Unworn:

Worn:

Spent some time last week just admiring these things. They’re pretty cool.

EDIT: in answer to Mike’s question in the first comment below, here’s a photo of some more worn teeth, showing that the level of wear in the one shown above is not unusual. Also, all of these worn teeth still had full roots, with no sign of the root resorption that would have preceded shedding of the tooth, so they were evidently going to be used for a while yet, probably a few months at least — BUT see the very useful comment from Jens Kosch below on the likely rapidity of tooth replacement in Camarasaurus.

DINO collections - more worn Camarasaurus teeth

Nothing too serious here, just a fun shot I got while in the collections at BYU this past week. The Brachiosaurus element is metacarpal 1 (thumb column) from BYU 4744, the Potter Creek material. I highlighted my own metacarpal 3. There is a metacarpal 3 from this specimen, but I didn’t see it on the shelf. According to D’Emic and Carrano (2019), the MC3 is 60cm long, vs 57cm for this MC1. So this photo could have been 3cm more impressive!

Oh, ignore the tag on the left that says “radius”. You could be forgiven for thinking that the bone I have my hand on is a radius, but the radius from this individual is 1.34 meters long, or about two-and-a-third times the length of this metacarpal.

Reference

D’Emic, M.D. and Carrano, M.T., 2019. Redescription of Brachiosaurid Sauropod Dinosaur Material From the Upper Jurassic Morrison Formation, Colorado, USA. The Anatomical Record.

Spotted this beauty in the collections at Dinosaur Journey this past summer. With the front end of the centrum blown off, taphonomy once again proves to be the poor man’s CT machine, giving us a great look at the pneumatic spaces inside the vertebra.

EDIT, Oct. 13, 2019 — WHOOPS! That ain’t a cervical. Based on the plates in Madsen (1976), it’s a dead ringer for the second dorsal vertebra.

Allosaurus fragilis cervicodorsal transition - Madsen 1976 plates 14-16

Vertebrae C7 through D3 of Allosaurus fragilis in anterior view, from plates 14-16 in Madsen (1976). Abbreviations: dp, diapophysis; li, interspinous ligament scar; nc, neural canal; ns, neural spine; pp, parapophysis; pr, prezygapophysis.

Reference

Madsen, Jr., J.H. 1976. Allosaurus fragilis: a revised osteology. Utah Geological and Mining Survey Bulletin 109: 1-163.

In a word, amazingly. After 6 days (counting public galleries last Sunday), 4300 photos, 55 videos, dozens of pages of notes, and hundreds of measurements, we’re tired, happy, and buzzing with new observations and ideas.

We caught up with some old friends. Here Mike is showing an entirely normal and healthy level of excitement about meeting CM 584, a specimen of Camarasaurus from Sheep Creek, Wyoming. You may recognize this view of these dorsals from Figure 9 in our 2013 PeerJ paper.

We spent an inordinate amount of time in the public galleries, checking out the mounted skeletons of Apatosaurus and Diplodocus (and Gilmore’s baby Cam, and the two tyrannosaurs, and, and…).

I had planned a trip to the Carnegie primarily to have another look at the Haplocanthosaurus holotypes, CM 572 and CM 879. I was also happy for the chance to photograph and measure these vertebrae, CM 36034, which I think have never been formally described or referred to Haplocanthosaurus. As far as I know, other than a brief mention in McIntosh (1981) they have not been published on at all. I’m planning on changing that in the near future, as part of the larger Haplocanthosaurus project that now bestrides my career like a colossus.

The 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 useful.

Incidentally, in previous posts and some upcoming videos, we’ve referred to this specimen as Brontosaurus excelsus, because McIntosh (1981) said that it might belong to Apatosaurus excelsus. I was so busy measuring and photographing stuff that it wasn’t until Friday that I realized that McIntosh made that call because CM 555 is from the same locality as CM 563, now UWGM 15556, which was long thought to be Apatosaurus excelsus but which is now (i.e., Tschopp et al. 2015) referred to Brontosaurus parvus. So CM 555 is almost certainly B. parvus, not B. excelsus, and in comparing the specimen to Gilmore’s (1936) plates of CM 563, Mike and I thought they were a very good match.

Finding the tray of CM 555 cervical ribs was a huge moment. It added a ton of work to our to-do lists. First we had to match the ribs to their vertebrae. Most of them had field numbers, but some didn’t. Quite a few were broken and needed to be repaired – that’s what I’m doing in the above photo. Then they all had to be measured and photographed.

It’s amazing how useful it was to be able to reassociate the vertebrae with their ribs. We only did the full reassembly for c6, in part because it was the most complete and perfect of all of the vertebrae, and in part because we simply ran out of time. As Mike observed in his recent post, it was stunning how the apatosaurine identity of the specimen snapped into focus as soon as we could see a whole cervical vertebra put back together with all of its bits.

