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

8 Comments »

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

Atterholt, Jessie, and Wedel, Mathew J. 2022. A computed tomography-based survey of paramedullary diverticula in extant Aves. The Anatomical Record, 1– 22. https://doi.org/10.1002/ar.24923
Benson, R.B., Butler, R.J., Carrano, M.T. and O’Connor, P.M., 2012. Air‐filled postcranial bones in theropod dinosaurs: physiological implications and the ‘reptile’–bird transition. Biological Reviews, 87(1), pp.168-193.
Bremer, John L. 1940 The pneumatization of the humerus in the common fowl and the associated activity of theelin. The Anatomical Record 77(2):197–211. doi:10.1002/ar.1090770209
Claessens LPAM, O’Connor PM, Unwin DM (2009) Respiratory evolution facilitated the origin of pterosaur flight and aerial gigantism. PLoS ONE 4(2): e4497. doi:10.1371/journal.pone.0004497
Fronimos, John A. 2023. Patterns and function of pneumaticity in the vertebrae, ribs, and ilium of a titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Texas, Journal of Vertebrate Paleontology 43:2. DOI: 10.1080/02724634.2023.2259444
Lambertz, M., Bertozzo, F. and Sander, P.M. 2018. Bone histological correlates for air sacs and their implications for understanding the origin of the dinosaurian respiratory system. Biology Letters 14(1): 20170514.
Sander, P.M., Christian, A., Clauss, M., Fechner, R., Gee, C.T., Griebeler, E.M., Gunga, H.C., Hummel, J., Mallison, H., Perry, S.F. and Preuschoft, H. 2011. Biology of the sauropod dinosaurs: the evolution of gigantism. Biological Reviews 86(1):117-155.
Taylor, Michael P., and Mathew J. Wedel. 2021. Why is vertebral pneumaticity in sauropod dinosaurs so variable? Qeios 1G6J3Q. doi:10.32388/1G6J3Q
Wedel, M.J. 2003. The evolution of vertebral pneumaticity in sauropod dinosaurs. Journal of Vertebrate Paleontology 23:344-357.
Witmer, L.M. 1997. The evolution of the antorbital cavity of archosaurs: a study in soft-tissue reconstruction in the fossil record with an analysis of the function of pneumaticity. Journal of Vertebrate Paleontology 17(Supplement 1): 1-76.

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

9 Comments »

Haplocanthosaurus neural canals are weird, part 2: getting comparative specimens from the grocery store

May 16, 2021

Anatomical features of the neural canal in birds and other dinosaurs. A. MWC 9698, a mid caudal vertebra of Apatosaurus in posterodorsal view. Arrows highlight probable vascular foramina in the ventral floor of the neural canal. B. LACM 97479, a dorsal vertebra of Rhea americana in left anterolateral view. Arrows highlight pneumatic foramina inside the neural canal. C. A hemisected partial synsacrum of a chicken, Gallus domesticus, obtained from a grocery store. Anterior is to the right. The bracket shows the extent of the dorsal recess for the glycogen body, which only spans four vertebrae. Arrows highlight the transverse grooves in the roof of the neural canal for the lumbosacral organ. D. Sagittal (left) and transverse (right) CT slices through the sacrum of a juvenile ostrich, Struthio camelus. The bracket shows the extent of the lumbosacral expansion of the spinal cord. Indentations in the roof of the neural canal house the lumbosacral organ. In contrast to the chicken, the ostrich has a small glycogen body that does not leave a distinct osteological trace. Yellow arrows show the longitudinal troughs in the ventral floor of the neural canal that house the ventral eminences of the spinal cord. Wedel et al. (2021: fig. 4).

This is the second in a series of posts on our new paper about the expanded neural canals in the tail vertebrae of the Snowmass Haplocanthosaurus. I’m not going to talk much about Haplo in this post, though. Instead, I’m going to talk about chickens, and about how you can see a lot of interesting spinal anatomy in a living dinosaur for about two bucks.

You know by now that Academia Letters publishes peer reviews, which is one of the things that drew me to this fairly new journal. More on that in a later post, but in the meantime, the peer reviews for the Haplo paper are on the right sidebar here. I confess, I had a total forehead-slap moment when I read the opening lines of Niels Bonde’s review:

This paper is interesting, and should be published and discussed by others with interest in dinosaur-bird relations. However, as these publications are also meant for the general public, I would recommend that 2 – 3 illustrations were added of the features mentioned for birds under nos. 3 – 6, because the general public (and many paleontologists) have no ideas about these structures, and what they look like.

The original submission only had figures 1 and 2. And this request is totally fair! If you are going to discuss six alternative hypotheses for some mysterious anatomical structure, it’s just responsible reporting to illustrate those things. That goes double if, as Niels Bonde noted, the anatomy in question is unfamiliar to a lot of people, even many paleontologists. Huxley’s quote after first reading Darwin’s Origin of Species flashed through my head: “How extremely stupid not to have thought of that.”

Slide 21 of my 2014 SVPCA talk on supramedullary diverticula in birds and other dinosaurs, illustrating pneumatic foramina in the roof, walls, and floor of the neural canal.

At the time I read that review, I already had images illustrating five of the six hypotheses. A juvenile ostrich synsacrum that Jessie Atterholt and I had CT scanned gave us three of them all by itself: the lumbosacral expansion of the spinal cord to run the hindlimbs, as in all limbed tetrapods and in some fish with sensitive fins; the transverse channels in the dorsal wall of the neural canal to accommodate the lumbosacral balance organ; and the paired troughs in the floor of the neural canal that house the ventral eminences of the spinal cord (Figure 4D in the image at the top of this post). I had good photos of pneumatic foramina in the walls and floor of the neural canal in a dorsal vertebra of a rhea from my 2014 SVPCA talk (Figure 4B), and some photos of small foramina, presumably for blood vessels rather than air spaces, in the floor of the neural canal in a caudal vertebra of Apatosaurus (Figure 4A).

What I did not have is a photo illustrating the fairly abrupt, dome-shaped space in the sacral neural canal that houses the glycogen body of birds. I mean, I had published images, but I didn’t want to wrestle with trying to get image reproduction rights, or with redrawing the images. Instead, I went to the grocery store to buy some chicken.

