The giant brachiosaur cervical of Arches National Park

December 31, 2017

As Matt recently noted, we both have a ton of photos from various expeditions that we’ve never got around to posting — not to mention a ton of specimens that we’ve seen but never got around to working on. Here is one of the most exciting:

As you can see, this is a massive cervical vertebra from a sauropod, probably a brachiosaurid, eroding right out of the ground. It’s in an undisclosed location in the Arches National Park, which we visited in May 2016. The neural arch is in amazingly good shape, though the end of the right prezygapophysis has broken off and been displaced slightly upwards. The postzygapophysesal facet is difficult to make out. Here’s a rough-and-ready interpretive drawing to get you oriented, with the completely missing parts speculatively sketched in light grey. (We don’t know how much more of this vertebra might be preserved underground.)

Apart from its size, the most striking thing about this vertebra is how very pneumatic it is — corroborating the long-standing hypothesis that pneumaticity tends to be positively allometric. If you compare with the much-loved 8th cervical vertebra of the Giraffatitan brancai paralectotype MB.R.2181 (formerly HMN SII), you can see similar “sculpted” features on the arch of that vertebra, but they are much less developed and ramified:

(This photo is in of course in left dorsolateral view, whereas the aspect of the Arches vertebra available to us is right lateral, and slightly ventral of true lateral.)

How big is the Arches vertebra? Stupidly, we didn’t have measuring equipment with us when we were visiting the park, so we don’t have an exact figure. But we can get some idea by extrapolating from the photo above. The stretched-out arm-span of an adult man is close to his height. I’m 1.8 m tall, so allowing for the downward slope of my arms, we might guess that the fingertip-to-fingertip measurement is about 1.7 m. If that’s right, measuring off the photo, the preserved portion of the vertebra is nearly twice that, at 3.3 m — and the complete length must have been somewhat longer, as the back end of the centrum is completely missing. Something in the region of 3.6 m might not be too far out. But as always, note that these are extremely speculative figures based on multiple layers of approximation.

We really need to get back out there, measure that thing properly, and of course try to find a way to have it excavated.

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22 Responses to “The giant brachiosaur cervical of Arches National Park”

  1. Andrew Stuck Says:

    THAT’S a cervical vert?!?!? Holy jeebus!
    It’s also a *very* good demonstration of the “search image” hypothesis for why large fossils were not studied in earnest until much later than fossils shells, teeth, and the like. I would have simply thought it was a small, pock-marked boulder. I doubt anybody before the time of Cuvier would’ve ever registered it as anything else either.


  2. You all are naughty and causing problems. ;)

  3. Matt Wedel Says:

    Three months and one day, dude. That’s all you had to wait. SMH.

  4. Mike Taylor Says:

    I know, I know. Just couldn’t help myself. Plus I didn’t want to telegraph that obviously.

  5. Matt Wedel Says:

    Guess we gotta keep people on their toes, yeah? Like my photo of the unscaled-but-possibly-157-meter shark a few posts ago.

  6. Mike Taylor Says:

    You know it, bro.

  7. ijreid Says:

    Just back from Hawaii, and that looks a lot like the air bubbles from within igneous rock …

  8. Matt Wedel Says:

    Definitely some hot air involved here.

  9. Chase Says:

    Wow! That’s just an awesome find!


  10. Ridiculous. Those are obviously pneumatic spaces within an insanely large skull bone

  11. Shahen Says:

    Omg but if 3,6 m this animal could be huge size…. 100 m long ? what the hell,,,,

  12. Chase Says:

    Now that I think about it, could asteroids just be sauropod verts?

  13. Chase Says:

    See Dr. Wedel’s comment above…

  14. Nima Says:

    I knew this day would come. A mega-brachiosaur to outclass the OK apatosaurines. Just like B. altithorax outclassed all the mounted apatosaurs of last century. Mega-brachiosaurs, scaly T. rex impressions, and the Tschoppers trend of splitting sauropods not lumping them. Sweet times, are we in the 90s again?

  15. Matt Wedel Says:

    Um…better check the previous comments.

  16. Andrew Stuck Says:

    Well I feel stupid…….

  17. Ronald Says:

    No! So not funny! I mean, I can really appreciate a good joke but not about (new, record) gigapods.
    I can still feel the pain of disappointment by the Stromer-Aegyptosaurus joke:
    https://svpow.com/2008/04/01/aegyptosaurus-lost/


  18. I suspect you both suffer from a rare form of pareidolia which, rather than human faces, you two see sauropod vertebrae in places they don’t exist. :-D

  19. Brad Lichtenstein Says:

    Just reading this now – wow! Same thoughts, look at how much now-empty space among the bone matrix! The rock to your right (left edge of picture) looks similar in that regard, is there any (other?) sign of anything articulated with it? And just exactly how DO you go about excavating something that bloody big?! (The last is intended to be rhetorical, it’s been done and I bet I can find someone’s time-lapse video if I were awake)

    Wow! Who found it? Without the blog context, I’d’ve thought it an unusually large-pored lava rock, though looking again, impossibly so and probably not in a volcanic context. But I assume you were given the location? (I’m not asking where, though it would be neat to see in person, but that’ll be a while for me)

  20. Brad Lichtenstein Says:

    Glad I read the comments after posting, rather than not at all. Took me 3 times through to get it, though. Sigh. Ha ha. Sigh. Agree with the other disappointed people.

  21. Brad Lichtenstein Says:

    I see that would probably at least triple, probably quadruple, the record length. Oh well. I guess volcanic rocks had much larger vesicles than I’d realized. Yeah, another 3 months and a day would have been nice!

  22. Matt Wedel Says:

    That’s wind-eroded sandstone, not volcanic in origin. We have _tons_ of pictures of weird sandstone from that trip, and we’ll probably dole out more of it in due time.


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