Everything’s better with cervical ribs

March 15, 2019

You’ll remember that we’ve been playing with CM 555, a subadult apatosaurine of indeterminate species, though John McIntosh assigned it to Brontosaurus (then Apatosaurus) excelsus. At the start of the week, we had the centra and neural arches of cervicals 1-14, plus there were some appendicular elements on a shelf that we’d not yet gone to. But then today, Matt found this drawer:

It contained a nice selection of cervical ribs that were part of the same specimen. Jackpot!

[You might notice that some of them have the specimen number 584 written on them. The history is that CM 555 and CM 584 came out of the same quarry, but most of the bones were initially thought to belong to a camarasaur which was designated CM 584. John McIntosh (1981:25) identified them as belonging to an apatosaurine, and they are now considered to be part of CM 555. The limb bones are catalogued separately as CM 556, but recognised as likely belonging to the same individual.]

Most of these ribs had field numbers written on them which were able to use to associate them with individual cervicals; and those that lacked these numbers, we could associate anyway, because the options were limited to a relatively small number of gaps. The upshot is that we know which vertebra each of these belongs to.

We have both ribs of C6, which is probably the best preserved single vertebra — centrum and arch — so I was able to rebuild the vertebra from its component parts. Matt was impressed:

And to be fair, I was pretty darned impressed myself:

Truly, this is a beautiful specimen. It was already pretty lovely, but putting the cervical ribs in place changed everything. It was totally transformed from a nice diplodocid cervical to an absolutely rock-solid slam-dunk apatosaurine — one to make grown men weep.

Here it is in right posterolateral view, just generally being awesome.


  • McIntosh, John S. 1981. Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the collections of Carnegie Museum of Natural History. Bulletin of the Carnegie Museum 18:1–67.


13 Responses to “Everything’s better with cervical ribs”

  1. FoundOnWeb Says:

    I can’t help but note that in the top two photos it looks like a little pot-bellied man with two big eyes, a big hat, and a moustache.

  2. Mike Taylor Says:

    FoundOnWeb, I see what you mean: that vertebra does have a Yosemite Sam vibe.

  3. MARCO Says:

    A rapid comparison with an old scan of B.excelsus cervicals material and I can totally see why McIntosh referred it to the species… Maybe you guys can point out some interesting difference!

  4. Cary Woodruff Says:

    Good Lord! I hadn’t seen those cervical ribs before. They definitely give the vert an entirely different vibe and beefy-to-the-max profile. So cool, and thanks for posting these awesome pics. Now we need good apatosaurine growth data…

  5. did you take sufficient photos so I can make you a 3d model?

  6. Matt Wedel Says:

    Hopefully so! Not only did we get a full 360 set of photos of the centrum, arch, and ribs all assembled as you see them in this post, we also got full sets of the separate elements. The gleam in our eye is to have photogrammetric models of all of the bits, so that people could 3D print a CM 555 c6 ‘kit’. With a drill, some rare-earth magnets and glue, one could make a set that snapped into articulation.

    We’re happy to send you photos, but we also don’t want to impose on your generosity. But if you’re offering…we’ll hook you up!

  7. Mike Taylor Says:

    We have big plans for 3D models!

    But we didn’t want to take advantage of you, so we were planning to ask the 3D Modeling Group at Matt’s university (yes, that’s a thing) to do this.

    However, if you want in, you are most certainly very welcome to participate!

    We have sets of photos that can be used to make the following 3D models:
    * The astragalus of CM 555 (should be easy)
    * The bite-marks on the tibia and fibula of same
    * The articulated centrum-arch-and-ribs of that specimen’s C6, as seen in this post
    * Separate photo-sets of each of those four component elements
    * Another cervical rib that is of particular interest
    * Potentially one or both of the big mounted sauropods in the public gallery

    And possibly some other bits that I’ve forgotten about. If youo fancy taking a stab at any of these, let me know and I can shoot the relevant photo-sets across to you!

  8. Mike Taylor Says:

    @Matt Jinx, buy me a beer.

  9. “impose”
    “take advantage”

    well, foff!

    wetransfer me the fuckin’ pics! That’s what I am here for.

  10. Mike Taylor Says:

    Many thanks, Heinrich! I will send you the first batch shortly!

  11. Mike Taylor Says:

    (For anyone who’s following along: I’ve sent Heinrich the photo batches for the astragalus, the interesting cervical rib, and the articulated C6 in this post. I think the first two should work fine. I am less sanguine about the third.)

  12. […] real colossus of the trip was CM 555, which we’ve already blogged about a couple of times. Just laying out all of the vertebrae and logging serial changes was hugely […]

  13. […] a lot of SV-POW! love over the years: it appears in several posts (like this one, this one, and this one), and in Fig 19 in our neural spine bifurcation paper (Wedel and Taylor 2013a). The section shown […]

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