Size comparison scale

[Fragillimus335]

Here is what I am trying to get at Grey. You find it completely reasonable to use a scientists work to extrapolate the size of a 100 ton shark. If you were to stumble on a 9 inch long Meg tooth, you could surly plug it into their formula, and get a somewhat defendable answer. I am doing the same for Amphicoelias. Carpenter made clear that he scaled it directly from Diplodocus, and guess what, when you do that, the animal comes out to be ~75 meters log and close to 250 tons. Just because the numbers are high doesn't mean more speculation is inherent. Also, being young doesn't disqualify a person from providing reasonable information.

By the way, the guys on SV-POW DO think 200+ ton sauropods are very possible, so that argument is out the door.

[Grey]

Wait a minute, I don't try to get a 100 tons shark with their methodology. I am not on the task to found the "bigger the better" with megalodon, take a look to the appropriate thread about its size issue.

No, Matt Weddel strictly responded to you (or your troll on SVPOW)about these suggestions and speculations. Do I need to quote him ?

1. You’re using simple scaling, and ignoring the near-certainty of allometry. For example, maybe in bigger sauropods the dorsal vertebrae are larger, proportional to body size, than in smaller sauropods. That would fit with what we know about sauropod vertebrae in general (i.e., they are larger in diameter, relative to body size, than the vertebrae of most non-sauropods), and with what we know about pneumaticity (i.e., it allows the animal to get more bone “outside” the air space–see for example this figure from the paper we published today). So although it’s untested, in that no one has gone and looked at how dorsal vertebra size scales across sauropods, either ontogenetically or phylogenetically, the likelihood that Amphicoelias was just a simple scale-up of something Diplodocus or even A. altus is pretty darned low. After all, Europasaurus is not just a perfect miniature of Giraffatitan or Brachiosaurus–precisely because of the problem of relative growth, which D’Arcy Thompson was writing about 96 years ago.

None of that means that the simple scaling-up is wrong. It means that itÂ’s untrustworthy, for a host of biological reasons that we are familiar with but you are either ignorant of or are choosing to ignore.

2. You’re only looking at the max possible size. If you don’t also look at the minimum possible size, you’re doing what we call “counting the hits and ignoring the misses”. In other words, you’re not doing science, you’re just arbitrarily picking the most exciting number and going with it. Don’t be surprised if practicing scientists first try to point this out gently, but then treat you like a child when you choose to ignore them.

3. YouÂ’re being a jerk. YouÂ’re acting like all of this is stuff that weÂ’ve never considered before, like weÂ’re a bunch of hidebound, blinkered ivory tower doofuses who are just out to rain on your parade. When in fact we have very good reasons for being skeptical of the numbers youÂ’re throwing around, because you keep insisting on mixing bad biology (point 1) with bad math (point 2).

Mike Taylor has argued that 200 tons super giants individuals of A. fragillimus are possible to have existed, hence blue-whale sized sauropods. He doesn't, and no one, has argued about + 200 tons sauropods in SV POW.

Zach Armstrong has made clear that the upper he argued (+150 tons, not +200 tons) is only a possibility, on the same level that the conservative maximum figure (49 m, 90 tons) are just as possible.

So no, I don't want engage a battle with you, but you're not honest about the actual belief there.

And my personnal research about C. megalodon (which is summarized in discussions with authors, not half-beaked speculations) has nothing to do with A. fragillimus. Megalodon is known by very umerous adult teeth and several methodology. These methods have all resulted in sizes estimate 11-20 m TL. There is some consensus that megalodon reached 16-18 m, and I use this the most often when discussing it. I'm not trying to establish sizes clearly exceeding the 20 m mark as a fact. I don't use 100 tons as a fact for megalodon. I like the possibility and occasionnaly use it when talking about upper sized comparisons but actually I don't have much faith in it, without strictly reject it.

Megalodon is known by thousands of various teeth. Amphicoelias is known by a single vertebra lost 132 years ago...See the difference ?

That's what you're doing with Amphicoelias. The 70 m, 250 tons figure is an enthusiastic and optimistic prediction and it is not hinted in SV POW. Sorry but if you argue otherwise, you're not honest.

[theropod]

But you are hinting them quite frequently, the same can be done with Amphicoelias then.

