An SV-POW! challenge: what is this vertebra?

May 25, 2016

Here is a vertebra that Matt and I saw on our recent travels through Utah:



I will explain in a subsequent post where we saw it, who gave us access, where and when it is from, and so on.

For now, I want people’s gut reactions: what is it?

34 Responses to “An SV-POW! challenge: what is this vertebra?”

  1. SM Says:


  2. ac Says:

    Some kinda of brachiosaurid?

  3. Andrew Says:

    While I have no idea what this is, other than some stinkin’ sauropod caudal vert (far anterior caudal? Ca1, Ca2?), I’ve used my sleuthing skills (zooming in on the second, anterior photo) to determine that this specimen is in the ‘College of Eastern Utah Prehistoric Museum’ collections. Which also means Ken Carpenter was the one who gave you access. And, having seen Eolambia material from their collections, and this is a total shot in the dark, this looks similar in color and preservation to fossils out of the Cedar Mountain.

    Sorry to jump the gun (in my defense, I’ve got next to no grasp of comparative sauropod vertebral anatomy), but it looks like your next post might have gotten scooped! ;)

  4. Andrew Says:

    *posterior photo

  5. Andrew Says:

    On the top, lateral photo, I can see the prezygapophysis on top and the postzygapophysis on bottom, but there’s a great big process sticking out on top, right next to the prezyg. Is that for a rib? Because it looks like there’s another articulate facet halfway down the pedicle, then another, right at the base of the pedicle, right above the centrum. What am I seeing there?

  6. Mike Taylor Says:

    The highest part of the vertebra in the top photo is the lateral process, which is swept somewhat forwards (probably by distortion). To its left on the photo is a much lower eminence which is the lateral view of the prezygs.

  7. Andrew Says:

    But right behind the prezyg, sticking out laterally, directly toward the camera? And might this be a posterior dorsal, instead of a caudal?

  8. Mike Taylor Says:

    Posterior to the prezyg is the parapophyseal facet — is that what you’re seeing?

    And, yes, we’re reading it as a dorsal, not a caudal.

  9. Andrew Says:

    Yup, that’s it. Parapophyseal facet.

    It looks like there’s a ridge extending central to that, with another articular facet at its end, right about the centrum. Is that the facet for the rib’s capitulum?

  10. Andrew Says:

    Never mind. I’m going to go center in the corner with a conical cap on my head.

    It’s been a minute since I’ve looked at vertebrae!

  11. Andrew Says:

    *sit in the corner

    Accursed autocorrect!

  12. Dean Says:

    I’ll stick my neck out and say a primitive brachiosaurid.

  13. Mickey Mortimer Says:

    Based on my gut without checking any references or reading any answers, I’ll guess anterior dorsal of Brachiosaurus. But knowing how rare brachiosaur material is in the Morrison, that’s probably unlikely…

  14. Mike Taylor Says:

    Andrew, I see that additional facet-looking structure you’re alluding to. I didn’t notice it when I was with the vertebra, and of course now it’s 7000 miles away. When I get a chance, I’ll look for it on my other photos and see whether I can make sense of it.

    Mickey, who said it was from the Morrison?

  15. tsk, tsk, MIKE! Did you not get photos for photogrammetry? I could calc you a model and you could easily CHECK for the facet-like structure!

  16. Mike Taylor Says:

    It’s a fair criticism, Heinrich. But remember that we did seven different museums in ten days. Only one of them (BYU) got more than a single day. At Price, we spent the morning at the Prehistoric Museum and only the afternoon in the CEUM collections (so I guess in effect that’s two different museums pushing our total up to eight!) and we had a lot of material to look at. So, no, this specimen did not get as much love as it deserved. Though I did photograph it from all six cardinal directions, at least.

  17. Mickey Mortimer Says:

    Fair enough, re: my Morrison assumption. Guess it could be an Abydosaurus or something…

  18. brian engh Says:

    While I am not so bold as to venture a hypothesis about the pictured bone, I would like to say that I’m stoked to see all the sauropocalypse posts on here!!!!

  19. Monolophosaurus Says:

    Cedarosaurus weiskopfae, final answer.

  20. Mike Taylor Says:

    That’s an intriguingly precise answer, Monolophosaurus. I realise I only asked for gut impressions, but if you’ve got specific reasons for favouring that ID, then I’d be interested to hear them.

  21. Monolophosaurus Says:

    Oh don’t ask me why, it’s just a completely random guess based on the fact that it is from Utah.

    I can’t tell you anything else other than that, I’m not an expert in anatomy or anything, I was honestly just randomly guessing at stuff.

    Probably a pretty premature guess, but that’s just the first thing I thought of.

  22. Mike Taylor Says:

    Oh, OK.

    Just for the record: this isn’t a quiz. We’re going to to reveal The Right Answer. We’re trying to figure out what the right answer is. I have an intuition about the bone, and I wonder if others’ intuitions matched mine.

