Largest sauropods

[theropod]

[quote author="Supercommunist" source="/post/1269/thread" timestamp="1369618888How would a hypothetical twelve ton animal kill an eighty ton one?
[/quote]
Not one, but if there´s more than one. Intelligence is a difficult matter, but I think carnosaurs were able to hunt cooperatively or at least attack synchronised in a croc-like manner.

Being a two hundred ton animal rather than a fifty ton one wouldn't radically increase the survival rate of their offspring if at all.

A 200t animal could produce bigger eggs and larger offspring. Or the young might just grow faster and longer.
As I said, a 200t Sauropod could be a very old specimen that survived longer than average.

Being bigger holds advantages even at extreme sizes. Or why are Blue Whales that large? To them it should pose just as much trouble, considering the surface their mouth can cover gets proportionally smaller.

Perhaps because they often swim through chilly waters and a larger mass helps insulate them? Also it is arguably more vulnerable to orcas than sauropods to giant theropods, since not only would they be better coordinated then large theropodic predators (if they did indeed hunt in packs anyway), but also because they are underwater hunters and thus are able to attack other exposed areas of a whale that ground dwelling predators would never be able exploit on a sauropod. Directly above for example.

[/quote]
Hmm, good points. on the other hand orcas have´conical teeth and limited gapes, not ideal for macropredation on animals many times bigger. The dentition and jaws of carnosaurs would have been more of a threath. and from my conversations with Grey and others, it appeared O. orca avoids attacking fully grown Blue whales.

[creature386]

May 27, 2013 2:19:02 GMT 5 Grey said:

Have you a source for this creature386 ?

I remember having read something like that on wikipedia once. I think I confused something.

[Grey]

Anyway, for me, until something substantial is found, there was no 200 tons sauropods. I accept the possible existence of 150 tons sauropod because of the possible range in A. fragillimus, but it could have been also 90 tons. That's what I retain from the guys of SV POW.

And damn ! Even if it was 90 tons, some enthusiasts still wouldn't be happy ?

[Fragillimus335]

Been doing some more scaling on the Broome titanosaur. From what I can tell its likely size range was 140-200 metric tons and 42-47 meters long. These estimates are based on direct scaling from different Hartman titanosaur skeletals. Not quite into Amphicoelias territory, but a close second.

[Grey]

A recent quote from Mike Taylor in SV POW :

Question :

Is there real and serious reasons to thin that A. fragillimus could have reached 200 tons in body mass and thus rivalling/exceeding the Blue whale ?

Answer :

I think we covered all that in some detail in the post. 200 tonnes is not beyond the realms of possibility, but not well supported by the extremely equivocal evidence we currently have.

Possibility, yes. Fact, no.

svpow.com/2010/02/19/how-big-was-amphicoelias-fragillimus-i-mean-really/

[Fragillimus335]

So looky there, an expert agrees that 200 tons for Amphicoelias is possible! Well, I guess that means you are wrong. You seem to equate higher numbers with greater uncertainty, which is a human bias. Saying 40 meters is more likely than 70 meters because 40 meters is lower is flat out incorrect.

[Grey]

200 tons is not beyond the possible according to Mike Taylor. According to you, 245 tons is almost factual. Sorry, I see a big difference.

[Fragillimus335]

I never said "almost factual" I said my best guess. So, you do acknowledge that 200+ ton weights are possible? I do too, and I think they are more likely than sub 150 ton estimates, based on the only published methods of estimating Amphicoelias's size. But by no means the ONLY possible size. I would be perfectly happy to find out Amphicoelias had freakishly big verts in a 55 meter body, but based on what we can tell it probably didn't.

[Grey]

No, I acknowledge that the 200 tons mark is possible to have been reached, I don't speak of 200 tons +.

Look closely the link and comments, Mike Taylor theorizes this not for the owner of the vertebra but for the likelihood tht larger individuals may have existed. That' the basis of his words.

I'm reading the page again, and nowhere I see Armstrong, Wedel or Taylor speaking of a 250 tons owner, nor even 200 tons. Armstrong simply says that Carpenter was very conserative and that a weight exceeding 150 tons could have been possible for the owner.

That's all. There's no direct support for a 200 tons sauropod in what I consult.

Matt Wedel

ItÂ’s incorrect because the mass of Amphicoelias is poorly constrained, not completely unconstrained. We can be pretty certain that it didnÂ’t mass 40 tons or 300 tons. Could it have massed 80 tons, or 120 tons? Certainly, given different starting assumptions. For my part, I find the process of exploring how changing those assumptions changes the final answer to be illuminating in its own right.

