Tutorial 48: my museum collections kit

November 26, 2025

I was on the road for most of August, September, and October, and in particular I made a ton of museum collections visits. When I visit a museum collection, I bring a specific set of gear that helps me get the photos, notes, and measurements that I want. All of this is YMMV — I’m not trying to predict what will work best for you, but to explain what has worked for me, and why. I’m reasonably happy with my current setup, but even after 28 years of museum visits, I’m still finding ways to improve it. Hence this post, which will hopefully serve as a vehicle for sharing tips and tricks.

A word about my program when I visit a collection, because not everyone needs or wants to do things my way. The closest museums with extensive sauropod collections are states away from where I live and work. If I’m in those collections at all, I’m traveling, and therefore on the clock. Time in collections is a zero-sum game: if I have the time to take 20 pages of notes, that could be 4 pages of notes of each of 5 specimens, 2 pages on 10, 1 page on 20, half a page on 40, etc. In practice, I usually make expansive notes early in the visit, one or two spreads per specimen with detailed sketches and exhaustive measurements of the most publication-worthy elements. I grade toward brevity over the course of the visit, and end with a mad desperate rush, throwing in crude sketches and rudimentary notes on as many newly-discovered (by me) specimens as possible. My collections visits are Discovery Time and Gathering Time, trying to get all the measurements and photographs I’ll want for the next year, or five, or forever. And, to the extent that I can suppress them, not Analysis Time or Graphing Time or Writing Time — I can do those things after hours and in my office back home, IF and only if I’ve spent my collections time efficiently gathering all the information I’ll need later.

The very first thing I do in any collection is a walking survey, to make sure I know roughly what specimens the collection contains and where to find them. For a sufficiently large collection — or even a single cabinet with 10 drawers of good stuff — I may draw a map in my notebook, on which I can note things I want to come back and document, and add new things as I find them.

Enough preamble, on to the gear. The first two or three entries here are in strict priority order, and after that things get very fuzzy and approximate.

1. Research Notebook

Seems obvious, right? Write stuff down, make sketches, capture the info that will be difficult or impossible to recapture later from photos. I have encountered people who don’t take a physical notebook, just a laptop or tablet, and take all their notes digitally. If that works for you, may a thousand gardens grow. For me, sketching is a fundamental activity — for fixing morphology in my mind, disciplining myself to see the whole object and its parts, creating a template on which to take further explanatory notes, and capturing the caveats, stray ideas, and odd connections that surround each specimen in a quantum fuzz in my mind (temporarily in my mind, hence the need for external capture). I also write priority lists in advance of specimens to document each day, and then cross them off, add new ones, and strike out duds with wild abandon in the heat of data collection.

I do a few specific things to increase the usefulness of my notebooks:

– Label the spines and covers with the notebook titles and years. These things live on the shelf directly over my desk, and I pull them down and rifle through them constantly. I also have notebooks for university service (committees, student advising, and so on), astronomical observations, and personal journaling, so “Research” is a useful tag for me.

– Number the pages, if they’re not already numbered, use the books chronologically from front to back, and create the table of contents retrospectively as I go — a tip I got from the Bullet Journal method.

– Paste a small envelope inside the back cover, if a pouch is not already built in, to hold all kinds of ephemera — index cards, scale bars, a bandage (just in case), stickers I acquire along the way, etc.

– Affix a section of measuring tape to the outer edge of the front or back cover. I got this tip from the naturalist John Muir Laws, whose Laws Guide to Nature Drawing and Journaling is wonderfully useful and inspiring (UPDATE: that book is now covered in its own post, here). The scale-bar-permanently-affixed-to-research-notebook has been a game-changer for me. Do you know how many times I’ve accidentally left a scale bar on a museum shelf, and then gotten to my next stop and had to borrow or fabricate one? I myself lost count long ago. But never again. If I’m in a hurry, small specimens go straight onto the notebook to be photographed, like the baby apatosaurine tibia above, and the notebook itself goes into the frame with large specimens. (This comes up again — if possible, and it’s almost always possible, put the specimen label in the photo with the specimen. No reason not to, and sometimes a lifesaver later on.)

Behold the thinness of the eminently pocketable IKEA paper tape. Folding instructions, because this seems to bedevil some folks: hold up one end, fold in half by grabbing the other end and bring it up in front, then do that three more times. Finished product is 65mm long, 25.4mm wide, and about 1mm thick when folded crisply and left under a heavy book overnight.

2. Measuring tapes

I find the flexible kind much more convenient and useful than retractable metal tape measures. I like the 1-2mm thick plastic type used by tailors and fabric sellers, because they have just enough inertia to stay where I put them, or drop in a predictable fashion when draped over something sufficiently large, as when measuring midshaft circumference of a long bone.

I LOVE the little plasticized paper tapes that hang on racks, free for the taking, near the entrances of IKEA stores. I tear them off by the dozen when I go to IKEA, cram them in my pockets, fold them flat when I get home, and stash them everywhere, including in my wallet. A few specific reasons they’re great:

– Folded flat, they’re about the thickness of a credit card, so there’s just no reason to be without one. I usually have one in my wallet, another in the envelope at the back of my research notebook, a couple more stashed in my luggage, a couple more stashed in my car, desk, tookbox, nightstand, etc.

– I can write on them. Especially handy if:

– I’ve torn off a section to serve as an impromptu scale bar. Which I never hesitate to do, because they’re free and I have dozens waiting in my toolbox and desk drawers at any one time. Torn off bits also make good bookmarks, classier, more cerebral, and less implicitly gross than the traditional folded square of toilet paper.

– I give them away to folks I’m traveling with, or that I meet in my travels, and they’re usually well-received.

I would NOT have figured out all these laminae if I hadn’t had a way to make them stand out.

3. Writing instruments in various colors

Up until about 2018 my notebooks were always monochrome pen or pencil. Then I realized that color is an extremely helpful differentiator for Future Matt, so now I highlight and color-annotate willy-nilly.

4. Calipers

I borrowed the digital calipers from Colin Boisvert to get the photo up top, having forgotten my own at home. As a sauropod worker, I don’t need sub-millimeter accuracy all the time. But digital calipers have three exceedingly useful functions: measuring the thickness of very thin laminae and bony septa; measuring the internal dimensions of small fossae and foramina; and measuring the depth of fossae and of concave articular surfaces. I also have a little titanium caliper on a lanyard that goes with me most places.

5. Small brush on a carabiner

This is the newest addition to the kit. I got the idea from Matthew Mossbrucker at the Morrison Museum in Morrison, Colorado. Colin and I visited him in September, immediately before our week-long stint in the collections at Dinosaur Journey. Matthew keeps a little brush carabinered to his belt at all times, and the utility was so instantly obvious that when Colin and I rolled into Fruita later that same day, I went to the hardware store and got my own. Cheap, weighs nothing, clips to anything, compact enough to cram in a pocket, good for lab and field alike. Genius!

6. Scale bar

Yes, I have my scale-bar-enhanced research notebook and my hoarder stash of IKEA paper tapes, but good old-fashioned scale bars are still useful, and I use them constantly. And lose them constantly, hence my multiple redundant backup mechanisms.

(Aside: I can’t explain why I hold onto some objects like grim death, but let others fall through my fingers like sand grains. I’ve only lost one notebook of any kind in my entire life — set it on top of the car while packing and then drove off [grrrr] — so I have no problem investing in nice notebooks and treating them like permanent fixtures. But I can’t hang onto pens and scale bars to save my life, hence my having gravitated to Bic sticks and IKEA paper tapes.)

7. Index cards

I try to get as much information into each photograph as possible. Ideally alongside the specimen I will have:

– a scale bar at the appropriate depth of field;

– the specimen tag with the number, locality, and other pertinent info;

– my notebook open to my sketch of the specimen, for easy correlation later (I don’t do this for every single view, just the ones that I think are particularly publication-worthy, or have info I’m likely to forget later);

– anything else I might want — serial position, anatomical directions, whether the photo is part of an anaglyph pair, and so on — written on an index card, which being a standard size will itself serve as an alternate/backup scale bar.

8. Pencil case

To hold all the smaller fiddly bits you see in the photo up top. I can’t now fathom why, but I resisted getting one of these for a loooong time. I was young and foolish then. Pretty useful all the time, absolutely clutch when it’s 4:58 pm and I’m throwing stuff in bags, caught between the Scylla of working as late as possible and the Charybdis of wanting to be polite to whatever kind, patient person is facilitating my visit. That is also when the pocket in the back of the notebook comes in especially handy.

Headlamp in action, casting low-angle light on a pneumatic fossa on the tuberculum of this sauropod rib. Note also the scale bar, elevated on a specimen box to be the same depth of field, and the notebook open to my sketch of the specimen.

9. Artificial lighting

This was another very late discovery for me — I don’t think I was regularly bringing my own lights prior to 2018. For me, portable, rechargeable lighting is useful in many circumstances and absolutely critical in two: casting low-angle light to pick out subtle pneumatic features, as in the photo above, and lighting up big specimens that I don’t have the time, energy, or space to pull off the shelves, as in the photo below.

I’m particularly taken with the big orange fan/light combo. It charges using a USB-C cable, has four settings for fan speed (handy when it’s hot, humid, or just oppressively still) and three for light intensity, a rotating hook that folds flat, and a USB power-out socket for charging phones, headlamps, fitness trackers, and what have you. I use it practically every day whether I’m on the road or not.

Magnetic flashlight hanging from steel shelving to illuminate Camarasaurus cervical vertebrae in the Utah Field House collections.

