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]

These are nice. Click through to empiggen.

I ripped them from Parker (1874), which appears to be a free download from JSTOR, here, and tweaked the colors just a bit.

If you are here for serious science, these guides to the abbreviations used in the plates will come in handy. I hacked the second one, below, to include the descriptions of the plates above, which are the last in the series, not the first.

EDIT: Nick Gardner pointed out that the copy of Parker (1874) at the Biodiversity Heritage Library is a slightly sharper scan, so if you’d prefer that version, it’s here.

Reference

Parker, W.K. 1874. On the structure and development of the skull in the pig (Sus scrofa). Philosophical Transactions of the Royal Society of London 164: 289-336.

 

Here’s how my pig skull turned out (prep post is here).

Verdict? I’m reasonably happy with it. As Mike wrote in the post that kicked off the “Things to Make and Do” series, “a pig skull is a serious piece of kit”. It’s big and substantial and it looks awesome sitting on the shelf. I learned a lot prepping it, and in particular I learned a couple of things that I will do differently next time:

  1. From now on I will cut the meat off first and grill only that, and not put the skull through the thermal stress of getting dry-cooked. Even with indirect heat, I think smoking the whole head did adversely affect the quality of the bone. The forehead and the rami of the mandibles in particular lost a little integrity. I painted the whole skull with a mix of 50% PVA (white glue, like Elmer’s) and 50% water, so it’s solid, but the surface bone is just slightly rough, I think because of degradation of the cortical bone.
  2. Before this I had only prepped small bones–small mammal and reptile skulls, vertebrae and long bones of domestic fowl, cannon bones and hooves of cattle. Stuff like that takes maybe an hour or two max to simmer, and to whiten, and that’s how I approached the pig skull. And it took forever, because I was doing short cycles, which meant doing a lot of them. I did a sheep skull this past holiday break, which I will post about soon, and I learned that the trick with bigger bones is just time. Simmer for 12 hours, not 2 hours, whiten for 2 or 3 nights, not just one. The sheep skull probably took more time from start to finish, but it was a lot less effort, because for much of that time it was just simmering, or soaking in dilute hydrogen peroxide.

With their deep lower jaws, pig skulls look rather lumpen in lateral view. But they look awesome in anterodorsal view, like dragon skulls. Here you can see that the prenasal bone is a little darker and less crisp than the other bones of the face. That’s because it was still ossifying from a big block of cartilage. I scraped off most of the cartilage, but not all, and what remained dried and hardened into an incredibly tough, translucent, slightly yellowish shell. 

I still have two pig heads on ice. I probably won’t do anything with either of them until I get some more time off, but I am looking forward to prepping another pig skull, in part to see how much better I can do the next time. But I’m still happy to have this one. To paraphrase another line from Mike’s old post, this is something that everyone ought to do.

Edit: here are some links about cooking pig heads and prepping skulls.

 

It’s been a minute, hasn’t it?

Up top, C10 and C11 of Diplodocus carnegii CM 84, from Hatcher (1901). Below, C9 and C10 of Apatosaurus louisae CM 3018, from Gilmore (1936). The Diplodocus verts are in right lateral view but reversed for ease of comparison, and the Apatosaurus verts are in left lateral view. Both sets scaled to the same cumulative centrum length. Just in case you forgot that apatosaurines are redonkulous.

References

  • 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.
  • Gilmore, Charles Whitney. 1936. Osteology of Apatosaurus, with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11:175–300.

This is a very belated follow-up to “Tutorial 12: How to find problems to work on“, and it’s about how to turn Step 2, “Learn lots of stuff”, into concrete progress. I’m putting it here, now, because I frequently get asked by students about how to get started in research, and I’ve been sending them the same advice for a while. As with Tutorial 25, from now on I can direct the curious to this post, and spend more time talking with them about what they’re interested in, and less time yakking about nuts and bolts. But I hope the rest of you find this useful, too.

Assuming, per Tutorial 12, that you’ve picked something to investigate–or maybe you’re trying to pick among things to investigate–what next? You need a tractable way to get started, to organize the things you’re learning, and to create a little structure for yourself. My recommendation: do a little project, with the emphasis on little. Anyone can do this, in any area of human activity. Maybe your project will be creating a sculpture, shooting and editing a video, learning–or creating–a piece of music, or fixing a lawn mower engine. My central interest is how much we still have to discover about the natural world, so from here on I’m going to be writing as a researcher addressing other researchers, or aspiring researchers.