I don’t know how universally true this is, but IME in the US when you buy a quartered chicken, the vertebrae are usually nicely hemisected by the band saw that separated the left and right halves of the animals. So you can see the neural canal in both the dorsal and sacral parts of the vertebral column. Here are the hemisected dorsal vertebrae in the breast quarter from a sectioned rotisserie chicken:

That’s just how it came to lie on my plate, but it’s not in anatomical position. Let’s flip it over to sit upright:

And label it:

I could and probably should do a whole post just unpacking this image, but I have other fish to fry today, so I’ll just note a couple of things in passing. The big interspinous ligament is the same one you can see in transverse section in the ostrich dissection photos in this post and this one. Also, the intervertebral joints heading toward the neck, on the left of the image, have much thicker intervertebral cartilage than the more posterior dorsals. That’s because the posterior ones were destined to fuse into a notarium. You can see a diagram and a photograph of a chicken notarium in figures 4 and 5, respectively, here. And finally, the big takeaway here is that the neural canal is normal, just a cylindrical tube to hold the spinal cord.

The thigh quarter usually has the pelvis and the hemisectioned synsacrum attached. Here’s a lateral view of the left half of the pelvis and synsacrum:

And the same thing labeled:

And now flipped around so we can see it in medial view:

And now that image labeled:

And, hey, there are three of our alternative hypotheses on display: the long (many vertebral segments) lumbosacral expansion of the spinal cord, which is reflected in a gradually expanded neural canal in the synsacrum; the shorter, higher dome-shaped recess for the glycogen body; and finally the transverse spaces for the lumbosacral balance organ.

Borrowed from http://humanorgans.org/spinal-cord/

As a refresher, there’s nothing terribly special about the lumbosacral expansion of the spinal cord — you have one, labeled as the ‘lumbar enlargement’ in the above diagram. Where the spinal cord has adjacent limbs to run, it has more neurons, so it gets fatter, so the neural canal gets fatter to accommodate it. The cord itself doesn’t look very expanded in the chicken photo above, but that chicken has been roasted rotisserie-style, and a lot of lipids probably cooked out of the cord during that process. What’s more important is that the neural canal is subtly but unmistakably expanded, over the span of many vertebrae.

The lumbosacral spinal cord of a 3-week-old chick in dorsal view. The big egg-shaped mass in the middle is the glycogen body. Watterson (1949: plate 1).

That’s in contrast to the recess for the glycogen body, which is colored in blue in the chicken photo. Glycogen bodies, like the egg-shaped one in the young chicken in the image immediately above, tend not to go on for many vertebral segments. Instead they balloon up and subside over the space of just 4 or 5 vertebrae, so they leave a different skeletal trace than other soft tissues.

Finally, there are the transverse spaces for the lumbosacral balance organ, which I discussed in this post. Those are the things that look like caterpillar legs sticking up from the sacral endocasts in the above figure from Necker (2006). In life, the spaces are occupied by loops of meningeal membranes, through which cerebrospinal fluid can slosh around, which in turn puts pressure on mechanoreceptive cells at the edge of the spinal cord and gives birds a balance organ in addition to the ones in their heads. In the photo of the cooked chicken, the delicate meninges have mostly fallen apart, leaving behind the empty spaces that they once occupied.

I really liked that chicken synsacrum, and I wanted to use it as part of Figure 4 of the new paper, but it needed a little cleaning, so I simmered it for a couple of hours on low heat (as one does). And it promptly fell apart. At least in the US, most of the chickens that make it to table are quite young and skeletally immature. That particular bird’s synsacrum wasn’t syn-anything, it was just a train of unfused vertebrae that fell apart at the earliest opportunity. I had anticipated that might be an issue, so I’d gotten a lot of chicken, including a whole rotisserie chicken and four thigh quarters from the deli counter at the local supermarket. Happily this fried chicken thigh quarter had a pretty good neural canal:

And it cleaned up nicely:

And with a little cropping, color-tuning, and labeling, it was ready for prime time:

I didn’t label them in the published version, for want of space and a desire not to muddy the waters any further, but the jet-black blobs I have colored in the lower part of that image are the exit holes that let the spinal nerves out of the neural canal so they could go serve the hindlimbs, pelvic viscera, and tail. We have them, too.

At my local grocery store, a fried chicken thigh costs about $1.65 if you get it standalone, or you can buy in bulk and save. You get to eat the chicken, and everything else I’ve done here required only water, heat, soap, and a little time. The point is that if I can do this, you can do this, and if you do, you’ll get to see some really cool anatomy. I almost added, “which most people haven’t seen”, but given how much chicken we eat as a society these days, probably most people’s eyes have fallen on the medial surface of a cooked chicken thigh quarter at one time or another. Better to say, “which most people haven’t noticed”. But now you can. Go have fun.

Way back in January of 2019, I finished up “Things to Make and Do, Part 25b” with this line: “I have one more thing for you to look for in your bird vertebrae, and that will be the subject of the next installment in this series. Stay tuned!” Here we are, 2.3 years later, and I’ve finally made good. So if there’s a promised post you’ve been waiting for, stick around, we may get to it yet.

References

Necker, R. 2006. Specializations in the lumbosacral vertebral canal and spinal cord of birds: evidence of a function as a sense organ which is involved in the control of walking. Journal of Comparative Physiology A, 192(5):439-448.
Watterson, R.L. 1949. Development of the glycogen body of the chick spinal cord. I. Normal morphogenesis, vasculogenesis and anatomical relationships. Journal of Morphology 85(2): 337-389.
Wedel, Mathew, Atterholt, Jessie, Dooley, Jr., Alton C., Farooq, Saad, Macalino, Jeff, Nalley, Thierra K., Wisser, Gary, Yasmer, John. 2021. Expanded neural canals in the caudal vertebrae of a specimen of Haplocanthosaurus. Academia Letters, Article 911, 10pp.

