I did a fieldwork!

This is going to set new records for “almost too late to be worth posting”, but here goes.

First up, this Wednesday evening, Oct. 18, at 6:00 PM (in about 18 hours), while most of the paleontologists in the West are at SVP in Albuquerque, I will giving a public lecture at the Canyonlands Natural History Assocation’s Moab Information Center, at the corner of Main St. and Center in Moab (link). The talk is titled, “Lost worlds of the Jurassic: Diverse dinosaurs and plants in the lower Morrison Formation of south-central Utah”, and it is free to the public. It’s a report on the fieldwork I’ve been doing in the Morrison Formation of southern Utah for the past few summers with John Foster, Brian Engh, and Jessie Atterholt. I promise lots of pretty pictures and probably more yapping about sauropods than anyone really needs. Did I mention it’s free? I hope to see you there.

Second, I will be at SVP myself, for a bit. Basically Friday night and Saturday. Gotta catch up with collaborators and go see Brian Engh pick up his Lanzendorf Paleoart Prize Saturday night. Why do you care? Western University of Health Sciences has an open position for an anatomist, and a lot of paleo folks have anatomy training, so…if you are interested in this position specifically, or if you have general questions about what it’s like to be a paleontologist teaching gross anatomy at a med school (spoiler: mostly awesome), come find me sometime Friday evening or Saturday and chat me up. I’ll probably be roaming the hallways and talking with folks instead of attending talks (sorry, talk-givers–you all rock, I’m just too slammed this year). And if you are on the job market, have some anatomy experience, and aren’t allergic to sun, palm trees, and amazing colleagues, please consider applying for the position. We’re taking applications through October 26, so don’t tarry. Here’s that link again.

Advertisements

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

The afternoon of Day 1 at TetZooCon 2018 was split into two parallel streams: downstairs, some talks that I would have loved to see; and upstairs, a palaeoart workshop that I was even keener not to miss out on.

There were talks by Luis Rey (on how palaeoart has had to be dragged kicking and screaming into accepting feathers and bright colours) and by Mark Witton (on the future of palaeoart — sadly, bereft of slides). Both fascinating.

But better still was the wide-ranging informal discussion between Luis, Mark, John Conway, Bob Nicholls and others on what palaeoart is actually all about. For Luis, it’s basically fun; for Mark, it’s primarily science communication; for John, it’s art first, and palaeontology only because that’s what he happens to be depicting; and for Bob, as well as all those things, it’s crucially important as a job of work, satisfying the requirements of those who commission that work. Obviously that’s a huge over-simplification: all of them have all these aspects going on in varying proportions. But that’s how I read it.

At the same time that all this was going on, we — maybe 60 or 70 of us? — were encouraged to create our own art, either attempting styles that are different to what we usually do, are using materials we’re not so familiar with. For the many excellent artists in the group, this challenge must have been interestingly novel. For non-artists like myself, it was just a chance to play.

I took the opportunity to try my hand with charcoal, in the hope of getting some suggestive or even impressionistic textures. Here’s my first work — an indeterminate brachiosaur with an inexplicably big head.

Aside from the head — I can’t do heads! — I’m reasonably happy with that. I got a decent sense of bulk in the torso, anyway.

Encouraged, I made a start on a second piece: a BRONTOSMASH!ing apatosaur that didn’t come out so well.

I’m happy with the forelimbs here, but something is dreadfully wrong with the torso and I can’t put a finger on what it is. If I’d had more time, I’d have put in the second hindlimb, which might have helped me figure out what was going wrong. The other thing I fluffed here was that I should have made the neck even fatter and more robust. Oh, and of course the head. I might return to this and see if I can sort out, if I can find some charcoal.

Anyway, it was a fascinating experience. And it’s left me with a new favourite art medium.

 

Last night, Fiona and I got back from an exhausting but very satisfying weekend spent at TetZooCon 2018, the conference of the famous Tetrapod Zoology blog run by Darren Naish — the sleeping third partner here at SV-POW!.

What made this particularly special is that Fiona was one of the speakers this time. She’s not a tetrapod zoologist, but a composer with a special interest in wildlife documentaries. She had half an hour on Music for Wildlife Documentaries – A Composer’s Perspective, with examples of her own work. I thought it was superb, but then I would — I’m biased. I’ll hand over to Twitter for a more objective overview:


Darren Naish: Now at #TetZooCon: Fiona Taylor on music in wildlife documentaries. Fiona is a professional composer.