Whether it’s a hook or a magnet, some kind of mechanism for suspending a light at odd heights and angles is super useful. I usually have a strong flashlight with an integral seat-belt cutter and window-smasher in the door pocket of my car, and its magnetic base makes it omnidirectionally functional in collections spaces, which are usually liberally supplied with steel in the form of shelving and cabinets.

Haplocanthosaurus CM 879 caudal 2 in left lateral view, with rolled-up paper neural canal visualizer and scale-bar-stuck-to-flashlight.

Sometimes I use a bit of blue tack to stick a scale bar to a flashlight, to create a free-standing, truly vertical scale bar that I can rapidly place at different distances from the camera. Beats leaning the scale bar against a stack of empty specimen boxes or a block of ethofoam (which in turn beats nothing at all).

What else?

USUALLY — Laptop

Not for recording notes or measurements — all of that goes into the notebook, which I scan and upload new stuff from every evening. Mostly for displaying PDFs of descriptive monographs, and hugely useful in that regard.

MAYBE — Monographs

When I have the freedom (= baggage allowance) to do so, I find it handy to bring hardcopies of descriptive monographs, both for quick reference and so I can photograph specimens alongside the illustrations. Doesn’t even have to be the same specimens, just comparable elements. In the photo above, MWC 7257, a partial sacral centrum of Allosaurus from the Mygatt-Moore Quarry, is sitting next to a plate from Madsen (1976), illustrating the same vertebra in a specimen from Cleveland Lloyd Dinosaur Quarry. Thanks to Colin Boisvert for bringing the specimen to my attention — I’ve got a longstanding thing for sacrals — and for loaning me his copy of Madsen (1976) for this photo.

OUT — Camera and tripod

I suspect that some folks will shake their heads in mute horror, but after a couple of decades of lugging dedicated cameras and tripods everywhere, I stopped. For the past few years I’ve been rolling with just my phone, which is objectively better than any dedicated camera I owned for the first half of my career. Sometimes I brace it in an ad hoc fashion against a chair or shelf or cabinet, but mostly I just shoot freehand. For my purposes, it does fine, and any minor improvements in field curvature or whatever that I’d get from a dedicated camera don’t outweigh the logistical hassle. Again: YMMV!

Over to you

So, that’s what I roll with right now. It was different six months ago, and will almost certainly be a little different six months hence, hopefully as a result of people responding to this post. With all that said: what’s in your kit?

P.S. Many thanks to Matthew Mossbrucker and Julia McHugh for their hospitality and assistance in their collections, and to Colin Boisvert for being such a great travel companion, research sounding board, and generous loaner-of-things-I’d-forgotten. The Wedel-Boisvert Morrisonpocalypse 2025 deserves more blogging.

 

doi:10.59350/c21vr-f8727

Posted by Matt Wedel
Filed in Allosaurus, camarasaurs, Carnegie Museum, caudal, cervical, collections, Dinosaur Journey Museum of Western Colorado, diplodocids, dorsal, Giant Oklahoma apatosaurine, how the sausage is made, measuring things, museums, notebook, OMNH, People we like, photography, ribs, sacral, stinkin' appendicular elements, stinkin' mammals, stinkin' SV-POW!sketeers, stinkin' theropods, tibia, tools, travel, Tutorial, Utah Field House of Natural History
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About that Saurophaganax paper

December 22, 2024

Newly out in VAMP:

Danison, Andy D., Wedel, Mathew J., Barta, Daniel E., Woodward, Holly N., Flora, Holley M., Lee, Andrew H., and Snively, Eric. 2024. Chimerism of specimens referred to Saurophaganax maximus reveals a new species of Allosaurus (Dinosauria, Theropoda). Vertebrate Anatomy Morphology Palaeontology 12:81-114.

Oh man, there is soooo much to say about this paper, which is a free download here. The short, short version is that OMNH 1123, the holotype specimen of the giant allosaurid Saurophaganax maximus, does not definitely belong to a theropod and may actually belong to a sauropod, and the same goes for some of the referred material, namely the atlas and chevrons. Since neither theropod nor sauropod material could be confidently assigned to Saurophaganax, we consider it a nomen dubium. That leaves a big ole pile of fossils from the Oklahoma panhandle that really do belong to a giant allosaurid, which we think is sufficiently distinct from Allosaurus fragilis and Allosaurus jimmadseni to warrant naming a new species, Allosaurus anax. If you want all the evidence and technical details and scientific reasoning, it’s in the paper, and some of it may make it into future blog posts. If you want to know what a weird ride this project has been, read on.

Who even are you?

The first point I want to make is that I myself have had just about every possible conflicting thought about the identity of OMNH 1123, the Saurophaganax holotype. I think chronologically I’ve gone through the following stages in this order: 

  1. thinking it belongs to a theropod, for essentially all of my life before Andy Danison contacted me and invited me onto the project;
  2. thinking it belongs to a sauropod, after Andy showed me how similar it is to the vertebrae of known juvenile sauropods;
  3. thinking it belongs to a theropod, more or less in a panic after I published my last post about Saurophaganax and then worried that we were wrong and we were going to make fools of ourselves (or, more flatteringly, I made the strongest case I could for a theropod identity to stress-test our hypothesis, which an accurate description of the outcome but a lie about my motivation);
  4. thinking it could plausibly belong to a sauropod, after Andy countered every point I raised in my “Saurophaganax is a theropod after all” push with photos of the same characters in the vertebrae of juvenile sauropods, which led to me agreeing with Andy and the other authors that designating Saurophaganax as a nomen dubium was the best move — this is the point of view that is crystallized forever in the new paper.

Also, I believe that at various points during the study the author team considered just about every possible scenario for dealing with the name Saurophaganax maximus, from thinking that it was a valid theropod genus and species, to thinking that it might be a valid sauropod genus and species (put a pin in that thought), to thinking that it was potentially valid but not definitively referrable to either Theropoda or Sauropoda, to realizing that if we couldn’t be certain if it was a theropod or sauropod, then no-one would be comfortable referring either theropod or sauropod material to it, which pushed us toward designating it a nomen dubium. We also considered a lot of potential taxonomic acts, including naming a new genus, naming a new species, or not naming the giant Oklahoma allosaurid and leaving it as Allosaurus sp. In the end, we decided a new species best captured our thinking about the material, and was most likely to be stable over the long run.

Am I sure about this?

Heck no! I’m the same guy who thought the Saurophaganax holotype was definitely a theropod, and definitely a sauropod. I remember the logic and evidence I used to reach each of those conclusions; I remember the certainty I felt in each one of those states; I remember the confidence that certainty gave me. But I think now that it was false confidence. I’m happy with the work we did in this paper, and I’m proud of it, and I think we came to the least-bad solution. But I’m sure this will not be the last word on Saurophaganax, and future authors may discover things we overlooked, or come back with a new perspective when and if new material of the giant Oklahoma allosaurid comes out of the ground.

Here’s what gives me pause: the accessory laminae in the Saurophaganax holotype are pretty much dead ringers for the spinoprezyg laminae (SPRLs) in the giant Oklahoma apatosaurine. I didn’t figure that out, Andy Danison did, and it’s one of those things that has just kept growing and growing in my mind, even after the paper was finalized. No other allosaurid or allosauroid or theropod of any description that I know of has prominent bars of bone in the same place, but they’d be expected in the neural arch of a juvenile diplodocid. And at this point I think it’s bordering on special pleading to argue that the giant Oklahoma allosaurid just happens to have these bars of bone, unique among theropods, that look identical to the SPRLs of a juvenile diplodocid, in a quarry dominated by diplodocids. So as of this evening/early morning, sitting here writing this post, I’ve about talked myself back around to thinking that the Saurophaganax holotype belongs to a sauropod, and possibly to a juvenile of the giant Oklahoma apatosaurine. 

The most obvious argument against is that whatever OMNH 1123 is, it had strongly-up-tilted transverse processes, like Haplocanthosaurus and a lot of theropods (see the Discussion in Boisvert et al. 2024) and very much unlike, say, OMNH 1366 and other dorsals of adult diplodocids. But I now think this is ontogenetically plastic — the juvenile Barosaurus specimens described by Melstrom et al. (2016) and Hanik et al. (2017) also have strongly up-tilted transverse processes. And in case I get hit by a bus before I can explain this more fully, it’s pretty clear that the neural arch telescopes in the dorsoventral direction over the course of ontogeny, and someone should work on that, too.

Anyway, the specter of Saurophaganax as a sauropod is a good segue to the next section.

What if we’re wrong?

I wrote up above about the comforting certainty of thinking that the Saurophaganax holotype definitely belonged to a theropod, or definitely belonged to a sauropod. I think that was in part because the intermediate idea, that OMNH 1123 could be either thing, feels inherently unstable to me. Surely someone will come along and point out some feature or combination of features that makes OMNH 1123 either definitely theropod or definitely sauropod. What then? Here are the possibilities I’ve thought of:

  1. OMNH 1123 definitely belongs to a theropod, and it’s diagnostic enough to hang a species name on: then it goes back to being Saurophaganax maximus or Allosaurus maximus depending on how people calibrate their genericometers, Allosaurus anax becomes a junior synonym, and we were just flat wrong (see our discussion of this possibility on p. 107 of the new paper).
  2. OMNH 1123 definitely belongs to a theropod, but it’s not diagnostic enough to hang a species name on: Saurophaganax remains a nomen dubium, just a nomen dubium with a home, and Allosaurus anax remains the valid name for the giant Oklahoma allosaurid.
  3. OMNH 1123 definitely belongs to a sauropod, but it’s not diagnostic enough to hang a species name on: Saurophaganax remains a nomen dubium, just a nomen dubium with a home (in Sauropoda or Neosauropoda this time), Allosaurus anax remains the valid name for the giant Oklahoma allosaurid, and the giant Oklahoma apatosaurine remains unnamed.
  4. OMNH 1123 definitely belongs to a sauropod, and it’s diagnostic enough to hang a species name on: well, Allosaurus anax remains the valid name for the giant Oklahoma allosaurid, and the implications for the giant Oklahoma apatosaurine are…real interesting.

