A. Recovered skeletal elements of Haplocanthosaurus specimen MWC 8028. B. Caudal vertebra 3 in right lateral view. C. The same vertebra in posterior view. Lines show the location of sections for D and E. D. Midsagittal CT slice. The arrow indicates the ventral expansion of the neural canal into the centrum. E. Horizontal CT slice at the level of the neural arch pedicles, with anterior toward the top. Arrows indicate the lateral expansions of the neural canal into the pedicles. B-E are shown at the same scale. Wedel et al. (2021: fig. 1).

New paper out today:

Wedel, Mathew; Atterholt, Jessie; Dooley, Jr., Alton C.; Farooq, Saad; Macalino, Jeff; Nalley, Thierra K.; Wisser, Gary; and Yasmer, John. 2021. Expanded neural canals in the caudal vertebrae of a specimen of Haplocanthosaurus. Academia Letters, Article 911, 10pp. DOI: 10.20935/AL911 (link)

The paper is new, but the findings aren’t, particularly. They’re essentially identical to what we reported in our 1st Paleo Virtual Conference slide deck and preprint, and in the “Tiny Titan” exhibit at the Western Science Center, just finally out in a peer-reviewed journal, with better figures. The paper is open access and free to the world, and it’s short, about 1600 words, so this recap will be short, too.

A. Photograph of a 3D-printed model of the first three caudal vertebrae of Haplocanthosaurus specimen MWC 8028, including endocasts of the neural canal (yellow) and intervertebral joints (blue), in right lateral view, and with the neural canal horizontal. B. Diagram of the same vertebrae in midsagittal section, emphasizing the volumes of the neural canal (yellow) and intervertebral joint spaces (blue). Anterior is to the right. Wedel et al. (2021: fig. 2).

John Foster and I described Museum of Western Colorado (MWC) specimen 8028, a partial skeleton of Haplocanthosaurus from Snowmass, Colorado, in late 2014. One weird thing about that specimen (although not the only weird thing) is that the neural canals of the tail vertebrae are bizarrely expanded. In most vertebrae of most critters, the neural canal is a cylindrical tunnel, but in these vertebrae the neural canals are more like spherical vacuities.

John and I didn’t know what to make of that back in 2014. But a few years later I started working with Jessie Atterholt on bird anatomy, which led me to do a little project on the whole freaking zoo of weird stuff that birds and other dinosaurs do with their neural canals, which led to the 1PVC presentation, which led to this. 

Caudal vertebra 3 of Haplocanthosaurus specimen MWC 8028 in left posterolateral (A), posterior (B), and right posterolateral (C) views, with close-ups (D and E). In A and B, a paintbrush is inserted into one of the lateral recesses, showing that the neural canal is wider internally than at either end. Wedel et al. (2021: fig. 3).

Of course there will be more posts and more yapping, as signaled by the ‘Part 1’ in the post title. Although I am extremely satisfied with the streamlined, 1600-word missile of information and reasoning that just dropped, there are parts that I want to unpack, that haven’t been unpacked before. But the paper launched at midnight-thirty, Pacific Daylight Time, I’m up way too late finishing this first post, and I reckon the rest will keep for a few hours at least.

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).

I have a ton of people to thank. John Foster, obviously, for initiating the line of research that led here. Julia McHugh for access to the MWC collections, and for being an excellent sounding board regarding the Morrison Formation, sauropod dinosaurs, and crafting ambitious but tractable research projects. Anne Weil for helping me be methodical in thinking through the logic of the paper, and Mike Taylor for helping me get it polished. Niels Bonde, Steven Jasinski, and David Martill for constructive reviews, which were published alongside the paper. We couldn’t take all of their suggestions because of space limitations, but figures 3 and 4 were born because they asked for them, and that’s not a small thing. Vicki and London Wedel for putting up with me at various points in this project, especially in the last few days as I’ve been going bonkers correcting page proofs. And finally, because I’m the one writing this blog post, my coauthors: Jessie Atterholt, Alton Dooley, Saad Farooq, Jeff Macalino, Thierra Nalley, Gary Wisser, and John Yasmer, for their contributions and for their patience during the unusually long gestation of this very short paper.

More to say about all that in the future. For now, yay, new paper. Have fun with it. Here’s the link again.

References

It is said that, some time around 1590 AD, Galileo Galilei dropped two spheres of different masses from the Leaning Tower of Pisa[1], thereby demonstrating that they fell at the same rate. This was a big deal because it contradicted Aristotle’s theory of gravity, in which objects are supposed to fall at a speed proportional to their mass.

Aristotle lived from 384–322 BC, which means his observably incorrect theory had been scientific orthodoxy for more than 1,900 years before being overturned[2].

How did this happen? For nearly two millennia, every scientist had it in his power to hold a little stone in one hand and a rock in the other, drop them both, and see with his own eyes that they fell at the same speed. Aristotle’s theory was obviously wrong, yet that obviously wrong theory remained orthodox for eighty generations.

My take is that it happened because people — even scientists — have a strong tendency to trust respected predecessors, and not even to look to see whether their observations and theories are correct. I am guessing that in that 1,900 years, plenty of scientists did indeed do the stone-and-rock experiment, but discounted their own observations because they had too much respect for Aristotle.

But even truly great scientists can be wrong.

Now, here is the same story, told on a much much smaller scale.

