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

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Matt and I have completed Day 2 of our excursion to the Carnegie Musuem in Pittsburgh. Day 1 was spent in the public galleries, because collections aren’t open on Sunday, but today we got into the Big Bone room.

One of our targets was CM 555, a very nice nearly complete neck (C1-C14) from a subadult apatosaurine — quite possibly Brontosaurus excelsus, which is what John McIntosh catalogued it as, though I am not yet 100% convinced it’s the same thing as YPM 1980, the holotype of that species.

We were able to lay out the full sequence on the floor, on styroforam sheets, and spend quality time just looking at it and thinking about it. I don’t just mean documenting it for later analysis, but making use of that precious time right there with the physical specimen to think through together what it’s telling us. We have a bunch of new insights, which we’ll share when we’re not completely exhausted.

Here’s Matt with the first six cervicals. C1 (the atlas) is as usual an unprepossessing lump, but then things get interesting. C2 to C6 are all unfused, so the centra and neural arches are separate.

Behind C6, the arches are fused to the centra (though the fusion lines are still apparent in C7 and C8). This is a nice example of how, in sauropods, serial position recapitulates ontogeny — one of the great confounding factors when studying isolated vertebrae.

We’ve learned a lot already from CM 555. Tomorrow will be spent with the two big mounted diplodocids (Diplodocus carnegii CM 84 and Apatosaurus louisae CM 3018). We’ll let you know how it goes. I predict: awesome.

Thanks to a comment from long-time reader Andrew Stuck, I realised he is also the tweeter @dinodadreviews, who pointed us to Xenoposeidon in a kids’ book. Now, a review on his website of Ted Rechlin‘s comic-book Jurassic has pointed me to what I think is the first depiction of the BRONTOSMASH! hypothesis in a kids’ book:

This is nice work: it captures the mass of the animals, and resists the nearly ubiquitous tendency to make their necks too slender and elegant. The necks do look rather too short here, but I think we can explain that away as perspective foreshortening.

You’d have to say, though, that it owes more than a little inspiration to the third of Brian Engh’s early sketches:

I suppose there are only a certain number of ways to draw two apatosaurs fighting.

Anyway, it’s great to see what we consider a solidly supported palaeobiological hypothesis out there influencing young hearts and minds. We should also take this as a well-deserved prod to get on with the actual paper, which after all was meant to follow hard on the heels of our 2015 SVPCA presentation.

By the way, folks: the spelling and punctuation is “BRONTOSMASH!”. Not “Brontosmash”, not “BRONTOSMASH”: all in capitals, with an exclamation mark. It’s “the BRONTOSMASH! hypothesis”.

 

WOW! I knew I was dragging a bit on getting around to this vertebral orientation problem, but I didn’t realize a whole month had passed. Yikes. Thanks to everyone who has commented so far, and thanks to Mike for getting the ball rolling on this. Previous posts in this series are here and here.

First up, this may seem like a pointlessly picky thing to even worry about. Can’t we just orient the vertebrae in whichever way feels the most natural, or is easiest? Do we have to think about this?

The alarmingly 3D pelvis of the mounted brontosaur at the AMNH. Note that sauropod pubes are usually illustrated lying flat, so what usually passes for ‘lateral’ view would be roughly from the point of view of the animal’s knee.

I think we do. For sauropods, vertebrae are usually oriented for illustration purposes in one of two ways. The first is however they sit most easily on their pallets. This is similar to the problem Mike and I found for ‘lateral’ views of sauropod pelvic elements when were on our AMNH/Yale trip in 2012. In an articulated skeleton, the pubes and ischia usually lean inward by 30-45 degrees from their articulations with the ilia, so they can meet on the midline, but when people illustrate the “lateral view” of a sauropod pubis or ischium, it’s often the ventro-lateral aspect that is face-up when the element is lying on a shelf or a pallet. Photographic lateral does not equal biological lateral for those elements. Similarly, if I’m trying to answer biological questions about vertebrae (see below), I need to know something about their orientation in the body, not just how they sit comfortably on a pallet.