As I see it, there is no problem here if we all accept estimates as what they are. C. megalodon is, after all, a giant shark known only from teeth, the largest of which we are talking about here, and some understudied centra. Amphicoelias is a giant sauropod somewhere in Diplodocoidea known from a partial neural arch. Now we are talking about this under the premise that Cope did not make his sauropod up, otherwise it all is pointless.

Both based on metods published in academic papers or at least supported by Grey's contacts attain enourmous maximum sizes. In Amphicoelias' case, isometric scaling the way Carpenter did indicates an animal 70m long.
In Megalodon's case, using the largest teeth with various methods yields max sizes of 18-21m, possibly approaching 100t.
Note that isometric scaling may be more conservative than allometric metods (seen in some of C. megalodon's estimates).

I don't see what exactly makes one better than the other. We can discuss both.

What exactly the experts state about the uncertainities involved is not relevant to the results, it just shows they must not be taken as facts

The punchline is “when you extrapolate the mass of an extinct animal of uncertain affinities from a 132-year-old figure of a partial bone which has not been seen in more than a century, you need to recognise that the error-bars are massive and anything resembling certainty is way misplaced.”

And really, isn't there some way to move posts? I remember on Carnivora that was done from time to time. Would help keep this thread tidy and clear...

[Grey]

There is no parallel with megalodon research which is known by thousand of teeth.

Hinting a possible 18-20 m TL for an extinct lamnid, figures suspected in several works, based on the possibility to use several methods on different teeth is one thing.

Hinting a 70 m, 250 tons sauropod, based on a partial bone lost a long back ago, with a long list of uncertainties and factors and the virtual impossibility to dig further is another thing. Sizes only somewhat discussed. I ask to anybody to bring me the quote of one of the guys on SVPOW talking about 250 tons animals.


I don't even hint on 100 tons body mass for megalodon, only when quoting the maximum size used in litterature, which does not mean I full trust it.

Megalodon itself is full of uncertainties, still the material is far more concrete.

No, I'm totally bored by this kind of discussions with over-enthusiastis self-made speculations and just unreasonnable over-optimistic estimates about animals long gone from which we have just no material.

Enough.

[Fragillimus335]

May 26, 2013 21:16:28 GMT 5 Grey said:

Wait a minute, I don't try to get a 100 tons shark with their methodology. I am not on the task to found the "bigger the better" with megalodon, take a look to the appropriate thread about its size issue.

No, Matt Weddel strictly responded to you (or your troll on SVPOW)about these suggestions and speculations. Do I need to quote him ?

1. You’re using simple scaling, and ignoring the near-certainty of allometry. For example, maybe in bigger sauropods the dorsal vertebrae are larger, proportional to body size, than in smaller sauropods. That would fit with what we know about sauropod vertebrae in general (i.e., they are larger in diameter, relative to body size, than the vertebrae of most non-sauropods), and with what we know about pneumaticity (i.e., it allows the animal to get more bone “outside” the air space–see for example this figure from the paper we published today). So although it’s untested, in that no one has gone and looked at how dorsal vertebra size scales across sauropods, either ontogenetically or phylogenetically, the likelihood that Amphicoelias was just a simple scale-up of something Diplodocus or even A. altus is pretty darned low. After all, Europasaurus is not just a perfect miniature of Giraffatitan or Brachiosaurus–precisely because of the problem of relative growth, which D’Arcy Thompson was writing about 96 years ago.

None of that means that the simple scaling-up is wrong. It means that itÂ’s untrustworthy, for a host of biological reasons that we are familiar with but you are either ignorant of or are choosing to ignore.

2. You’re only looking at the max possible size. If you don’t also look at the minimum possible size, you’re doing what we call “counting the hits and ignoring the misses”. In other words, you’re not doing science, you’re just arbitrarily picking the most exciting number and going with it. Don’t be surprised if practicing scientists first try to point this out gently, but then treat you like a child when you choose to ignore them.

3. YouÂ’re being a jerk. YouÂ’re acting like all of this is stuff that weÂ’ve never considered before, like weÂ’re a bunch of hidebound, blinkered ivory tower doofuses who are just out to rain on your parade. When in fact we have very good reasons for being skeptical of the numbers youÂ’re throwing around, because you keep insisting on mixing bad biology (point 1) with bad math (point 2).