I don’t think #1 is likely, but I don’t think it’s impossible. Option #2 seems the least likely to me: if OMNH 1123 belongs to a theropod, surely the unprecedented accessory laminae would make it highly diagnostic — this was the cornerstone of Dan Chure’s case in his 1995 paper naming Saurophaganax. Option #3 seems the most likely to me, for reasons explained above; instead of accessory laminae that are unique among theropods,* the weird bars of bone in OMNH 1123 would be bog-standard SPRLs, and the specimen could plausibly belong to any of several diplodocids known from Oklahoma Morrison.

* To be clear, the fact of some accessory laminae somewhere would not be unique to OMNH 1123 among theropods, but accessory laminae that mimic sauropod SPRLs would be.

It’s not super obvious which of these critters — if either — the name Saurophaganax might apply to. Gotta say, I did not have that on my bingo card before this year. Clash of the Titans exhibit at the Sam Noble Museum (OMNH).

Option #4 doesn’t seem very likely to me, but it is fascinating to consider the implications. I’ve long suspected that the giant Oklahoma apatosaurine represents a new species at least, based on a bunch of characters I’m not going into in this post, but I’ve never done the thesis-equivalent of work that it would take to persuasively demonstrate that. There is a scenario in which OMNH 1123 might be shown to belong to Apatosaurinae, in which case the combination Apatosaurus maximus could be on the table. Or Saurophaganax might become the third genus of apatosaurine alongside Apatosaurus and Brontosaurus, which seems insane, but there’s a plausible path to that result. OMNH 1123 wouldn’t be my first pick of holotype for the giant Oklahoma apatosaurine, and it could belong to a non-apatosaurine diplodociod, in which case no issues would arise for Apatosaurinae. Still, by lobbing the specimen vaguely (but not definitively!) sauropod-wards we may have created future headaches for sauropod workers in the Oklahoma Morrison. But we had to slay the dragon in front of us, not all the dragons everywhere forever.

Also, I should note that I’m a firm nominalist: to me names are hypotheses, and we should keep them around as long as they’re useful. I’m betting that Allosaurus anax is going to be a better fit for the giant Oklahoma allosaurid, but time will tell. And speaking of the name… 

The name

I love the name Allosaurus anax. I didn’t come up with it, Andy did. Here’s why I like it so much: 

  1. Most importantly, although we came to different conclusions than Chure (1995) about the identity of OMNH 1123, we like and respect Dan Chure and his work, and we didn’t want the new paper to be seen as a criticism of his work. I always thought Dan showed a lot of generosity of spirit in creating the name Saurophaganax maximus, honoring J. Willis Stovall and salvaging Stovall’s intent with the original, defunct name Saurophagus maximus. Similarly, I thought it was just perfect that Andy wanted to honor Chure’s work and salvage his intent by creating the species name Allosaurus anax.
  2. The species name anax means “king”, and there’s a nice parallel there to Tyrannosaurus rex. Allosaurus rex would sound derivative. I’m hardly unbiased here, but to me Allosaurus anax sounds wicked awesome.

Did someone say wicked awesome?

Our reviewers

If I could have picked any two peer reviewers in the world for this paper, I would have picked Jerry Harris and Tom Holtz. Jerry because he’s described skeletons of an allosauroid (Acrocanthosaurus, in Harris (1998) and a diplodocoid (Suuwassea, in Harris & Dodson 2004 and numerous subsequent papers), so he has experience with all of the clades where OMNH 1123 might land, and because he consistently gives very careful, constructive reviews. Tom Holtz because he’s extremely sharp on theropod morphology but knows a thing or two about non-theropod dinosaurs, too, and also provides very thoughtful reviews. In the actual event, we got them both, and I couldn’t be happier.

My coauthors

Wow, what a great team this was to work with. I went to grad school with Andrew Lee, but we never managed to publish together before this. I’ve admired Eric Snively’s work for years but never published with him before either, ditto for Holly Woodward and Danny Barta. Funny true story: the authorship order of the paper is different from that of the SVP abstract because Holly thought that she hadn’t done enough to earn second author status, and she wanted someone else to take it. But Danny and I both felt that way about our own contributions. In the end I let them persuade me, but I still feel odd about it — so much of what I did on this paper was just get schooled by Andy Danison. At best I think I was the whetstone to his blade, but he did all the cutting.

And that brings me at last to Andy. Good heavens, he worked his butt off on this project, in museum collections and in the literature, finding stuff I’d never noticed and making connections that had escaped me, and then explaining his findings to us with piercing clarity. It was humbling but also exhilarating, because I got to learn new stuff about sauropod vertebrae. I hope to get some of that stuff into a future post, but for now it’s way late and I must sleep. Congratulations, team! It’s been satisfying to work with each of you.

Parting shot: it’s beginning to look a lot like S’naxmas

Jenny and I were talking tonight about some of the big Jurassic Park/Jurassic World dinosaurs we have around the house, and I discovered that the Jurassic World Super Colossal Allosaurus was a thing. What could be better for a dinosaur-obsessed guy who just helped rename the real world super colossal Allosaurus? Jenny got online and found it in stock at the local Target, and I ended up racing through the store in the last five minutes before they closed to score one for myself. 

I hope to do some more blogging about this project. We didn’t go into it in a lot of detail in the paper, but some of the stuff Andy found has wild implications for Morrison sauropods. And it would be kinda cool to do a post-mortem on why I was certain that OMNH 1123 was a sauropod, then a theropod, and now maybe sauropod again. And talk about the referred specimens. And about pneumaticity. Just maybe not until after Christmas. Then again, who knows. I’m publishing on stinkin’ theropods now, so anything is possible. Watch this space.

Previous posts on Saurophaganax:

References

 

doi:10.59350/ffgmk-zjj78

Posted by Matt Wedel
Filed in Allosaurus, diplodocids, dorsal, Giant Oklahoma apatosaurine, stinkin' mammals, stinkin' SV-POW!sketeers, stinkin' theropods, toys
Tags: , , ,
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New paper: Atterholt et al. (2024) on neural canal ridges in dinosaurs

August 29, 2024

Bony spinal cord supports (arrows) in caudal vertebrae of several specimens of Camarasaurus. (a) Right lateral view of neural canal with broken vertebral arch, clearly exposing a bony spinal cord support (MWC 5496). (b) Anterolateral oblique view of the neural canal of the third caudal vertebra (SUSA 515) with a broken vertebral arch displaying a bony spinal cord support. (c) Right lateral view into the neural canal of the fifth caudal vertebra of SUSA 515, also with a broken arch allowing clear visualization of a bony spinal cord support. (d) Posterior view showing bony spinal cord supports in profile (CM 584). All scale bars = 5 cm. Atterholt et al. (2024: fig. 5).

New paper out, er, yesterday:

Atterholt, J., Wedel, M.J., Tykoski, R., Fiorillo, A.R., Holwerda, F., Nalley, T.K., Lepore, T., and Yasmer, J. 2024. Neural canal ridges: a novel osteological correlate of postcranial neuroanatomy in dinosaurs. The Anatomical Record, 1-20. https://doi.org/10.1002/ar.25558

This one started a bit over 10 years ago, on April 9, 2014. That morning I was at the off-site storage facility of the Perot Museum in Dallas, looking at juvenile Alamosaurus material from Big Bend National Park. I found this cute little unfused caudal neural arch, BIBE 45885:

Pro tip: before you go on to the next page or the next specimen, photograph the specimen with your notes and sketch. Trust me on this.

As you can see from my notes, I clocked the little ridges on the inside of the neural canal, but I didn’t know what to make of them. (BTW I’ve used this little feller in a bunch of talks and in my MTE paper last summer with Jessie — see Wedel & Atterholt 2023 and this post.)

That afternoon I was at SMU’s Shuler Museum of Paleontology looking at the holotype of Astrophocaudia, SMU 61732, which was then a new genus, having only been named the year before by Mike D’Emic (2013). And what should I see in this nice caudal:

Now I am not always the fastest on the uptake, but if you smack me in the face twice I start paying attention. Surely it was not a coincidence that the caudal vertebrae of these two not-super-closely-related sauropods had little ridges inside their neural canals. The problem was, I had no idea what they were. For a brief period I got excited by the possibility that they might be some epiphenomenon of big spinal veins, like those of crocs, or big paramedullary diverticula, like those of birds, but they didn’t look quite right for either of those applications (more on this in a future post, maybe, and in the discussion section of the new paper, definitely). I was just flat stumped.

Fast forward to the summer of 2018, by which time I was working with Jessie Atterholt on paramedullary diverticula — laying the groundwork for what would become Atterholt & Wedel (2022) — and generally getting interested in all things neural canal related, including the weird expanded neural canals in the Snowmass Haplocanthosaurus (see Wedel et al. 2021). I wrote to David and Marvalee Wake at Berkeley, both of whom had served on my dissertation committee, and who between them knew more about vertebrate morphology than anyone else I knew, to ask of they’d ever seen similar expansions of the neural canal. To my delight, David wrote right back, “This is a mystery to me. In salamanders there are little strut-like processes from the inside of the neural canal extending inward to support the cord. These are at least partly bony.” That didn’t help with Haplocanthosaurus — at that time still the newer mystery — but it did seem to solve my then 4-year-old quest to figure out what was going on in the Alamosaurus and Astrophocaudia caudals.