Well into the 2010s, it was well known that in sauropods, caudal vertebrae past the first handful are pneumatized only in diplodocines and in saltasaurine titanosaurs. As a bright young sauropod researcher, for example, I knew this from the codings in important and respected phylogenetic analysis such as those of Wilson (2002) and Upchurch et al. (2004).

Until the day I visited the Museum für Naturkunde Berlin and actually, you know, looked at the big mounted Giraffatitan skeleton in the atrium. And this is what I saw:

That’s caudal vertebrae 24–26 in left lateral view, and you could not wish to see a nicer, clearer pneumatic feature than the double foramen in caudal 25.

That observation led directly to Matt’s and my 2013 paper on caudal pneumaticity in Giraffatitan and Apatosaurus (Wedel and Taylor 2013) and clued us into how much more common pneumatic hiatuses are then we’d realised. It also birthed the notion of “cryptic diverticula” — those whose traces are not directly recorded in the fossils, but whose presence can be inferred by traces on other vertebrae. And that led to our most recent paper on pneumatic variation in sauropods (Taylor and Wedel 2021) — from which you might recognise the photo above, since a cleaned-up version of it appears there as Figure 5.

The moral

Just because “everyone knows” something is true, it doesn’t necessarily mean that it actually is true. Verify. Use your own eyes. Even Aristotle can be wrong about gravity. Even Jeff Wilson and Paul Upchurch can be wrong about caudal pneumaticity in non-diplodocines. That shouldn’t in any way undermine the rightly excellent reputations they have built. But we sometimes need to look past reputations, however well earned, to see what’s right in front of us.

Go and look at fossils. Does what you see contradict what “everyone knows”? Good! You’ve discovered something!

 

References

Notes

1. There is some skepticism about whether Galileo’s experiment really took place, or was merely a thought experiment. But since the experiment was described by Galileo’s pupil Vincenzo Viviani in a biography written in 1654, I am inclined to trust the contemporary account ahead of the unfounded scepticism of moderns. Also, Viviani’s wording, translated as “Galileo showed this by repeated experiments made from the height of the Leaning Tower of Pisa in the presence of other professors and all the students” reads like a documentary account rather than a romanticization. And a thought experiment, with no observable result, would not have demonstrated anything.

2. Earlier experiments had similarly shown that Aristotle’s gravitational theory was wrong, including in the works of John Philoponus in the sixth century — but Aristotle’s orthodoxy nevertheless survived until Galileo.

 

A month after I and Matt published our paper “Why is vertebral pneumaticity in sauropod dinosaurs so variable?” at Qeios, we were bemoaning how difficult it was to get anyone to review it. But what a difference the last nineteen days have made!

In that time, we’ve had five reviews, and posted three revisions: revision 2 in response to a review by Mark McMenamin, version 3 in response to a review by Ferdinand Novas, and version 4 in response to reviews by Leonardo Cotts, by Alberto Collareta, and by Eduardo Jiménez-Hidalgo.

Taylor and Wedel (2021: Figure 2). Proximal tail skeleton (first 13 caudal vertebrate) of LACM Herpetology 166483, a juvenile specimen of the false gharial Tomistoma schlegelii. A: close-up of caudal vertebrae 4–6 in right lateral view, red circles highlighting vascular foramina: none in Ca4, two in Ca5 and one in Ca6. B: right lateral view. C: left lateral view (reversed). D: close-up of caudal vertebrae 4–6 in left lateral view (reversed), red circles highlighting vascular foramina: one each in Ca4, Ca5 and Ca6. In right lateral view, vascular foramina are apparent in the centra of caudal vertebrae 5–7 and 9–11; they are absent or too small to make out in vertebrae 1–4, 8 and 12–13. In left lateral view (reversed), vascular foramina are apparent in the centra of caudal vertebrae 4–7 and 9; they are absent or too small to make out in vertebrae 1–3, 8, and 10–13. Caudal centra 5–7 and 9 are therefore vascularised from both sides; 4 and 10–11 from one side only; and 1–3, 8 and 12–13 not at all.

There are a few things to say about this.

First, this is now among our most reviewed papers. Thinking back across all my publications, most have been reviewed by two people; the original Xenoposeidon description was reviewed by three; the same was true of my reassessment of Xenoposeidon as a rebbachisaur, and there may have been one or two more that escape me at the moment. But I definitely can’t think of any papers that have been under five sets of eyes apart from this one in Qeios.

Now I am not at all saying that all five of the reviews on this paper are as comprehensive and detailed as a typical solicited peer review at a traditional journal. Some of them have detailed observations; others are much more cursory. But they all have things to say — which I will return to in my third point.

Second, Qeios has further decoupled the functions of peer review. Traditional peer review combines three rather separate functions: A, Checking that the science is sound before publishing it; B, assessing whether it’s a good fit for the journal (often meaning whether it’s sexy enough); and C, helping the authors to improve the work. When PLOS ONE introduced correctness-only peer-review, they discarded B entirely, reasoning correctly that no-one knows which papers will prove influential[1]. Qeios goes further by also inverting A. By publishing before the peer reviews are in (or indeed solicited), it takes away the gatekeeper role of the reviewers, leaving them with only function C, helping the authors to improve the work. Which means it’s no surprise that …

Third, all five reviews have been constructive. As Matt has written elsewhere, “There’s no way to sugar-coat this: getting reviews back usually feels like getting kicked in the gut”. This is true, and we both have a disgraceful record of allowing harshly-reviewed projects to sit fallow for far too long before doing the hard work of addressing the points made by the reviewers and resubmitting[2].

