Obscure vertebral anatomy term of the day: bouton
October 25, 2022
Long-time readers will recall that I’m fascinated by neurocentral joints, and not merely that they exist (although they are pretty cool), but that in some vertebrae they migrate dorsally or ventrally from their typical position (see this and this).
A few years ago I learned that there is a term for the expanded bit of neural arch pedicle that contributes to the centrum in vertebrae with ventrally-migrated neurocentral joints: the bouton, which is French for ‘button’. Here’s an example in the unfused C7 of a subadult sheep. Somebody gifted me a handful of these things a few years ago, and I’ve been meaning to blog about them forever. Many thanks, mysterious benefactor. (I mean, only mysterious to me, because my memory is crap; I’m sure you know who you are, and if you ever read this, feel free to remind me. And thanks for the dead animal parts!)
Guess what? You have these things, too! Or at least you did; if you’re old enough to be reading this, your boutons fused with the rest of the separate bits of your vertebrae a long time ago, between the ages of 2 and 5 (according to Bagnall et al. 1977). Here’s a diagram from Schaefer et al. (2009: p.99) showing the separate centrum and neural arch elements in a thoracic vertebra of a human toddler. So, hey, cool, we all had boutons, just like sheep. And just like some sauropods. (You didn’t think I was going to do a whole OVATOD post without sauropods, did you?)
Here’s our old friend BIBE 45885, an unfused caudal neural arch (or perhaps neural ring) of Alamosaurus, which I’ve been freaking out over for five years now. Those fat bits of neural arch that very nearly close off the neural canal ventrally? Boutons, baby! Big, beautiful boutons. In this photo it looks like the paired boutons meet on the midline, but in fact they merely overlap from this point of view — there is a narrow (<1mm) squiggly gap between them. Given how narrow that gap is, I suspect the two boutons probably would have fused to each other before either of them fused to the centrum, if this particular animal hadn’t died first.
Here’s an unfused dorsal centrum of Giraffatitan, MB.R. 3823, which I yapped about in this post. This vertebra is the spiritual opposite of the Alamosaurus caudal shown above: instead of the neural canal being nearly enclosed by bits of the neural arch wrapping around ventrally, the neural canal is nearly enclosed dorsally by bits of the centrum sticking up on either side and wrapping around dorsally. As with the boutons of the Alamosaurus caudal, the two expanded bits of centrum stuff in this Giraffatitan dorsal approach each other very closely but don’t quite meet; you can fit a piece of paper between them, but not a heck of a lot more. In essence, those “two expanded bits of centrum stuff” are centrum boutons that project up into what I suppose we’ll keep calling a ‘neural arch’ even though it’s neither very neural nor an arch. Or perhaps anti-boutons? With apologies to Gould and Vrba (1982), here we have another missing term in the science of form.
Why do we, and sheep, and prolly lots of other mammals, and some sauropods, have boutons? Presumably to strengthen the neurocentral joints by expanding the joint surface area. I don’t know if anyone has ever tested that — if you do, please let me know in the comments.
Many thanks to Thierra Nalley, who may be the only person I know besides Mike who spends more time thinking about vertebrae than I do, for introducing me to the term ’bouton’ a few years ago. If for some reason you want to corrupt your sensibilities reading about primate vertebrae, you could do a lot worse than checking out Thierra’s papers.
I don’t expect we’ll have a ton of OVATOD posts, in part because there aren’t a heck of a lot of vertebra parts that we haven’t already blogged about. But who knows, maybe Mike will write about prepostepipophyses or something. Stay tuned!
References
- Bagnall, K.M., Harris, P.F., and Jones, P.R.M. 1977. A radiographic study of the human fetal spine. 2. The sequence of development of ossification centers in the vertebral column. Journal of Anatomy 124(3): 791–802.
- Gould, S.J. and Vrba, E.S. 1982. Exaptation—a missing term in the science of form. Paleobiology 8(1): 4-15.
- Schaefer, M., Black, S., and Scheuer, L. 2009. Juvenile Osteology: A Laboratory and Field Manual. Academic Press, Burlington, MA, 369pp.
P.S. Can we all pitch in and make ’bouton’ the new ‘aglet‘? Please? Please?
I’m not 100% sure what this is, but it exists
October 8, 2022
Darren, the silent partner at SV-POW!, pointed me to this tweet by Duc de Vinney, displaying a tableau of “A bunch of Boners (people who study bones) Not just paleontologists, some naturalists and cryptozoologists too”, apparently commissioned by @EDGEinthewild:
As you can see, Darren, Matt and I (as well as long-time Friend Of SV-POW! Mark Witton) somehow all made it into the cartoon, ahead of numerous far more deserving people. Whatever the criterion was, and whatever reason Edge In The Wild had for wanting this, I am delighted to be included alongside the likes of Owen, Osborn, Cope, Marsh, and Bob Bakker. Even if the caricatures are not especially flattering.
Here is an edit showing only the three of us, which I am sure I will find many fruitful uses for:
My thanks to Duc de Vinney for creating this!