Arteries of the anterior leg, from Gray’s Anatomy (1918: fig. 553). Freely available courtesy of Bartleby.com.

I’ll start with a couple of examples, both from my own not-too-distant history. A few years ago I got to help some of my colleagues from the College of Podiatric Medicine with a research project on the perforating branch of the peroneal artery (Penera et al. 2014). I knew that vessel from textbooks and atlases and from having dissected a few out, but I had never read any of the primary (journal) literature on it. As the designated anatomist on the project, I needed to write up the anatomical background. So I hit the journals, tracked down what looked like the most useful papers, and wrote a little 2-page summary. We didn’t use all of it in the paper, and we didn’t use it all in one piece. Some sentences went into the Introduction, others into the Discussion, and still others got dropped entirely or cut way down. But it was still a tremendously useful exercise, and in cases like this, it’s really nice to have more written down than you actually need. Here’s that little writeup, in case you want to see what it looks like:

Wedel 2013 anatomy of the perforating branch of the peroneal artery

Pigeon spinal cord cross-section, from Necker (2006: fig. 4).

More recently, when I started working with Jessie Atterholt on weird neural canal stuff in dinosaurs, I realized that I needed to know more about glycogen bodies in birds, and about bird spinal cords generally. I expected that to be quick and easy: read a couple of papers, jot down the important bits, boom, done. Then I learned about lumbosacral canals, lobes of Lachi, the ‘ventral eminences’ of the spinal cord in ostriches, and more, a whole gnarly mess of complex anatomy that was completely new to me. I spent about a week just grokking all the weird crap that birds have going on in their neural canals, and realized that I needed to crystallize my understanding while I had the whole structure in my head. Otherwise I’d come back in a few months and have to learn it all over again. Because it was inherently visual material, this time I made a slide deck rather than a block of text, something I could use to get my coauthors up to speed on all this weirdness, as well as a reminder for my future self. Here’s that original slide deck:

Wedel 2018 Avian lumbosacral spinal cord specializations

If you’re already active in research, you may be thinking, “Yeah, duh, of course you write stuff down as you get a handle on it. That’s just learning.” And I agree. But although this may seem basic, it isn’t necessarily obvious to people who are just starting out. And even to the established, it may not be obvious that doing little projects like this is a good model for making progress generally. Each one is a piton driven into the mountainside that I’m trying to climb: useful for me, and assuming I get them out into the world, useful for anyone I’d like to come with me (which, for an educator and a scientist, means everyone).

A view down the top of the vertebral column in the mounted skeleton of Apatosaurus louisae, CM 3018, showing the trough between the bifurcated neural spines.

If you’re not active in research, the idea of writing little term papers may sound like purgatory. But writing about something that you love, that fascinates you, is a very different proposition from writing about dead royalty or symbolism because you have to for a class.* I do these little projects for myself, to satisfy my curiosity, and it doesn’t feel like work. More like advanced play. When I’m really in the thick of learning a new thing–and not, say, hesitating on the edge before I plunge in–I am so happy that I tend to literally bounce around like a little kid, and the only thing that keeps me sitting still is the lure of learning the next thing. That I earn career beans for doing this still seems somewhat miraculous, like getting paid to eat ice cream.

* YMMV, history buffs and humanities folks. If dead royalty and symbolism rock your world but arteries and vertebrae leave you cold, follow your star, and may a thousand gardens grow.

Doing little projects is such a convenient and powerful way to make concrete progress that it has become my dominant mode. As with the piece that I wrote about the perforating branch of the peroneal artery, the products rarely get used wholesale in whatever conference presentation or research paper I end up putting together, but they’re never completely useless. First, there is the benefit to my understanding that I get from assembling them. Second, they’re useful for introducing other people to the sometimes-obscure stuff I work on, and nothing makes you really grapple with a problem like having to explain it to others. And third, these little writeups and slideshows become the Lego bricks from which I assemble future talks and papers. The bird neural canal slide deck became a decent chunk of our presentation on the Snowmass Haplocanthosaurus at the 1st Palaeontological Virtual Congress (Wedel et al. 2018)–and it’s about to become something even better.

