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Post by theropod on Jun 5, 2014 1:41:06 GMT 5
Puertasaurus has been estimated to be in that region as well (Nima’s work btw), and newspapers tend to be a little enthusiastic about the lenghts of new findings in many cases (they proposed the same for Argentinosaurus AFAIK). The weight estimate based on a quantitative method wasn’t significantly larger than Argentinosaurus’, and neither are the actual bones by the seem of it.
Imo the find is rather notable for its completeness than for its extreme size. It is big, but in regular already-known-before-giant-sauropod territory (Puertasaurus, Argentinosaurus, Alamosaurus, Mamenchisaurus sinocanadorum etc.). But it is that very completeness that will prove extremely useful if properly described.
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Fragillimus335
Member
Sauropod fanatic, and dinosaur specialist
Posts: 573
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Post by Fragillimus335 on Jun 20, 2014 6:23:51 GMT 5
Some classic sauropod genera that have ridden the size roller coaster through the decades and their current largest specimens.
Diplodocus-33 meters/~20-25t
Brachiosaurus-28 meters/45-50t Adult estimation
Giraffatitan-27 meters/40-45t
Apatosaurus-possibly 32 meters/55t
Supersaurus-38-40m/45-55t
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Post by creature386 on Jun 20, 2014 16:46:52 GMT 5
What are these hypothetical adult estimations based on? Adding some meters and then scaling up?
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Post by theropod on Jun 20, 2014 19:48:28 GMT 5
Those all seem to base on actual specimens. Paul 1988 lists a BYU specimen of B. althithorax that has a 2.42m long humerus and a 2.37m long femur as compared to 2.04 and 2.03 m respectively in the holotype (i.e. 18.63% and 16.75% bigger ), which would have been between 24 and 25m long ( source1→ source2→). So adult Brachiosaurus is actually quite gigantic, as Scott Hartman also implied on his size chart. In terms of Giraffatitan brancai, There are remains that are ~12-13% bigger than the holotype→ which janensch measured at 22.46m. Mass figures seem to vary a lot, but even with the most conservative ones we get something in the ballpark of the weight figures Fragillimus335 listed. |
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Post by creature386 on Jun 20, 2014 21:56:59 GMT 5
As for Giraffatitan, I got less than 35 t when scaling up from your 12 to 13% bigger number (assuming you meant linear dimensions) and using the not really conservative 23 t figure (Taylor 2009), but you have a point on B. altithorax. There I can confirm his estimates. Bibliography: "A Re-Evaluation of Brachiosaurus altithorax Riggs, 1903 (Dinosauria, Sauropoda) and Its Generic Separation from Giraffatitan brancai (Janensch, 1914)" by Michael P. Taylor, 2009, Journal of Vertebrate Paleontology 31(3):727-727. doi: dx.doi.org/10.1080/02724634.2011.557115 |
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blaze
Paleo-artist 
Posts: 766
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Post by blaze on Jun 20, 2014 22:45:13 GMT 5
The giant BYU specimen that Paul (1988) is talking about is BYU 5001, he says so some pages later, according to Taylor et al. (2009) this specimen is now known as BYU 9462 as while its identity is definitely brachiosaurid it is different enough to the coracoid found with B. altithorax that it just can't be the same taxon, Taylor et al. (2009) says this about its size.
BUT, Paul (2012) notes that the corocoid found with the B. altithorax holotype is very big both in absolute terms compared to those of other brachiosaurids (assuming Janensch, 1961 got the dimensions of that of G. brancai wrong), in relative terms compared to the ilium and is also more rectangular rather than squarish in shape. He say that this could be diagnostic characters but he expresses doubt of it being B. altithorax.
So as far as we know, the "giant" BYU specimen might or might not be giant and it might or might not be B. altithorax. But is generally thought that the B. altithorax holotype is in a similar ontogenic stage as HM SII G. brancai so it's also suggested that adult B. altithorax were 12-13% bigger in linear dimensions.
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Post by creature386 on Jun 20, 2014 22:53:35 GMT 5
I am not sure if we should take the same increase in size as for Giraffatitan because similar is very unprecise. It is for example possible that both animals were comparable in size and that the Brachiosaurus altithorax we know is bigger than Giraffatitan because of a slightly higher, but similar ontogenetic stage. Hence, I can live with a 34 t Giraffatitan now, but I would be a bit careful about an over 40 t Brachiosaurus altithorax.
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Post by theropod on Jun 20, 2014 23:12:52 GMT 5
Paul doesn’t just list the scapulocoracoid, he also lists some other giant elements (femur, humerus and a rib), what about those?
He just writes "BYU", so all that really means is that they are somewhere in BYU collections, not that they are all from the same specimen.
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Post by theropod on Jun 20, 2014 23:27:16 GMT 5
Taylor’s 23t estimate is certainly among the more conservative ones: svpow.com/2014/06/09/how-heavy-was-giraffatitan-brancai-i-mean-really/I still feel quite confortable with it though, since it is fairly recent and incorporates a lot of recent research on the animal. I’m sorry, I screwed up on the Giraffatitan, lenght and weight are both a little high. |
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Post by creature386 on Jun 20, 2014 23:37:19 GMT 5
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Post by ultimatedinoking95 on Jun 20, 2014 23:45:21 GMT 5
I really depends on what you mean by "largest". is this going by length or weight?
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Post by creature386 on Jun 20, 2014 23:50:42 GMT 5
You can post a candidate for both categories, but I believe most go by weight.
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Post by theropod on Jun 21, 2014 1:01:41 GMT 5
Primarily its body mass, although both lenght and height are also of interest.
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blaze
Paleo-artist
Posts: 766
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Post by blaze on Jun 23, 2014 21:48:06 GMT 5
Find of a 2m long Apatosarus femur. Linkbtw have you seen Nima's updated Brachiosaurus?theropodThe other BYU material does not contain an scapulocorocoid and comes from other quarries, there's no reason to lump them all as an individual of the same size and since the scapulocorocoid is the only none-estimate measurement there I think it's clear that he is referring to only that specimen with the name BYU. But BYU 4744 (BYU 9754 according to Jensen) does indeed appear to be Brachiosaurus, maybe B. altithorax, and it defintely represents a larger animal. |
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Post by theropod on Jun 23, 2014 22:34:35 GMT 5
blaze: Yes, I actually linked it in one of my previous posts. So you mean the femur, humerus and rib where just extrapolation based on the scapulocoracoid? If that is the case, why aren’t the humerus and femur perfectly in proportion with those of the holotype, and why aren’t all the spaces that Paul left blank in his table filled with extrapolated figures? Is the specimen you mean this one→?
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