Posted by Matt Wedel
Filed in anatomical preparations, chicken, dorsal, nervous system, neural canal, sacral, stinkin' theropods

2 Comments »

Cross-sectional asymmetry of sauropod vertebrae

March 13, 2021

FIGURE 7.1. Pneumatic features in dorsal vertebrae of Barapasaurus (A–D), Camarasaurus (E–G), Diplodocus (H–J), and Saltasaurus (K–N). Anterior is to the left; different elements are not to scale. A, A posterior dorsal vertebra of Barapasaurus. The opening of the neural cavity is under the transverse process. B, A midsagittal section through a middorsal vertebra of Barapasaurus showing the neural cavity above the neural canal. C, A transverse section through the posterior dorsal shown in A (position 1). In this vertebra, the neural cavities on either side are separated by a narrow median septum and do not communicate with the neural canal. The centrum bears large, shallow fossae. D, A transverse section through the middorsal shown in B. The neural cavity opens to either side beneath the transverse processes. No bony structures separate the neural cavity from the neural canal. The fossae on the centrum are smaller and deeper than in the previous example. (A–D redrawn from Jain et al. 1979:pl. 101, 102.) E, An anterior dorsal vertebra of Camarasaurus. F, A transverse section through the centrum (E, position 1) showing the large camerae that occupy most of the volume of the centrum. G, a horizontal section (E, position 2). (E–G redrawn from Ostrom and McIntosh 1966:pl. 24.) H, A posterior dorsal vertebra of Diplodocus. (Modified from Gilmore 1932:fig. 2.) I, Transverse sections through the neural spines of other Diplodocus dorsals (similar to H, position 1). The neural spine has no body or central corpus of bone for most of its length. Instead it is composed of intersecting bony laminae. This form of construction is typical for the presacral neural spines of most sauropods outside the clade Somphospondyli. (Modified from Osborn 1899:fig. 4.) J, A horizontal section through a generalized Diplodocus dorsal (similar to H, position 2). This diagram is based on several broken elements and is not intended to represent a specific specimen. The large camerae in the midcentrum connect to several smaller chambers at either end. K, A transverse section through the top of the neural spine of an anterior dorsal vertebra of Saltasaurus (L, position 1). Compare the internal pneumatic chambers in the neural spine of Saltasaurus with the external fossae in the neural spine of Diplodocus shown in J. L, An anterior dorsal vertebra of Saltasaurus. M, A transverse section through the centrum (L, position 2). N, A horizontal section (L, position 3). In most members of the clade Somphospondyli the neural spines and centra are filled with small camellae. (K–N modified from Powell 1992:fig. 16.) [Figure from Wedel 2005.]

Here’s figure 1 from my 2005 book chapter. I tried to cram as much pneumatic sauropod vertebra morphology into one figure as I could. All of the diagrams are traced from pre-existing published images except the horizontal section of the Diplodocus dorsal in J, which is a sort of generalized cross-section that I based on broken centra of camerate vertebrae from several taxa (like the ones shown in this post). One thing that strikes me about this figure, and about most of the CT and other cross-sections that I’ve published or used over the years (example), is that they’re more or less bilaterally symmetrical.

We’ve talked about asymmetrical vertebrae before, actually going back to the very first post in Xenoposeidon week, when this blog was only a month and a half old. But not as much as I thought. Given how much space asymmetry takes up in my brain, it’s actually weird how little we’ve discussed it.

The fourth sacral centrum of Haplocanthosaurus CM 879, in left and right lateral view (on the left and right, respectively). Note the distinct fossa under the sacral rib attachment on the right, which is absent on the left.

Also, virtually all of our previous coverage of asymmetry has focused on external pneumatic features, like the asymmetric fossae in this sacral of Haplocanthosaurus (featured here), in the tails of Giraffatitan and Apatosaurus (from Wedel and Taylor 2013b), and in the ever-popular holotype of Xenoposeidon. This is true not just on the blog but also in our most recent paper (Taylor and Wedel 2021), which grew out of this post.

Given that cross-sectional asymmetry has barely gotten a look in before now, here are three specimens that show it, presented in ascending levels of weirdness.

First up, a dorsal centrum of Haplocanthosaurus, CM 572. This tracing appeared in Text-fig 8 in my solo prosauropod paper (Wedel 2007), and the CT scout it was traced from is in Fig 6 in my saurischian air-sac paper (Wedel 2009). The section shown here is about 13cm tall dorsoventrally. The pneumatic fossa on the left is comparatively small, shallow, and lacks very distinct overhanging lips of bone. The fossa on the right is about twice as big, it has a more distinct bar of bone forming a ventral lip, and it is separated from the neural canal by a much thinner plate of bone. The fossa on the left is more similar to the condition in dorsal vertebrae of Barapasaurus or juvenile Apatosaurus, where as the one on the right shows a somewhat more extensive and derived degree of pneumatization. The median septum isn’t quite on the midline of the centrum, but it’s pretty stout, which seems to be a consistent feature in presacral vertebrae of Haplocanthosaurus.

Getting weirder. Here’s a section through the mid-centrum of C6 of CM 555, which is probably Brontosaurus parvus. That specific vert has gotten a lot of SV-POW! love over the years: it appears in several posts (like this one, this one, and this one), and in Fig 19 in our neural spine bifurcation paper (Wedel and Taylor 2013a). The section shown here is about 10cm tall, dorsoventrally. In cross-section, it has the classic I-beam configuration for camerate sauropod vertebrae, only the median septum is doing something odd — rather than attaching the midline of the bony floor of the centrum, it’s angled over to the side, to attach to what would normally be the ventral lip of the camera. I suspect that it got this way because the diverticulum on the right either got to the vertebra a little ahead of the one on the left, or just pneumatized the bone faster, because the median septum isn’t just bent, even the vertical bit is displaced to the left of the midline. I also suspect that this condition was able to be maintained because the median septa weren’t that mechanically important in a lot of these vertebrae. We use “I-beam” as a convenient shorthand to describe the shape, but in a metal I-beam the upright is as thick or thicker than the cross bits. In contrast, camerate centra of sauropod vertebrae could be more accurately described as a cylinders or boxes of bone with some holes in the sides. I think the extremely thin median septum is just a sort of developmental leftover from the process of pneumatization.