We’ll come back to sauropods, I promise. But first we gotta talk about meninges for a bit.

What’s the mater?

One of the bedrock bits of the chordate body plan is a connective tissue notochord running down the body axis, with a big nerve cord sitting on top and a big artery hanging just below. In vertebrates the notochord is mostly replaced by the vertebral column, and we refer to the big nerve cord as the spinal cord and to the big artery as the aorta. The vertebral column doesn’t just give the body stiffness and flexibility and something to hang muscles on, it also has a dorsal bony loop to protect the spinal cord, which we call the neural arch, and in the tail a ventral bony loop to protect the aorta, which we call the hemal arch (the V-shaped hemal arch bones are more commonly referred to as ‘chevrons’). The spinal cord runs through the neural arches of successive vertebrae, which collectively form a protective tube: the neural canal.

(NB: in human anatomy we tend to call the hole for the spinal cord in any one vertebra the ‘vertebral foramen’, and the canal formed by the stacked vertebral foramina the ‘spinal canal’, but in comparative anatomy we tend to use ‘neural canal’ for both the neural arch passage in a single vertebra and the tube formed by all the neural arches.)

The meninges and associated tissues in a mammal.

The spinal cord isn’t just flopping around in the neural canal willy-nilly. Like the brain, the spinal cord is jacketed in a series of protective membranes collectively called the meninges (singular: meninx). Mammals and most (all?) other tetrapods have three meninges:

  • outermost is the dura mater, or “tough mother” (same root as ‘durable’)
  • just inside the dura is the continuous layer of the arachnoid mater, or “spider(web) mother”
  • below the continuous layer of the arachnoid is the subarachnoid space, where cerebrospinal fluid (CSF) circulates; this space is crossed by numerous strands of arachnoid that reach down to the pia, and which look like spiderwebs in dissection, hence the name ‘arachnoid’ (thin blue radiating lines in the diagram above)
  • innermost, sitting intimately on top of the spinal cord and spinal nerve roots, is the pia mater, or “tender mother”

In mammals the space between the dura mater and the bony walls of the neural arch is filled with epidural fat. This isn’t unhealthy fat, this is fat used as packing peanuts — the lightest, cheapest thing the body can build.

(We’re a fat-0bsessed culture so it may sound weird to hear fat described as ‘light’ and ‘cheap’, but in fact it is. The metabolic demand of keeping fat cells alive is negligible,* and every other tissue or fluid is heavier and more expensive to maintain. The yellow marrow in the shafts of your long bones is made of fat, and your body will not use that fat for energy even if you are starving to death, because it would just have to be replaced with something heavier and more costly.

*Negligible, but not zero, and the work required to push blood through the extra miles of arteries that serve the fat deposits in obese people can put a lot of extra strain on the heart.)

The human spinal cord in dorsal view, with the denticulate ligaments indicated by asterisks. From Ceylan et al. (2012).

Last but not least there are denticulate ligaments, little sideways extensions of the pia mater that anchor the spinal cord to the inside of the dura mater. I drew them in pink in the diagram, but in dissection they are shiny white or silver; ‘denticulate’ means ‘little tooth’.

Some of these terms have entered the popular lexicon from medicine, particularly ‘meningitis’ and ‘epidural’. Meningitis is an inflammation of the meninges around the brain and spinal cord, which is exactly as horrible and life-threatening as it sounds. An epidural injection is used to deposit anesthetic medication into the epidural fat, where it can soak down through the meninges and bathe the dorsal root ganglia and the dorsal half of the spinal cord, where the sensory neurons (including those that relay pain) are located. In a lumbar puncture, a needle is driven through the dura and the continuous layer of the arachnoid into the subarachnoid space, usually to draw CSF for diagnostic purposes.

The meninges and associated tissues in a non-mammal. NB: this is generalized and simplified, and many structures that may also occupy the neural canal, like spinal veins and paramedullary diverticula, are not shown.

Here’s an important fact I didn’t know in 2014, having been educated most deeply on humans: many non-mammals don’t have epidural fat. Instead, the dura mater can be in contact with or even fused with the periosteum lining the inside of the neural arch, and the denticulate ligaments don’t just go to the dura, they go through it, to contact bone. And any time there’s connective tissue anchoring to bone, there’s a possibility that it will leave an attachment scar.

How do we know this? Salamanders, baby! Bony spinal cord supports were first identified in the northern two-lined salamander, Eurycea bislineata, by Wake and Lawson (1973) — Wake here meaning David Wake, who 41 years later would give me the clue I needed to interpret what I was seeing in sauropod caudal vertebrae. The trail went cold for a while after the 70s, but Skutschas (2009) and Skutschas & Baleeva (2012) found bony spinal supports — a.k.a. neural canal ridges (NCRs) — in a host of salamanders and fish.

The Floodgates Open

When you’re used to sauropods, even “giant” salamanders are pretty dinky. Unedited photo of a vertebra of the Chinese giant salamander, Andrias davidianus, LACM 162475. See the cropped version in Figure 1c of our new paper.

Standing on shoulders of Wake & Lawson and Skutschas & Baleeva, Jessie and I started finding neural canal ridges in all kinds of critters. We visited the herpetology collections at the LACM to verify that we could find them in salamanders, and documented them for the first time in the giant salamanders Andrias japonicus and Andrias davidianus. Skutschas & Baleeva (2012: fig. 5) had figured NCRs in a salmon (Salmo); on a visit to the OMNH I found them in a tuna (Thunnus). Jessie and I visited Dinosaur Journey in Fruita, Colorado, and found examples in Camarasaurus, Diplodocus, and more Apatosaurus vertebrae than you can shake a stick at (as always, many thanks to the MWC Director of Paleontology Julia McHugh for being an awesome host!).

Then other people started finding them. Jessie gave a talk on NCRs at SVPCA in 2019, the lovely meeting on the Isle of Wight, and Femke Holwerda said she’d seen them in a cetiosaur. At the same meeting Mick Green showed us rebbachisaruid material he’d collected from the Isle of Wight, and we found them in a rebbachisaur caudal. Jessie and I went to look for NCRs in the Raymond Alf Museum right here in Claremont, California, and Tara Lepore, who was helping us that day, found them in a hadrosaur caudal.

We even started finding them in previously published papers. Here’s a caudal vertebra of a juvenile Rapetosaurus from Curry-Rogers (2009: fig. 27):

This was a watershed moment — it meant that we could potentially expand our search for NCRs using the published literature. Later Jessie visited the Field Museum and was able to confirm the presence of NCRs in all the real (not cast or reconstructed) vertebrae of the mounted Rapetosaurus.

It gets better! Back in 2009 some goober named Wedel had been an author on the paper describing Brontomerus, and whadda we have here in Figure 6 of that paper?

Brontomerus caudal vertebra OMNH 61248. Taylor et al. (2011: fig. 6).

Truly, we notice what we are primed to notice, and sometimes not a heck of a lot more. In my defense, since getting my antennae out for NCRs I have had my hopes raised and then dashed many times by slightly offset cracks that just happen to run through the midpoint of the neural arch (it makes sense, the bone is thinnest there and most likely to crack), which is presumably what I inferred back when. For a better look at the NCRs in Brontomerus, see Figure 6 in the new paper.

Averianov & Lopatin (2020: fig. 8)

In 2020, Alexander Averianov and Alexey Lopatin described neural canal ridges in the holotype of the Mongolian sauropod Abdarainurus, and they identified them as bony spinal cord supports of the kind described by Skutschas & Baleeva (2012) — correctly, in our view. They’d been unaware of our work, which is not surprising since we’d only presented it in 2019 at SVPCA, and we’d been unaware of theirs. I was, in truth, a little chagrined to have dawdled long enough to be beaten into print (he writes, four and half years later!), but I sent Alexander a congratulatory note and he sent a very gracious response. Anyway, Jessie and I were happy to have more examples, and happy that Averianov & Lopatin’s interpretation of the NCRs agreed with ours.

Ugh — Allosaurus MWC 5492 on the left, hadrosaur RAM 23434 on the right. What a dark day for SV-POW! Scale bars are not sauropod sized so who cares. Atterholt et al. (2024: fig. 8).

And yes, Colin Boisvert, your groady perverted waaaay-too-abundant Allosaurus gets a look in. I hope you’re happy. Traitor.

What now? A short NYABPQ

(Not Yet Asked But Plausible Questions)

How do we know these things in sauropods and other dinos are ossified spinal cord supports and not some other wacky thing? I’d like to write a whole post on this, but in the meantime check out section 4.1 “Alternative hypotheses” on pages 14-16 of the new paper.

But what does it all mean? Section 4.2, “Functional implications”, has some half-baked ideas, but in truth we don’t know yet! We’re hoping someone else will figure that out.

What’s your favorite table in any paper ever? What an oddly specific and specifically flattering question, fictional interlocutor! The answer is Table 3 on page 17 of the new paper, in which we categorize the zoo of neural canal weirdness that we knew of when the paper went to press.

Wait — “that we knew of when the paper went to press”? What the heck does that obvious hedge mean? It means this rabbit hole goes all the way down, and we haven’t yet hit terminal velocity.

You’re kind of a weird dork, huh? Accurate!

I found NCRs in some critter in which they haven’t been documented yet — what should I do? Publish — publish! Jessie and I just spent six years getting this damned thing done and out, and we still have a shedload of weird neural canal stuff we haven’t even touched yet. We are the opposite of territorial, we’d strongly prefer for everyone and their dog to come play in our sandbox (not really ours but you know what I mean) and find lots of cool things and publish a million awesome papers and make neural canals the next hot thing. See Section 4.3, “Directions for future work”.