The contrast with the reviews from Qeios has been striking. Each one has sent me scampering back to the manuscript, keen to make (most of) the suggested changes — hence the three revised versions that I’ve posted in the last fortnight. I think there are at least two reasons for this, a big one and a small one.

  • The big reason, I think, is that the reviewers know their only role is to improve the paper. Well, that’s not quite true: they also have some influence over its evaluation, both in what they write and in assigning a 1-to-5 star score. But they know when they’re writing their reviews that whatever happens, they won’t block publication. This means, firstly, that there is no point in their writing something like “This paper should not be published until the authors do X”; but equally importantly, I think it puts reviewers in a different and more constructive mindset. They feel themselves to be allies of the authors rather than (as can happen) adversaries.
  • The smaller reason is it’s easier to deal with one review at a time. I understand why journals solicit multiple reviews: so the handling editor can consider them all in reaching a decision. I understand why the authors get all the reviews back at once. But that process can’t help but be discouraging: because, once the decision has been made, they’re all on hand and there’s no point in stringing them out. One at a time may not be better, exactly; but it’s emotionally easier.

Is this all upside? Well, it’s too early to say. We’ve only done this once. The experience has certainly been more pleasant — and, crucially, much more efficient — than the traditional publishing lifecycle. But I’m aware of at least two potential drawbacks:

First, the publish-first lifecycle could be exploited by cranks. If the willingness to undergo peer-review is the mark of seriousness in a researcher — and if non-serious researchers are unwilling to face that gauntlet — then a venue that lets you make an end-run around peer-review is an obvious loophole. How serious a danger is this? Only time will tell, but I am inclined to think maybe not too serious. Bad papers on a site like Qeios will attract negative reviews and low scores, especially if they start to get noticed in the mainsteam media. They won’t be seen as having the stamp of having passed peer-review; rather, they will be branded with having publicly failed peer-review.

Second, it’s still not clear where reviewers will come from. We wrote about this problem in some detail last month, and although it’s worked out really well for our present paper, that’s no guarantee that it will always work out this well. We know that Qeios itself approached at least one reviewer to solicit their comments: that’s great, and if they can keep doing this then it will certainly help. But it probably won’t scale, so either a different reviewing culture will need to develop, or we will need people who — perhaps only on an informal basis — take it on themselves to solicit reviews from others. We’re interested to see how this develops.

Anyway, Matt and I have found our first Qeios experience really positive. We’ve come out of it with what I think is a good paper, relatively painlessly, and with much less friction than the usual process. I hope that some of you will try it, too. To help get the process rolling, I personally undertake to review any Qeios article posted by an SV-POW! reader. Just leave a comment here to let me know about your article when it’s up.

 

Notes

[1] “No-one knows which papers will prove influential”. As purely anecdotal evidence for this claim: when I wrote “Sauropod dinosaur research: a historical review” for the Geological Society volume Dinosaurs: A Historical Perspective, I thought it might become a citation monster. It’s done OK, but only OK. Conversely, it never occurred to me that “Head and neck posture in sauropod dinosaurs inferred from extant animals” would be of more than specialist interest, but it’s turned out to be my most cited paper. I bet most researchers can tell similar stories.

[2] One example: my 2015 preprint on the incompleteness of sauropod necks was submitted for publication in October 2015, and the reviews[3] came back that same month. Five and a half years later, I am only now working on the revision and resubmission. If you want other examples, we got ’em. I am not proud of this.

[3] I referred above to “harsh reviews” but in fact the reviews for this paper were not harsh; they were hard, but 100% fair, and I found myself agreeing with about 90% of the criticisms. That has certainly not been true of all the reviews I have found disheartening!

 

Today marks the one-month anniversary of my and Matt’s paper in Qeios about why vertebral pneumaticity in sauropods is so variable. (Taylor and Wedel 2021). We were intrigued to publish on this new platform that supports post-publication peer-review, partly just to see what happened.

Taylor and Wedel (2021: figure 3). Brontosaurus excelsus holotype YPM 1980, caudal vertebrae 7 and 8 in right lateral view. Caudal 7, like most of the sequence, has a single vascular foramen on the right side of its centrum, but caudal 8 has two; others, including caudal 1, have none.

So what has happened? Well, as I write this, the paper has been viewed 842 times, downloaded a healthy 739 times, and acquired an altmetric score 21, based rather incestuously on two SV-POW! blog-posts, 14 tweets and a single Mendeley reader.

What hasn’t happened is even a single comment on the paper. Nothing that could be remotely construed as a post-publication peer-review. And therefore no progress towards our being able to count this as a peer-reviewed publication rather than a preprint — which is how I am currently classifying it in my publications list.

This, despite our having actively solicited reviews both here on SV-POW!, in the original blog-post, and in a Facebook post by Matt. (Ironically, the former got seven comments and the latter got 20, but the actual paper none.)

I’m not here to complain; I’m here to try to understand.

