Fragillimus335
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Post by Fragillimus335 on Aug 26, 2013 21:47:45 GMT 5
New giant sauropod in the mix? A team of French paleontologists have uncovered a sizable bone bed of sauropods, hadrosaur, and ornithomimids. They recovered an almost perfectly complete titanosaur femur that measured 2.2 meters in length! A femur this size points to an animal in the 25-30 meter and 40-50 ton range. But that isn't all, this femur was quite gracile for such a big animal, and soon after an even more massive fragmentary femur was found on the site. The paleontologists stated it to be around 25% larger in all dimensions than the 2.2 meter femur! That indicates a total length of ~2.75 meters for this giant titanosaur, resulting in body sizes of about ~35-37 meters and ~100 metric tons! I hop they pick a decent name for this beast!
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Post by Grey on Aug 26, 2013 22:00:55 GMT 5
Can you give a source ?
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Post by creature386 on Aug 26, 2013 22:10:03 GMT 5
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stomatopod
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Gluttonous Auchenipterid
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Post by stomatopod on Aug 26, 2013 22:21:47 GMT 5
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blaze
Paleo-artist 
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Post by blaze on Aug 27, 2013 4:52:44 GMT 5
What if it just had a long femur? I think is a little too optimistic to start again with 35m+, 100t+ estimates like the initial estimates of Argentinosaurus and Puertasaurus, Zach Armstrong skeletal of Alamosaurus has a ~1.8m long femur for a 17m long, 19 tonnes individual, based on this the french giant would be ~27m, as big as what Armstrong estimates the largest individual of Alamosaurus to be (which he estimates its femur at 2.6-2.7m too) with a mass of 74 tonnes, Hartman's estimate of this individual is also in that ballpark, 28m long IIRC.
Edit: sorry coherentsheaf, I edited my comment for clarity and messed up your quote hehe.
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Post by coherentsheaf on Aug 27, 2013 4:58:28 GMT 5
What if it just had a long femur? for example, Zach Armstrong skeletal of Alamosaurus has a ~2m long femur for a 17m long, 19 tonnes individual. It still pretty big though, it does appear to rival Alamosaurus, Armstrong has estimated the femur of the largest Alamosaurus (the giant tibia, which he estimates its owner at 27m long while Hartman estimates at 28m long) to be around 2.6-2.7m long too, going by this, I think is a little too optimistic to start estimating 35m+, 100 tonnes again like what happened with Argentinosaurus and Puertasaurus. Note also that the femur is described as gracile which lends weight to this interpretation. |
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Fragillimus335
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Post by Fragillimus335 on Aug 27, 2013 8:32:31 GMT 5
35 meters for a titanosaur with a 2.2 meter femur is probably exaggeration, but quite possible for the owner of the 2.75 meter femur. @sheaf/Blaze If I recall correctly Alamosaurus is like one of the longest-femured titanosaurs out there...? I use the exact same methodology as you do to claim possible lengths of ~35 meters using Argentinosaurus as a proxy. You seem to think that lower/more conservative estimates are inherently more "correct", that view is a fallacy of the human mind. |
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Deleted
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Post by Deleted on Aug 28, 2013 10:00:20 GMT 5
Lower =/= Conservative
Conservative = No extra assumptions/liberties
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Post by coherentsheaf on Aug 28, 2013 14:06:00 GMT 5
35 meters for a titanosaur with a 2.2 meter femur is probably exaggeration, but quite possible for the owner of the 2.75 meter femur. @sheaf/Blaze If I recall correctly Alamosaurus is like one of the longest-femured titanosaurs out there...? I use the exact same methodology as you do to claim possible lengths of ~35 meters using Argentinosaurus as a proxy. You seem to think that lower/more conservative estimates are inherently more "correct", that view is a fallacy of the human mind. Nope. I view them as more likely because they are more likely. If we ere to plot the totality of animal sizes on a density plot, the larger the animals are the fewer of them exist. From there it is a straightforward application of Bayes theorem that more conservative explanations should have more weight. |
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Deleted
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Post by Deleted on Aug 28, 2013 22:35:13 GMT 5
35 meters for a titanosaur with a 2.2 meter femur is probably exaggeration, but quite possible for the owner of the 2.75 meter femur. @sheaf/Blaze If I recall correctly Alamosaurus is like one of the longest-femured titanosaurs out there...? I use the exact same methodology as you do to claim possible lengths of ~35 meters using Argentinosaurus as a proxy. You seem to think that lower/more conservative estimates are inherently more "correct", that view is a fallacy of the human mind. Nope. I view them as more likely because they are more likely. If we ere to plot the totality of animal sizes on a density plot, the larger the animals are the fewer of them exist. From there it is a straightforward application of Bayes theorem that more conservative explanations should have more weight. And more conservative does not mean lower, it simply means less assumptions/liberties. |
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Post by coherentsheaf on Aug 28, 2013 22:36:35 GMT 5
Nope. I view them as more likely because they are more likely. If we ere to plot the totality of animal sizes on a density plot, the larger the animals are the fewer of them exist. From there it is a straightforward application of Bayes theorem that more conservative explanations should have more weight. And more conservative does not mean lower, it simply means less assumptions/liberties. Depends on the context. In context of size it most often means lower. |
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Deleted
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Post by Deleted on Aug 28, 2013 22:44:30 GMT 5
And more conservative does not mean lower, it simply means less assumptions/liberties. Depends on the context. In context of size it most often means lower. And sometimes it can mean higher It is only associated with lower by most, because most of the liberties/assumptions assumed in liberal estimates make the size larger. What they overlook is that extra assumptions/liberties can also make the size smaller. Example: Cau's ~12.5-meter Spinosaurus(I did not say that he believes it, just brought this up as an example) has a load of assumptions/liberties, therefore it is liberal, not conservative, a conservative estimate for Spinosaurus would actually be higher(Scott Hartman's IPHG 1912 is ~14 meters long) The bottom line is that conservative/liberal is a matter of method, not the magnitude of the resulting numbers. |
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blaze
Paleo-artist
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Post by blaze on Aug 29, 2013 0:54:07 GMT 5
It does appear to have a long femur as restored by Zach, he gives his reasons on Deviantart, but, even if we ignore known femora, scaling from Opisthocoelicaudia will yield an even longer femur so it doesn't seem to be a special case. The tail, I think, is probably the main reason of the "low" length, as Alamosaurus has a short-ish tail.
