A new view of Brachiosaurus

August 6, 2008

Considering how much time I’ve spent playing around mounted sauropod skeletons, I cannot believe it never occurred to me to do this:

This is the mounted Brachiosaurus skeleton in the United terminal at Chicago O’Hare. It used to be in the main hall of the Field Museum, but they booted it out to make room for some vulgar overstudied theropod (ht to Paul Barrett for that supremely useful phrase). The indoor version was moved to O’Hare, and they made a second, weatherproof cast which is now mounted outside the northwest corner of the Field Museum.

We spend so much time looking at drawings or photos of bones or entire skeletons in lateral view. It is nice to get a kick-in-the-brainpan reminder that sauropods existed in 3D. And it is always rewarding to see something familiar from a new angle.

Lots of good stuff here. Anterior is toward the bottom of the photo; you can see the scapulae arcing back over the anterior ribs, the coracoids sternal plates converging and disappearing out of the bottom of the image, and the humeri angling out to either side. The thing does not really sprawl as much as it might seem from this picture–keep in mind that there is a lot of vertical foreshortening going on. Speaking of, you can see the neck zooming off into space at the bottom center. At the top of the image you can see the sacrum and the preacetabular blades of the ilia flaring out to either side.

The seven posterior dorsals are cast from the holotype of Brachiosaurus altithorax, as are the sacrum, the first couple of caudals, one humerus, one ilium, and one femur. The rest of the mounted skeleton is either mirrored from available elements or subbed in from Brachiosaurus brancai.

I’m posting this because (a) it’s a really cool photo, and (b) it illustrates something peculiar, which is that the dorsal vertebrae of Brachiosaurus are oddly–one might even say freakishly–slender. This is true of both the B. altithorax and B. brancai dorsals. I was recently standing under yet another copy of this skeleton and someone I was with asked if those were even the right vertebrae, because even to non-specialists they look too small.

I WILL have more to say about that one of these days, but for now just dig the austere beauty.

Photo (c) Tristan Savatier – www.loupiote.com – Used by permission.

13 Responses to “A new view of Brachiosaurus

  1. Allen Hazen Says:

    They’re load-bearing structural elements, at a scale where weight reduction is important. I’d EXPECT sauropod dorsals to be much deeper than they are wide, for the same reason that the I-beams forming the main structure of bridge decks are mounted with the broad web vertical rather than horizontal.

    (Do you know the book “Why buildings stand up” (title may not be quite right) by Mario Salvadori? It’s a popularization of architectural engineering, and fun to read.)

  2. Darren Naish Says:

    Yes, Salvadori did ‘Why Buildings Stand Up’. Levy and Salvadori wrote ‘Why Buildings Fall Down: How Structures Fail’, and Gordon wrote ‘Structures: Or Why Things Don’t Fall Down’.

  3. Dave Godfrey Says:

    Wow. Its a view very few of us get to see, which is a pity. Totally understandable, of course, and a conservators’ nightmare, were you to allow visitors underneath even casts.

    I remember being fascinated by the size of these things from the side when I first saw them. They’re even more impressive from underneath.

  4. Katie Brakora Says:

    That is a kickass photo.

  5. Nathan Myers Says:

    Yes, this vantage is a good way to study the fornication, where there is any.

  6. Graham King Says:

    Neat photo!
    Given the absence of sternal elements of the ribcage (I am guessing this is usual?) how much leeway is there for varying the articulation angle between ribs and vertebrae? I am asking, because these ribs seem quite straight for most of their length, and I am wondering if sauropods were notably slab-sided (bodies laterally flattened, narrow for their depth)… Despite many recent restorations STILL showing them as barrel-bodied behemoths.
    This is a question that (it seems to me) often arises with partial ribcages. (The NMH Stegosaurus mount seems ludicrously splay-ribbed to me).
    Can you elucidate for me?

  7. Matt Wedel Says:

    Given the absence of sternal elements of the ribcage…

    Arf! Those things disappearing out the bottom of the picture are the paired sternal plates, not the coracoids as I had originally IDed them. That is now fixed in the main text of the post.

    these ribs seem quite straight for most of their length, and I am wondering if sauropods were notably slab-sided (bodies laterally flattened, narrow for their depth)

    Good observation on the ribs, and you’re right, sauropods were for the most part very slab-sided. See the Nigersaurus mount in anterior view here.

  8. Nathan Myers Says:

    Speaking of structural support and nigersaurus… I wonder if anyone has explored the notion of air sacs as actual structural elements in sauropod necks. It would depend on an ability to pinch the diverticula closed at the foramen, temporarily. Of course the best candidate to use such a system would be nigersaurus, whose bones seem better-suited as a scaffolding for balloons than to hold anything up directly.

    One could imagine nigersaurus gradually pumping its neck sacs up to higher pressure to raise its head, and releasing the air when it’s time to drink.

    We need some sort of explanation for why nigersaurus is so different from the other sauropods — low-mineral environment? Low-energy diet? — and for how it was able to exist at all with so much less skeletal strength. Structural pneumatics might be part of that.

  9. Mike from Ottawa Says:

    There is, of course, more recent, albeit sadly no longer extant, precedent for such structural use of pneumaticity in the form of Nasobema lyricum and Tyrannonasus imperator.

  10. Zach Miller Says:

    What the hell is Tyrannosaurus imperator?

    Great photo. The brachiosaur at the Field Museum is one of my favorite mounts at that particular location. Sue is great, sure, but her wishbone is still a belly rib and I couldn’t find anybody to bug about that last time I was there.

  11. Nathan Myers Says:

    OK, I was joking about nigersaurus’s head bobbing as it pumped its neck up.

    Seriously, though, I don’t know any reason why pressurized sacs couldn’t have helped provide compressive support. Bone would want to re-grow if the foramen were closed off, but that could be solved various ways. Anyway the foramena couldn’t be closed permanently, as the sacs would need to be re-pressurized on occasion.

    Zach: snouters.


  12. […] has two more dorsals than the one in the Field Museum picnic area, despite Matt having posted a ventral-view photo of the airport mount that clearly shows the twelve dorsals and a lateral-view photo of the museum mount that clearly […]


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