On one level, of course, this is easy to understand: writing a more-than-trivial comment on a scholarly article is work, and it garners very little of the kind of credit academics care about. Reputation on the Qeios site is nice, in a that-and-two-bucks-will-buy-me-a-coffee kind of way, but it’s not going to make a difference to people’s CVs when they apply for jobs and grants — not even in the way that “Reviewed for JVP” might. I completely understand why already overworked researchers don’t elect to invest a significant chunk of time in voluntarily writing a reasoned critique of someone else’s work when they could be putting that time into their own projects. It’s why so very few PLOS articles have comments.

On the other hand, isn’t this what we always do when we write a solicited peer-review for a regular journal?

So as I grope my way through this half-understood brave new world that we’re creating together, I am starting to come to the conclusion that — with some delightful exceptions — peer-review is generally only going to happen when it’s explicitly solicited by a handling editor, or someone with an analogous role. No-one’s to blame for this: it’s just reality that people need a degree of moral coercion to devote that kind of effort to other people’s project. (I’m the same; I’ve left almost no comments on PLOS articles.)

Am I right? Am I unduly pessimistic? Is there some other reason why this paper is not attracting comments when the Barosaurus preprint did? Teach me.

References

 

This is RAM 1619, a proximal caudal vertebra of an apatosaurine, in posterior view. It’s one of just a handful of sauropod specimens at the Raymond M. Alf Museum of Paleontology. It’s a donated specimen, which came with very little documentation. It was originally catalogued only to a very gross taxonomic level, but I had a crack at it on a collections visit in 2018, when I took these photos. I told Andy Farke and the other Alf folks right away, I just never got around to blogging about it until now.

Why do I think it’s an apatosaurine? A few reasons: 

  • it’s slightly procoelous, which is pretty common for diplodocids, whereas caudals of Haplocanthosaurus, Camarasaurus, and Brachiosaurus are all either amphicoelous or amphiplatyan;
  • it has big pneumatic fossae above the transverse processes, unlike Haplo, Cam, and Brachio, but it lacks big pneumatic fossae below the transverse processes, unlike Diplodocus and Barosaurus
  • and finally the clincher: the centrum is taller than wide, and broader dorsally than ventrally.

In the literature this centrum shape is described as ‘heart-shaped’ (e.g., Tschopp et al. 2015), and sometimes there is midline dorsal depression that really sells it. That feature isn’t present in this vert, but overall it’s still much closer to a heart-shape than the caudals of any non-apatosaurine in the Morrison. Hence the literal 11th-hour Valentine’s Day post (and yes, this will go up with a Feb. 15 date because SV-POW! runs on England time, but it’s still the 14th here in SoCal, at least for another minute or two).

RAM 1619 in postero-dorsal view.

Back to the pneumaticity. Occasionally an apatosaurine shows up with big lateral fossae ventral to the transverse processes–the mounted one at the Field Museum is a good example (see this post). And the big Oklahoma apatosaurine breaks the rules by having very pneumatic caudals–more on that in the future. But at least in the very proximal caudals of non-gigantic apatosaurines, it’s more common for there to be pneumatic fossae above the transverse processes, near the base of the neural arch. You can see that in caudal 3 of UWGM 15556/CM 563, a specimen of Brontosaurus parvus:

I don’t think I’d figured out this difference between above-the-transverse-process (supracostal, perhaps) and below-the-transverse-process (infracostal, let’s say) pneumatic fossae when Mike and I published our caudal pneumaticity paper back in 2013. I didn’t start thinking seriously about the dorsal vs ventral distribution of pneumatic features until sometime later (see this post). And I need to go check my notes and photos before I’ll feel comfortable calling supracostal fossae the apatosaurine norm. But I am certain that Diplodocus and Barosaurus have big pneumatic foramina on the lateral faces of their proximal caudals (see this post, for example), Haplocanthosaurus and brachiosaurids have infracostal fossae when they have any fossae at all in proximal caudals (distally the fossae edge up to the base of the neural arch in Giraffatitan), and to date there are no well-documented cases of caudal pneumaticity in Camarasaurus (if that seems like a hedge, sit tight and W4TP). 

RAM 1619 has asymmetric pneumatic fossae, which is pretty cool, and also pretty common, and we think we have a hypothesis to explain that now–see Mike’s and my new paper in Qeios.

And if I’m going to make my midnight deadline, even on Pacific Time, I’d best sign off. More cool stuff inbound real soon.

References

Taylor 2015: Figure 8. Cervical vertebrae 4 (left) and 6 (right) of Giraffatitan brancai lectotype MB.R.2180 (previously HMN SI), in posterior view. Note the dramatically different aspect ratios of their cotyles, indicating that extensive and unpredictable crushing has taken place. Photographs by author.

Here are cervicals 4 and 8 from MB.R.2180, the big mounted Giraffatitan in Berlin. Even though this is one of the better sauropod necks in the world, the vertebrae have enough taphonomic distortion that trying to determine what neutral, uncrushed shape they started from is not easy.

Wedel and Taylor 2013b: Figure 3. The caudal vertebrae of ostriches are highly pneumatic. This mid-caudal vertebra of an ostrich (Struthio camelus), LACM Bj342, is shown in dorsal view (top), anterior, left lateral, and posterior views (middle, left to right), and ventral view (bottom). The vertebra is approximately 5cm wide across the transverse processes. Note the pneumatic foramina on the dorsal, ventral, and lateral sides of the vertebra.