Stegosaurus NHMUK PV R36730 caudal 34. Right now this one Stego and the hadrosaur pictured above are it for NCRs in Ornithischia — but probably not for long. Maidment et al. (2015: fig. 49).

I haven’t found NCRs but I’d like to — what should I do? Go look in a bunch of neural canals. Seriously. That’s the gig. You might find some in the literature, but I wouldn’t count on a lot. You know who figures dinosaur caudals (1) in AP view (2) with the neural canals fully prepped (3) at sufficient detail to spot NCRs? Very few folks. At a reviewer’s request I spent some time plowing through a bunch of dino literature, and out of all the papers I checked, Susie Maidment’s stegosaur was the only new hit (Maidment et al. 2015, and kudos to Susie for the comprehensive illustrations). But someone who had access to a collection to ‘crawl’, logging all the NCRs, could do bang-up business. I know because that’s what Jessie and I did at Dinosaur Journey in 2018 and 2022, which is why there are so many MWC specimens in the new paper. Outside of Sauropoda we’ve found NCRs in Allosaurus, Ceratosaurus, Stegosaurus, and an indeterminate hadrosaur, and I don’t need to tell you that that is hardly a comprehensive survey of Dinosauria. We didn’t do more because we’re mortal and we wanted to get our sauropod paper out before it metastasized further, not because we were done, or even started, really. So if you want to discover new anatomy in dinosaurs, here’s a path with a very high likelihood of success.

What are you going to do next? The Greater Atterholt-Wedel Neural Canal Exploration Project (GAWNCEP) is still rolling, mostly under Jessie’s direction at the moment. As promised above, more weirdness is coming, watch this space. And when I’m not GAWNCEPtualizing, I, ahem, owe some folks some work on some projects. Just a few!

Special Thanks

Because you’re not supposed to thank your own coauthors in the acknowledgements: many thanks to Ron Tykoski and Tony Fiorillo for never giving up during the entire decade that it took to get from our first coauthored conference presentation to our first coauthored paper. Thanks to Femke and Tara for finding more NCRs and joining us on the paper, to John Yasmer for CT wizardry, and to Thierra Nalley for 3D recon wizardry and for being our resident non-sauropod vertebra expert. Y’all are great folks and it’s a pleasure to share the byline with you.

Dingler (1965: fig. 12) showing the elaborate ladder-like denticulate ligament system that suspends the spinal cord inside the synsacrum of a goose. Caption and labels translated by London Wedel.

At a crucial point in this project I needed a translation of Dingler (1965), which is was only available in German. I hired my son, London Wedel, then a high school senior taking German 4, to translate it. That translation will go up on the Polyglot Paleontologist at some point, but in the meantime you can get it here (Dingler 1965 bird spinal cord paper (translation)) and at the hyperlink in the references below. London just started classes at European University Viadrina Frankfurt (Oder), pursuing his long-held dream of attending university in Germany, and I couldn’t be prouder.

David Wake was the lecturer for the evolution course in my first semester at Berkeley. I invited him to serve on my qualifying exam committee because I knew he would terrify me into working my butt off — not, I must clarify, because he was a terrifying person, but because the depth and breadth of his erudition intimidated the crap out of me. I invited him to serve on my dissertation committee for the same reason. He always pushed me to think more broadly — in time, space, development, function, phylogeny, and evolution. Those seeds didn’t all germinate right away, but I can see that a lot of my intellectual range now is a result of his example and his prodding back then. I never had the opportunity to collaborate with David directly, but I get immense satisfaction from the fact that this entire project was born out of a suggestion of his. My coauthors Jessie Atterholt and Tara Lepore are also proud Berkeley grads, and we’re all happy to dedicate the new paper to the memory of David Wake.

References

 

doi:10.59350/p92gp-ey130

Posted by Matt Wedel
Filed in Abdarainurus, Alamosaurus, Allosaurus, Astrophocaudia, Brontomerus, camarasaurs, caudal, cross sections, dorsal, EKNApods, goose, gratuitous Cam-posting just to make Jessie happy, hadrosaurs, hands used as scale bars, juvenile, neural canal, neural canal ridges, Rapetosaurus, Stegosaurus, stinkin' appendicular elements, stinkin' every thing that's not a sauropod, stinkin' mammals, stinkin' ornithischians, stinkin' salamanders, stinkin' theropods, titanosaur, Titanosauriformes
30 Comments »

New paper out today on the Dry Mesa Haplocanthosaurus

June 18, 2024

Skeletal inventory of the Haplocanthosaurus bones found at Dry Mesa Dinosaur Quarry. Boisvert et al. (2024: fig. 2).

This morning saw the publication of my new paper with Colin Boisvert, Brian Curtice, and Ray Wilhite:

Boisvert, Colin, Curtice, Brian, Wedel, Mathew, & Wilhite, Ray. 2024. Description of a new specimen of Haplocanthosaurus from the Dry Mesa Dinosaur Quarry. The Anatomical Record, 1–19. http://doi.org/10.1002/ar.25520

Colin’s nexus of sauroponderous awesomeness

First off, big congratulations to Colin, who is having a banner season. On May 22 he gave his Masters thesis defense talk at BYU, on digital and physical articulation of the neck of BYU 18531, the “big pink apatosaur” from the Mill Canyon Quarry. You’ve seen that specimen in a few of our previous posts (notably here, midway down here, lurking in the background here), and Colin and his advisor, Brooks Britt, kindly gave Mike and me permission to publish some photos of one of the vertebrae in our recent cervical rib paper (Wedel and Taylor 2023).

As luck would have it, Colin is at NAPC this week, and this very morning he gave back-to-back talks. His second talk was a shorter version of his thesis defense talk, and his first talk was on (drumroll) Haplocanthosaurus: “Eleven specimens from ten locales in eight collections across three states, the diversity of known Haplocanthosaurus specimens in the Morrison Formation”, with Brian and Ray and me as coauthors. By sheer dumb luck, our paper dropped literally an hour or two before Colin’s Haplo talk, so when he got to the Dry Mesa individual he was able to plug the hot-off-the-presses new publication. That timing could not have been more perfect. Incidentally, the NAPC program and abstract book are both free downloads at this page; Colin’s abstracts are back-to-back on pages 125 and 126 (by internal numbering, pp. 135-136 of the PDF). 

Colin Boisvert, dropping knowledge at NAPC 2024.

 

It’s an especially momentous day because this is Colin’s first peer-reviewed journal publication — or, more accurately, of the several things he’s working on, this was the first to make it across the finish line. You’ll be hearing a lot more from Colin in the near future. (As Brian Curtice has pointed out, when someone has “vert” right in their name, we should be primed to expect great things. [NB: Colin’s last name is pronounced “bwa-VAIR” not “BOW-iss-vert”; replacing ‘vert’ with ‘air’ is, of course, the most sauropod-appropriate thing ever.]) We shall watch his career with great interest.

Enough back-patting, what’s this paper about anyway?

The quick version is that this paper is the longer, more complete, and more paleobiologically-informed version of our short paper for the 14th Symposium on Mesozoic Terrestrial Ecosystems and Biota (MTE14) last June (Curtice et al. 2023 and this post). As soon as we’d presented that, we realized that we needed to properly describe and illustrate every element of the Dry Mesa Haplo. Colin took point, and a year later, here we are.

So what do we have of this beast? Seven dorsal vertebrae and a right tibia, all found reasonably close together in a little pocket in the vast expanse of Dry Mesa Dinosaur Quarry. The vertebrae are obviously referable to Haplocanthosaurus because of their dorsally-oriented transverse processes, which instantly mark out Haplo from all the other known Morrison sauropods (note the caveat and hold that thought for the next a future post). The tibia is also referable to Haplo based on its chunkiness and the flared distal end, and it’s the right size to be from the same individual as the vertebrae. 

BYU 17531, a block of three anterior dorsal vertebrae preserved in articulation. The vertebrae are shown in right lateral (a), anterior (b), posterior (c), ventral (d), and dorsolateral (e) views. Scale bars are 10 cm. dp, diapophysis; hyp, hyposphene; nsp, neural spine; pcdl, posterior centrodiapophyseal lamina; pf, lateral pneumatic fossa; podl, postzygodiapophyseal lamina; poz, postzygapophysis; pp, parapophysis; prz, prezygapophysis; spol, spinopostzygapophyseal lamina. Boisvert et al. (2024: fig. 3).

Our best bit is BYU 17531, a series of 3 articulated anterior dorsal vertebrae. They record the migration of the parapophysis from low on the centrum up onto the neural arch, which is always nice to see. The block of three is a little sheared left-to-right, as shown in part D of the above figure. I’d love to get them CT scanned to investigate the articulations between the zygapophyses and the centra, a desire that only manifested as I was writing this post, looked again at the figure, and thought, “Oh, hey, intervertebral joint spacing!”

BYU 17530, a posterior dorsal vertebra. The vertebra is shown in anterior (a), posterior (b), left lateral (c), right lateral (d), dorsal (e), and ventral (f ) views. Scale bars are 10 cm. cprl, centroprezygapophyseal lamina; dp, diapophysis; hpn, hypantrum; hyp, hyposphene; lat. cpol, lateral centropostzygapophyseal lamina; nc, neural canal; pcdl, posterior centrodiapophyseal lamina; pf, pneumatic fossa; poz, postzygaphopysis; pp, parapophysis; prz, prezygapophysis; spdl, spinodiaapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Boisvert et al. (2024: fig. 6).

We also have four more posterior dorsals. I put them side-by-side in the skeletal inventory figure, but that was mostly out of laziness parsimony; most are too poorly preserved for us to get a firm fix on their serial position. We know that the best preserved of the bunch, BYU 17530, must be a pretty posterior dorsal, because the transverse processes are skinny and the neural spine is flared laterally (more anterior dorsals have dorsoventrally thicker transverse processes and narrower neural spines — see Hatcher 1903: plate 1, crucial bits of which are replicated at the top of this image).