The other way that vertebrae are commonly oriented is according to what we might call the “visual long axis” of the centrum—so for example, dorsoventrally tall but craniocaudally short proximal caudals get oriented with the centrum ‘upright’, whereas dorsoventrally short but craniocaudally long distal caudals get oriented with the centrum ‘horizontal’, even if they’re in the same tail and doing so makes the neural canals or articular faces be oriented inconsistently down the column. (I’m not going to name names, because it seems mean to pick on people for something I just started thinking about myself, but if you go plow through a bunch of sauropod descriptions, you’ll see what I’m talking about.)

Are there biological questions where this matters? You bet! There are some questions that we can’t answer unless we have the vertebrae correctly oriented first. One that comes to mind is measuring the cross-sectional area of the neural canal, which Emily Giffin did a lot of back in the 90s. Especially for the Snowmass Haplocanthosaurus, what counts as the cross-sectional area of the neural canal depends on whether we are looking at the verts orthogonal to their articular faces, or in alignment with the course of the canal. I think the latter is pretty obviously the way to go if we are measuring the cross-sectional area of the canal to try and infer the diameter of the spinal cord—we’d want to see the canal the same way the cord ‘sees’ it as it passes through—but it’s less obvious if we’re measuring, say, the surface area of the articular face of the vertebra to figure out, say, cartilage stress. It doesn’t seem unreasonable to me that we might want to define a ‘neural axis’ for dealing with spinal-cord-related questions, and a ‘biomechanical axis’ for dealing with articulation-related questions.

Caudal 3 of the Snowmass Haplocanthosaurus, hemisected 3D model.

With all that in mind, here are some points.

To me, asking “how do we know if a vertebra is horizontal” is an odd phrasing of the problem, because “horizontal” doesn’t have any biological meaning. I think it makes more sense to couch the question as, “how do we define cranial and caudal for a vertebra?” Normally both the articular surfaces and the neural canal are “aimed” head- and tail-wards, so the question doesn’t come up. Our question is, how do we deal with vertebrae for which the articular surfaces and neural canal give different answers?

For example. Varanus komodoensis caudal.

(And by the way, I’m totally fine using “anterior” and “posterior” for quadrupedal animals like sauropods. I don’t think it causes any confusion, any more than people are confused by “superior” and “inferior” for human vertebrae. But precisely because we’re angling for a universal solution here, I think using “cranial” and “caudal” makes the most sense, just this once. That said, when I made the image above, I used anterior and posterior, and I’m too lazy now to change it.)

I think if we couch the question as “how do we define cranial and caudal”, it sets up a different set of possible answers than Mike proposed in the first post in this series: (1) define cranial and caudal according to the neural canal, and then describe the articular surfaces as inclined or tilted relative to that axis; (2) vice versa—realizing that using the articular surfaces to define the anatomical directions may admit a range of possible solutions, which might resurrect some of the array of possible methods from our first-draft abstract; (3) define cranial and caudal along the long axis of the centrum, which is potentially different from either of the above; (4) we can imagine a range of other possibilities, like “use the zygs” or “make the transverse processes horizontal” (both of which are subsets of Mike’s method C) but I don’t think most of those other possibilities are sufficiently compelling to be worthy of lengthy discussion.

