We were probably wrong about caudal pneumaticity in Ca13 of the Brontosaurus excelsus holotype YPM 1980
March 20, 2023
This is one of those posts where the title pretty much says it all, but here’s the detailed version.
Recap: the 2013 paper
In Matt’s and my 2013 paper Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus (Wedel and Taylor 2013b), we wrote about the Brontosaurus excelsus holotype 1980:
Much more convincing, however, are two isolated lateral fossae: one on the left side of caudal 9, the other on the right side of caudal 13 (Figure 10). Both of these are much larger than the aforementioned foramina – about 6 cm across – and have distinct lips. There is absolutely no trace of similar fossae in any of the other caudals, so these fossae represent a bilateral pneumatic hiatus of at least seven vertebrae
And we illustrated the right side of Ca13 in our figure 10:

Wedel and Taylor (2013:figure 10). An isolated pneumatic fossa is present on the right side of caudal vertebra 13 in Apatosaurus excelsus holotype YPM 1980. The front of the vertebra and the fossa are reconstructed, but enough of the original fossil is visible to show that the feature is genuine.
Fast forward to 2023
The Yale Brontosaurus has been dismounted and sent to RCI in Canada for some long overdue TLC. It’s being re-prepared, and Brian Curtice has seen the material close up. The news from Brian is not good: I quote some of his emails. First, on 26 January:
The 1980 caudal 13 it isn’t pneumatic. That whole hole is plaster. The 2 verts in front of it have similar damage but on the opposite side. It looks like they were damaged during preservation, excavation, or preparation.
Then on 27 January:
Quick caudal pneumatic update: other than the fact 1980 has a large number of what I dub nutrient foramina there isn’t any shiny surfaces, no odd sculpting, fluting, etc. the bone is exquisite in these areas but will soon be painted black.
Later that day:
It was also exceptionally difficult to sometimes tell what was actual bone. Barbour [1890 — ed.] is spot on at what Marsh had done. The preparators sometimes couldn’t be sure without acetone and an air scribe… I did the best I could but my goodness it was tough and may have errors. Thus I stayed towards what I was positive on.
On 3 February, I wrote back to Brian asking:
My question about the “pneumatic fossa” in caudal 13 is: why did they sculpt it like that? It would have been the simplest thing in the world to give it a simple flat lateral aspect, like the other caudals, so what made them put the fossa in? One possible answer is that that’s what the bone was actually like, but smashed up, and they “repaired” it. I guess we are unlikely ever to know.
He replied the same day:
There are 3 caudals (11-13, pics attached) with similarly damaged bone, punky and smashed and “beat up”, with 11 and 12 having the damage on the left and ventral and 13 on the right. I suspect they were lying close to one another. I couldn’t tell if it was trampling, but it didn’t seem like it was from being hacked from the ground.
[…]
As to why they did it? I suspect because 13’s damage wasn’t as jagged, they could plaster over it easier? We’ll never know for sure.
Brian sent a photo of the re-prepared caudal 13, showing … well, see for yourself:
Truthfully, I don’t find this especially compelling. But that’s about the inadequacy of photos for this kind of work. My inclination is to trust Brian’s interpretation, while wondering how Matt and I were both fooled back in June 2012 when we visited YPM together and spent significant time gazing at this caudal.
So what now?
The good news for us is that this doesn’t really change any of our arguments or conclusion in the 2013 paper. We said that there is previously undocumented evidence of caudal pneumaticity in apatosaurines[1] — and there still is, in the other specimen we figured, FMNH P25112, in our figure 9. And the significant conclusion of the papers was the intermittent and unpredictable pneumatization along the tails of sauropods is compelling evidence for extensive “cryptic pneumaticity” — that is, for soft-tissue pneumatization alongside vertebrae that did not penetrate the bone. That conclusion is still good.
But still: one of the data-points we relied on in making that argument no longer looks solid, and it feels like the honest thing is to document that. It probably doesn’t warrant a follow-up paper or even an erratum. But it does warrant a blog-post, and this is it.
Thanks to Brian for bringing it to our attention!
Notes
[1]. In the paper we said “in Apatosaurus“, not “in apatosaurines”. But that was back when Apatosaurus was the only recognized apatosaurine, so it amounted t0 the same thing. If we were writing it in the post-Tschopp-et-al. world of today, we’d say “in apatosaurines”.
References
- Barbour, Erwin H. 1890. Scientific News: 5. Notes on the Paleontological Laboratory of the United States Geological Survey under Professor Marsh. The American Naturalist 24(280): 388-400.
- Wedel, Mathew J., and Michael P. Taylor. 2013. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus.PLOS ONE 8(10):e78213. 14 pages. doi:10.1371/journal.pone.0078213 [PDF]
An arresting image of an apatosaur vertebra
March 3, 2023
Here’s a cool photo of an apatosaur cervical in anterior view. This is from R. McNeill Alexander’s wonderful book Bones: The Unity of Form and Function, which was published in 1994. The whole book is packed with gorgeous full-color photos like this, and you can still get new copies for cover price (f’rinstance).