Old tricks in new wineskins
October 6, 2022
It’s been a while since we checked in on our old friends Elsevier, Springer Nature and Wiley — collectively, the big legacy publishers who still dominate scholarly publishing. Like every publisher, they have realised which way the wind is blowing, and flipped their rhetoric to pro-open access — a far cry from the days when they were hiring PR “pit bulls” to smear open access.
These days, it’s clear that open access is winning. In fact, I’ll go further: open access has won and now we’re just mopping up the remaining pockets of resistance. We’ve had our D-Day. That doesn’t mean there isn’t still lots of work to get through before we arrive at our VE-Day, but it’s coming. And the legacy publishers, having recognised that the old journal-subscriptions gravy train is coasting to a halt, are keen to get big slices of the OA pie.
Does this change in strategy reflect a change of heart in these organization?
Reader, it does not.
Just in the last few days, these three stories have come up:
- Elsevier has raised the price of access to its chemical database Reaxys from £13,500 per institution to £38,000: an increase of 181% in four years, or 29.5% per year cumulative. UK universities are quite rightly considering not renewing their subscription.
- Springer has started demanding colour charges for online-only papers, as though “colour pixels cost more money” — this despite the Springer website saying that no such charges should be levied. Swansea University Library Research Support is quite rightly telling researchers to push back on these unacceptable charges — but they shouldn’t have to.
- Most egregiously, Wiley suddenly removed 1,380 textbooks from one of its bundles, leaving at least one professor “to reorganize her entire syllabus to prevent her students from having to pay out of pocket for their required class textbook”. Others of course will quite understandably not bother, leaving students hundreds of dollars out of pocket.
Widespread outrage at the last of these has forced Wiley to back down and temporarily reinstate the missing textbooks, though only for the next eight months. It’s clear that courses which used these books will need to re-tool — hopefully by pivoting to open textbooks.
All of this tells as unwelcome truth that we just need to accept: that the big publishers are still not our friends. We must make our decisions accordingly.
Vertebrae of Haplocanthosaurus (A-C) and a giraffe (D-F) illustrating three ways of orienting a vertebra: articular surfaces vertical — or at least the caudal articular surface vertical (A and D), floor of the neural canal horizontal (B and E), and similarity in articulation (C and F). See the paper for details! Taylor and Wedel (2002: fig. 6).
This is a lovely cosmic alignment: right after the 15th anniversary of this blog, Mike and I have our 11th coauthored publication (not counting abstracts and preprints) out today.
This one started back in 2018, with Mike’s post, What does it mean for a vertebra to be “horizontal”? That post and subsequent posts on the same topic (one, two, three) provoked interesting discussions in the comment threads, and convinced us that there was something here worth grappling with. We gave a presentation on the topic at the 1st Palaeontological Virtual Congress that December, which we made available as a preprint, which led to us writing the paper in the open, which led to another preprint (of the paper this time, not the talk).
Orienting vertebrae with the long axis of the centrum held horizontally seems simple enough, but choosing landmarks can be surprisingly complex. Taylor and Wedel (2022 fig. 5).
This project represented some interesting watersheds for us. It was not our first time turning a series of blog posts into a paper — see our 2013 paper on neural spine bifurcation for that — but it was our first time writing a joint paper in the open (Mike had started writing the Archbishop description in the open a few months earlier). It was also the last, or at least the most recent, manuscript that we released as a preprint, although we’ve released some conference presentations as preprints since then. I’m much less interested in preprints than I used to be, for reasons explained in this post, and I think Mike sees them as rather pointless if you’re writing the paper in the open anyway, which is his standard approach these days (Mike, feel free to correct me here or in the comments if I’m mischaracterizing your position).
So, we got it submitted, we got reviews, and then…we sat on them for a while. We have both struggled in the last few years with Getting Things Done, or at least Getting Things Finished (Mike’s account, my own), and this paper suffered from that. Part of the problem is that Mike and have far too many projects going at any one time. At last count, we have about 20 joint projects in various stages of gestation, and about 11 more that we’ve admitted we’re never going to get to (our To Don’t list), and that doesn’t count our collaborations with others (like the dozen or so papers I have planned with Jessie Atterholt). We simply can’t keep so many plates spinning, and we’re both working hard at pruning our project list and saying ‘no’ to new things — or, if we do think of new projects, we try to hand them off to others as quickly and cleanly as possible.
Two different ways of looking at a Haplocanthosaurus tail vertebra. Read on for a couple of recent real-life examples. Taylor and Wedel (2022: fig. 2).
Anyway, Mike got rolling on the revisions a few months ago, and it was accepted for publication sometime in late spring or early summer, I think. Normally it would have been published in days, but the Journal of Paleontological Techniques was moving between websites and servers, and that took a while. But Mike and I were in no tearing rush, and the paper is out today, so all is well.
One of the bits of the paper that I’m most proud of is the description of cheap and easy methods for determining the orientation of the neural canal. For neural canals that are open, either because they were fully prepped or never full of matrix to begin with, there’s the rolled-up-piece-of-paper method, which I believe first appeared on the blog back when I was posting photos of the tail vertebrae of the Brachiosaurus altithorax holotype. For neural canals that aren’t open, Mike came up with the Blu-tack-and-toothpick method, as shown in Figure 12 in the new paper:
A 3d print of NHMUK PV R2095, the holotype of Xenoposeidon, illustrating the toothpick method of determining neural canal orientation. Taylor and Wedel (2022: fig. 12).