EDIT 3 days later: John Whitlock reminded me in the comments of Zurriaguz and Alvarez (2014), who looked at asymmetry in the lateral pneumatic foramina in cervical and dorsal vertebrae of titanosaurs, and found that consistent asymmetry along the cervical column was not unusual. They also explicitly hypothesized that the asymmetry was caused by diverticula on one side reaching the vertebrae earlier than diverticula on other other side. I believe they were the first to advance that idea in print (although I should probably take my own advice and scour the historical literature for any earlier instances), and needless to say, I think they’re absolutely correct.

Both of the previous images were traced from CTs, but the next one is traced from a photo of a specimen, OMNH 1882, that was broken transversely through the posterior centrum. To be honest, I’m not entirely certain what critter this vertebra is from. It is too long and the internal structure is too complex for it to be Camarasaurus. I think an apatosaurine identity is unlikely, too, given the proportional length of the surviving chunk of centrum, and the internal structure, which looks very different from CM 555 or any other apatosaur I’ve peered inside. Diplodocus and Brachiosaurus are also known from the Morrison quarries at Black Mesa, in the Oklahoma panhandle, which is where this specimen is from. Of those two, the swoopy ventral margin of the posterior centrum looks more Diplodocus-y than Brachiosaurus-y to me, and the specimen lacks the thick slab of bone that forms the ventral centrum in presacrals of Brachiosaurus and Giraffatitan (see Schwarz and Fritsch 2006: fig. 4, and this post). So on balance I think probably Diplodocus, but I could easily be wrong.

Incidentally, the photo is from 2003, before I knew much about how to properly photograph specimens. I really need to have another look at this specimen, for a lot of reasons.

Whatever taxon the vertebra is from, the internal structure is a wild scene. The median septum is off midline and bent, this time at the top rather than the bottom, the thick ventral rim of the lateral pneumatic foramen is hollow on the right but not on the left, and there are wacky chambers around the neural canal and one in the ventral floor of the centrum.

I should point out that no-one has ever CT-scanned this specimen, and single slices can be misleading. Maybe the ventral rim of the lateral foramen is hollow just a little anterior or posterior to this slice. Possibly the median septum is more normally configured elsewhere in the centrum. But at least at the break point, this thing is crazy.

What’s it all mean? Maybe the asymmetry isn’t noise, maybe it’s signal. We know that when bone and pneumatic epithelium get to play together, they tend to make weird stuff. Sometimes that weirdness gets constrained by functional demands, other times not so much. I think it’s very seductive to imagine sauropod vertebrae as these mechanically-optimized, perfect structures, but we have other evidence that that’s not always true (for example). Maybe as long as the articular surfaces, zygapophyses, epipophyses, neural spine tips, and cervical ribs — the mechanically-important bits — ended up in the right places, and the major laminae did a ‘good enough’ job of transmitting forces, the rest of each vertebra could just sorta do whatever. Maybe most of them end up looking more or less the same because of shared development, not because it was so very important that all the holes and flanges were in precisely the same places. That might explain why we occasionally get some really odd verts, like C11 of the Diplodocus carnegii holotype.

That’s all pretty hand-wavy and I haven’t yet thought of a way to test it, but someone probably will sooner or later. In the meantime, I think it’s valuable to just keep documenting the weirdness as we find it.

References

Schwarz D, and Fritsch G. 2006. Pneumatic structures in the cervical vertebrae of the Late Jurassic Tendaguru sauropods Brachiosaurus brancai and Dicraeosaurus. Eclogae Geologicae Helvetiae 99:65–78.
Taylor, Michael P., and Mathew J. Wedel. 2021. Why is vertebral pneumaticity in sauropod dinosaurs so variable? Qeios 1G6J3Q. doi:10.32388/1G6J3Q
Wedel, M.J. 2005. Postcranial skeletal pneumaticity in sauropods and its implications for mass estimates; pp. 201-228 in Wilson, J.A., and Curry-Rogers, K. (eds.), The Sauropods: Evolution and Paleobiology. University of California Press, Berkeley.
Wedel, M.J. 2009. Evidence for bird-like air sacs in saurischian dinosaurs. Journal of Experimental Zoology 311A(8):611-628.
Wedel, M.J., and Taylor, M.P. 2013a. Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications. Palarch’s Journal of Vertebrate Palaeontology 10(1): 1-34.
Wedel, M.J., and Taylor, M.P. 2013b. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus. PLOS ONE 8(10):e78213. doi:10.1371/journal.pone.0078213
Zurriaguz, V.L. and Alvarez, A. 2014. Shape variation in presacral vertebrae of saltasaurine titanosaurs (Dinosauria, Sauropoda). Historical Biology 26(6): 801-809.

Posted by Matt Wedel
Filed in camarasaurs, cervical, cross sections, diplodocids, Diplodocus, dorsal, Haplocanthosaurus, pneumaticity, sacral, Saltasaurus, titanosaur

10 Comments »

What can sauropod sacra tell us about neck posture?

April 22, 2020

Daniel Vidal et al.’s new paper in Scientific Reports (Vidal et al. 2020) has been out for a couple of days now. Dealing as it does with sauropod neck posture, it’s obviously of interest to me, and to Matt. (See our earlier relevant papers Taylor et al. 2009, Taylor and Wedel 2013 and Taylor 2014.)

Overview

To brutally over-summarise Vidal et al.’s paper, it comes down to this: they digitized the beautifully preserved and nearly complete skeleton of Spinophorosaurus, and digitally articulated the scans of the bones to make a virtual skeletal mount. In doing this, they were careful to consider the neutral pose of consecutive vertebrae in isolation, looking at only one pair at a time, so as to avoid any unconscious biases as to how the articulated column “should” look.

Then they took the resulting pose, objectively arrived at — shown above in their figure 1 — and looked to see what it told them. And as you can well see, it showed a dramatically different pose from that of the original reconstruction.

Original skeletal reconstruction of Spinophorosaurus nigerensis (Remes et al. 2009:figure 5, reversed for ease of comparison). Dimensions are based on GCP-CV-4229/NMB-1699-R, elements that are not represented are shaded. Scale bar = 1 m.