[Fragillimus335]

May 31, 2013 7:36:07 GMT 5 Grey said:

No, I acknowledge that the 200 tons mark is possible to have been reached, I don't speak of 200 tons +.

Look closely the link and comments, Mike Taylor theorizes this not for the owner of the vertebra but for the likelihood tht larger individuals may have existed. That' the basis of his words.

I'm reading the page again, and nowhere I see Armstrong, Wedel or Taylor speaking of a 250 tons owner, nor even 200 tons. Armstrong simply says that Carpenter was very conserative and that a weight exceeding 150 tons could have been possible for the owner.

That's all. There's no direct support for a 200 tons sauropod in what I consult.

Matt Wedel

ItÂ’s incorrect because the mass of Amphicoelias is poorly constrained, not completely unconstrained. We can be pretty certain that it didnÂ’t mass 40 tons or 300 tons. Could it have massed 80 tons, or 120 tons? Certainly, given different starting assumptions. For my part, I find the process of exploring how changing those assumptions changes the final answer to be illuminating in its own right.

Here is Armstrong's quote again with the relevant parts bolded in case you missed it.

However, where did Carpenter get the length estimate for A. fragillimus? He based it off of D. carnegii, as mentioned above and cited the stats for the latter from Paul (1994). However, Paul (1994) did not list a mass of 11,500 kg and a length of 26.25 meters for D. carnegii. He listed a mass of 11 tonnes and a length of 24.8 meters. So where did the mass estimates that Carpenter cited come from? I don't know. Am I missing something here? Maybe someone else can help me out here.

But that's not all. If A. fragillimus is supposed to be 2.2 times larger in linear dimensions, then going backwards from the estimated height of 2.7 meters estimated for the lone preserved dorsal in A. fragillimus means that the dorsal vertebrae of D. carnegii should 2.7/2.2=1.22 meters tall. Now, my digital copy of Hatcher's (1901) description of the CMNH 84 specimen of D. carnegii lists the 9th dorsal as 94.6 cm tall and the 10th dorsal as 96.6 cm tall (even the supposed "11th dorsal" was only 105.1 cm tall). So, somehow Carpenter thought that the comparable dorsal in D. carngeii was somewhere between 25.4 and 27.4 cm taller than it actually was. In fact, Lucas et al.'s (2006) taxonomic revision lists the 9th dorsal as about 1.2 meters tall for the "seismosaur" specimen. So Carpenter in essence assumed that an individual Diplodocus with seismosaur-sized vertebrae only massed about 11.5 tonnes and was 26.25 m long, even though more recent estimates of the seismosaur's size are around 30 tonnes in mass and 30-32 meters in length.

So what happens if we scale off the actual measurements listed for the CMNH 84 D. carnegii specimen? Well, assuming the dorsal in A. fragillimus was the 10th dorsal, then it was 2.7/0.966=2.79 times larger in linear dimensions than that *Diplodocus* specimen. If that specimen was indeed 24.8 meters as Paul (1994) says, than an estimated length for A. fragillimus is around 69 meters, a full 11 meters longer than Carpenter originally estimated. The disparity is even worse if we assume a 26.25 m Diplodocus individual which gives us an estimated length of around 73 meters.

What about mass? Well, if A. fragillimus was 2.79 times larger in linear dimensions than D. carnegii, then it was (2.79)^3=21.7 times more voluminous and therefore more massive. So, assuming that the CMNH 84 specimen was indeed 11.5 tonnes, then A. fragillimus should be 21.7*11.5=249 tons (!). This is almost 130 tonnes heavier than estimated by Carpenter, and is larger than the largest Blue Whale specimens that I have heard about, the largest of which may have been at least 200 tonnes in mass based off oil yield. Even using Greg Paul's more precise estimate of 11.4 tonnes listed on his website for the CMNH 84 Diplodocus still gives a mass of over 247 tonnes. I find this mass estimate of nearly 250 tonnes difficult to swallow. Paul uses a density of 0.9 for the body excluding the neck, even if we assume that this should be about 0.8 as indicated by work done on pneumaticity in sauropods done by Matt Wedel, this would mean we could reduce the mass to be about 88% of of the original mass which reduces it only to 219 tonnes, which is still fairly unbelievable. So, here's the big question: is there some major flaw in my reasoning here?

For the record, I think Carpenter's estimated height for A. fragillimus is reasonable. I did a similar scaling technique using GIMP's measuring tools and got an estimated height of 2.65 meters for the vertebrae based off of A. altus. Using this slightly reduced measurement, you still get a mass estimate of around 235-237 tonnnes (depending on how many decimal places you want to truncate) which is still around 110 tonnes heavier than estimated by Carpenter and is still heavier the heaviest known Blue Whales.