  23. Nathan Myers Says:

    I’m going to go with an entirely ossified, unusually large rodent.

    But what do you think about EU’s determination that results of all research funded by the European public will be open access? I see a bit of weasel-wording about release of research data, but even that seems like a step forward, seeing as how most research data isn’t released even when the papers are OA.

  24. ijreid Says:

    Its definitely a Macronarian, no Diplodocus about it.

    I’m gonna be unique and say is looks a bit wide along the entire length for a brachiosaurid, so I’m guessing Sauroposeidon (or Paluxysaurus) for you sceptics of their synonymy.

  25. Andrew Says:

    What formation in Utah is contemporaneous with the Antlers/Cloverly?

    And is there osteological overlap for Paluxysaurus? There sure ain’t for Sauroposeidon!

    P.S. Mike never responded to my guess that this was Cedar Mountain…

  26. Brad Lichtenstein Says:

    Yeah, I’m with Andrew. Except on second look, I don’t think that’s a T-rib attach, so sauropod caudal. Assume it’s not the PR2 you mention from that stop. Not to chide, since I keep finding myself making similar “been here before, thought I knew better”, but wasn’t one of your protips to keep a scale device in your pocket, like for a keychain to ensure it’s always there? Seems too big for the ankylosaur caudals I did find trying to google the specimen ID, but same basic shape. All of which is not helpful if you’re really unsure. I guess that’s the …frustration? Joy? of the profession, to often have so little material to work with. Was anything else articulated?

  27. Jackal! Is it a jackal? It’s a jackal. Jackal?

  28. Mitchell Lukens Says:

    First, I like your answer, Zachary. Family Guy deserves a huge nod. Second, no scale bar?
    I agree its a dorsal (I think D7 or D8 based on the convexity of the anterior condyle). The centrum’s pleurocoels are high enough for Brachiosaurus, but the length of the lateral/transverse process is interesting…
    I also agree that it is from a macronarian sauropod, based on the lack of bifurcation in the neural spine.
    My guess is a basal titanosauriform, along the lines of Cedarosaurus.

  29. Mitchell Lukens Says:

    In the left lateral view of the vertebra in the top photo, the anterior-to-posterior length of the neural arch suggests macronarian, along with its rather short, ventral-to-dorsal height.

  30. Nima Says:

    This could be a macronarian but looks an awful lot like Amphicoelias in side view. The forward tilt to the spine is a bit hard to find in any macronarian I know of. And the dorsal known from A. altus is not bifid either, this seems a close match.

  31. ijreid Says:

    Nima, I have to say it is definitely not Amphicoelias altus. For one, A. altus is held in the AMNH, and as was stated above this one is from the College of Eastern Utah Prehistoric Museum.

    Also, while the side view does look a lot like a previous A. altus image posted on this blog, the specific details scream it is something different.

    To respond to Andrew, Paluxysaurus jonesi is known from cranial, cervical and appendicular material, in addition to 3 nearly or fully complete anterior dorsal vertebrae (d1, d2, and d3).

  32. Andrew Says:

    So… Nothing that would confirm that this was the same critter.

  33. Mike, I hear you about “too much stuff in too little time” :) Even if you are as fast as I have become and need only 7 minutes for this vert, doing 20 or 30 models will seriously eat into your time budget.

    Still, would have been cool ;)

  34. Nima Says:


    I would love for this critter to be a brachiosaur or even a Paluxysaurus… given that I like macronarians so much more than diplodocids in general.

    I just don’t see that happening with those tiny diapophyses (narrow ribcage, narrower than I’ve seen in any macronarian). They look very diplodocid. The lack of bifurcation in the spine indicates it could be from the posterior dorsals. And the forward tilt in the spine is similar to some diplodocids’ middle and posterior dorsals. Then there’s always the chance it could be a basal diplodocoid (rather than a flagellicaudatan) without any neural spine bifurcation at all.

    If we only went by the side view, it could pass for a Paluxysaurus anterior dorsal, those also have forward-tilted neural spines. But in front view, the stubby little diapophyses pretty much kill that theory stone cold. I know, it sucks… but those piddly lumps don’t belong anywhere near a Paluxysaurus, let alone a brachiosaurid. Giraffatitan for example has roughly 3x as much proportional elongation in the diapophyses of its posterior dorsals (relative to approximate vertebra height), and around 5-6x the elongation in the huge wing-like diapophyses of its anterior dorsals.

    And just because it’s not stored in the same museum as the A. altus holotype, doesn’t mean it’s not A.altus. It’s inevitable there are likely other A. altus specimens sitting undescribed in museum collections. That said, this was just a cursory impression based on Ken Carpenter’s Amphicoelias paper. It does resemble many other diplodocoids as well.

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