Dorsal 12 of CM 572 in anterior (a), posterior (b) and right lateral (c) views, compared to BYU 17530, the best preserved posterior dorsal vertebra in anterior (d), posterior (e), and right lateral (f) views. Scale bar is 10 cm. Boisvert et al. (2024: fig. 7).

BYU 17530 is a pretty good match for D12 in CM 572, as shown in our figure 7. The top half of the anterior centrum face of the BYU vert is blown off, so we can see the large pneumatic fossae in the centrum, as well as the narrow median septum of bone that separates them. But that’s about the only significant damage, so I call BYU 17530 the “good dorsal”.

BYU 17689, a posterior dorsal vertebra. The vertebra is shown in anterior (a), posterior (b), left lateral (c), right lateral (d), dorsal (e), and ventral (f) views. Scale bars are 10 cm. cprl, centroprezygapophyseal lamina; dp, diapophysis; hpn, hypantrum; hyp, hyposphene; lat. cpol, lateral centropostzygapophyseal lamina; nc, neural canal; pcdl, posterior centrodiapophyseal lamina; pf, pneumatic fossa; poz, postzygaphopysis; pp, parapophysis; prz, prezygapophysis; spdl, spinodiapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Boisvert et al. (2024: fig. 8).

At the other end of the preservation quality spectrum, BYU 17689 is just happy to be here. The very tall neural arch pedicles and vaulted space over the neural canal are pure Haplo, and it’s from the same part of the quarry, same preservation, and right size to belong to our critter, but whew, that is a shard of excellence* for sure.

* For newer readers, sauropod vertebrae are never “pieces of crap”, no matter how badly broken. Rather, they are “shards of excellence”. The same idea could be extended to other clades. I can envision referring to poorly-preserved pneumatic vertebrae of theropods as “fragments of adequacy”. Broken ornithopod vertebrae are the “morning eye-boogers of Time”.

Haplocanthosaurus and Camarasaurus tibiae compared. USNM V 4275, a left Haplocanthosaurus tibia and astragalus (a), compared to BYU 12865, a right tibia (b), and YPM 5861, a left Camarasaurus tibia (c). Scale bar is 20 cm. The yellow line on USNM V 4275 represents the transition from tibia to astragalus. The cnemial crests for the two Haplocanthosaurus tibiae are incomplete. ap, anterior process; cc, cnemial crest; pp, posterior process. Boisvert et al. (2024: fig. 10).

The tibia, BYU 12865, is a little crushed and has some mid-shaft damage, but the flaring distal end is in good shape, enough to show that the bone is consistent with Haplocanthosaurus morphology.

What’s it all mean?

Why do we care about this critter?

First, as the title of Colin’s NAPC talk makes clear, there aren’t that many Haplos in the world — 11 to date, compared to over 200 for all the camarasaurs in the Morrison — so each new one is nice to have. In particular, the Dry Mesa Haplo has only the second set of articulated anterior dorsals for the genus, and the tibia helped us figure some things out regarding other Haplo specimens; more on that another time, perhaps.

Second, as we punched up in our MTE14 paper last year, this Haplocanthosaurus means that a minimum of six sauropod genera were present at Dry Mesa, making it the most diverse sauropod quarry in the world. I already wrote a whole post about that (link), so I’m not going to belabor it here, but it bears thinking about. Maybe six isn’t an unusual number of sauropods in an ecosystem, it just takes a quarry with 4000+ bones to capture them all. 

Third, a little push from our editor at the Anatomical Record got us thinking about why Haplocanthosaurus dorsal vertebrae are so distinctive. More on that in the next a future post.

For more posts on Haplocanthosaurus, see the running list on this page (link).

References

 

doi:10.59350/xfex2-2b397

Posted by Matt Wedel
Filed in conferences, dorsal, Haplocanthosaurus, Morrison Formation, NAPC 2024, People we like, stinkin' appendicular elements, stinkin' mammals, tibia
5 Comments »

Fossils of Jimbo the Supersaurus on exhibit

June 14, 2024

To answer Mike’s question from the last post, here’s a nice dorsal of Jimbo. All the material’s from the same quarry and has consistent preservation, and this dorsal is a monster. I didn’t try to measure it through the glass.

Hey guess what? It’s gonna be another really short photo post. Here are some pix of the Jimbo material on display at the Wyoming Dinosaur Center. Many thanks to Tom Moncrieffe of the WDC for taking a good chunk of his day to show me around.

Two partial cervical vertebrae, with part of a little one in between them, and a sectioned rib up on the shelf. I didn’t try to measure these through the glass either, but I’d estimate that each of the cervical centra is a meter and change in length, and both were a few cm longer when complete.

 

I don’t know if this pneumatic dorsal rib was too big, too dense, or too expensive to CT scan, but Dave Lovelace and colleagues did the next best thing: they sectioned it with a big rock saw. Pretty cool if you ask me.

 

Next cabinet going around clockwise has these dorsal vertebrae and a couple of broken neural spine tops. The vertebra on the left is the one shown in lateral view at the top of this post.

 

A tibia and a fibula. This is where it gets a little weird. I measured the other fibula, not on display, as being 116cm long. That sounds big, but it’s only a few cm larger than the fibulae of CM 3018 or AMNH 6341. So either Jimbo was unusually short-legged for the size of its vertebrae, or these limb bones belong to a different individual.

 

A proximal caudal and a huge chevron in the next cabinet.

 

And the rest of the caudals in that cabinet, a selection from different spots down the tail, with chevrons.

I have roughly 2376 interesting things I want to blog about, but my head is already about to split open with all the fascinating sauropod anatomy I’ve seen in the past few days, and I’m staring down the barrel of three more days of this. Stay tuned!

 

doi:10.59350/jp61r-esb50

Posted by Matt Wedel
Filed in caudal, cervical, diplodocids, dorsal, fibula, museums, stinkin' appendicular elements, Supersaurus, tibia, Wyoming Dinosaur Center
6 Comments »

Quick pix of ‘Jimbo’, the Wyoming Supersaurus

June 13, 2024

Another quick photo post from the road. The Tate Museum has a quality in common with the Oxford Museum of Natural History, where the guiding philosophy seems to have been, “Let’s put one of every interesting thing in the world in one big room.” Tucked into a corner is this small assemblage of cast bits of ‘Jimbo’, the Wyoming Supersaurus specimen described by Lovelace et al. (2008). 

Here’s a tibia.

And a dorsal vertebra. I’m such a ninny, because the centrum is a little out-of-round I assumed that this was a cast of BYU 9044, the ‘Ultrasauros’ holotype vertebra. I didn’t figure out that it was a piece of Jimbo until I was on the road. *facepalm*

Anyway, in sauropod circles we refer to vertebrae like this as “real darn big”, the last size category before “stupidly huge”.

A dorsal rib, upside down. Pneumatic! Some cool art by Russell Hawley lurking behind.

And here’s the Jimbo mount at the Wyoming Dinosaur Center in Thermopolis. 

Both the Tate and the WDC need a lot more nice things said about them by me, but this trip is still in progress, so all that will just have to wait.

Reference

 

doi:10.59350/mfqy0-3z472

Posted by Matt Wedel
Filed in casts, conferences, diplodocids, dorsal, museums, ribs, stinkin' appendicular elements, stinkin' mammals, stinkin' SV-POW!sketeers, Supersaurus, Tate 2024, Tate Geological Museum, tibia, Wyoming Dinosaur Center
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Four paths to studying pneumaticity inexpensively, and why you should

March 29, 2024

Why study pneumatic vertebrae? Becuz I wubs dem. UwU

This is one of those things that has been sitting in my brain, gradually heating up and getting denser, until it achieved criticality, melted down my spinal cord, and rocketed out my fingers and through the keyboard. Stand by for caffeine-fueled testifyin’ mode.

Part 1: Why Study Pneumaticity

Last item first: why you should study pneumaticity. The honest reason that primarily motivates me is that pneumaticity is frickin’ cool. Air inside bones! And endlessly novel — pneumatization is opportunistic and invasive (Witmer 1997), and it never quite works out the same way twice. So every time I see a pneumatic bone, inside or out, my antennae are up, because I suspect it will have its own little quirks and oddities, any one of which might unlock something new about the morphogenetic process of pneumatization or its functional importance.

D10 and sacrum of Diplodocus AMNH 516 in left lateral and ventral views (Osborn 1904: figure 3). Even 120 years later, there’s a lot going on here that we don’t fully understand.

If you need something more respectable than “Whoa, dude!” to put on a thesis proposal or a grant application, how’s this: we think that skeletal pneumaticity was a key innovation for both sauropods (Sander et al. 2011) and theropods (Benson et al. 2012) [edit: and pterosaurs {Claessens et al. 2009}], but our documentation of it is very poor. For a lot of sauropod genera, we’ve only CT-scanned one or two vertebrae, often from the same quarry, usually from a single individual. For a lot more, we’ve scanned none at all. As I wrote back in 2018, “Someone just needs to sit down with a reasonably complete, well-preserved series that includes posterior dorsals, all the sacrals, and the proximal caudals–or ideally several such series–and trace out all of the pneumatic features” (link). The same principle — “crawling” one or more specimens to document everything — could be extended to address intraspecific and interspecific variation, the extent to which pneumatic traces might relate to nerve and blood vessel pathways, and ontogenetic changes. We know that vertebral pneumatization got more extensive and more complex through an individual animal’s maturation, but we don’t know much about how and when that happened, or if it ever stopped in large and long-lived individuals. I don’t know what we’ll find when people get around to doing this, but there won’t be any boring answers — indeed, much of what I thought about the early evolution of pneumaticity for the last 25 years is probably wrong.