I remember stumbling across this image not long after I started working on sauropod vertebrae back in the late 90s, and being completely taken aback by the size of the cervical ribs. Up to that point I’d mostly been grokking the long, graceful cervicals of brachiosaurs, and the ridiculously overbuilt apatosaurine cervical morphology was a real kick in the brainpan. That’s well-trod ground here at SV-POW!, but this is still a beautiful photo. I suspect that the vertebra has been at least somewhat restored — some of the texturing on the condyle and under the diapophyses looks suspiciously like it was applied with tools or maybe just human fingers — but in general this is a pretty faithful representation of what an apatosaur cervical looks like from the front.
One thing that always strikes me about views like this is that you could take the centrum of this vertebra, strip off the neural arch and all the apophyses, and stick it through either one of the cervical ribs loops without scraping the sides. If life, the cervical rib loops held the (comparatively small) vertebral arteries and the (comparatively gigantic) intertransverse diverticula. We know this because that’s how birds are built, and because different apatosaurine specimens show pneumatic traces almost all the way around the inside of the cervical rib loop. The same is true in theropods like Majungasaurus, as Pat O’Connor showed in a lovely figure in his 2006 paper (O’Connor 2006: fig. 16). The volume of air in each of the paired cervical rib loops would have simply dwarfed the volume of air inside or even alongside the centrum. I wanted to visualize that better so I took my trusty old CT cross-section of OMNH 1094 and pasted it on top of this vert, stretching it a bit in GIMP to improve the fit:
Another thing that this photo shows nicely are the pneumatic fossae on the anterior surfaces of the cervical ribs. I’ve seen those features on loads of apatosaur cervical ribs, but I’ve never seen them discussed anywhere. I have thoughts on why those fossae are there, but that story will have to keep for another time.
References
- Alexander, R. McNeill. 1994. Bones: The Unity of Form and Function. Macmillan General Reference, New York, 224 pp.
- O’Connor, P.M. 2006. Postcranial pneumaticity: an evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs. Journal of Morphology 267: 1199-1226.
How the Concrete Diplodocus paper came to be
February 23, 2023
Last time, I told you about my new paper, The Concrete Diplodocus of Vernal (Taylor et al. 2023), and finished up by saying this: “But Mike, you ask — how did you, a scientist, find yourself writing a history paper? It’s a good question, and one with a complicated answer. Tune in next time to find out!”
Paper 1
The truth is, I never set out to write a history paper. My goal was very different: to belatedly write up my and Matt’s 2016 SVPCA presentation, How Big Did Barosaurus Get? (Taylor and Wedel 2016). In that talk, we discussed a half-prepared jacket at BYU that contains three Barosaurus cervicals which are significantly larger than those of the well-known specimen AMNH 6341. And we went on to note that the giant “Supersaurus” cervical BYU 9024 is morphologically indistinguishable from those of Barosaurus, even though it’s going on for twice the size.
That paper (codename: superbaro) is in progress, and I would estimate it’s about 40% done. But in that paper, I needed to write a brief section in the introduction about AMNH 6341, the keystone specimen for Barosaurus, from which all our perceptions of that animal derive. And it turned out that in that section I had a lot to say, to the point where …
Paper 2
It became apparent that this section needed to be pulled out and become its own paper on the AMNH Barosaurus. As I worked on this, trying to get to the bottom of the complicated history of the mounted cast in the museum’s atrium, I got a lot of help from Peter May of Research Casting International, and from AMNH alumni Lowell Dingus and Gene Gaffney, to the point where they have all been added as authors to the ongoing manuscript.
That paper (codename: baromount) is in progress, and I would estimate it’s about 80-90% done. But in that paper, I needed to write a section on the sources of the various elements that make up the cast — they are not all from AMNH 6341, which is pretty complete as sauropods go but still has a lot of gaps. It turned out, after some poking about, that significant parts of the skeleton were Diplodocus casts, and that they had been made from molds taken from a concrete cast in Vernal, Utah. I started to write up the background information on this, but quickly realised that there was a lot to say, and that it needed to be extracted out into its own paper.
Paper 3

Taylor et al (2023:figure 4). Assembly of the outdoor concrete Diplodocus at the Utah Field House in 1957. (A) In right posterolateral view. The sacrum and fused ilia having been mounted on the main support to begin the process, the hind limbs, last four dorsal vertebrae and first caudal vertebra have now been added. (B) In left anterodorsolateral view, probably taken from the roof of the museum. The mount is almost complete, with only the forelimbs, their girdles and the dorsal ribs yet to be attached. Note that, contra Untermann (1959, p. 367–368), the skull is already in place. Both images scanned by Aric Hansen for the J. Willard Marriott Digital Library, image IDs 1090660 and 1090647. Used by permission, Uintah County Library Regional History Center.
That paper, of course, became The Concrete Diplodocus of Vernal. As I was working on it, I found myself constantly consulting park manager Steve Sroka, and quickly realised that the manuscript had reached the stage of being co-authored. Later in the process, significant contributions from Ken Carpenter went beyond the point of pers. comms, and he was added as a third author. (This paper also received a lot of help from other people, and the acknowledgements are correspondingly extensive and effusive.)
So that is the origin story of yesterday’s paper. But there is another chapter in this story …
Paper 4
As I was writing the section of this paper about the original Carnegie Diplodocus, and in particular about the composition of the mounted skeleton from which the original molds were (mostly) made, it became apparent that this, too, was a long and complicated story. And even though that story has been told in detail multiple times (most notably by Nieuwland 2019), there was still plenty to be told. So this section needed to be pulled out of the CDoV paper (where only a brief summary remains) and become its own paper.