IF we accept “neural canal”, “articular surfaces”, and “centrum long axis” as our strongest contenders, I think it makes most sense to go with the neural canal, for several reasons:

  • In a causative sense, the neural tube/spinal cord does define the cranial/caudal axis for the developing skeleton. EDIT: Actually, that’s a bit backwards. It’s the notochord, which is later replaced by the vertebral column, that induces the formation of the brain and spinal cord from the neural plate. But it’s still true that the vertebrae form around the spinal cord, so it’s not wrong to talk about the spinal cord as a defining bit of soft tissue for the developing vertebrae to accommodate.
  • The neural canal works equally well for isolated vertebrae and for articulated series. Regardless of how the vertebral column is oriented in life, the neural canal is relatively smooth—it may bend, but it doesn’t kink. So if we line up a series of vertebrae so that their neural canals are aligned, we’re probably pretty close to the actual alignment in life, even before we look at the articular surfaces or zygs.
  • The articulated tails of Opisthocoelicaudia and big varanids show that sometimes the articular surfaces simply are tilted to anything that we might reasonably consider to be the cranio-caudal axis or long axis of the vertebra. In those cases, the articular surfaces aren’t orthogonal to horizontal OR to cranio-caudal. So I think articular surfaces are ruled out because they break down in the kinds of edge cases that led us to ask the question in the first places.

Opistocoelicaudia caudals 6-8, stereopair, Borsuk-Bialynicka (1977:plate 5).

“Orient vertebrae, isolated or in series, so that their neural canals define the cranio-caudal axis” may seem like kind of a ‘duh’ conclusion (if you accept that it’s correct; you may not!), but as discussed up top, often vertebrae from a single individual are oriented inconsistently in descriptive works, and orientation does actually matter for answering some kinds of questions. So regardless of which conclusion we settle on, there is a need to sort out this problem.

That’s where I’m at with my thinking. A lot of this has been percolating in my hindbrain over the last few weeks—I figured out most of this while I was writing this very post. Is it compelling? Am I talking nonsense? Let me know in the comments.

Well, that didn’t take long. Earlier today, my subterranean hacker collective released thousands of emails exchanged by Mike Taylor and Brian Engh, which touched on numerous issues of national and global security. Of most interest to SV-POW! readers will be this correspondence from just a few hours ago:

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Mike: Artwork attached. [Scroll down to see Mike’s submission.–MJW]

Brian: NAILED IT.

I haven’t been responding here to entrants but i feel pretty safe calling this one the winner already. Thank you for submitting. We can now sit back and laugh as all the other feeble entrants squabble knowing that you’ve already got this one in the bag.

Mike: Thanks, Brian. I hesitated before submitting this, thinking it might not be fair to up-and-coming artists who need the win more than I do; but in the end, I decided that was patronising. If they’re going to win the prize, they have to beat me on merit. You never know: it could happen.

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So, it looks like Brian has made his decision and the contest is effectively over. Although Mike says that someone else winning the contest “could happen”, Brian’s already signaled his intention to “laugh as all the other feeble entrants squabble”, which hardly sounds like he’s going to be giving anyone else a fair shake.

In Brian’s defense, the art that Mike submitted is glorious:

So complex and subtle is this work, so playful in its blending of traditional and cutting-edge thinking, so packed with detail, life history, and sheer emotion, that I feel certain that it will usher in a new era of paleoart as the dominant aesthetic expression on this planet.

Still, I don’t see how #TheSummonENGH2018 is going to survive the inevitable scandal of having a winner secretly chosen on the second day of the contest. I’m torn between towering admiration for my friends and colleagues, and fear for the rifts this may cause in the paleoart community.

I’ve reached out to representatives of both Mike and Brian for comment, and I’ll keep you updated on this developing story as more information becomes available.

Back in the spring of 1998, Kent Sanders and I started CT scanning sauropod vertebrae. We started just to get a baseline for the Sauroposeidon project, but in time the data we collected formed the basis for my MS thesis, and for a good chunk of my dissertation as well. Mostly what we had available to scan was Morrison material. Between imperfect preservation, inexpert prep (by WPA guys back in the ’30s), and several moves over the decades, most of the verts from the Oklahoma Morrison have their neural spines and cervical ribs broken off. One of the first things I had to figure out was how to tell broken vertebrae of Camarasaurus from those of Apatosaurus (at the time; Brontosaurus is back in contention now). Here’s a thing I made up to help me sort out cervical centra of Camarasaurus and whatever the Oklahoma apatosaurine turns out to be. It’s a recent production, but it embodies stuff from my notebooks from 20 years ago. Should be useful for other times and places in the Morrison as well, given the broad spatiotemporal overlap of Camarasaurus and the various apatosaurines.

