limit then has little to do with the actual size limit of the species.
Livyatan undoubtedly was full grown. But so is a 12m sperm whale female, and for all we know, Livyatan could be a female just as well as a male, it's osteology doesn't tell us anything on that point if I'm not mistaken.
I do not, so could you please take a few seconds to actually look at what I'm arguing?
That any isolated specimen automatically represents the maximum size of the species....
Oh yes, you do. You even bash on people who don't.
My last point is my only point, you'd just have to read the rest carefully enough to see what it means...
Discussions with authorities are fine, but they are not an unchallengeable truth, they are speculations, the same that you are doing. and saying which one was larger involves for them to make a guess on average size.
You have to have another look at what you answered to me the last time I told you you wouldn't convince me...
This is a discussion forum, you cannot complain about somebody actually discussing here. I have also argued nearly the same as coherentsheaf did, you just didn't want to assume that.
You have to understand that just misconstructing everything into something like the above ("Livyatan 13.5m-17.5m on average and megalodon 13.5m...") will not help you discuss things. You very well know all I argued is that adult C. megalodon (ones at or pretty close to their maximum size) most likely would have averaged ~14.5m (of course, with a good degree of variation depending on the region, and for the whole species), since that's what all the data I gave you suggest. I am fairly confident Livyatan has a comparable average size, that's all.
It is very well possible this is wrong, it may even be probable, but on it's own this is the most probable to assume at now.
Yes, thank you.
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Post by Deleted on Sept 21, 2013 22:59:45 GMT 5
Any single specimen should be assumed to represent the upper known size limit. Known data. It also should be assumed to represent the lower known size limit as well, since there is no known smaller specimens. Thus, it simultaneusly is both the largest and smallest known specimen, which can get quite problematic in comparisons. The thing with taxa known from single specimens is that the one size it has represents all the known maximum, minimum, and average, all in one figure, and there comes the dilemma of comparing it to taxa known from multiple specimens. To be safe, compare the single figure to the maximum and minimum, and average too if average size is applicable. Two or three scenarios. If a range is proposed for the single specimen: Compare upper bound to to maximum sizes Compare the average between the upper and lower bounds, to the average of a species, if applicable Compare lower bound to minimum adult sizes Feel free to disagree, but this is what I feel is the safest way. I don't think average is applicable for megalodon, because most known material we have of it are nothing more than teeth. I tend towards the ~13.5 meter figure for Livyatan btw. |
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Post by Grey on Sept 22, 2013 1:43:06 GMT 5
On individual sizes, and among these individuals the largest represent the largest size known or estimated for the species.
Your quote of Zhuchengtyrannus talks about the size range, not any specific average size for Tyrannosaurus and Tarbosaurus. They say it enters the size range of others large tyrannosaurids. Like Kent's chapter where he says that the Cetorhinus and Rhincodon are comparable to megalodon in size. He does not say they can reach the upper sizes of meg (though for Rhincodon it's debatable), he does not say they are equal to the average size of megalodon, he says the enter the size range known or estimated for megalodon.
I don't compare the size range in very sexually dimorphic species with an animal known by a single specimen plausibly representing a male. So I separate genders. Livyatan is, in the paper, stated in the size range of adult bull Physeter. So compare it with the size range of bulls, not cows.
I won't do it for you (size of mature female GW, size of average female GW and maximum size of female GW= proportionally larger variation than in adult full grown bull Physeter).
If meg biology and life history appears to have significant difference with the white shark, your basis on Gottfried works becomes potentially worthless.
Stop growing at 13.5 m ? That's odd then that several sizes estimates based on this table from Gottfried yeilds sharks at 15.9 m, 17 m and perhaps 20.3 m...
And whatever, meg is not a white shark.
The sperm whales reported were all mature but possibly not all fully grown as they were killed and not animals that achieved their life the Livyatan holotype.
At first, it is almost impossible that 30 m, 200 tonnes active macro-predators lived in the Earth trophic systems. This kind of figures is for SF amateurs and kids.
Because of the points I've listed it is just as probable it was quite large individual as this represents an average individual.