That paper (codename: carnegie) is in progress, and I would estimate it’s about 90-95% done. It, too, has acquired co-authors, including Ilja Nieuwland himself and three Carnegie staff members, but cannot be completed yet as I await an important contribution from an indisposed co-author. Still, it should not be too long before that one is submitted — to be followed by baromount, and then finally superbaro.
So what’s happened here is that a perfectly innocent morphological description paper, based on a conference abstract and a 15-minute talk, has mutated into four substantial papers (of which, admittedly, only one is published so far).
The moral of this story
One moral is that I evidently have very little idea what I am going to work on at any given point in my career. As I was putting together the sidebar page on the Concrete Diplodocus paper, I stumbled across another sidebar page titled Mike’s open projects, which I made in 2020. It lists eight projects that I was going to work on. Of those, one (What do we mean by “cranial” and “caudal” on a vertebra?, Taylor and Wedel 2022) is complete; one (the superbaro project) has advanced but been interrupted by its three offspring papers; and the other six have pretty much not advanced at all (though I do still plan to do them all). Meanwhile, I have done a ton of work on projects that weren’t even on my radar back then, including pneumatic variation (Taylor and Wedel 2021) and finally putting a stake through the heart of neck incompleteness (Taylor 2022).
That’s the bad moral. But there is also a good moral. This is a nice example of what Matt wrote about way back in 2011, for Tutorial 12: How to find problems to work on. Once you actually get started working on something — anything — it will tend to sprout buds. And those buds can easily — too easily, sometimes — become new projects of their own. There is no such thing as a linear programme of research, at least not in my experience. Just an endlessly ramifying tree of fascinating areas that beg to be worked on.
References
- Nieuwland, Ilja. 2019. American dinosaur abroad: a cultural history of Carnegie’s plaster Diplodocus. University of Pittsburgh Press. ISBN: 978-0822945574. doi:10.2307/j.ctvh4zh5n
- Taylor, Michael P., and Mathew J. Wedel. 2016. How big did Barosaurus get?. p. 30 in Anonymous (ed.), SVPCA and SPPC 2016 Liverpool Abstract Book. 49 pp.
- Taylor, Michael P., and Wedel, Mathew J. 2022. What do we mean by the directions “cranial” and “caudal” on a vertebra? Journal of Paleontological Techniques 25:1-24.
- Taylor, Michael P., Steven D. Sroka and Kenneth Carpenter. 2023. The Concrete Diplodocus of Vernal — a Cultural Icon of Utah. Geology of the Intermountain West 10:65-91. doi:10.31711/giw.v10.pp65-91
… and I’m guessing that if you read this blog, you like at least one of these things.
Today sees the publication of a paper that I’m particularly pleased with, partly because it’s so far outside my usual area: The Concrete Diplodocus of Vernal — a Cultural Icon of Utah (Taylor et al. 2023). Let’s jump in by taking a look at the eponymous concrete Diplodocus:

Taylor et al. (2023:figure 5). The completed outdoor Diplodocus mount in a rare color photograph. Undated (but between 1957 and 1989). Scanned by Eileen Carr for the J. Willard Marriot Digital Library, image ID 415530. Used by permission, Uintah County Library Regional History Center.
(On of the things I love about this photo is that it has the same 1950s energy as the Carnegie Tyrannosaurus mount that I posted a while back.)
This paper tells the neglected story of how the Utah Field House museum in Vernal acquired the original Carnegie Diplodocus molds in 1957, after they had languished, unloved and overlooked, in their Pittsburgh basement for forty years; how they were used to cast a Diplodocus from actual concrete (one part cement to three parts aragonite, for those who care); how the molds then went on a series of adventures, never actually yielding another complete skeleton, before being lost or destroyed; how the concrete cast stood for 30 years before the harsh Utah weather degraded it past the point of safety; how it was then used to make a fresh set of molds, and replaced by a new lightweight cast taken from those molds; and how the molds were then used to create a new generation of Diplodocus casts.
It’s a long and fascinating story with lots of twists and turns that I necessarily omitted from that summary — which is why it runs to 27 pages in the lavishly illustrated PDF. I urge you to go and read it for yourself: we wrote it to be an engaging story, and I hope it’s a pretty easy read. (My wife found it interesting, and she once literally fell asleep while I was running a talk to solicit her feedback, so that’s really something.)

Taylor et al. (2023:figure 3). Field House Museum director G. Ernest Untermann (left), and his wife, Staff Scientist Billie Untermann (right), grouting the cast dorsal vertebrae of the Field House’s concrete Diplodocus. 24 January 1957. Scanned by Aric Hansen for the J. Willard Marriot Digital Library, image ID 1086940. Used by permission, Uintah County Library Regional History Center.
This paper was submitted on 2 November 2022, so it’s taken less than five months to go through peer review, editorial processes, typesetting with four(!) rounds of page proofs and online publication. This of course is how it should always be — it’s a bit stupid that I am drawing attention to this schedule like it’s something extraordinary, but the truth is that it is extraordinary. At any rate that makes it fifteen times faster than my long-delayed (mostly my fault) paper on neck incompleteness (Taylor 2022).