For a related thing in the same vein, see Tutorial 30: how to identify Morrison sauropod cervicals.

More elephant seals soon, I promise.

UPDATE 20 Feb 2018

Ken Carpenter sent this by email, with a request that I post it as a comment. Since it includes an image, I’m appending to the post, because it makes an important point that I neglected to mention.

Camar post cerv

Ken: Sorry, Matt. Not so easy. The last cervical of Camarasaurus from the Cleveland Lloyd Quarry is more apatosaurine-like than Camarasaurus-like based on your posting. Note the position of both zygapohyses with both ends of the centrum.

My response: Yes, good catch. I meant to say in the post that my distinguishing characters break down at the cervico-dorsal transition. Even so, in this Cleveland Lloyd vert the postzyg is still forward of a line drawn directly up from the cotyle. I’ve never seen that in an apatosaurine–going into the dorsal series, the postzygs tend to be centered over a line projected up from the rim of the cotyle. (If anyone knows of counterexamples, speak up!)

For distinguishing cervico-dorsals, apatosaurines tend to have much taller neural spines than Camarasaurus, and this carries on through the rest of the dorsal series. In apatosaurine dorsals, the height of the spine above the transverse processes always equals or exceeds the height of the arch below the transverse processes. In Camarasaurus, the height of the dorsal neural spines is always less than or equal to the height of the arch. The shapes of the spines are fairly different, too. Maybe that will be the subject of a future post.

Turns out that if Mike and I don’t post about sauropods for a while, people start doing it for us! This very interesting project by Tom Johnson of Loveland, Colorado, first came to my attention when Tom emailed Mark Hallett about it and Mark kindly passed it on to me. I got in touch with Tom and asked if he’d be interested in writing it up for SV-POW!, and here it is. Many thanks to Tom for his willingness to share his work with us. Enjoy! – Matt Wedel

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The sauropod formerly known as Apatosaurus in the American Museum of Natural History was the first permanently mounted sauropod dinosaur in the world, and for many years, the most famous (Brinkman 2010). The greater part of the skeleton consists of the specimen AMNH 460 from the Nine Mile Crossing Quarry north of Como Bluff, Wyoming, supplemented with bones from other AMNH specimens from Como Bluff, Bone Cabin Quarry, and with plaster casts of the forelimbs of the holotype specimen of Brontosaurus excelsus (YPM 1980) at the Yale Peabody Museum.

A herd of Brontosaurus skeleton models parading before four box covers issued between the 1950s and 1990s.

Like many aging boomer dinophiles, my dinosaur epiphany was the result of books, movies, and toys available in the 1950s, but especially a series of plastic model dinosaur skeletons that appeared around 1958. The Brontosaurus was my personal favorite, and, like the Tyrannosaurus and Stegosaurus models in the series, was very obviously based on the AMNH mount. The models were reissued at least three times over the years and can still be found either “mint in box” or more often in various stages of completion.

Apatosaurus lousiae 1/12 scale skeleton, modelled by Phil Platt, assembled and photographed by Brant Bassam. Image courtesy of BrantWorks.com.

The crème de la crème today, of course, is the 1:12 scale Apatosaurus skeleton model by Phil Platt, available from Gaston Design in Fruita, Colorado. A particularly nice example is the one completed and mounted by Brant Bassam of BrantWorks. The Platt skeleton is a replica in the true sense of the word. The plastic models are pretty crude in comparison, as cool as they appeared to us as kids.