Here’s one of the free caudal vertebrae of an ostrich, Struthio camelus, LACM Ornithology Bj342. It’s a bit asymmetric–the two halves of the neural spine are aimed in slightly different directions, and one transverse process is angled just slightly differently than the other–but the asymmetry is pretty subtle and the rest of the vertebral column looks normal, so I don’t think this rises to the level of pathology. It looks like the kind of minor variation that is present in all kinds of animals, especially large-bodied ones.

This is a dorsal vertebra of a rhea, Rhea americana, LACM Ornithology 97479, in posteroventral view. Ink pen for scale. I took this photo to document the pneumatic foramina and related bone remodeling on the dorsal roof of the neural canal, but I’m showing it here because in technical terms this vert is horked. It’s not subtly asymmetric, it’s grossly so, with virtually every feature–the postzygapophyses, diapophyses, parapophyses, and even the posterior articular surface of the centrum–showing fairly pronounced differences from left to right.

That rhea dorsal looks pretty bad for dry bone from a recently-dead extant animal, but if it was from the Morrison Formation it would be phenomenal. If I found a sauropod vertebra that looked that good, I’d think, “Hey, this thing’s in pretty good shape! Only a little distorted.” The roughed-up surface of the right transverse process might give me pause, and I’d want to take a close look at those postzygs, but most of this asymmetry is consistent with what I’d expect from taphonomic distortion.

Which brings me to my titular question, which I am asking out of genuine ignorance and not in a rhetorical or leading way: can we tell these things apart? And if so, with what degree of confidence? I know there has been a lot of work on 3D retrodeformation over the past decade and a half at least, but I don’t know whether this specific question has been addressed.

Corollary question: up above I wrote, “It looks like the kind of minor variation that is present in all kinds of animals, especially large-bodied ones”. My anecdotal experience is that the vertebrae of large extant animals tend to be more asymmetric than those of small extant animals, but I don’t know if that’s a real biological phenomenon–bone is bone but big animals have larger forces working on their skeletons, and they typically live longer, giving the skeleton more time to respond to those forces–OR if the asymmetry is the same in large and small animals and it’s just easier to see in the big ones.

If either of those questions has been addressed, I’d be grateful for pointers in the comments, and thanks in advance. If one or both have not been addressed, I think they’re interesting but Mike and I have plenty of other things to be getting on with and we’re not planning to work on either one, hence the “Hey, you! Want a project?” tag.

References

We’ve noted many times over the years how inconsistent pneumatic features are in sauropod vertebra. Fossae and formamina vary between individuals of the same species, and along the spinal column, and even between the sides of individual vertebrae. Here’s an example that we touched on in Wedel and Taylor (2013), but which is seen in all its glory here:

Taylor and Wedel (2021: Figure 5). Giraffatitan brancai tail MB.R.5000, part of the mounted skeleton at the Museum für Naturkunde Berlin. Caudal vertebrae 24–26 in left lateral view. While caudal 26 has no pneumatic features, caudal 25 has two distinct pneumatic fossae, likely excavated around two distinct vascular foramina carrying an artery and a vein. Caudal 24 is more shallowly excavated than 25, but may also exhibit two separate fossae.

But bone is usually the least variable material in the vertebrate body. Muscles vary more, nerves more again, and blood vessels most of all. So why are the vertebrae of sauropods so much more variable than other bones?

Our new paper, published today (Taylor and Wedel 2021) proposes an answer! Please read it for the details, but here’s the summary:

  • Early in ontogenly, the blood supply to vertebrae comes from arteries that initially served the spinal cord, penetrating the bone of the neural canal.
  • Later in ontegeny, additional arteries penetrate the centra, leaving vascular foramina (small holes carrying blood vessels).
  • This hand-off does not always run to completion, due to the variability of blood vessels.
  • In extant birds, when pneumatic diverticula enter the bone they do so via vascular foramina, alongside blood vessels.
  • The same was probaby true in sauropods.
  • So in vertebrae that got all their blood supply from vascular foramina in the neural canal, diverticula were unable to enter the centra from the outside.
  • So those centra were never pneumatized from the outside, and no externally visible pneumatic cavities were formed.

Somehow that pretty straightforward argument ended up running to eleven pages. I guess that’s what you get when you reference your thoughts thoroughly, illustrate them in detail, and discuss the implications. But the heart of the paper is that little bullet-list.

Taylor and Wedel (2021: Figure 6). Domestic duck Anas platyrhynchos, dorsal vertebrae 2–7 in left lateral view. Note that the two anteriormost vertebrae (D2 and D3) each have a shallow pneumatic fossa penetrated by numerous small foramina.

(What is the relevance of these duck dorsals? You will need to read the discussion in the paper to find out!)

Our choice of publication venue

The world moves fast. It’s strange to think that only eleven years ago my Brachiosaurus revision (Taylor 2009) was in the Journal of Vertebrate Palaeontology, a journal that now feels very retro. Since then, Matt and I have both published several times in PeerJ, which we love. More recently, we’ve been posting preprints of our papers — and indeed I have three papers stalled in peer-review revisions that are all available as preprints (two Taylor and Wedels and a single sole-authored one). But this time we’re pushing on even further into the Shiny Digital Future.

We’ve published at Qeios. (It’s pronounced “chaos”, but the site doesn’t tell you that; I discovered it on Twitter.) If you’ve not heard of it — I was only very vaguely aware of it myself until this evening — it runs on the same model as the better known F1000 Research, with this very important difference: it’s free. Also, it looks rather slicker.