Read more: theworldofanimals.proboards.com/thread/50/size-comparison-scale?page=3#ixzz2UpniZOgK

[Grey]

I've read it. Another Zach's comment.

IÂ’m not sure a 200 ft long A. fragillimus is completely unsupported. Even using MikeÂ’s reduced size estimate for the A. fragillimus dorsal you still get, by isometric scaling from extrapolating from Diplodocus a length of at least 59.25 meters for A. fragillimus, which is about 194 ft. As I made clear in my comment here itÂ’s definitely possible that A. fragillimus was around 70 meters (or about 230 ft) long if we assume isometric scaling.

The trouble with that is that I canÂ’t think of any large animal that is a close isometrically to a significantly smaller animal. An even bigger trouble is that we are basically missing a whole dimension of information on A. fragillimus. What if it had a super anteroposteriorly short centrum like some other sauropods? Our length estimate could be way off.

For instance, letÂ’s say Futalognkosaurus was 26 meters long. The description says its anterior dorsal are 100 cm wide across the transverse processes. In Puertasaurus the width of its anterior dorsal (probably the 2nd) is 168 cm. So, it we assumed perfect isometric scaling that logically we would assume it was 68% longer too, right? Wrong. If we did so we would give a length estimate of over 43 meters long. However, if you look at the illustrations in the description of Puertasaurus is it quite clear that the dorsal centrum is very short anteroposteriorly and the illustration suggest it is between 30 to 32 cm long (excluding the anterior condyle). The description of Futalognkosaurus suggest a 2nd dorsal centrum length of about 28 or 29 cm long. This suggests that at least in the dorsal column, Puertasaurus was maybe only 10 or 11% longer thatn Futalognkosaurus suggesting a length of less than 29 meters long, 14 meters shorter than suggested by comparing the widths of the dorsal vertebrae.

If something similar was the case with A. fragillimus, it could easily be only 2/3 of the longest length estimate I gave, which would be 2/3 of 73 meters or “only” about 48 meters (~157 ft) long. It’s just too fragmentary to be sure.

Second, I think I made it clear in my comments that have been referenced that the size estimates I gave are uncertain. To quote myself:

The trouble with that is that I canÂ’t think of any large animal that is a close isometrically to a significantly smaller animal. An even bigger trouble is that we are basically missing a whole dimension of information on A. fragillimus. What if it had a super anteroposteriorly short centrum like some other sauropods? Our length estimate could be way off.

I then refer to the dimensions of Puertasaurus and Futalognkosaurus for empirical support to show that isometric scaling from a lone vertebra is likely to be misleading.

This is not one-sided.

[Fragillimus335]

I know, but I am just reiterating the fact that ~250 ton estimates are not imaginary hogwash, just one end of the possibility spectrum. Also, I would assume Cope would have noted any vast departure from basic diplodocid proportions, like an unusually short vert. In fact since he assigned it to A. altus, we can assume it was somewhat similar overall, and A. altus's dorsals are not unusually short. But this is just blind speculation.

[Grey]

It does not change the fact that isometric scaling is likely to be misleading.

Amphicoelias was certainly huge, but Armstrong only recall the upper you quote as one possiblity and quickly recalls the other side of the coin and the massive doubts and potential margin of errors.

I simply critic that you act and post all the time models of animals strictly at the highest boundary, more and more as a factual data. In my opinion that's enjoyable enthusiasm but bad science.

More rigourously, Amphicoelias is listed in the 90-150 tons range and I'm perfectly fine with this.

I personnally find more concrete giants like Alamosaurus or Argentinosaurus less boring and less dangerous for the intellectual honesty.

I can understand your liking and enthusiasm. I like for example some extinct, problematic species like megalodon for example but when I post comparisons of megalodon, I don't strictly post the highest, largest estimates or reconstructions. And I don't try to disprove scientific thoughts on that subject and indicate that megalodon was more likely much larger than usually thought. And I could do it, there are plenty means to use and favor the most optimistics and liberal methods. But merely, I prefer to contribute with them (through mail) and discover the truth, rather than my preference.

[Fragillimus335]

Same here, the only difference is that I feel the 150-220 ton weight range more likely. Still not excluding lower estimates though! I will try to put more conservative scales up along with my preferred more liberal ones.

[Fragillimus335]

Here is my updated scale! Upper estimate ~80m and 235 tons, lower estimate ~55m and 120 tons.




Dang, that vert is wayy too far back on the smaller Amp, but you get the idea!