CT sections through a cervical vertebra of an apatosaurine, OMNH 1094 (Wedel 2003b: fig. 6). Scale bar is 10cm. How many other apatosaurine vertebrae (and not just cervicals) have you seen published cross-sections of? I know the answer, and it’s not great!

Whether you want to work on pneumaticity or not, definitely do not make the mistake of looking at the existing literature and assuming “it’s all been done“. I’ve probably spilled more ink about dinosaur pneumaticity than anyone else alive, and I’m telling you that the field is wide open. Just off the top of my head:

  • Sometimes pneumatized sauropod vertebrae have more bone than they need, because fossae are embossed into otherwise flat plates of bone that would be lighter if they lacked those fossae. What’s up with that? Does it ever happen in theropods (avian or otherwise) or pterosaurs?
  • I mentioned that pneumatic bones rarely look identical under the hood. Heck, they rarely look identical on the surface. Whether it’s internal or external asymmetry, or variable laminae, or some other thing, there’s a LOT of variation. How does that small-scale morphogenetic opportunism jibe with the apparent macroevolutionary importance of pneumaticity in sauropods and theropods [edit: and pterosaurs]?
  • Related: my a priori assumption is that pneumaticity was functionally important in non-avian theropods, more functionally important in sauropods (because size), and most functionally important in pterosaurs (because size x flight). That’s a wild guess, totally untested — but I’ll bet someone will figure out a way to test it, and variation vs developmental constraint seems like fertile ground for that testing.
  • Also related: does skeletal asymmetry (pneumatic or otherwise) have any predictable relationship with body size, either ontogenetically or phylogenetically? See this post and this one for some related noodling (but no answers).
  • For internal pneumatization, do bigger and older individuals make more chambers that are about the same size as the chambers in smaller individuals, or does the subadult level of complexity stay the same through adulthood, and the chambers get bigger but not more numerous? And is there even a single answer, or do different things happen in different lineages? These seem like fundamental questions, and I have my suspicions, but AFAIK neither I nor anyone else has addressed this. Put a pin this, it will come up again later in this post.
  • Barosaurus cervicals have a more complex internal structure than Diplodocus or Apatosaurus cervicals (check out the eroded condyle of this vertebra). Is that because Barosaurus cervicals are longer? Is there a functional reason we never see crazy long vertebral centra that are camerate?
  • Want to work on birds? Do some injections and dissections and see how often diverticula follow nerves and blood vessels as they develop. This idea, which has a lot of circumstantial support (Taylor and Wedel 2021), is based on a single observation from a paper published nearly a century ago (Bremer 1940).
  • Heck, if you’re doing injections and dissections, just document the diverticular network in a single bird, full stop. That’s a descriptive paper right there. Bird pneumaticity is so grossly understudied that whole classes of diverticula are still being described for the first time (Atterholt and Wedel 2022).
  • Rather work on sauropods or non-avian theropods? We could use a lot more work on pneumosteum (Lambertz et al. 2018), and on the histological signals of pneumaticity, in basically everything from pig sinuses to the tail of Diplodocus — especially basal sauropodomorphs and early theropods where pneumaticity was just getting up and running.
  • Don’t want to do histo? CT scan something. Anything. And write it up. Especially dorsals, sacrals, and caudals — the published sample is skewed toward cervicals because they’re long and skinny and fit through the machines better. Don’t have access to a CT machine? No worries, that’s what the second half of this post is about.
  • Don’t want to mess with machines at all? Crawl some skeletons — or maybe just like one fairly complete diplodocid or titanosaur — and describe the pneumatic (and maybe also vascular) features on the ventral surfaces of the vertebrae. That’s a whole class of diverticula (or maybe multiple classes) about which we know basically zip, other than that sometimes cervicals and caudals have foramina on their ventral surfaces (but not dorsals or sacrals — why?). You  might be able to get a short review paper just canvasing examples in the literature — but if you don’t go look at specimens in person, you’ll miss a lot, because these features are are rarely described or illustrated.
  • Want a project you can do on the couch in your jammies? Wedel (2003) is my most-cited paper by some distance, but it’s waaay out of date. Comb the literature and write an up-to-date version of that paper just based on all the new stuff that’s been published in the past two decades. Here’s a fun starter: I made a big deal in that paper about camerate vertebrae in a then-undescribed titanosaur from Dalton Wells in the Cedar Mountain Formation. In time that critter proved to be Moabosaurus, a turiasaur and not a titanosaur. The whole idea of camerate titanosaurs needs a re-look. And I didn’t write anything about turiasaurs back then because the clade hadn’t been recognized yet. My top paper, and at this point it might as well have been scratched out on clay tablets. (Note: this is a good thing. That paper is out of date because there’s been so much progress. If it was still cutting-edge, it would mean the field of sauropod pneumaticity was dead. But still — someone go knock that thing off its perch.)

Posterior dorsal vertebra, TMM 45891-4, Lithostrotia incertae sedis, left postzygapophysis in posterior view showing exposed camellae and apneumatic trabecular bone along the articular surface. Abbreviations: art, articular surface of postzygapophysis; atb, apneumatic trabecular bone; cam, camella. Scale bar is in cm. Fronimos (2023: fig. 5). [This is really important; there’s almost no documentation out there about what the contact looks like between pneumatic chambers and apneumatic trabecular bone — when that occurs at all.  – MJW]

Before we go on, that list is by no means exhaustive. It is the product of long familiarity but not of long intentional thought; it’s literally the stuff that I thought of on the fly while composing this post. I could probably make it four times longer if I wanted to spend a day thinking of all the projects that are crying out to be done. Also, I’m writing quickly, and using the examples that are closest to hand, which are inevitably Wedel-centric. But many more potential projects are lurking in a quantum fuzz around the papers of Richard Buchmann, Ignacio Cerda, Federico Fanti, John Fronimos, Lucio Ibiricu, Liz Martin, Pat O’Connor, Daniela Schwarz, Nate Smith, Guillermo Windholz, Virginia Zurriaguz, and their students and collaborators. Plug those names into Google Scholar and go catch the cutting edge — so you can push it further. But also go look at all the specimens you possibly can, to build the baseline you’ll need to recognize important weirdness from background-radiation weirdness.

How to Study Pneumaticity on the Cheap

I think there is an assumption, or a perception, that you need to CT scan fossils to study pneumaticity. Access to CT scanners can be logistically complex, and expensive. Can be, not has to be. And there’s a lot of crucial work to be done without a CT machine. Let’s get to it.

This part never gets old. BYU 12613, a posterior cervical of Diplodocus or Kaatedocus, getting lined up for the CT scout image at Hemet Global Medical Center.

1. Collaborate with a radiologist. Okay, but what if you do want to CT scan some fossils? Do what I do, and ask around to see if there’s a radiologist who is interested in collaborating. Most hospital CT machines are not busy all the time — there’s usually one slow afternoon each week, or each month. And in my experience, most radiologists are down to look at something interesting and different, like a dinosaur bone, as a break from the endless parade of concussions, degenerated lumbar discs, and cirrhotic livers.  The collaboration piece is key. I’m not a radiologist, and minimally I need a professional who can write up the machine specs and scan settings for the Materials and Methods section of the paper. But often the radiologist will see interesting things in the scan that I would have missed, or I’ll see interesting things in the scans that may turn out to be mundane features that look weird in cross-section. And I’m more than happy to trade authorship on whatever papers come out of the scans, and acknowledgement and good press for the hospital, in exchange for the professional’s expertise and time on the machines. Specific advice? Be humble, be polite. Once I’m through the hospital doors I’m not the expert in anything other than safely handling the fossils, and I make it clear that I’m there to be safe, respect their turf, let them direct the logistics, and learn as much as I can. All the radiologists I’ve worked with have been happy to share their knowledge, and curious about the fossils and what we hope to learn from the scans.

Posterior dorsal vertebra, TMM 45891-4, Lithostrotia incertae sedis, in posterior view. Cross sections shown are A, the neural spine in ventral view with anterior to the top of the page; B, the left neural arch pedicel in dorsal view with anterior to the top; and C, the right dorsolateral margin of the cotyle in oblique posterior dorsolateral view with dorsomedial to the top. Abbreviations: cpaf, centroparapophyseal fossa; ct, cotyle; nc, neural canal; prsl, prespinal lamina. Scale bar equals 10 cm. Fronimos (2023: fig. 2).

2. Use broken specimens. I’ve blogged before about how breaks and erosion are nature’s CT machines (here, here, here, and here, for starters), and I’ve favorably discussed the utility of broken specimens in my papers, but I figured broken specimens would always be distant also-rans in the quest to document pneumaticity. Then I read Fronimos (2023) — hoo boy. John Fronimos set out to document pneumaticity in a Late Cretaceous titanosaur from Texas (maybe Alamosaurus, maybe not), and he crushed it. It’s one of the best danged sauropod pneumaticity papers I’ve ever read, period, and the fact that he did it all without CT scanning anything makes it all the more impressive. And it’s not only a great descriptive paper — John’s thoughts on the evolution and function of pneumaticity in sauropods are comprehensive, detailed, insightful, and forward-looking. Up above I mentioned reading broadly to get caught up; if you work on sauropod pneumaticity, or want to, or just want to understand the state of the art, the discussion section of Fronimos (2023) is the new bleeding edge. Also, remember the pin we placed up above, on the question of whether pneumatic chambers get bigger or more numerous or both over ontogeny? With the right collection you could answer that with only broken specimens.