I got so deeply into this paper when I was lead-authoring it that the phrase “the Concrete Diplodocus of Vernal” really started to echo around in my head. That is why the paper ends by expressing this wish:
Our dearest hope for this paper is that it inspires someone to create a Dungeons and Dragons module in which the Concrete Diplodocus of Vernal is a quest artifact with magical powers.
But Mike, you ask — how did you, a scientist, find yourself writing a history paper? It’s a good question, and one with a complicated answer. Tune in next time to find out!
References
- Taylor, Michael P., Steven D. Sroka and Kenneth Carpenter. 2023. The Concrete Diplodocus of Vernal — a Cultural Icon of Utah. Geology of the Intermountain West 10:65-91. doi:10.31711/giw.v10.pp65-91
- Taylor, Michael P. 2022. Almost all known sauropod necks are incomplete and distorted. PeerJ 10:e12810. doi:10.7717/peerj.12810
DIY dinosaurs: more dinosaur bone standees
January 25, 2023

Michelle Stocker with an apatosaur vertebra (left) and a titanosaur femur (right), both made from foam core board.
In the last post I showed the Brachiosaurus humerus standee I made last weekend, and I said that the idea had been “a gleam in my eye for a long time”. That’s true, but it got kicked into high gear late in 2021 when I got an email from a colleague, Dr. Michelle Stocker at Virginia Tech. She wanted to know if I had any images of big sauropod bones that she could print at life size and mount to foam core board, to demonstrate the size of big sauropods to the students in her Age of Dinosaurs course. We had a nice conversation, swapped some image files, and then I got busy with teaching and kinda lost the plot. I got back to Michelle a couple of days ago to tell her about my Brach standee, and she sent the above photo, which I’m posting here with her permission.
That’s OMNH 1670, a dorsal vertebra of the giant Oklahoma apatosaurine and a frequent guest here at SV-POW!, and MPEF-PV 3400/27, the right femur of the giant titanosaur Patogotitan, from Otero et al. (2020: fig. 8). (Incidentally, that femur is 236cm [7 feet, 9 inches] long, or 35cm longer than our brachiosaur humerus.) For this project Michelle vectorized the images so they wouldn’t look low-res, and she used 0.5-inch foam core board. She’s been using both standees in her Age of Dinosaurs class at VT (GEOS 1054) every fall semester, and she says they’re a lot of fun at outreach events. You can keep up with Michelle and the rest of the VT Paleobiology & Geobiology lab group at their research page, and follow them @VTechmeetsPaleo on Twitter.
Michelle’s standees are fully rad, and naturally I’m both jealous and desirous of making my own. I’ve been wanting a plywood version of OMNH 1670 forever. If I attempt a Patagotitan femur, I’ll probably follow Michelle’s lead and use foam core board instead of plywood — the plywood Brach humerus already gets heavy on a long trek from the house or the vehicle.
Speaking of, one thing to think about if you decide to go for a truly prodigious bone is how you’ll transport it. I can haul the Brach humerus standee in my Kia Sorento, but I have to fold down the middle seats and either angle it across the back standing on edge, or scoot the passenger seat all the way forward so I can lay it down flat. I could *maybe* get the Patagotitan femur in, but it would have to go across the tops of the passenger seats and it would probably rest against the windshield.

Thierra Nalley and me with tail vertebrae of Haplocanthosaurus (smol) and the giant Oklahoma apatosaur (ginormous), at the Tiny Titan exhibit opening.
As long as I’m talking about cool stuff other people have built, a formative forerunner of my project was the poster Alton Dooley made for the Western Science Center’s Tiny Titan exhibit, which features a Brontosaurus vertebra from Ostrom & McIntosh (1966) blown up to size of OMNH 1331, the largest centrum of the giant Oklahoma apatosaurine (or any known apatosaurine). I wouldn’t mind having one of those incarnated in plywood, either.
I’ll bet more things like this exist in the world. If you know of one — or better yet, if you’ve built one — I’d love to hear about it.
References
- Alejandro Otero , José L. Carballido & Agustín Pérez Moreno. 2020. The appendicular osteology of Patagotitan mayorum (Dinosauria, Sauropoda). Journal of Vertebrate Paleontology, DOI: 10.1080/02724634.2020.1793158
- Ostrom, John H., and John S. McIntosh. 1966. Marsh’s Dinosaurs. Yale University Press, New Haven and London. 388 pages including 65 absurdly beautiful plates.