I know both methods work because I recently had occasion to use them, studying the Haplocanthosaurus holotypes (see this post). For CM 572, the neural canal of the first caudal vertebra is full of matrix, so I used a variant of the toothpick method. I didn’t actually have Blu-tack or toothpicks, so I cut thin pieces of plastic from the edge of an SVP scale bar and stuck them in bits of kneadable eraser. It worked just fine:
The neural canal of caudal 2 was prepped, so I could use the rolled-up-piece-of-paper method:
(Incidentally, Mike and I refer to our low-tech orientation-visualizers as “neural-canal-inators”, in honor of Dr. Heinz Doofenshmirtz from Phineas and Ferb.)
In the above photos, notice how terribly thin the base of the neural arch is, antero-posteriorly. Both of these vertebrae are in pretty good shape, without much breakage or missing material, and their morphology is broadly consistent with that of other proximal caudals of Haplocanthosaurus, so we can’t write this off as distortion. As weird as it looks, this is just what Haplo proximal caudals were like. And with the neural canals held horizontally, the first two caudals end up oriented like so:
Now, as we pointed out in the paper, the titular question is not about determining the posture of the vertebrae in life, it’s about defining the directions ‘cranial’ and ‘caudal’ for isolated vertebrae — Mike asked the question back when for the holotype (single) dorsal vertebra of Xenoposeidon. But an interesting spin-off for me has been getting confronted with the weirdness of vertebrae whose articular surfaces are nowhere near orthogonal with their neural canals. I tilted those CM 572 Haplo caudals so that their neural canals were horizontal partly because that’s the preferred orientation that Mike and I landed on in the course of this work, but also partly because to me, that’s a more arresting image than the preceding ones with the articular faces held vertically. I’m both freaked out and fascinated, and that seems like a promising combination — there are mysteries here that cry out to be solved.
As usual, we have loads of people to thank. In addition to all those listed in the Acknowledgments of the new paper, I’m grateful to Matt Lamanna and Amy Henrici of the Carnegie Museum of Natural History for letting me play with study the Haplo specimens in their care. Mike and I also owe a huge thanks to the editorial team at the Journal of Paleontological Techniques. We reached out to them a few days ago to ask if it might be possible to get our in-press paper done and out in time for SV-POW!’s anniversary weekend, and they pitched in to make it happen.
What’s next? We weighed the evidence and formulated what the best solution we could think of. Now it’s up to the world to decide if that was a useful contribution. The comment thread is open — let’s find out.
Happy 15th birthday to SV-POW!
October 1, 2022
Matt and I, with our silent partner Darren, started SV-POW! fifteen years ago to the day, as a sort of jokey riff on NASA’s Astronomy Picture of the Day. Our first post, on 1 October 2007, was a photograph of what we called “the most iconic of sauropod vertebrae, the 8th cervical of the Brachiosaurus brancai type specimen HMN SII”. Now, here in glorious monochrome, is that same vertebra fifteen years on!
(The specimen that it’s from is now recognised as belonging to the separate brachiosaurid genus Giraffatitan, and it’s the paralectotype of the species Giraffatitan brancai.)
Obviously what we’re seeing here is not the real thing — very heavy and very fragile — but a life-sized 3D model, carved out of styrofoam by a CNC machine (computerized carving machine) using surface-scan data of the original specimen. This was done at Research Casting International, and we bring you this photo courtesy of Peter May, Garth Dallman, and the rest of the folks at RCI.
The inside of RCI’s workshop is an interesting place — I’ve never been there myself, but it’s at least Matt’s second visit, and it’s very high on my To Visit list. I especially like the “RAPTOR” box just behind and above Matt’s head.
This photo, unfortunately, makes the vertebra look smaller than it is, because when Matt took the selfie he was holding it further back than his own head. It’s still interesting, though, to see where the balance point is for holding it one-handed. It seems that the rear half of the vertebra is denser than the front half. But of course, that’s only when it’s a solid constant-density volume. The real bone, with all its pneumatic internal structures, might have been quite different.
Needless to say, HMN SII:C8 (or MB.R.2181:C8, as we must now call it) is a very old friend on this blog, to the point where it should probably have a category of its own. Among many other appearances it’s popped up in tutorials 2 (Basic vertebral anatomy), 4 (Laminae) and 21 (How to measure the length of a centrum), as well as Bifid Brachiosaurs, Batman! (6 September 2009), What a 23% longer torso looks like (20 September 2009), Plateosaurus is pathetic and its doppelganger Plateosaurus is comical (16 January and 5 September 2013), and of course Copyright: promoting the Progress of Science and useful Arts by preventing access to 105-year-old quarry maps (11 October 2015).
If you want to see more exciting photos of this glorious vertebra — and indeed of many other sauropod vertebrae — stay tuned for the next fifteen years!
Sauropod Vertebra Picture of the Week 