Mike Taylor has argued that 200 tons super giants individuals of A. fragillimus are possible to have existed, hence blue-whale sized sauropods. He doesn't, and no one, has argued about + 200 tons sauropods in SV POW.

Zach Armstrong has made clear that the upper he argued (+150 tons, not +200 tons) is only a possibility, on the same level that the conservative maximum figure (49 m, 90 tons) are just as possible.

So no, I don't want engage a battle with you, but you're not honest about the actual belief there.

And my personnal research about C. megalodon (which is summarized in discussions with authors, not half-beaked speculations) has nothing to do with A. fragillimus. Megalodon is known by very umerous adult teeth and several methodology. These methods have all resulted in sizes estimate 11-20 m TL. There is some consensus that megalodon reached 16-18 m, and I use this the most often when discussing it. I'm not trying to establish sizes clearly exceeding the 20 m mark as a fact. I don't use 100 tons as a fact for megalodon. I like the possibility and occasionnaly use it when talking about upper sized comparisons but actually I don't have much faith in it, without strictly reject it.

Megalodon is known by thousands of various teeth. Amphicoelias is known by a single vertebra lost 132 years ago...See the difference ?

That's what you're doing with Amphicoelias. The 70 m, 250 tons figure is an enthusiastic and optimistic prediction and it is not hinted in SV POW. Sorry but if you argue otherwise, you're not honest.

Well here's our problem, first of all, that is a troll, not me. Also, I DO acknowledge that these are highly imprecise and very possibly wrong estimates, but they are still possible. The scientific rigor/material needed to publish this kind of work in a paper is currently not available. I AM NOT SAYING THIS IS HOW BIG AMPHICOELIAS MUST BE, just that is a very possible end point given Carpenter's basic assumptions. Every diplodocid sauropod with vertebra like Amphicoelias would be over 150t if they had dorsals 2.7 meters tall.

[Grey]

Here we start to be agreed. That's not a very possible point, that's a possibility no more likely than others.

I was only annoyed by your manner to claim this as a factual or a very likely factual thought, when that's not.

That's the reason why I don't appreciate your comparison scale, no offense, because I don't think it represents the most likely reality of these species.

I know it was your troll but frankly, given the enthusiasm in respective posts, I tell you I have my doubts. And the writing style is really similar. Anyway, I don't accept 200 tons sauropods as a factual data, and absolutely not at 250 tons.

[theropod]

I think then we also can agree that Balaenoptera musculus being the largest animal known is no fact but a more cautious assumption.

[Grey]

If we assume that not everything has been found, yes. But that's common knowledge.

[Grey]

Not accurate but not totally unreasonnable either in some ways depending the animal, a comparison chart in the Jurassic Park style that I like very much for the graphics and at last place giants theropods alongside giants sea reptiles. Makes me wonder if mosasaurines and perhaps tylosaurines were the largest mesozoïc predators after all, reminiscent of McHenry's paper,...

[theropod]

The proportions are wrong in some, but a nice style for the drawings.

[Grey]

Kronosaurus




Carcharocles







I like these giant living ancients monsters... That's maybe not scientific but in human psyche they are close to the supreme monsters our mind can conceive.

But reastically in my opinion, of the two, Kronosaurus would certainly have been more dangerous to humans (divers, swimmers...) than Carcharocles.


By the way, is the skull of the Harvard Kronosaurus still accurate, I don't remember...?

[Fragillimus335]

My current best guess for Amphicoelias's size. ~80 meters long and ~245 tons. The scale bar is 4 meters. As you can see, the 2.7 meter vertebra fits pretty well in a 75-80 meter body.

[Grey]

I think we're looking at scientifical, rigorous scales here, no personnal best guess.

[Fragillimus335]

May 31, 2013 5:08:44 GMT 5 Grey said:

I think we're looking at scientifical, rigorous scales here, no personnal best guess.

Try fitting that vertebra into anything much smaller.

Every step of this estimate is defensible, please tell me which part you disagree with. I know it is speculation, but it is perfectly scientific speculation.

[Fragillimus335]

Mawsonia was VERY big! This is the largest specimen, at 6.3 meters long, along with a big Great white shark, a Bawitius, and a Neoceratodus.