Apatosaurus cervical ribs and the tyranny of 2D images
December 8, 2022
Some quick backstory: lots of sauropods have long, overlapping cervical ribs, like the ones shown here in Sauroposeidon (diagram from this old post):
These long cervical ribs are ossified tendons of ventral neck muscles, presumably longus colli ventralis. We know they’re ossified tendons because of their bone histology (Klein et al. 2012), and we suspect that they’re longus colli ventralis because those tendons look the same in birds, just less ossified, as in this rhea (same specimens as these even older posts: 1, 2):
Diplodocoids have apomorphically short cervical ribs, which never extend very far past the end of their respective centra and sometimes don’t overlap at all. Still, we assume the long ventral neck muscles were there, just without long ossified tendons. Which brings me to Apatosaurus, which has cervical ribs that are anteroposteriorly short but famously massive, extending very below and/or to the sides of the cervical centra — for a truly breathtaking example see this post. Here are C3 through C7 in CM 3018, the holotype of Apatosaurus lousiae (Gilmore 1936: plate 24):
At least for me, it’s hard to resist the temptation to mentally scoot those vertebrae together into articulation, and imagine that the very swoopy-looking and maybe even down-turned cervical ribs allowed the ventral tendon bundles to wrap around the bottom of each cervical rib protuberance, something like this:
But it’s just not so, because like all 2D images, Gilmore’s plate distorts 3D reality. If you get to see the mounted skeleton in person, it’s clear that the cervical ribs are all more or less in line, and none of them are pointed at the big protuberances, which stick way out ventrolaterally.
Here I’ve drawn in the likely trajectories of the longus colli ventralis tendons. My little red pathways don’t precisely match the cervical ribs as mounted, but there’s a lot of distortion and restoration going on. For example, comparing with Gilmore’s plate we can see that the cervical ribs of C5, which point downward compared to all the others, only do that because someone forced them to — the whole anterior portion of the rib, where the shaft would actually join to the capitulum and tuberculum, is reconstructed. Even if I’m a little off, it’s clear that the cervical ribs shafts point backward, they’re all more or less in two parallel lines, and none of them point down and out toward the ventrolateral processes. The photo contains a mountain of useful morphological information that you’d never get from the lateral views.
My takeaways from all this:
- If a person has only seen 2D images of a specimen, and especially if those 2D images have only been orthogonal views with no obliques, their little island of knowledge is surrounded by at least a sizeable lake of ignorance, if not a small ocean.
- That doesn’t mean that seeing specimens in person is the only antidote — 3D models and 3D prints are extremely useful, and for specimens that are difficult to manipulate because of their size or fragility, they may be more useful than seeing or handling the specimen, at least for some questions.
- For Apatosaurus specifically, those ventrolateral processes cry out for explanation. They’re fairly solid knobs of bone that stick way out past the ossified tendons of the ventral-most neck muscles. That’s a super-weird — and super-expensive — place to invest a bunch of bone if you’re not using it for something fairly important, especially in a lineage that had just spent the last 80-100 million years making their necks as light as possible.
- Pursuant to that last point, we’re now in — ugh-ouch-shame — our 8th year of BrontoSMASH!!, with still just the one conference presentation to show for it (Taylor et al. 2015). Prolly time we got moving on that again.
References
- Klein, N., Christian, A., & Sander, P. M. (2012). Histology shows that elongated neck ribs in sauropod dinosaurs are ossified tendons. Biology letters, 8(6), 1032-1035.
- Taylor, M.P., Wedel, M.J., Naish, D., and Engh, B. 2015. Were the necks of Apatosaurus and Brontosaurus adapted for combat? 63rd Symposium on Vertebrate Palaeontology and Comparative Anatomy, Meeting Proceedings, p. 71, and PeerJ PrePrints 3:e1347v1. https://doi.org/10.7287/peerj.preprints.1347v1
Here’s that ventral-view apatosaur cervical anaglyph you ordered
December 4, 2022
Just to wash our mouths out after all the theropod-related unpleasantness yesterday:
What we’re seeing here, in glorious 3D, is the 7th cervical vertebrae of BYU 1252-18531. This is an apatosaurine at the Brigham Young University Museum of Paleontology which the museum has catalogued as “Apatosaurus excelsus” (i.e. Brontosaurus excelsus), and which Tschopp et al. (2015) tentatively referred to Brontosaurus parvus, but which I suspect is most likely good old Apatosaurus louisae.
It’s in the rarely seen ventral view, which really emphasizes the ludicrously over-engineered cervical ribs. Get your 3D glasses on and marvel at how they come lunging out of the screen at you, like giant insects in a 1950s B-movie.
So beautiful.
Putative atlantal ribs of Diplodocus
November 23, 2022
Last time, I showed you a photo of the head and neck of the London Diplodocus and asked what was wrong. Quite a few of you got it right (including Matt when we were chatting, but I asked him not to give it away by posting a comment). The 100 SV-POW! dollars, with their cash value of $0.00, go to Orribec, who was the first to reply that the atlas (cervical 1) is upside-down.
Here is again, from the other side:

The Natural History Museum’s Carnegie Diplodocus cast, skull and anterior cervical vertebrae in left lateral view. Photograph by Mike Taylor.
I noticed this — when it seems the people putting up the skeleton did not, unless this is a deliberate joke — because I happened to be particularly tuned into atlas ribs at the time. You can see what appears a tiny rib hanging below the atlas, but no neural arch above it projecting up and back to meet the prezygapophyses of the axis (cervical 2). In fact the “cervical rib” on this left side is the neural arch of the right side, rotated 180 degrees about the axis of the neck.
Here’s how this should look, from the Carnegie Museum’s own Diplodocus:

The Carnegie Museum’s Diplodocus mount, skull and anterior cervical vertebrae in left lateral view. Photograph by Matt Lamanna.
In this picture, the atlas seems to be pretty much fused onto the axis, as seen in Gilmore (1936: figure 6) which Matt helpfully reproduced in Tutorial 36.
