Barosaurus lentus AMNH 6341 dorsal sequence

April 18, 2012

I’ve been thinking about Barosaurus lately.

<homer>Mmmm … Barosaurus</homer>

The best (and only, really) good recent treatment of Barosaurus is in John McIntosh’s chapter of the 2005 IUP Thunder Lizards volume.  The main weakness of that chapter is that, while a lot of material is illustrated, the figures are rather small and not particularly well reproduced — and, in the case of the two-page spread of dorsal vertebrae, monumentally confusing:

Barosaurus lentus AMNH 6341 dorsal vertebrae 1 to 9 (A-I) in anterior, left side, and posterior views. From McIntosh (2005:fig. 2.5)

Quick!  find the fourth dorsal in posterior view!  [˙ʇɟǝן ɯoʇʇoq ʇɐ s,ʇı :ɹǝʍsuɐ]

To get a better sense of the variation along the column, I scanned the two pages, loaded them into GIMP, joined them together, cleaned up the “white” of the background while retaining all the contrast I could, then moved each of the 27 illustrations to its own layer.  Then I was able to rearrange them to my liking, align them, and produce this modified version:

Barosaurus lentus AMNH 6341 dorsal vertebrae 1 to 9 in anterior (top), left lateral (middle), and posterior (bottom) views. Modified from McIntosh (2005:fig. 2.5)

So here it is for anyone else who finds it useful.

(One character that varies sequentially is of course the degree of neural spine bifurcation.  But we won’t be flogging that dead horse any more — we’re done blogging, and the paper is in prep.)

References

  • McIntosh, J.S. 2005. The genus Barosaurus Marsh (Sauropoda, Diplodocidae); pp. 38-77 in Virginia Tidwell and Ken Carpenter (eds.), Thunder Lizards: the Sauropodomorph Dinosaurs. Indiana University Press, Bloomington, Indiana, 495 pp.
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10 Responses to “Barosaurus lentus AMNH 6341 dorsal sequence”

  1. Duke of Time Says:

    Obviously the later is more well rearranged than the previous, which implies that the original author was still suffering from the hangover of writing his pages that he didn’t care to sort them in a more natural “correlationship”. But then, GIMP is underrated despite being free and easy to use and free to run even in low end computers.

    On an unrelated note, I’m doing a small/medium study of the Apatosaurus’ skeleton to recreate its fleshy form in 3D, for the sake of its awesomeness. Can I has your feedback whenever I have it in a more advanced stage of development? I don’t want to make a regular JP-like Apatosaurus but the “real deal” and I lack of those years of knowledge you all sport proudly. I’ll be very grateful, and of course, credits to this blog and its team will be sprinkled all over the place (since I love this blog, some propaganda about it will not hurt, right?).

    ~ from Spain with love

  2. Mike Taylor Says:

    Sure, we’ll be happy to comment on your Apatosaurus!

  3. Don Cox Says:

    What is really needed is 3D models that could be printed out using a 3D printer.

    DC

  4. Mike Taylor Says:

    Yes indeed! Although for now, I’d settle for better photos. (The ones in the book are small, and printed at rather low resolution using half-toning. I am trying to obtain the originals that the book was printed from, but no luck so far.)

  5. Matt Wedel Says:

    Duke–good luck with your Apatosaurus. I’m with Mike–we’d love to see it when it’s shareable. You probably already know about this series of relevant posts, but if not, you do now.

  6. Dean Says:

    I am suddenly struck by the similarity between dorsal eight of Barosaurus and Amphicoelias f. At least to my untrained eye that is… Is there any other, more complete Barosaurus dorsal material that could be used for comparison?

  7. Matt Wedel Says:

    Lull’s (1919) stuff, maybe. Although IMHO the real question is, is there ANY Morrison diplodocid that couldn’t be A. fragillimus, if you knocked enough bits off? That is, is there something specific about that Barosaurus dorsal beyond its coincidental pattern of busted-ness that puts you in mind of A. f.? I ask because I spent a lot of time last week looking at big dorsals of Apatosaurus, most of them with some damage, and they didn’t look all that different from the Barosaurus dorsals figured above.

  8. Dean Says:

    To me it was the relative lateral thinness of the neural spine, and the shape of the, pardon my lack of correct jargon, little upside down kite-shaped thingy that is even with the postzygs.

    To a lesser extent, the relative height of the neural spine in relation to reconstructed total height.

  9. Mike Taylor Says:

    If I properly understand you, the upside-down kite is the hyposphene. It’s a projection that fits neatly into a corresponding gap on the anterior face of the next vertebra, which is called the hypantrum.

    But the features you’re describing here are all pretty typical of diplodocids, especially given the variation in proportions along the spinal column. I agree with Matt that the big guy could be Barosaurus, but there’s no compelling reason to favour that identity over any other.

  10. Dean Says:

    Yes, it is the hyposphene, :)

    There is so much we can’t tell from our meager sauropod vert supply. It’s about time we actually do find a couple perfectly preserved skeletons in a cave somewhere!

    (glow worms not included.)


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