First three caudal vertebrae MWC 5742, an apatosaurine from the Twin Juniper Quarry, in left lateral view. Note that caudal 2 (center) has a matrix-filled pneumatic fossa or foramen just ventral to the broken-off transverse process, whereas caudal 1 (left) has a smaller neurovascular foramen in the same place.

3. Study external pneumatic features. This has already come up a few times in this post, but let me draw the threads together here. Whether it’s documenting serial changes in pneumatization along the vertebral column in a single individual, or externally-visible asymmetry, or pneumaticity on the ventral surfaces of vertebrae, or how and whether pneumatic and neurovascular features relate to each other, there is a ton of work to be done that just requires collections access, a notebook, a camera, and time. And it lends itself to collaboration; two sets of eyes will see a lot more. (If you have the freedom to choose, ideally you might want one fairly big and strong person to manhandle the bones [safely, for the sake of the bones and the humans], and one fairly slim and flexible person to scramble up ladders and fit into odd nooks and crannies.)

A bird (possibly an anhinga?) doing weird things with its larynx, from the oVert trailer.

4. Use publicly-available CT data. Okay, admittedly there’s probably not enough of this out there yet to use on anything other than birds (or mammals, if you’re into sinuses), but hey, we need bird studies, too. Bird studies hit twice — first because birds are interesting objects of study in their own right, and second because they’re our baseline for interpreting pneumaticity in fossils. (By quick count, I’ve figured drawings, photos, or CT scans of bird vertebrae in more than dozen of my papers, and in half a dozen cases they were vertebrae I prepped myself at home.) Of the four paths, this is the one I have the least experience with, but the new “oVert” (openVertebrate) collection on MorphoSource is a good place to start. Wet specimens may have a bit of a learning curve in terms of distinguishing pneumatic and non-pneumatic bones, and most of the extra-osseous pneumatic diverticula have probably collapsed, but with free access to CT scans of “>13,000 fluid-preserved specimens representing >80% of the living genera of vertebrates” I’ll bet people will think of plenty of cool stuff to do. Here’s the oVert trailer:

Conclusion: Let’s Roll

We need more pneumaticity studies. There is just so much we don’t know. I’ve been working on sauropod pneumaticity more often than not since 1998, and I’m stoked about how much basic descriptive work remains to be done, because I’m an anatomy geek at heart, and describing weird anatomy is deeply satisfying for me, as is reading other people’s descriptions of weird anatomy. But I’m also in despair about how much basic descriptive work remains to be done, because the answers to so many questions are still over the horizon from us, and probably will be for the rest of my life.

Domestic turkey Meleagris gallopavo domesticus, 9th cervical vertebra, hemisected, in right medial view. From this post.

So please, if you’re interested, come do this work. Whether you’re a grad student at a major institution with an NSF pre-doc fellowship and several years of runway in which to do unfettered research, or just some person sitting on a couch thinking about dinosaur bones (er, like me right now), now you have some ideas to work on (or reach beyond), and some inexpensive ways to work on them. If you’re curious and want to get your feet wet before you commit, remember that you can get extant dinosaur carcasses at the grocery store, and prep and section your own pneumatic dinosaur bones at the kitchen table. There is a very accessible on-ramp here for anyone who has the time and inclination. Let’s do this thing.

References

 

doi:10.59350/bvpaq-czq07

Posted by Matt Wedel
Filed in Apatosaurus, cervical, cross sections, CT, diplodocids, Diplodocus, dorsal, everything's better cut in half, Giant Oklahoma apatosaurine, just freakin' wall-to-wall turkeys everywhere man, Kaatedocus, opportunities, pneumaticity, sacral, stinkin' mammals, stinkin' SV-POW!sketeers, stinkin' theropods, Things I should have posted ten years ago, titanosaur
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Morphological convergence in tendaguriid dorsal vertebrae and cephalopods

October 26, 2023

I’ve been away for two weeks with Fiona in Kefalonia, one of the Greek islands. While we were there, we ate this excellent meal:

Excellent Greek meal. Back row: grilled octopus; middle row (left to right): sardines, shrimp saganaki; front row: deep-fried calamari

Excellent Greek meal. Back row: grilled octopus; middle row (left to right): sardines, shrimp saganaki; front row: deep-fried calamari

As we made our way through the calamari, we noticed this chunk:

One piece of deep-fried calamari

Take a closer look and I think you will be struck, as I was, by the resemblance to an anterior dorsal vertebra of a tendaguriid sauropod in posterior view:

Close-up of the same piece of calamari

Here for comparison is the more anterior of the two known dorsal vertebrae of the enigmatic sauropod Tendaguria:

Bonaparte, Heinrich and Wilde (1999:figure 11B): anterior dorsal vertebra of Tendaguria in posterior view

Bonaparte, Heinrich and Wilde (1999:figure 11B): anterior dorsal vertebra of Tendaguria in posterior view.

If you doubt me, take a look at this red-cyan anaglyph and appreciate the perfect 3D structure, with the diapophyseal wings stretching out laterally from a point some way anterior to the cotyle. (Evidently the neural arch has been destroyed by post-mortem damage):

Red-cyan anaglyph of the same piece of calamari

What are we seeing here? An unprecendented example of horizontal gene transfer? Or simply convergance based on similarity of lifestyle?

References

  • Bonaparte, Jose F., Wolf-Dieter Heinrich and R. Wild. 2000. Review of Janenschia WILD, with the description of a new sauropod from the Tendaguru beds of Tanzania and a discussion on the systematic value of procoelous caudal vertebrae in the sauropoda. Palaeontographica Abt. A 256(1-3):25-76.

 

doi:10.59350/yjdha-3sq58

Posted by Mike Taylor
Filed in dorsal, stinkin' invertebrates, titanosaur
2 Comments »

Giant titanosaurs were just ridiculous

September 13, 2023

Here’s Mike with the cast dorsal vertebra of Argentinosaurus that’s on display at the LACM. I tried to get myself equidistant from both Mike and the vert when I took the photo, but even I couldn’t quite believe it when I looked at it on my laptop. Surely, I thought, there must be some subtle foreshortening going on, to make the Argentinosaurus vert look bigger than it is. So I did some cypherin’.

The LACM dorsal has a clearly reconstructed centrum, and in all other ways, including the position of the parapophyses and the slightly reclined neural spine, it’s a good match for this vertebra figured in Bonaparte and Coria (1993: fig. 2). The scale bar there is 50cm. In my scan, it’s 242 pixels, and the total height of the vertebra is 800 pixels, or 1.65 meters, or 5’5″. Mike’s about 1.8 meters, and the photo confirms that he’s a little taller than the vertebra, but not by much. I think that photo is a pretty accurate representation of the size of the vertebra relative to a normal human being Mike.

Which is kinda crazy. I’m no stranger to big vertebrae — my first project turned out to be Sauroposeidon, and I’ve spent more time looking at Giraffatitan and Supersaurus verts than is probably healthy — but damn. Even I am used to big vertebrae that are still smaller than a person. Fair play to you, Argentinosaurus.

(I’m contractually obligated to remind everyone that despite frequent claims to the contrary, Argentinosaurus is still the largest dinosaur known from measurable bones.) 

Reference

Bonaparte, J.F. and Coria, R.A. 1993. Un nuevo y gigantesco saurópodo titanosaurio de la Formación Río Limay (Albiano-Cenomaniano) de la Provincia del Neuquén, Argentina. Ameghiniana 30(3):271-282.

 

doi:10.59350/faw7v-kwx03

Posted by Matt Wedel
Filed in Argentinosaurus, dorsal, LACM, museums, public galleries, size, stinkin' mammals, stinkin' SV-POW!sketeers, titanosaur
9 Comments »

Just chillin’ with my homie FMNH PR 25107

September 5, 2023

That’s FMNH PR 25107, better known as a the holotype of Brachiosaurus altithorax — the biggest known dinosaur at the time of its description (Riggs 1903) and still for my money one of the most elegant, along with its buddy and one-time genus-mate Giraffatitan brancai.

I had a spare morning in Chicago two Tuesday ago, and Bill Simpson (collection manager of fossil vertebrates at the Field Museum) managed to fit it a collections visit for me at very short notice. I harvested some good science that morning — there’s a short Taylor and Wedel manuscript in review from that visit — but it would gave been churlish not to also take the opportunity to bathe in the sheer brachiosaurosity of it all.

Brachiosaurus altithorax holotype FMNH PR 25107 in collections at the Field Museum of Natural HIstory, Chicago. In the foreground, the femur. Behind it, at ground level, five of the seven presacral vertebrae and the sacrum; and on the shelf to the left, “Rib B”. On the top shelf, “Rib A”, the first two caudals and fragments of several more dorsal ribs. The remainder of the holotype (two more presacral vertebrae and the humerus) is on display in the public gallery.

I’m not too vain to take a selfie or two:

Me, with the 4th presacral vertebra of the Brachiosaurus altithorax holotype FMNH PR 25107 (i.e., the last-but-three dorsal vertebra), here seen in left posterolateral view.

Oh look, there I am again!

Me with all five of the most posterior presacral vertebrae, here seen in right posterolateral view.

“But tell me, Mike”, you ask: “Do they have a model skull based on that of Giraffatitan hidden away in collections?”

Why, yes! Yes, they do!

My ugly mug, again — this time with the even uglier mug of the model skull.

Yes, I have to admit it. Brachiosaurus taken as a whole may be as elegant as they come, but its skull taken alone is a minger. Forgive me. But it’s true.

 

doi:10.59350/h293j-2xa41

Posted by Mike Taylor
Filed in Brachiosaurus, collections, dorsal, Field Museum (Chicago)
3 Comments »
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