In particular, they found that as the sacrum is distinctly “wedged” (i.e. its anteroposterior length is greater ventrally than it is dorsally, giving it a functionally trapezoidal shape, shown in their figure 1A), so that the column of the torso is inclined 20 degrees dorsally relative to that of the tail. They also found lesser but still significant wedging in the last two dorsal vertebrae (figure 1B) and apparently some slight wedging in the first dorsal (figure 1C) and last cervical (figure 1D).

The upshot of all this is that their new reconstruction of Spinophorosaurus has a strongly inclined dorsal column, and consequently a strongly inclined cervical column in neutral pose.

Vidal et al. also note that all eusauropods have wedged sacra to a greater or lesser extent, and conclude that to varying degrees all eusauropods had a more inclined torso and neck than we have been used to reconstructing them with.

Response

I have to be careful about this paper, because its results flatter my preconceptions. I have always been a raised-neck advocate, and there is a temptation to leap onto any paper that reaches the same conclusion and see it as corroboration of my position.

The first thing to say is that the core observation is absolutely right, — and it’s one of those things that once it’s pointed out it’s so obvious that you wonder why you never made anything of it yourself. Yes, it’s true that sauropod sacra are wedged. It’s often difficult to see in lateral view because the ilia are usually fused to the sacral ribs, but when you see them in three dimensions it’s obvious. Occasionally you find a sacrum without its ilium, and then the wedging can hardly be missed … yet somehow, we’ve all been missing its implications for a century and a half.

Sacrum of Diplodocus AMNH 516 in left lateral and (for our purposes irrelevant) ventral views. (Osborn 1904 figure 3)

Of course this means that, other thing being equal, the tail and torso will not be parallel with each other, but will project in such a way that the angle between them, measured dorsally, is less than 180 degrees. And to be fair, Greg Paul has long been illustrating diplodocids with an upward kink to the tail, and some other palaeoartists have picked up on this — notably Scott Hartman with his very uncomfortable-looking Mamenchisaurus.

But I do have three important caveats that mean I can’t just take the conclusions of the Vidal et al. paper at face value.

1. Intervertebral cartilage

I know that we have rather banged on about this (Taylor and Wedel 2013, Taylor 2014) but it remains true that bones alone can tell us almost nothing about how vertebrae articulated. Unless we incorporate intervertebral cartilage into our models, they can only mislead us. To their credit, Vidal et al. are aware of this — though you wouldn’t know it from the actual paper, whose single mention of cartilage is in respect of a hypothesised cartilaginous suprascapula. But buried away the supplementary information is this rather despairing paragraph:

Cartilaginous Neutral Pose (CNP): the term was coined by Taylor for “the pose found when intervertebral cartilage [that separates the centra of adjacent vertebrae] is included”. Since the amount of inter-vertebral space cannot be certainly known for most fossil vertebrate taxa, true CNP will likely remain unknown for most taxa or always based on estimates.

Now this is true, so far as it goes: it’s usually impossible to know how much cartilage there was, and what shape it took, as only very unusual preservational conditions give us this information. But I don’t think that lets us out from the duty of recognising how crucial that cartilage is. It’s not enough just to say “It’s too hard to measure” and assume it didn’t exist. We need to be saying “Here are the results if we assume zero-thickness cartilage, here’s what we get if we assume cartilage thickness equal to 5% centrum length, and here’s what we get if we assume 10%”.

I really don’t think it’s good enough in 2020 to say “We know there was some intervertebral cartilage, but since we don’t know exactly how much we’re going to assume there was none at all”.

The thing about incorporating cartilage into articulating models is that we would, quite possibly, get crazy results. I refer you to the disturbing figure 4 in my 2014 paper:

Figure 4. Effect of adding cartilage to the neutral pose of the neck of Diplodocus carnegii CM 84. Images of vertebra from Hatcher (1901:plate III). At the bottom, the vertebrae are composed in a horizontal posture. Superimposed, the same vertebrae are shown inclined by the additional extension angles indicated in Table 2.

I imagine that taking cartilage into account for the Spinophorosaurus reconstruction might have given rise to equally crazy “neutral” postures. I can see why Vidal et al. might have been reluctant to open that can of worms; but the thing is, it’s a can that really needs opening.

2. Sacrum orientation

As Vidal et al.’s figure 1A clearly shows, the sacrum of Spinophorosaurus is indeed wedge-shaped, with the anterior articular surface of the first sacral forming an angle of 20 degrees relative to the posterior articular surface of the last:

But I don’t see why it follows that “the coalesced sacrum is situated so that the posterior face of the last sacral centrum is sub-vertical. This makes the presacral series slope dorsally and allows the tail to be subhorizontal (Figs. 1 and 4S)”. Vidal et al. justify this by saying:

Since a subhorizontal tail has been known to be present in the majority of known sauropods[27, 28, 29], the [osteologically induced curvature] of the tail of Spinophorosaurus is therefore compatible with this condition.

But those three numbered references are to Gilmore 1932, Coombs 1975 and Bakker 1968 — three venerable papers, all over fifty years old, dating from a period long before the current understanding of sauropod posture. What’s more, each of those three was about disproving the previously widespread assumption of tail-dragging in sauropods, but the wedged sacrum of Spinophorosaurus if anything suggests the opposite posture.

So my question is, given that the dorsal and caudal portions of the vertebral column are at some specific angle to each other, how do we decide which (if either) is horizontal, and which is inclined?

Three interpretations of the wedged sacrum of Spinophorosaurus, in right lateral view. In all three, the green line represents the trajectory of the dorsal column in the torso, and the red line that of the caudal column. At the top, the tail is horizontal (as favoured by Vidal et al. 2020) resulting in an inclined torso; at the bottom, the torso is horizontal, resulting in a dorsally inclined tail; in the middle, an intermediate posture shows both the torso and the tail slightly inclined.

I am not convinced that the evidence presented by Vidal et al. persuasively favours any of these possibilities over the others. (They restore the forequarters of Spinophorosaurus with a very vertical and ventrally positioned scapula in order to enable the forefeet to reach the ground; this may be correct or it may not, but it’s by no means certain — especially as the humeri are cross-scaled from a referred specimen and the radius, ulna and manus completely unknown.)