That model is: publish first, then filter. This is the opposite of the traditional scholarly publishing flow where you filter first — by peer reviewers erecting a series of obstacles to getting your work out — and only after negotiating that course to do get to see your work published. At Qeios, you go right ahead and publish: it’s available right off the bat, but clearly marked as awaiting peer-review:

And then it undergoes review. Who reviews it? Anyone! Ideally, of course, people with some expertise in the relevant fields. We can then post any number of revised versions in response to the reviews — each revision having its own DOI and being fixed and permanent.

How will this work out? We don’t know. It is, in part, an experiment. What will make it work — what will impute credibility to our paper — is good, solid reviews. So if you have any relevant expertise, we do invite you to get over there and write a review.

And finally …

Matt noted that I first sent him the link to the Qeios site at 7:44 pm my time. I think that was the first time he’d heard of it. He and I had plenty of back and forth on where to publish this paper before I pushed on and did it at Qeios. And I tweeted that our paper was available for review at 8:44 — one hour exactly after Matt learned that the venue existed. Now here we are at 12:04 my time, three hours and 20 minutes later, and it’s already been viewed 126 times and downloaded 60 times. I think that’s pretty awesome.

References

  • Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806. [PDF]
  • Taylor, Michael P., and Mathew J. Wedel. 2021. Why is vertebral pneumaticity in sauropod dinosaurs so variable? Qeios 1G6J3Q. doi: 10.32388/1G6J3Q [PDF]
  • Wedel, Mathew J., and Michael P. Taylor 2013b. 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]

A life-size silhouette of the Snowmass Haplocanthosaurus, with Thierra Nalley, me, and Jessie Atterholt for scale. Photo by Jeremiah Scott.

Tiny Titan, a temporary exhibit about the Snowmass Haplocanthosaurus project, opened at the Western Science Center in Hemet, California, last night. How? Why? Read on.

Things have been quieter this year on the Haplo front than they were in 2018, for many reasons. My attention was pulled away by a lot of teaching and other day-job work–we’re launching a new curriculum at the med school, and that’s eaten an immense amount of time–and by some very exciting news from the field that I can’t tell you about quite yet (but watch this space). Things are still moving, and there will be a paper redescribing MWC 8028 and all the weird and cool things we’ve learned about it, but there are a few more timely things ahead of it in the queue.

One of the things going on behind the scenes this year is that Jessie Atterholt, Thierra Nalley, and I have been working with Alton Dooley, the director of the Western Science Center, on this exhibit. Alton has had a gleam in his eye for a long time of using the WSC’s temporary exhibit space to promote the work of local scientists, and we had the honor of being his first example. He also was not fazed by the fact that the project isn’t done–he wants to show the public the process of science in all of its serendipitous and non-linear glory, and not just the polished results that get communicated at the end.

Everything’s better cut in half. Photo by Jessie Atterholt.

Which is not to say that the exhibit isn’t polished. On the contrary, it looks phenomenal. Thanks to a loan from Julia McHugh at Dinosaur Journey in Colorado, most of the real fossils are on display. We’re only missing the ribs and most of the sacrum, which is too fragmentary and fragile to come out of its jacket. As you can see from the photo up top, there is a life-size vinyl silhouette of the Snowmass Haplo, with 3D prints of the vertebrae in approximate life position. Other 3D prints show the vertebrae before and after the process of sculpting, rescanning, and retrodeformation, as described in our presentation for the 1st Palaeontological Virtual Congress last year (that slideshow is a PeerJ Preprint, here). The exhibit also includes panels on “What is Haplocanthosaurus” and its relationships, on pneumaticity in sauropods, on the process of CT scanning and 3D modeling, and on the unusual anatomical features of the Snowmass specimen. The awesome display shown above, with the possibly-bumpy spinal cord and giant intervertebral discs reconstructed, was all Alton–he did the modeling, printing, and assembly himself.

Haplo vs Bronto. Thierra usually works on the evolution and development of the vertebral column in primates, so I had to show her how awesome vertebrae can be when they’re done right. Photo by Brittney Stoneburg.

My favorite thing in the exhibit is this striking comparison of one the Snowmass Haplo caudals with a proximal caudal from the big Oklahoma apatosaurine. This was Alton’s idea. He asked me if I had any photos of caudal vertebrae from really big sauropods that we could print at life size to compare to MWC 8028, and my mind went immediately to OMNH 1331, which is probably the second-largest-diameter vertebra of anything from all of North America (see the list here). It was also Alton’s idea to fill in the missing bits using one of Marsh’s plates of Brontosaurus excelsus from Como Bluff in Wyoming. It’s a pretty amazing display, and it turns out to have been a vehicle for discovery, too–I didn’t realize until I saw the verts side-by-side that the neural canal of the Snowmass Haplo caudal is almost as big as the neural canal from the giant apatosaurine caudal. It’s not a perfect comparison, because the OMNH fossil doesn’t preserve the neural canal, and the Como specimen isn’t that big, but proportionally, the Snowmass Haplo seems to have big honkin’ neural canals, not just at the midpoint (which we already knew), but all the way through. Looks like I have some measuring and comparing to do.