(Digression 1: you might think that this atlas is the real thing, since the Carnegie’s mount is the one with the real CM 84/94/307 material in it. But no: the atlas does not belong to any of those, which all lack this element. It seems to be a sculpture, but we can’t figure out what it’s based on.)
(Digression 2: you might notice that the London and Carnegie skulls are rather different. That’s because the London cast still has the original skull supplied in 1907, which is a sculpture based on CM 622 (rear) and USNM 2673 (the rest), while the Carnegie’s mount at some point had its skull replaced by a cast of CM 11161 — though no-one knows when.)
(Digression 3: the diplodocine originally catalogued as CM 662, on which the rear of the skull was based, was named as the holotype of a new species Diplodocus hayi by Holland (1924), traded to the Cleveland Museum of Natural History in 1956 where it was numbered CMNH 10670, then traded on the Houston Museum of Natural History in 1963 where istbecame HMNS 175, mounted in Houston in 1975, remounted between 2013 and 2015, and finally moved to its own new genus Galeamopus by Tschopp et al. 2015. Yes, this stuff gets complicated.)
In fact, it’s amazing how much stuff we actually don’t know about these classic specimens, including the source of the atlas for both the Carnegie mount and the various casts — which are not the same. If only there was a single definitive publication that gathered everything that is known about these mounts. Oh well, maybe some day.
Now everyone knows that all the Carnegie Diplodocus mounts around the world were cast from the same molds, and so they all have the same altas <SCREEEECH> wait what?

The Muséum National d’Histoire Naturelle’s Carnegie Diplodocus cast, posterior part of skull and anterior cervical vertebrae in left lateral view. Photograph by Vincent Reneleau.
Here we are in Paris, and the atlas has these two honking great ribs. I have not seen these in any other Carnegie Diplodocus. I know they’re absent from the Berlin cast (thanks to Daniela Schwarz), from the Vernal re-cast (personal observation) and of course from the London cast. I would welcome observations (or even better, photos) from anyone who’s in a position to look at the Vienna, Bologna, Moscow, La Plata, Madrid or Mexico City casts.
So where did these atlas ribs come from? As with so much of this, no-one really knows. It’s especially mysterious as the Paris mount is supposed to be completely unchanged since its initial mounting. But some clue to the origin of the ribs in this mount is found in Holland (1906:249–250):
Accompanying the elements of the atlas sent to the writer for study by the kindness of Professor Osborn [i.e. AMNH 969] are two bones, undoubtedly cervical ribs. They are both bones belonging on the right side of the centra. They are reported to have been found at the same place at which the atlas was found. The writer is inclined to think that the larger of these two bones (Fig. 20), was probably the rib of the atlas and indeed it requires but little effort to see that it might very well have served such a function, and that the smaller bone (Fig. 21) was the rib of the axis. Were the stump of the rib which remains attached to the axis in the Carnegie Museum, and which Mr. Hatcher has figured, removed, this smaller rib might take its place and would undoubtedly articulate very neatly to the facet
In case you’re too lazy to go and look at Holland’s illustrations for yourself, here they are.
The atlas rib:
The axis rib:
Holland went on:
In case the view entertained by the writer is correct, the form of the atlas and the axis with their attached ribs would be as given in the accompanying sketch (Fig. 22) rather than as given in the figure which has been published by Mr. Hatcher. Such a location of these parts has in its favor the analogy of the crocodilian skeleton.
Here is that composite atlas/axis complex:
(This arrangement with closely appressed atlas and axis ribs should ring a bell for anyone who’s looked much at croc necks, as for example in Taylor and Wedel 2013:figure 19.)
The atlas ribs on the Paris mount look a decent match for the one illustrated by Holland (1906:figure 20), so it seems a reasonable guess that they were sculpted based on that element. But that only leaves us with two more mysteries:
- Why do we see these atlas ribs only on the Paris cast, not in the Carnegie original or any of the other casts (that I know of)?
- Why does this cast have atlas ribs based on one of Holland’s elements, but not axis ribs based on the other?
Anyone?
References
- Holland, W. J. 1906. Osteology of Diplodocus Marsh with special reference to the restoration of the skeleton of Diplodocus carnegiei Hatcher presented by Mr Andrew Carnegie to the British Museum, May 12 1905. Memoirs of the Carnegie Museum 2(6):225–278.
- Holland, William J. 1924. The skull of Diplodocus. Memoirs of the Carnegie Museum 9(3):379–403.
- Gilmore, Charles W. 1936. Osteology of Apatosaurus with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11:175–300 and plates XXI–XXXIV.
- Taylor, Michael P., and Mathew J. Wedel. 2013b. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs. PLOS ONE 8(10): e78214. 17 pages. doi:10.1371/journal.pone.0078214
What’s wrong with this picture? No, really: what’s wrong?
November 21, 2022
Last Saturday I was at a wedding at Holy Trinity Brompton, a London church that is conveniently located a ten-minute stroll from the Natural History Museum. As I am currently working on a history paper concerning the Carnegie Diplodocus, I persuaded my wife, my eldest son and his fiancée to join me for a quick scoot around the “Dippy Returns” exhibition.
Here is a photo that I took:
Something is wrong here — and I don’t just mean the NHM exhibition’s stygian lighting.