The operative word at the start of the last paragraph is ‘concrete’. I don’t think this was always the case, but now that I’m in my mid-40s ‘what I know’ is basically equivalent to ‘what I remember’, which is basically equivalent to ‘what I’ve written down’. (And sometimes not even then–Mike and I both run across old posts here on SV-POW! that we’ve forgotten all about, which is a bit scary, given how often we put novel observations and ideas into blog posts.) Anyway, this is why I like the expression ‘crystallize my understanding’: the towers of comprehension that I build in my head are sand castles, and if I don’t find a way to freeze them in place, they will be washed away by time and my increasingly unreliable cerebral machinery.

Really nice Stegosaurus plate on display at Dinosaur National Monument.

Also, if I divide my life into the things I could do and the things I have done, only the things in the latter category are useful. So if you are wondering if it’s worthwhile to write a page to your future self about valves in the cerebral arteries of rats, or all of the dinosaurs from islands smaller than Great Britain, or whatever strange thing has captured your attention, I say yes, go for it. Don’t worry about finding something novel to say; at the early stages you’re just trying to educate yourself (also, talks and papers need intro and background material, so you can still get credit for your efforts). I’ll bet that if you set yourself the goal of creating a few of these–say, one per year, or one per semester–you’ll find ways to leverage them once you’ve created them. If all else fails, start a blog. That might sound flip, but I don’t mean for it to. I got my gig writing for Sky & Telescope because I’d been posting little observing projects for the readers of my stargazing blog.

A final benefit of doing these little projects: they’re fast and cheap, like NASA’s Discovery missions. So they’re a good way to dip your toes into a new area before you commit to something more involved. The more things you try, the more chances you have to discover whatever it is that’s going to make you feel buoyantly happy.

You may have noticed that all of my examples in this post involved library research. That’s because I’m particularly interested in using little projects to get started in new lines of inquiry, and whenever you are starting out in a new area, you have to learn where the cutting edge is before you can move it forward (Tutorial 12 again). Also, as a practical consideration, most of us are stuck with library research right now because of the pandemic. Obviously this library research is no substitute for time in the lab or the field, but even cutters and diggers need to do their homework, and these little projects are the best way that I’ve found of doing that.

P.S. If you are a student, read this and do likewise. And, heck, everyone else who writes should do that, too. It is by far the advice I give most often as a journal editor and student advisor.

P.P.S. As long as you’re reading Paul Graham, read this piece, too–this whole post was inspired by the bit near the end about doing projects.

References

This beautiful image is bird 52659 from Florida Museum, a green heron Butorides virescens, CT scanned and published on Twitter.

(The scan is apparently from MorphoSource, but I can’t find it there.)

There is lots to love here: for example, you can see that the long bones of the arm are pneumatic, because the margins of the bones show up more strongly than the cores. But you won’t be surprised that I am interested mostly in the neck.

As you can see, while the vertebrae of the neck are pulled back into a strong curve, the trachea doesn’t bother, and just sort of hangs there from the base of the head to the top of the lungs, cheerfully crossing over (i.e. passing to the side of) the vertebral sequence. So the trachea here is not much more than half the length of the vertebral sequence.

Now this is the opposite of what we see in some birds. Here, for example, is a trumpet manucode Phonygammus keraudrenii (a bird-of-paradise) as illustrated in Katrina van Grouw’s book The Unfeathered Bird:

Yes, all those coils visible in the torso are the trachea, which is many times longer than it needs to be to connect the head to the lungs. Birds-of-paradise do this sort of thing a lot (Clench 1978).

And they are not alone: cranes and others also have elongated and contorted tracheal trajectories. So it’s odd that herons seem to do the opposite.

But the heron is even odder than that. As we have noted before, herons can stretch their necks out to the point where you would scarcely believe the unstretched and stretched animals are the same thing. But they are:

The CT-scanned heron at the top of this post is in a pose intermediate between the two shown here. But since it can adopt the long-necked pose on the right, it’s apparent that the trachea can become long enough to connect the head and lungs in that pose. Which means it must be able to stretch to nearly twice the length we see in the CT scan.

Don’t try this at home, kids!

References

  • Clench, Mary H. 1978. Tracheal elongation in birds-of-paradise. The Condor 80(4):423–430. doi:10.2307/1367193