3. Distortion

Finally, we should mention the problem of distortion. This is not really a criticism of the paper, just a warning that sacra as preserved should not be taken as gospel. I have no statistics or even systematic observations to back up this assertion, but the impression I have, from having looked closely at quite a lot of sauropod vertebra, is the sacra are perhaps more prone to distortion than most vertebrae. So, for example, the very extreme almost 30-degree wedging that Vidal et al. observed in the sacrum of the Brachiosaurus altithorax holotype FMNH PR 25107 should perhaps not be taken at face value.

Now what?

Vidal el al. are obviously onto something. Sauropod sacra are screwy, and I’m glad they have drawn attention in a systematic way to something that had only been alluded to in passing previously, and often in a way that made it seems as though the wedging they describe was unique to a few special specimens. So it’s good that this paper is out there.

But we really do need to see it as only a beginning. Some of the things I want to see:

Taking cartilage into account. If this results in silly postures, we need to understand why that is the case, not just pretend the problem doesn’t exist.
Comparison of sauropod sacra with those of other animals — most important, extant animals whose actual posture we can observe. This might be able to tell us whether wedging really has the implications for posture that we’re assuming.
Better justification of the claim that the torso rather than the tail was inclined.
An emerging consensus on sauropod shoulder articulation, since this also bears on torso orientation. (I don’t really have a position on this, but I think Matt does.)
The digital Spinophorosaurus model used in this study. (The paper says “The digital fossils used to build the virtual skeleton are deposited and accessioned at the Museo Paleontológico de Elche” but there is no link, I can’t easily find them on the website and they really should be published alongside the paper.)

Anyway, this is a good beginning. Onward and upward!

References

Bakker, Robert T. 1968. The Superiority of Dinosaurs. Discovery 3:11–22.
Coombs, Walter P. 1975. Sauropod habits and habitats. Palaeogeography, Palaeoclimatology, Palaeoecology 17:1-33.
Gilmore, Charles W. 1932. On a newly mounted skeleton of Diplodocus in the United States National Museum. Proceedings of the United States National Museum 81:1-21.
Hatcher, John Bell. 1901. Diplodocus (Marsh): its osteology, taxonomy, and probable habits, with a restoration of the skeleton. Memoirs of the Carnegie Museum 1:1-63.
Osborn, Henry F. 1904. Manus, sacrum and caudals of Sauropoda. Bulletin of the American Museum of Natural History 20:181-190.
Taylor, Michael P. 2014. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs. PeerJ 2:e712. doi:10.7717/peerj.712
Taylor, Michael P., and Mathew J. Wedel. 2013c. 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
Taylor, Michael P., Mathew J. Wedel and Darren Naish. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54(2):213-230.
Vidal, Daniel, P Mocho, A. Aberasturi, J. L. Sanz and F. Ortega. 2020. High browsing skeletal adaptations in Spinophorosaurus reveal an evolutionary innovation in sauropod dinosaurs. Scientific Reports 10(6638). Indispensible supplementary information at https://static-content.springer.com/esm/art%3A10.1038%2Fs41598-020-63439-0/MediaObjects/41598_2020_63439_MOESM1_ESM.pdf
doi:10.1038/s41598-020-63439-0

Posted by Mike Taylor
Filed in 3D models, cartilage, dorsal, mounts, necks, new papers, sacral, skeletal reconstructions, Spinophorosaurus, Tails, timely, torso

29 Comments »

Sacral pneumatization in sauropods was complex

October 16, 2018

Here’s D10 and the sacrum of Diplodocus AMNH 516 in left lateral and ventral view, from Osborn (1904: fig. 3). Note how the big lateral pneumatic foramina, here labeled ‘pleurocoelia’, start out up at the top of the centrum in D10 and kind of pinch out up there, seemingly entirely absent by S3 (although there is a suspicious-looking shadowed spot above and behind the sacral rib stump labeled ‘r3’). Then on S4 and S5 the big foramina are back, but now they’re low on the centrum, ventral to the sacral ribs. In ventral view, the foramina on D10, S1, and S2 aren’t visible–they’re both over the curve of the centrum, and in the case of S1 and S2, obscured by the sacral ribs. But in S4 and S5, the big lateral foramina are visible in ventral view.

I’ve been interested in a while in this seeming hand-off in centrum pneumatization from dorsolateral, which prevails in the dorsal vertebrae, to ventrolateral, which prevails in the posterior sacral and caudal vertebrae. Almost all sauropod dorsals have the pneumatic foramina quite high on the centrum, sometimes even encroaching on the neural arch. But if sauropod caudals have pneumatic fossae or foramina on the centrum, they’re usually quite low, and almost always below the caudal rib or transverse process (there may also be pneumatic fossae on the neural arch and spine)–for evidence, see Wedel and Taylor (2013b). To me this implies two different sets of diverticula.

I think that in part because sometimes you get both sets of diverticula acting on a single vert. Here’s the centrum of sacral 4 of Haplocanthosaurus CM 879 in right dorsolateral view; anterior is to the right.

Here’s the same thing annotated (yeah, it does look a little like an Ent who is alarmed because his left eye has been overgrown by a huge nasal tumor). This vert has two sets of pneumatic features on the centrum: a big lateral fossa below the sacral rib articulation, presumably homologous with the same feature in S4 of the Diplodocus above; and a smaller dorsolateral fossa above and behind sacral rib articulation.

Unfortunately, CM 879 doesn’t tell us much about how these two sets of diverticula might have changed along the column. The centra of S1-S3 were not found, S5 lacks both sets of fossae, the first caudal has fossae both on the centrum, below the caudal rib, and low on the arch, and the second and subsequent caudals lack both sets of fossae. (I wrote a LOT more about pneumaticity in this individual in my 2009 air sacs paper, which is linked below.)

Working out how these diverticula change serially is a tractable problem. 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. As far as I know, that’s never been done, but feel free to correct me if I’ve missed something. I’m neck deep in other stuff, so if someone wants that project, have at it. (If you happen to look into this, I’d be grateful for a heads up, so we don’t run over each other if I do get a yen to investigate further myself.)

