(I wrote this post eleven months ago, but for some reason didn’t get around to posting it. Well, now I have. Not now, when I’m writing this sentence, but now, when you’re reading it.)

Back in 2019, when Matt and I were at the Carnegie Museum, we got to use a mobile stair platform to get up close and personal with the usually inaccessible cervical sequences of the mounted sauropod holotypes Diplodocus carnegii CM 84 (and lots of other specimens) and Apatosaurus louisae CM 3018.

As we’ve noted before, there are not a lot of dorsal views of sauropod vertebrae in the literature. While we were there, we were able to nab some of the anterior part of the neck of Apatosaurus, and from these I have prepared this composite image:

However, in Gilmore’s classic 1936 monograph primarily on this specimen, he illustrated this pair of vertebrae as follows:

As you can see, the upper part of the neural arch, including the postzygapophyses, the whole neural spine, and both the atlas rib and axis rib were all missing, and had to be reconstructed.

The axis rib is none of our concern since it doesn’t exist, even as a sculpture, on the mounted skeleton. (I wonder why not? Did it ever exist? Was it once there, but removed?) But here is the photographic composite from above, once more, this time with the faked up parts desaturated:

I suppose there is a moral here, which is our old friend: beware of taking mounted skeletons too literally. Even the best of them (and CM 3018 absolutely is among the very best!) can be terribly misleading.

Finally, here is a low-quality red-green anaglyph of the anterior part of the neck (first four cervicals) in dorsal view. This isn’t great as we didn’t think to take a good stereopair. Instead, this is made from near-duplicate photos where the camera just happened to move slightly between shots, so there is just a tiny bit of stereo separation.

Enjoy!

doi:10.59350/rxg46-akp95