Who can tell me what it is? $100 in SV-POW! Dollars(*) awaits the first person to get it right in the comments.
(*) Cash value: $0.00.
I am co-authoring a manuscript that, among other things, tries to trace the history of the molds made by the Carnegie Museum in the early 1900s, from which they cast numerous replica skeletons of the Diplodocus carnegii mount (CM 84, CM 94, CM 307 and other contributing specimens). This turns out to be quite a mystery, and I have become fascinated by it.
Below is the relevant section of the manuscript as it now stands. Can anyone out there shed any further light on the mystery?
So far as we have been able to determine, the casting of the concrete Diplodocus of Vernal was probably the last time the Carnegie Museum’s original molds were used. However, that was not Untermann’s intention. In his 1959 account, he wrote (p368–369):
Several museums in the United States and from lands as distant as Japan and Italy have expressed a desire to acquire the molds and cast a Diplodocus of their own from either plaster or some of the newer synthetics. To date no museum has apparently been able to make satisfactory arrangement for the acquisition of the molds and the casting of a skeleton. We still have the molds in Vernal, and any museum, anywhere, is welcome to them just for hauling them off. […] The Diplodocus on the lawn of the Utah Field House is the eleventh replica to be cast from the molds […] Does anyone wish to cast the twelfth?
From here, though, the story becomes contradictory. Sassaman (1988) reported that “the molds finally fell apart because of old age soon after it [the concrete Diplodocus] was made”. Similarly, Ilja Niewland (pers. comm., 2022) said that “The original moulds were thrown away somewhere during the 1960s (nobody at the [Carnegie Museum] could be more specific than that)”, suggesting that the molds may have been returned to their origin.
Both these accounts seem to be in error, as shown by a 1960 report in the Vernal Express newspaper (Anonymous 1960a; Figure H; see also Carr and Hansen 2005). This says that in the middle of July 1960, the molds were collected by the Rocky Mount Children’s Museum (now the Rocky Mount Imperial Center, Children’s Museum & Science Centre) in North Carolina, with the intention that they would be used to create a twelfth cast which would be mounted outside the museum building next to the Tar River in Rocky Mount’s Sunset Park. But was such a cast ever created? A sequence of reports in the Rocky Mount Evening Telegram from April to July 1960 (Williams 1960, Bell 1960a, Bell 1960b, Anonymous 1960b) enthusiastically announce and discuss the impeding arrival, and the later articles say that museum board president Harold Minges has left for Utah to collect to molds — but then the newspaper goes silent on the subject, and the project is never mentioned again. There is no positive evidence that the molds even arrived in Rocky Mount, far less that they were used to create a new mount. Thus newspaper reports from both Utah and North Carolina say that the molds set out on their journey from one to the other, but neither confirms that they ever arrived. On the other hand, there is also no report of the molds being lost or destroyed, so perhaps the most likely interpretation is that they arrived in Rocky Mount, but were found to be in worse condition than expected and quietly left in storage. This interpretation is supported by Rea (2001:210) who reported that “from Vernal the molds kept travelling — first, to the Rocky Mount Children’s Museum in Rocky Mount, North Carolina, although a cast was never made there”. Similarly, Moore (2014:234-235) stated that “From Vernal, Utah, [CM] molds of Diplodocus carnegii are shipped to Rocky Mount Children’s Museum in Rocky Mount, North Carolina. Because of the age-related damage to the molds, a cast was never prepared”.
Hurricane Floyd devastated Rocky Mount in 1999, with flooding from the River Tar destroying the original Children’s Museum along with all its exhibits and records (Leigh White, pers. comm., 2022), so no records survive that could confirm the molds’ arrival or any subsequent use. The museum was located next door to a municipal water treatment facility that also flooded and released unknown chemicals, so museum property that might have otherwise been salvageable in that area was deemed contaminated and required to be destroyed. If the molds were in storage at the Children’s Museum at this time, then this was likely the end of their story.
The Children’s Museum was re-established at the newly built Imperial Centre, where it still resides, but no trace exists there of molds or casts of Diplodocus. Corroborating the hypothesis that no cast ever existed, most staff who worked at the museum in the 1980s do not recall any such cast (Leigh White, pers. comm., 2022). Contradicting this, however, Jan Engle Hicks, Curator of Education at the Rocky Mount Children’s Museum from 1971–2002, has a memory of Diplodocus casts being on exhibit at the museum when she started work in 1971. She does not recall if they were still part of the museum collection in 1999 when the collection was destroyed.
Whether or not a cast was made at Rocky Mount, it is possible that this was not the end for the molds. Rea (2001:210) continues: “Eventually the molds found their way to the Houston Museum of Science, where they were used to fill in gaps in the Diplodocus hayi skeleton that had been swapped from Pittsburgh to Cleveland before ending up in Houston”, citing a personal communication from John S. McIntosh. (The skeleton in question is that of CM 662, which became CMNH 10670 in Cleveland, then HMNS 175 in Houston. Having been nominated as the holotype of the new species Diplodocus hayi by Holland (1924:399), the species was later moved to its own new genus Galeamopus by Tschopp et al. (2015:267).)