(Oh, about the title: we don’t know if the Snowmass Haplo was fully grown or not, but not all haplocanthosaurs were small. The mounted H. delfsi in Cleveland is huge, getting into Apatosaurus and Diplodocus territory. Everything we can assess in the Snowmass Haplo is fused, for what that’s worth. We have some rib chunks and Jessie will be doing histo on them to see if we can get ontogenetic information. I’ll keep you posted.)

Brian’s new Haplocanthosaurus restoration, along with some stinkin’ mammals. Photo by Jessie Atterholt.

Brian Engh contributed a fantastic life restoration of Haplocanthosaurus pro bono, thanks to this conversation, which took place in John Foster’s and ReBecca Hunt-Foster’s dining room about a month ago:

Brian: What are you drawing?

Me: Haplocanthosaurus.

Brian: Is that for the exhibit?

Me: Yup.

Brian (intense): Dude, I will draw you a Haplocanthosaurus.

Me: I know, but you’re a pro, and pros get paid, and we didn’t include a budget for paleoart.

Brian (fired up): I’m offended that you didn’t just ask me to draw you a Haplocanthosaurus.

Then he went to the Fosters’ couch, sat down with his sketchbook, and drew a Haplocanthosaurus. Not only is it a stunning piece on display in the exhibit, there are black-and-white printouts for kids to take and color (or for adults to take to their favorite tattoo artists, just sayin’). [Obligatory: this is not how things are supposed to work. We should all support original paleoart by supporting the artists who create it. But Brian just makes so damn many monsters that occasionally he has to kick one out for the heck of it. Also, I support him on Patreon, and you can, too, so at a stretch you could consider this the mother of all backer rewards.]

One special perk from the opening last night: Jessica Bramson was able to attend. Who’s that, you ask? Jessica’s son, Mike Gordon, found the first piece of bone from the Snowmass Haplo on their property in Colorado over a decade ago. Jessica and her family spent two years uncovering the fossils and trying to get paleontologists interested. In time she got in touch with John Foster, and the rest is history. Jessica lives in California now, and thanks to John’s efforts we were able to invite her to the exhibit opening to see her dinosaur meet the world. Stupidly, I did not get any photos with her, but I did thank her profusely.

A restored, retrodeformed caudal of the Snowmass Haplocanthosaurus, 3D-printed at life size for the exhibit. Photo swiped from the WSC Facebook page.

I owe a huge thanks to Alton Dooley for taking an interest in our work, and to the whole WSC crew for their hard work creating and promoting the exhibit. You all rock.

The exhibit will run through the end of March, 2020, at least. I deliberately did not show most of it, partly because I was too busy having fun last night to be diligent about taking photos, but mostly because I want you to go see it for yourself (I will do a retrospective post with more info after the exhibit comes down, for people who weren’t able to see it in person). If you make it out to Hemet, I hope you have half as much fun going through the exhibit as we did making it.

Two professionals, hard at work.

After this year’s SVPCA, Vicki and London and I spent a few days with the Taylor family in the lovely village of Ruardean. It wasn’t all faffing about with the Iguanodon pelvis, the above photo notwithstanding. Mike and I had much to discuss after the conference, in particular what the next steps might be for the Supersaurus project. Mike has been tracking down early mentions of Supersaurus, and in particular trying to determine the point at which Jensen decided that it might be a diplodocid rather than a brachiosaurid. I recalled that Gerald Wood discussed Supersaurus in his wonderful 1982 book, The Guinness Book of Animal Facts and Feats. While on the track of Supersaurus, I stumbled across this amazing claim in the section on Diplodocus (Wood 1982: p. 209):

According to De Camp and De Camp (1968) these giant sauropods may have been able to regenerate lost parts, and they mention another skeleton collected in Wyoming which appeared to have lost about 25 per cent of its tail to a carnosaur and then regrown it — along with 21 new vertebrae!

De Camp and De Camp (1968) is a popular or non-technical book, The Day of the Dinosaur. Used copies can be had for a song, so I ordered one online and it was waiting for me when I got back to California.

The Day of the Dinosaur is an interesting book. L. Sprague De Camp and Catherine Crook De Camp embodied the concept of the “life-long learner” before there was a buzzword to go with it. He had been an aerospace engineer in World War II, and she had been an honors graduate and teacher, before they turned to writing full time. Individually and together, they produced a wide range of science fiction, fantasy, and nonfiction books over careers that spanned almost six decades. The De Camps’ writing in The Day of the Dinosaur is erudite in range but conversational in style, and they clearly kept up with current discoveries. They also recognized that science is a human enterprise and that, like any exploratory process, it is marked by wildly successful leaps, frustrating wheel-spinning, and complete dead ends. I was pleasantly surprised to find that the authors were completely up to speed on plate tectonics, an essentially brand-new science in 1968, and they explain it as an alternative to older theories about immensely long land bridges or sunken continents.

At the same time, the book arrived just before the end-of-the-1960s publications of John Ostrom and Bob Bakker that kicked off the Dinosaur Renaissance, so there’s no mention of warm-blooded dinosaurs. The De Camps’ sauropods and duckbills are still swamp-bound morons, “endlessly dredging up mouthfuls of soft plant food and living out their long, slow, placid, brainless lives” (p. 142), stalked by ‘carnosaurs’ that were nothing more than collections of teeth relentlessly driven by blind instinct and hunger. The book is therefore an artifact of a precise time; there was perhaps a year at most in the late 1960s when authors as technically savvy as the De Camps would have felt obliged to explain plate tectonics and its nearly-complete takeover of structural geology (which had just happened), but not to comment on the new and outrageous hypothesis of warm-blooded, active, terrestrial dinosaurs (which hadn’t happened yet).