We also measured and photographed the limb bones, including the bite marks on the radius (above, in two pieces) and ulna (below, one piece). Those will of course go into the description.

And there WILL BE a description. We measured and photographed every element, shot video of many of them, and took pages and pages of notes. Describing even an incomplete sauropod skeleton is a big job, so don’t expect that paper this year, but it will be along in due course. CM 555 may not be the most complete Brontosaurus skeleton in the world, but our ambition is to make it the best-documented.

In the meantime, we hopefully left things better documented than they had been. All of the separate bits of the CM 555 vertebrae – the centra, arches, and cervicals ribs – now have the cervical numbers written on in archival ink (with permission from collections manager Amy Henrici, of course), so the next person to look at them can match them up with less faffing about.

We have people to thank. We had lunch almost every day at Sushi Fuku at 120 Oakland Avenue, just a couple of blocks down Forbes Avenue from the museum. We got to know the manager, Jeremy Gest, and his staff, who were unfailingly friendly and helpful, and who kept us running on top-notch food. So we kept going back. If you find yourself in Pittsburgh, check ’em out. Make time for a sandwich at Primanti Bros., too.

We owe a huge thanks to Calder Dudgeon, who took us up to the skylight catwalk to get the dorsal-view photos of the mounted skeletons (see this post), and especially to Dan Pickering, who moved pallets in collections using the forklift, and moved the lift around the mounted skeletons on Tuesday. Despite about a million ad hoc requests, he never lost patience with us, and in fact he found lots of little ways to help us get our observations and data faster and with less hassle.

Our biggest thanks go to collections manager Amy Henrici, who made the whole week just run smoothly for us. Whatever we needed, she’d find. If we needed something moved, or if we needed to get someplace, she’d figure out how to do it. She was always interested, always cheerful, always helpful. I usually can’t sustain that level of positivity for a whole day, much less a week. So thank you, Amy, sincerely. You have a world-class collection. We’re glad it’s in such good hands.

What’s next? We’ll be posting about stuff we saw and learned in the Carnegie Museum for a long time, probably. And we have manuscripts to get cranking on, some of which were already gestating and just needed the Carnegie visit to push to completion. As always, watch this space.

References

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.

References

  • 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.

 

We’ve posted a lot here about how crazy the cervical vertebrae of apatosaurines are (for example: 1, 2, 3), and especially the redonkulosity of their cervical ribs. But I think you will agree with me that this is still an arresting sight:

That’s MWC 1946, a mid-cervical from the Mygatt-Moore Quarry that was figured by Foster et al. (2018: fig. 18 A-B) and referred with the rest of the Mygatt-Moore apatosaur material to Apatosaurus cf. louisae (entirely correctly, in my view). This is a ventral view, with the condyle down by the scale bar.

Here’s the same thing cropped from the background to emphasize its unbelievableness:

and mirrored and restored a bit in GIMP to give a taste of its probable appearance in life (if you had an apatosaur, an x-ray machine, and a lot of confidence about not getting stepped on):

For obvious reasons, my nickname for this specimen is the Brontosmasher.

Keep in mind that the centrum was full of air in life, whereas the cervical ribs and the bony struts that support them are just huge slabs of bone. I strongly suspect that the volume of bone in the cervical ribs and their supporting struts is vastly more than in the centrum and neural arch. I will soon have the ability to test that hypothesis–I have this specimen on loan from Dinosaur Journey for CT scanning and 3D modeling. Watch this space.

Many thanks to Julia McHugh at Dinosaur Journey for access to the specimen and assistance during my frequent visits.

Reference

  • Foster, J.R., Hunt-Foster, R.K., Gorman, M.A., II, Trujillo, K.C., Suarez, C.A., McHugh, J.B., Peterson, J.E., Warnock, J.P., and Schoenstein, H.E. 2018. Paleontology, taphonomy, and sedimentology of the Mygatt-Moore Quarry, a large dinosaur bonebed in the Morrison Formation, western Colorado—implications for Upper Jurassic dinosaur preservation modes: Geology of the Intermountain West 5: 23–93.

I am still building up to a big post on vertebral orientation, but in the meantime, check out this caudal vertebra of a Komodo dragon, Varanus komodoensis. This is right lateral view–the vert is strongly procoelous, and the articular ends of the centrum are really tilted relative to the long axis. I find this encouraging, for two reasons. First, it helped me clarify my thinking on how we ought to orient vertebrae, which Mike wrote about here and here. And second, it gives me some hope, because if we can figure out why tilting your articular surfaces makes functional sense in extant critters like monitors, maybe we can apply those lessons to sauropods and other extinct animals.

This is LACM Herpetology specimen 121971. Many thanks again to Neftali Camacho for access and assistance, and to Jessie Atterholt for basically doing all the other jobs while I was faffing about with this Komodo dragon.