References

Osborn, Henry F. 1904. Manus, sacrum and caudals of Sauropoda. Bulletin of the American Museum of Natural History 20:181-190.
Wedel, M.J. 2009. Evidence for bird-like air sacs in saurischian dinosaurs. Journal of Experimental Zoology 311A:611-628.
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]

Posted by Matt Wedel
Filed in diplodocids, Diplodocus, Haplocanthosaurus, Hey you! Want a project?, pneumaticity, sacral

5 Comments »

The camarasaur that was more than it seeemed

July 21, 2018

This is SUSA 515, a partial skeleton of Camarasaurus on display in the Museum of Moab. (SUSA stands for Southeastern Utah Society of Arts & Sciences.) It was described by John Foster in 2005.

I like this thing. The neural spines are blown off so you can see right down into the big pneumatic cavities in the dorsal vertebrae. And unlike the plastered, painted, and retouched-to-seeming-perfection mounted skeletons in most museums, this specimen reflects how most sauropod specimens look when they come out of the ground. With a few dorsal centra, a roadkilled sacrum, and some surprisingly interesting caudals, it puts me strongly in mind of MWC 8028, the Snowmass Haplocanthosaurus (another John Foster joint: see Foster and Wedel 2014).

Frankly, it doesn’t look like much: 17 centra and some odd bits of pelvis. Surely, with so many good Camarasaurus specimens in the world, this one couldn’t possibly have anything new to tell us about the anatomy of that genus. And yet, it has a couple of unusual features that make it worthy of attention. My colleagues and I are working on those things right now, and you’ll be hearing more about this specimen in the very near future.

References

Foster, J.R. 2005. New sauropod dinosaur specimens found near Moab, Utah, and the sauropod fauna of the Morrison Formation. Canyon Legacy: Journal of the Dan O’Laurie Museum of Moab 55:22-27.
Foster, J.R., and Wedel, M.J. 2014. Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado. Volumina Jurassica 12(2): 197–210. DOI: 10.5604/17313708 .1130144

Posted by Matt Wedel
Filed in camarasaurs, caudal, dorsal, Museum of Moab, museums, public galleries, sacral

3 Comments »

Sauropod neural canals are weird, part 1b: more offset neural arch joints

January 22, 2018

In the first installment in this series (link), we looked at a couple of weird sauropod vertebrae with neurocentral joints that were situated either entirely dorsal or ventral to the neural canals. This post has more examples of what I am calling “offset” neurocentral synchondroses.

I decided it made more sense to refer to the synchondrosis as being offset, instead of referring to the neural canal as offset. Because the neural canal in all of these vertebrae is right where it pretty much always is, just dorsal to the articular surfaces of the centrum. In an adult, fused vertebra, there’d be no sign that anything unusual had ever happened. So I think it makes more sense to talk about the neurocentral joint having migrated dorsally or ventrally relative to the canal, rather than vice versa. If you know differently, or if these weirdos have been addressed before elsewhere and I’ve just missed it, please let me know in the comments!

Here’s a plate from Marsh (1896) showing caudal vertebrae of Camarasaurus (“Morosaurus” in O.C. Marsh parlance), which echo the Alamosaurus caudal from the first post in having the neurocentral joint almost entirely ventral to the neural canal. The neural arch here doesn’t just arch over the canal dorsally, it also cuts under it ventrally, at least in part.

This plate is also nice because it shows the relationships among the arch, centrum, and caudal ribs before they fuse. Here’s the caption, from Marsh (1896):

Here’s the preceding plate, Plate 33, with illustrations of an unfused Camarasaurus sacrum.

And its caption:

This plate not only shows how the sacral ribs fuse to the arch and spine medially, and to each other laterally (forming the sacrocostal yoke), it also shows a last sacral that is very similar to the aforementioned caudals in the position of the neurocentral joint. But interestingly that neurocentral joint offset only seems to be present in the last ~~caudal~~ sacral – the lower figure shows widely-separated neurocentral joint surfaces in the more anterior centra, indicating that the neural arches (not figured in this dorsal view) did not wrap around the neural canal to approach the midline. (I think we’re looking at S2 through S5 here, and missing a dorso-sacral.)

So now I’m freaked out, wondering if this neural arch wrap-around in the caudals is common to most sauropods and I just haven’t looked at enough juvenile caudals to have spotted it before. As always, feel free to ablate my ignorance in the comments, particularly if you know of more published examples. I’m a collector.

The neural canal of that last sacral also has a very interesting cross-sectional shape, like a numeral 8. I have some thoughts on that, but they’ll keep for a future post in this series.

Posted by Matt Wedel
Filed in "Morosaurus", camarasaurs, caudal, fusion, neural canal, sacral

8 Comments »

Yes, sauropod neck vertebrae got longer as the animals grew up

November 21, 2016

Fig. 14. Vertebrae of Pleurocoelus and other juvenile sauropods. in right lateral view. A-C. Cervical vertebrae. A. Pleurocoelus nanus (USNM 5678, redrawn fromLull1911b: pl. 15). B. Apatosaurus sp. (OMNH 1251, redrawn from Carpenter &McIntosh 1994: fig. 17.1). C. Camarasaurus sp. (CM 578, redrawn from Carpenter & McIntosh 1994: fig. 17.1). D-G. Dorsal vertebrae. D. Pleurocoelus nanus (USNM 4968, re- drawn from Lull 1911b: pl. 15). E. Eucamerotus foxi (BMNH R2524, redrawn from Blows 1995: fig. 2). F. Dorsal vertebra referred to Pleurocoelus sp. (UMNH VP900, redrawn from DeCourten 1991: fig. 6). G. Apatosaurus sp. (OMNH 1217, redrawn from Carpenter & McIntosh 1994: fig. 17.2). H-I. Sacral vertebrae. H. Pleurocoelus nanus (USNM 4946, redrawn from Lull 1911b: pl. 15). I. Camarasaurus sp. (CM 578, redrawn from Carpenter & McIntosh 1994: fig. 17.2). In general, vertebrae of juvenile sauropods are characterized by large pneumatic fossae, so this feature is not autapomorphic for Pleurocoelus and is not diagnostic at the genus, or even family, level. Scale bars are 10 cm. (Wedel et al. 2000b: fig. 14)

The question of whether sauropod cervicals got longer through ontogeny came up in the comment thread on Mike’s “How horrifying was the neck of Barosaurus?” post, and rather than bury this as a comment, I’m promoting it to a post of its own.