Due to the loss of the Rocky Mount Children’s Museum records, we cannot tell whether they ever shipped the molds to Houston; and we have not been able to obtain information from the Houston Museum. Brian Curtice (pers. comm., 2022) reports that he was in Houston in 1995 and did not see the molds in the collection, nor hear of their ever having been there. In the absence of evidence that the molds ever made it to Houston, it seems at least equally likely that the missing bones in HMNS 175 were cast and supplied by Dinolab, using the second-generation molds described blow, and that Rea (2001) misreported this.
As recently as 1988, Rolfe (1988) wrote on behalf of the Royal Museum of Scotland, “At present I am exploring the possibility of re-using the Carnegie Museum, Pittsburgh moulds, although there is considerable doubt about whether they are up to the job, after so much previous use”. Sadly, his letter does not mention their then-current whereabouts.
In an unpublished manuscript, Madsen (1990:4) wrote that “The fate of the initial set of molds is somewhat in question, but Wann Langston (personal communication, 1989) suggests that they seem to have been lost, strayed, or stolen during transport from ? to ?. Principles contacted in regards to the disposition of the molds could not provide specific information.”. Infuriatingly, the question marks are in the original. Since both Langston and Madsen are now deceased, there is no way to discover on which of the molds’ journeys Langston thought they were lost or destroyed. It is unlikely, at least, that Langston had in mind the their initial journey from Vernal to Rocky Mount. Kirby (1998:4) wrote that “Somewhere along the line, as the story goes, the molds received from the Carnegie had been shipped to a school down south and never arrived. So they were lost”. Since Rocky mount is about 2000 miles east (not south) of Vernal, “a school down south” could not have referred, in a Utah publication, to a museum out east. The Houston museum also does not seems an especially likely candidate for this designation, being 1300 miles southeast of Vernal.
Putting it all together, there is no way that all the reports cited here can be accurate. Perhaps the most likely scenario is this: the molds were successfully shipped to Rocky Mount in July 1960 (Anonymous 1960a, Anonymous 1960b) but found to be unusable (Rea 2001:210, Moore 2014:234-235) and left in storage. At some later point there were shipped to a school in a southern state (Kirby 1998:4) but did not arrive (Langston cited in Madsen 1990:4). This may have happened in late 1988 or early 1989, between Rolfe’s (1988) letter that expressed an interest in using the molds and Langston’s personal communication to Madsen in 1989. Where the molds are now, and why they did not arrive, we can only speculate. As Madsen (1990:4) concluded, “It is truly a mystery that an estimated 3–6 tons of plaster molds could simply vanish!”
References
Anonymous. 1960a. Dinosaur molds take long ride to No. Carolina children’s home. Vernal Express, 14 July 1960, page 15. https://newspapers.lib.utah.edu/ark:/87278/s6zk6w6s/21338221
Anonymous. 1960b. Something ‘big’ for a fact. Rocky Mount Evening Telegram, 8 July 1960, page 4A. https://newspaperarchive.com/rocky-mount-evening-telegram-jul-08-1960-p-4/
Bell, Mae. 1960a. Dinosaur’s coming here brings questions galore. Rocky Mount Evening Telegram, 14 May 1960, page 2. https://newspaperarchive.com/rocky-mount-evening-telegram-may-14-1960-p-2/
Bell, Mae. 1960b. ‘Dinosaur’ soon to arrive here. Rocky Mount Evening Telegram, 3 July 1960, page 3A. https://newspaperarchive.com/rocky-mount-evening-telegram-jul-08-1960-p-8/
Carr, Elaine, and Aric Hansen. 2005. William Randolf Turnage, Dee Hall, and Ernest Untermann [archive photograph with metadata]. University of Utah, J. Willard Marriott Digital Library, image 1086142. https://collections.lib.utah.edu/details?id=1086142
Holland, William J. 1924. The skull of Diplodocus. Memoirs of the Carnegie Museum 9(3):379–403.
Kirby, Robert. 1998. Danny and the dinosaurs. Chamber Spirit (newsletter of the Vernal area Chamber of Commerce) 3(4):1–6.
Madsen, James H. 1990. Diplodocus carnegiei: Production and design of replica skeletons. Unpublished draft manuscript. (No author is named in the manuscript, but Madsen’s son Chris believes it is his work.)
Moore, Randy. 2014. Dinosaurs by the Decades: A Chronology of the Dinosaur in Science and Popular Culture. Greenwood, Westport, Connecticut.
Rea, Tom. 2001. Bone Wars: The Excavation and Celebrity of Andrew Carnegie’s Dinosaur. University of Pittsburgh Press, Pittsburgh, PA.
Rolfe, William D. I. 1988. Untitled letter to LuRae Caldwell (Utah Field House). 24 October 1988.
Sassaman, Richard. 1988. Carnegie had a dinosaur too. American Heritage 39(2):72–73.
Tschopp, Emanuel, Octávio Mateus and Roger B. J. Benson. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 2:e857. doi:10.7717/peerj.857
Untermann, G. Ernest. 1959. A replica of Diplodocus. Curator 2(4):364–369. doi:10.1111/j.2151-6952.1959.tb00520.x
Williams, Oliver. Pre-historic dinosaur to tower over city; giant animal four times taller than man. Rocky Mount Evening Telegram, 24 April 1960, page 3B. https://newspaperarchive.com/rocky-mount-evening-telegram-apr-24-1960-p-11/