Based on Argentinosaurus, to get 35-37m from this supposedly 2.75m long femur, you need to assume that Argentinosaurus was 32-34m long which doesn't seem to be the correct length, as Calvo et al have said since 2009, Futalongkosaurus is likely to be 26m long assuming a tail that's 50% of total body length and Argentinosaurus is only 15% larger than it in linear dimensions which will make Argentinosaurus 30m long and concequently, this giant femur will come from a 33m long titanosaur but remember, only 16.5m of that is neck and body, if we were to give it Alamosaurus tail proportions (tail roughly 40% of total body length) it'll only be 28m long, or just slightly larger than what I estimated in my previous post, either way, 28 or 33m the difference is only tail and it will only be ~3.7% larger than the largest Alamosaurus and 11.5% heavier, or about 82 tonnes, or 85 tonnes based on Zachs Argentinosaurus, but of course, we can use Mazzetta's Argentinosaurus estimate instead, which will make it 97 tonnes, but that assumes a 1.0 kg/L density IIRC.
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Fragillimus335
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Post by Fragillimus335 on Aug 29, 2013 3:54:05 GMT 5
It does appear to have a long femur as restored by Zach, he gives his reasons on Deviantart, but, even if we ignore known femora, scaling from Opisthocoelicaudia will yield an even longer femur so it doesn't seem to be a special case. The tail, I think, is probably the main reason of the "low" length, as Alamosaurus has a short-ish tail. Based on Argentinosaurus, to get 35-37m from this supposedly 2.75m long femur, you need to assume that Argentinosaurus was 32-34m long which doesn't seem to be the correct length, as Calvo et al have said since 2009, Futalongkosaurus is likely to be 26m long assuming a tail that's 50% of total body length and Argentinosaurus is only 15% larger than it in linear dimensions which will make Argentinosaurus 30m long and concequently, this giant femur will come from a 33m long titanosaur but remember, only 16.5m of that is neck and body, if we were to give it Alamosaurus tail proportions (tail roughly 40% of total body length) it'll only be 28m long, or just slightly larger than what I estimated in my previous post, either way, 28 or 33m the difference is only tail and it will only be ~3.7% larger than the largest Alamosaurus and 11.5% heavier, or about 82 tonnes, or 85 tonnes based on Zachs Argentinosaurus, but of course, we can use Mazzetta's Argentinosaurus estimate instead, which will make it 97 tonnes, but that assumes a 1.0 kg/L density IIRC. Where do you get that Argentinosaurus was only 15% longer than Futalognkosaurus? Hartman's Futalognkosaurus is pretty small at ~23 meters long, and it has a dorsal series 3.04 meters long. Zach's Argentinosaurus has what he acknowledges as a possibly too short torso, and it is 4.27 meters long. That's a 140% difference, possibly up to 150% with a slightly longer torso. Using Hartman's 23 meter Futa, that gives us a minimum bound of ~32.2 meters...With a longer torso for Argentino, is increases to ~34.5 meters. Personally I think ~26 meters is more likely for Futalognkosaurus, and as both Zach, Nima, and the mounted reconstruction believe, would have a dorsal series ~3.5 meters long. This makes Argentino ~22%-33% longer. This again results in lengths of roughly 32-34.5m. |
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blaze
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Post by blaze on Aug 29, 2013 5:26:19 GMT 5
Coria and pals, your beef is with them then.
Either way, we can remove Futalongkosaurus out of the picture, it doesn't affect what I said, based of Zach's skeletals of either Alamosaurus or Argentinosaurus you get lengths 28-32m and weights in the 80 tonne range for the owner of that big femur, and we aren't even counting that the femora was described as gracile, meaning it really is just a long femur and might not even represent an animal bigger than known sauropods.
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