Livyatan type could be an average specimen but as well it could be a large one because of the points. Based on indications that it was an adult which achieved its life. based on the total absence of isolated material pointing toward larger specimens.
But I don't have much faith either in you average or large range. Because we simply don't know.
Well, that's just what I wrote. But at 13.5 m it could also represent a female. But again, I'm not interested in these meaningless speculations.
No, I've highlighted you the points that could also make think it was more in the higher range of its species. I've not argued anything about Livyatan size status. That's your job.
I always discuss what we know, not what we don't know, contrary to you.
To now, the larger individual known represents the known size limit for the species, until update.
So you start speculating it was a female with the same sexual dimorphism than in Physeter ? In the goal to speculate about +20 m Livyatan in your next step ?
And that's curious how you use the particular biology of Physeter (unique huge sexual dimorphism) or reject it in other occasions (template as size/proportions).
If so, you're really not objective.
You do. You argue to know the average size of megalodon. But actually no one knows.
Maximum size known.
An update of mine, I don't say it is more likely to be a large individual than an average one, but that the probabilities are similar.
Have I said a 18 m meg is average sized ? Have I said Livyatan was average sized ? No, we don't know the intraspecific variations. Period.
The points by Siversson, Kent and others I've talked with are not speculation but observations on the extant datas. Observations that I had made myself before discussing with them.
And as for speculations, between Kent's speculations and theropod speculations, there's indeed a hierarchy. Sorry, but I'll always favor the guess of these guys over your. And frankly if you really become paleontologist, I hope you'll improve your observations skills and objectivity and forget your beloved speculations.
Actually you can convince me on some matters where NO SPECULATION is involved, like the actual scientific measurement of sharks teeth (I guess you're proud of that case).
But I cannot convince you of anything, you have a gigantic ego and really think to have superior skills in any paleontological field. That's why I don't feel any pleasure discussing with you.
Nearly is quite a difference. And I much more appreciate to discuss with coherentsheaf, despite we sometimes share opposed views, than with you, you should wonder why.
Between us, I don't like read you. That's no offense, that's my tastes, the structure of your posts is not appealing to read IMO. And I don't appreciate how you regard paleontology and your overenthusiasm, typical of the psyche of a teen male (bigger, bigger, bigger...). That's at least what I feel reading you since a while.
That's your opinion and I'm fairly sure it is most likely wrong because you ignore the contradicting factors I've listed in both cases.
Here is a speculative statement : Livyatan has a comparable average size to megalodon.
Here is an actual scientific statement : Livyatan is in the size range of adult megalodon.
Think about the difference.
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Post by Grey on Sept 22, 2013 1:45:13 GMT 5
Any single specimen should be assumed to represent the upper known size limit. Known data. It also should be assumed to represent the lower known size limit as well, since there is no known smaller specimens. Thus, it simultaneusly is both the largest and smallest known specimen, which can get quite problematic in comparisons. The thing with taxa known from single specimens is that the one size it has represents all the known maximum, minimum, and average, all in one figure, and there comes the dilemma of comparing it to taxa known from multiple specimens. To be safe, compare the single figure to the maximum and minimum, and average too if average size is applicable. Two or three scenarios. If a range is proposed for the single specimen: Compare upper bound to to maximum sizes Compare the average between the upper and lower bounds, to the average of a species, if applicable Compare lower bound to minimum adult sizes Feel free to disagree, but this is what I feel is the safest way. I don't think average is applicable for megalodon, because most known material we have of it are nothing more than teeth. I tend towards the ~13.5 meter figure for Livyatan btw. The lower known size limit yes and no at the same time, because if we know that Livyatan reached 13.5-17.5 m, we also know that it reached smaller sizes than this. I would have nothing against a depiction of an 11-12 m Livyatan in a drawing or so, if this is precised this does not correspond to the maximum size/to an adult Livyatan. I prefer to compare Livyatan specimen with notable megs specimens individually, not to loosely calculate an average range because of all the uncertainties for the already proposed figures and the various factors I've listed above. I don't tend toward any of the proposed figures for Livyatan but I know that some paleontologists I've talked with considers 13.5-14 m to be the most probable size. |
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