The book may also appeal to folks with an interest in mid-century paleo-art, as the illustrations are a glorious hodge-podge of Charles R. Knight, Neave Parker, photos of models and mounted skeletons from museums, life restorations reproduced from the technical literature, and original art produced for the book, including quite a few line drawings by one L. Sprague De Camp. Roy Krenkel even contributed an original piece, shown above (if you don’t know Krenkel, he was a contemporary and sometime collaborator of Al Williamson and Frank Frazetta, and his art collection Swordsmen and Saurians is stunning and still gettable at not-completely-ruinous prices; I’ve had mine since about 1997).

ANYWAY, as entertaining as The Day of the Dinosaur is, it doesn’t do much to help us regenerate the tale of the regenerated tail. Here’s the entire story, from page 114:

Sauropods, some students think, had great powers of regenerating lost parts. One specimen from Wyoming is thought to have lost the last quarter of its tail and regrown it, along with twenty-one new tail vertebrae. That is better than a modern lizard can do; for the lizard, in regenerating its tail, grows only a stumpy approximation of the original, without new vertebrae.

That’s it. No sources mentioned or cited, so no advance over Wood in terms of tracking down the origin of the story.

Massospondylus tail with traumatic amputation at caudal 25 (Butler et al. 2013: fig. 1A).

To be clear, I don’t really think there is a sauropod that regrew its tail, especially since we have evidence for traumatic tail amputation without regeneration in the basal sauropodomorph Massospondylus (Butler et al. 2013), in the theropod Majungasaurus (Farke and O’Connor 2007), and in a hadrosaur (Tanke and Rothschild 2002). But I would love to learn how such a story got started, what the evidence was, how it was communicated, and most importantly, how it took on a life of its own.

If anyone knows any more about this, I’d be very grateful for any pointers. The comment thread is open.

References

  • Butler, R. J., Yates, A. M., Rauhut, O. W., & Foth, C. 2013. A pathological tail in a basal sauropodomorph dinosaur from South Africa: evidence of traumatic amputation? Journal of Vertebrate Paleontology 33(1): 224-228.
  • De Camp, L. S., and De Camp, C. C. 1968. The Day of the Dinosaur. Bonanza Books, New York, 319 pp.
  • Farke, A. A., & O’Connor, P. M. 2007. Pathology in Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology, 27(S2): 180-184.
  • Krenkel, R. G. 1989. Swordsmen and Saurians: From the Mesozoic to Barsoom. Eclipse Books, 152 pp.
  • Tanke, D. H., & Rothschild, B. M. 2002. DINOSORES: An annotated bibliography of dinosaur paleopathology and related topics—1838-2001. Bulletin of the New Mexico Museum of Natural History and Science, vol. 20.
  • Wood, G. L. 1982. The Guinness Book of Animals Facts & Feats (3rd edition). Guinness Superlatives Ltd., Enfield, Middlesex, 252 pp.

Regular readers will remember that we followed up our 1VPC talk about what it means for a vertebra to be horizontal by writing it up as a paper, and doing it in the open. That manuscripts is now complete, and published as a preprint (Taylor and Wedel 2019).

Taylor and Wedel (2018: Figure 5). Haplocanthosaurus sp. MWC 8028, caudal vertebra ?3, in cross section, showing medial aspect of left side, cranial to the right, in three orientations. A. In “articular surfaces vertical” orientation (method 2 of this paper). The green line joins the dorsal and ventral margins of the caudal articular surface, and is oriented vertically; the red line joins the dorsal and ventral margins of the cranial articular surface, and is nearly but not exactly vertical, instead inclining slightly forwards. B. In “neural canal horizontal” orientation (method 3 of this paper). The green line joins the cranial and caudal margins of the floor of the neural canal, and is oriented horizontally; the red line joins the cranial and caudal margins of the roof of the neural canal, and is close to horizontal but inclined upwards. C. In “similarity in articulation” orientation (method 4 of this paper). Two copies of the same vertebra, held in the same orientation, are articulated optimally, then the group is rotated until the two are level. The green line connects the uppermost point of the prezygapophyseal rami of the two copies, and is horizontal; but a horizontal line could join the two copies of any point. It happens that for this vertebra methods 3 and 4 (parts B and C of this illustration) give very similar results, but this is accidental.

The preprint has all the illustrations and their captions at the back of the PDF. If you prefer to have them inline in the text, where they’re referenced — and who wouldn’t? — you can download a better version of the manuscript from the GitHub archive.

By the way, you may have noticed that what started our written in Markdown has mutated into an MS-Word document. Why? Well, because journals won’t accept submissions in Markdown. It eas a tedious and error-prone job to convert the Markdown into MS-Word, and not one I am keen to repeat. For this reason, I think I am unlikely to use Markdown again for papers.

References

  • Taylor, Michael P., and Mathew J. Wedel. 2019. What do we mean by the directions “cranial” and “caudal” on a vertebra? PeerJ PrePrints 7:e27437v2. doi:10.7287/peerj.preprints.27437v2

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