The short answer is, yeah, in most sauropods, and maybe all, the cervical vertebrae did lengthen over ontogeny. This is obvious from looking at the vertebrae of very young (dog-sized) sauropods and comparing them to those of adults. If you want it quantified for two well-known taxa, fortunately that work was published 16 years ago – I ran the numbers for Apatosaurus and Camarasaurus to see if it was plausible for Sauroposeidon to be synonymous with Pleurocoelus, which was a real concern back in the late ’90s (the answer is a resounding ‘no’). From Wedel et al. (2000b: pp. 368-369):

Despite the inadequacies of the type material of Pleurocoelus, and the uncertainties involved with referred material, the genus can be distinguished from Brachiosaurus and Sauroposeidon, even considering ontogenetic variation. The cervical vertebrae of Pleurocoelus are uniformly short, with a maximum EI of only 2.4 in all of the Arundel material (Table 4). For a juvenile cervical of these proportions to develop into an elongate cervical comparable to those of Sauroposeidon, the length of the centrum would have to increase by more than 100% relative to its diameter. Comparisons to taxa whose ontogenetic development can be estimated suggest much more modest increases in length.

Carpenter & McIntosh (1994) described cervical vertebrae from juvenile individuals of Apatosaurus and Camarasaurus. Measurements and proportions of cervical vertebrae from adults and juveniles of each genus are given in Table 4. The vertebrae from juvenile specimens of Apatosaurus have an average EI 2.0. Vertebrae from adult specimens of Apatosaurus excelsus and A. louisae show an average EI of 2.7, with an upper limit of 3.3. If the juvenile vertebrae are typical for Apatosaurus, they suggest that Apatosaurus vertebrae lengthened by 35 to 65% relative to centrum diameter in the course of development.

The vertebrae from juvenile specimens of Camarasaurus have an average EI of 1.8 and a maximum of 2.3. The relatively long-necked Camarasaurus lewisi is represented by a single skeleton, whereas the shorter-necked C. grandis, C. lentus, and C. supremus are each represented by several specimens (McIntosh, Miller, et al. 1996), and it is likely that the juvenile individuals of Camarasaurus belong to one of the latter species. In AMNH 5761, referred to C. supremus, the average EI of the cervical vertebrae is 2.4, with a maximum of 3.5. These ratios represent an increase in length relative to diameter of 30 to 50% over the juvenile Camarasaurus.

If the ontogenetic changes in EI observed in Apatosaurus and Camarasaurus are typical for sauropods, then it is very unlikely that Pleurocoelus could have achieved the distinctive vertebral proportions of either Brachiosaurus or Sauroposeidon.

apatosaurus-cm-555-c6-centrum-and-arch-united

C6 of Apatosaurus CM 555 – despite having an unfused neural arch and cervical ribs, the centrum proportions are about the same as in an adult.

A few things about this:

From what I’ve seen, the elongation of the individual vertebrae over ontogeny seems to be complete by the time sauropods are 1/2 to 2/3 of adult size. I get this from looking at mid-sized subadults like CM 555 and the hordes of similar individuals at BYU, the Museum of Western Colorado, and other places. So to get to the question posed in the comment thread on Mike’s giant Baro post – from what I’ve seen (anecdata), a giant, Supersaurus-class Barosaurus would not necessarily have a proportionally longer neck than AMNH 6341. It might have a proportionally longer neck, I just haven’t seen anything yet that strongly suggests that. More work needed.
Juvenile sauropod cervicals are not only shorter than those of adults, they also have less complex pneumatic morphology. That was the point of the figure at the top of the post. But that very simple generalization is about all we know so far – this is an area that could use a LOT more work.
I’ve complained before about papers mostly being remember for one thing, even if they say many things. This is the canonical example – no-one ever seems to remember the vertebrae-elongating-over-ontogeny stuff from Wedel et al. (2000b). Maybe that’s an argument for breaking up long, kitchen-sink papers into two or more separate publications?

Reference

Wedel, M.J., Cifelli, R.L., and Sanders, R.K. 2000b. Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon. Acta Palaeontologica Polonica 45:343-388.

Posted by Matt Wedel
Filed in Apatosaurus, camarasaurs, cervical, diplodocids, dorsal, juvenile, ontogeny, Pleurocoelus, pneumaticity, sacral

8 Comments »

SV-POW! on the road – Matt’s public lecture at the Oklahoma Museum of Natural History

March 14, 2016

Just a quick heads up for any SV-POW! readers within convenient striking distance of Norman, Oklahoma, this Wednesday, March 16. Like all of the lectures in the “Dinosaurs Past & Present” series at OMNH, this one is free to the public. I hope to see some of you there!

Posted by Matt Wedel
Filed in Apatosaurus, diplodocids, sacral, stinkin' mammals, stinkin' SV-POW!sketeers, SV-POW! on the road, timely, travel

10 Comments »

	LeeB on More raptors with their heads…
	ncmncm on SV-POW! is an AI-free zon…
	More raptors with th… on Yet more lying necks: Backward…
	Mike Taylor on Book Week 2025, Day 2: The Ris…
	Victoria R on Book Week 2025, Day 2: The Ris…

November 26, 2025

1. Research Notebook

2. Measuring tapes

3. Writing instruments in various colors

4. Calipers

5. Small brush on a carabiner

6. Scale bar

7. Index cards

8. Pencil case

9. Artificial lighting

USUALLY — Laptop

MAYBE — Monographs

OUT — Camera and tripod

Over to you

March 29, 2024

Part 1: Why Study Pneumaticity

How to Study Pneumaticity on the Cheap

Conclusion: Let’s Roll

References

May 16, 2021

References

March 13, 2021

References

April 22, 2020

Overview

Response

1. Intervertebral cartilage

2. Sacrum orientation

3. Distortion

Now what?

References

October 16, 2018

References

July 21, 2018

References

January 22, 2018

November 21, 2016

March 14, 2016

Support SV-POW!

Search

Recent Posts

Recent Comments

Pages

Categories

Archives

Subscribe to Blog via Email

RSS

Blog Stats