I was interested in skeletal illustrations I have seen of Tyrannosaurus rex, which compare the completeness of various specimens by showing the actual bones included by coloring them red. A 2005 study of Apatosaurus by Upchurch et. al. examined eleven of the most complete Apatosaurus individuals, and I was interested to see the actual bones known for each specimen. Using published descriptions, red markers, and copies of a skeletal silhouette of Apatosaurus (permission obtained from the artist), I prepared a comparison of the most completely known Apatosaurus specimens. It was clear, of course, that Apatosaurus louisae (CM 3018) is the most complete specimen of the Apatosaurus/Brontosaurus group. But it also was apparent that old AMNH 460 included a substantial portion of the skeleton, even if it is a composite.

I grabbed some additional markers and, using the illustration of the mount in William Diller Matthew’s popular book Dinosaurs (Matthew 1915, fig. 20, which I trust is in the public domain by now), I color-coded the bones according to the composition as listed in Matthew’s (1905) article:

  • AMNH 460, Nine-Mile Crossing Quarry: 5th, 6th, 8th to 13th cervical vertebrae; 1st to 9th dorsal; 3rd to 19th caudal; all ribs; both coracoids; “parts of” sacrum and ilia; both ischia and pubes; left femur and astragalus; and “part of” the left fibula. RED
  • AMNH 222, Como Bluff: right scapula, 10th dorsal vertebra, right femur and tibia. GREEN
    (Visitors to AMNH: you can see the rest of AMNH 222 under the feet of the hunched-over Allosaurus)
  • AMNH 339, Bone Cabin Quarry: 20th to 40th caudal vertebrae. LIGHT BLUE
  • AMNH 592, Bone Cabin Quarry: metatarsals of the right hind foot. VIOLET
  • YPM 1980, Como Bluff: left scapula, forelimb long bones (casts). YELLOW
  • The remaining parts of the skeleton are either modeled in plaster or are unspecified (“a few toe bones”). BLACK

It occurred to me that I might have sufficient spare parts of old ITC and Glencoe Brontosaurus models to create a three-dimensional version. I did, and painting prior to assembly definitely made the job easier.

There are obviously limitations to using Matthew’s (1915) reconstruction (e.g., only 13 cervicals) and the model (12 cervicals). It is also not clear from Matthew’s description how much of the sacrum and ilia were restored. Nevertheless, the painted model does provide a colorful, if crude, visualization of the composition of the composite.

Here are some more photos of the finished product:

A view from the front of the model, compared with a historical AMNH photo of the forelimbs and pelvic girdle.

Long considered a specimen of Brontosaurus excelsus or Apatosaurus excelsus, AMNH 460 was referred to Apatosaurus ajax by Upchurch et. al. in 2005. In the most comprehensive analysis of diplodocid phylogeny to date, Tschopp et. al. (2015) found AMNH 460 to be an “indeterminate apatosaurine” pending a “detailed analysis of the specimen.” What to call it? Oh, yeah, that’s been covered in another post!

This is a nostalgia shot for the old brontophiles. Notice that the Triceratops is entering the lake for a swim!

Tom Johnson with the mounted skeleton of Amphicyon, a Miocene “bear-dog”,
in the Raymond Alf Museum of Paleontology in Claremont, California.

References

  • Brinkman , Paul D. (2010). The Second Jurassic Dinosaur Rush, University of Chicago Press, 2010.
  • Matthew, William Diller, (1905). “The Mounted Skeleton of Brontosaurus,” The American Museum Journal, Vol. V, No. 2, April.
  • Matthew, W.D. (1915). Dinosaurs, With Special Reference to the American Museum Collections, American Museum of Natural History, New York.
  • Tschopp, Emanuel, Octávio Mateus, and Roger Benson. (2015). “A Specimen-Level Phylogenetic Analysis and Taxonomic Revision of Diplodocidae (Dinosauria, Sauropoda).” Ed. Andrew Farke. PeerJ 3 (2015): e857.
  • Upchurch, P., Tomida, Y., Barrett, P.M. (2005). “A new specimen of Apatosaurus ajax (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA”. National Science Museum Monographs (Tokyo) 26 (118): 1–156.