The “Ultrasauros” holotype vertebra

December 22, 2010

I recently stumbled across this rather good photograph of the holotype vertebra of our old buddy “Ultrasauros“, thanks to Wikipedia contributor Ninjatacoshell, and thought you’d like to see it:

This is a rather legendary vertebra, but until recently there were no good photographs of it on the web (I know because I tried to find one for my talk at the Dinosaurs: A Historical Perspective conference in 2008).

See It’s Ultrasaurus… I mean, um, Ultrasauros… err, Supersaurus! for the now-traditional run-down of the taxonomic mess surrounding this specimen.

In other news, everyone in palaeontology should read Heinrich Mallison’s recent article No 4WD For Plateosaurus over on the Palaeontologia Electronica blog.  He highlights a lot of important issues that have general applicability.

15 Responses to “The “Ultrasauros” holotype vertebra”

  1. Nick Gardner Says:

    Maybe if you contacted someone at WPL, they could get more pictures for you.

  2. Brock Says:

    the specimen belongs to BYU and is on long term loan to the Museum of Ancient Life at Thanksgiving Point, Lehi, Utah. there is also a large scapula and the sacrum with illia on display.

  3. Does anyone know how tall this vertebra is and what position it is in the vertebral column (e.g., D7 or D10, etc.)?

  4. Mike Taylor Says:

    Zach, according to Curtice et al. (1996:table 2), it’s 1330 mm tall, and it’s a posterior dorsal that is probably “either presacral 1 or 2” (p92), i.e. either the last or penultimate dorsal vertebra.

  5. Dean Says:

    Score one for the mammals, my entire skeleton is longer than that puny vert!!!

  6. Dean Says:

    BTW, check out this website,
    Is that an Amphicoelias in the back with the pimped out neck?

  7. Peter Adlam Says:

    I recently happened upon a picture of the late Jim Jenson standing beside the huge front leg of “Ultrasauros”, which leads me to ask a few questions. Did he really find a complete forelimb?Was the leg from Brachiosaurus altithorax? If that leg is valid at actual size how tall/long was the whole animal? It looks to be about 40% to 50% taller than the berlin Giraftitan, i am guessing the leg is a constructed representation of how the leg would look rather than a cast of the actual leg because if the whole front leg was found they would probably be the most talked about sauropod bones in the world and the fact is i’ve heard pretty much nothing about these remains for years.

  8. Mike Taylor Says:

    Hi, Peter. I believe I know the picture you’re talking about: it’ll be either this one of Jensen in the lab or this one out in the desert. (It looks like this forelimb may have ended up in the NMMNHS.)

    The bad news is, no, this is not a complete forelimb fossil. The worse is that it’s not even partly cast from real material: it’s a pure sculpture, based presumably on the forelimb of Giraffatitan brancai, but scaled up according to Jensen’s idea of how big “Ultrasaurus” was. The only part of the model that might have been cast from real material is the scapulocoracoid, which is the only real brachiosaur element that Jensen found and described from the Dry Mesa quarry. But in fact, the scapula in these pictures looks much too small in comparison with the other elements; or to put it another way, all the other elements are too big — which suggests that Jensen exaggerated the sizes of the sculpted limb bones well beyond what the scapulocoracoid warranted.

    But the good news is, your sense of awe is not misplaced. Real brachiosaur forelimbs are actually not much less impressive than this. See for example me next to the right forelimb of the Berlin Giraffatitan mount, which is real bone. Or here I am photographing the Chicago Brachiosaurus mount from the side, in very much the same scale. (The Chigago mount is a cast, based on a hybrid of real Brachiosaurus elements, some bits of Giraffatitan, and some sculptures, but the scaling is good.)

    My rule of thumb, based on a lot of posing for photos around the Chicago mount, is that if I stand next to the forelimb and reach up, I can just rest my hand on the top of the ulna without stretching.

  9. Peter Adlam Says:

    Thankyou for clearing that up, also didn’t you say in another post that the 12m tall 22.2m long Giraffatitatan was a subadult? If so how much larger would it have been fully grown?

  10. Peter Adlam Says:

    Just looked at the picture and the forelimbs are impressive but the neck of Girraftitan is a real beuty and isn’t that Diplodocus Carnegi being dwarfed? Well in height anyway because i’m pretty sure that Diplodocus was longer or is it, how long is that Diplodocus mount?

  11. Mike Taylor Says:

    Yes, the lack of fusion between the scapulae and coracoids of the mounted Giraffatitan shows that it is indeed subadult; and the same is true of the Brachiosaurus altithorax holotype FMNH P25107, which has no scapular material but does include a weird coracoid which was definitely not fused to its scapula.

    How much bigger did Giraffatitan get? We don’t know the upper limit, but we do at least know that specimen XV1, represented only by an isolated fibula, was 15% larger than SII (the mounted skeleton) in linear dimension, and so 1.15^3 = 1.52 times as voluminous and heavy.

  12. Mike Taylor Says:

    Yes, that’s a cast of the Diplodocus carnegii holotype CM 84 (with some bits filled in from other specimens) looking frankly pathetic back there. The length of that animal is often given as 27 m, but I’ve not been able to track down the source of that much-quoted number. If it’s right, it’s a bit longer than Giraffatitan, but not much.

  13. Peter Adlam Says:

    An adult giraffatitan 15 % larger would be in the region of 13.8m tall and 25.5m long with brachiosaurus a similar size and maybe a large individual could reach the 30m long gigapod marker thus being a possible 16.2m tall.This is impressive and not far short off Sauroposeidon. Also i find the length of Giraffatitan and Brachiosaurus very deceptive because it had such a stumpy tail, the creatures were far larger than the length suggests. Is their a reason for Brachiosaurids having such short tails? Is it because they had most of their weight supported at the front of the torso by the forelimbs and thus didn’t need a long tail to counterbalance itself?

  14. Mike Taylor Says:

    Janensch (1950b:102) gives the total length of the HMN SII mounted Giraffatitan as 22.46 m.

    XV1 is 13% longer than the fibulae of SII, not 15% as I misstated in the previous comment. If the whole animal was longer in proportion, that would give us a total length of 22.46 x 1.13 = 25.38 m for XV1. Long, but still still not as long as the usual length given for Diplodocus.

    You are right that Brachiosaurus was proportionally longer in the trunk and probably the tail than Giraffatitan (Paul 1988, Taylor 2009), but we have no direct evidence that there were larger individuals than the holotype FMNH P25107, which is the “same size” as regards femur and humerus lengths as HMN SII. It might have been about the same length as HMN XV1, but not so proportionally bulky.

    We don’t really know why Brachiosaurus had such short tails. They do seem to have carried a greater proportion of their mass on the forelimbs, but that is really a consequence of the short tail rather than a cause, as the tail reduction shift the centre of mass forwards — see Alexander’s (1989) brilliant and digestible little book Mechanics of Dinosaurs and Other Extinct Giants, which everyone should read. The bizarre things about brachiosaurs is that despite carrying all that mass up front, they have the most proportionally slender humeri of any sauropods — exactly the opposite of what we’d expect.

  15. […] a new comment on an oldish post, Peter Adlam asked: I recently happened upon a picture of the late Jim Jenson standing beside the […]

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