Ellie Mowforth: Next up, it’s “Music for Wildlife Documentaries”. I am SHOCKED to hear that not everyone shares my love for the waddling penguin comedy trombone. #TetZooCon

Nathan Redland: Nature documentaries are entertainment, not just education: and the composer’s budget comes from the studio, not an academic institution #TetZooCon

“If these shows were just a string of facts about animals, most of us wouldn’t watch. That’s why they carve out stories in editing, why they use intense music, and why they recreate the sound effects — because story-telling is what engages us.”
— Simon Cade.

Will Goring: Very effective demonstration; same image, 5 different scores = 5 different interpretations. #TetZooCon

… and here is the relevant segment of video, together with the script that Fiona used:

Picture of wolf

We’re going to play “What kind of wolf is this?” or perhaps a better question is: “what is the music telling us to feel about this wolf?” I written 5 brief musical clips in 5 very different styles I’m hoping will showhow very differently we can be led into feeling about one image.

  1. This wolf is bad, suspense, about to kill something cute.
  2. Preparing to spring into action, attack.
  3. This wolf is sad, it has just lost its pups, if it doesn’t eat soon, it will starve.
  4. This wolf is cute, and cuddly and very playful. You just want to stroke him.
  5. This wolf is noble, kingly, will survive because his race has always survived, with dignity.

Alberta Claw: #TetZooCon Taylor: Provides detailed analysis of musical accompaniment in several documentary clips. Only a few seconds long each, but incredible amount of nuance and thought goes into these decisions.

Dr Caitlin R Kight: I responded exactly as she predicted and would have even without the explanation, but it was more interesting to know why I was feeling what I was, when I was!

Samhain Barnett: At 25 frames a second, a drumbeat has to occur within 2 frames of a nut being cracked, for our brains to accept it as in sync. Computers have made composers lives a lot easier here. #TetZooCon

(I’d like to show the video clip that that last tweet pertains to, but complicated rightsholder issues make that impractical. Sorry.)

Alberta Claw: #TetZooCon Taylor: Given the power of music to influence emotions, documentary composers have responsibility to think about the effects of music. Peer-reviewed research has shown that musical accompaniment can impact motivation of viewers to contribute to shark conservation.

Here are two sketches from Sara Otterstätter, who did this for every talk:

First one: About music in Nature documentaries. Useful or manipulative? #TetZooCon #sketch #sketchbook

Second one: Show documentaries always reality? #TetZooCon #Sketching #sketch

And two final comments …

Filipe Martinho: Quite often the most interesting talks are completely outside my area. Fiona Taylor gave an amazing eye and ear opener on the role of music in nature documentaries and #scicomm. #TetZooCon

Flo: Thanks to Fiona Taylor I will from now on listen more carefully to the music accompanying wildlife docs. #TetZooCon #musicforwildlifedocumentaries


We both had a great time at TetZooCon. As I said in an email to Darren after I got home, “It made me wonder what they heck I’d been thinking, missing the last few”. I don’t plan to repeat that mistake.

Hearing the talks through the ears of someone without much background was an interesting experience. Some of the speakers did a fantastic job of providing just enough background to make their work comprehensible to an intelligent layman: for example, Jennifer Jackson on whales, Robyn Womack on bird circadian rhythms and Albert Chen on crown-bird evolution. There’s a tough line to walk in figuring out what kind of audience to expect at an
event like this, and I take my hat off to those who did it so well.

 

WOW! I knew I was dragging a bit on getting around to this vertebral orientation problem, but I didn’t realize a whole month had passed. Yikes. Thanks to everyone who has commented so far, and thanks to Mike for getting the ball rolling on this. Previous posts in this series are here and here.

First up, this may seem like a pointlessly picky thing to even worry about. Can’t we just orient the vertebrae in whichever way feels the most natural, or is easiest? Do we have to think about this?

The alarmingly 3D pelvis of the mounted brontosaur at the AMNH. Note that sauropod pubes are usually illustrated lying flat, so what usually passes for ‘lateral’ view would be roughly from the point of view of the animal’s knee.

I think we do. For sauropods, vertebrae are usually oriented for illustration purposes in one of two ways. The first is however they sit most easily on their pallets. This is similar to the problem Mike and I found for ‘lateral’ views of sauropod pelvic elements when were on our AMNH/Yale trip in 2012. In an articulated skeleton, the pubes and ischia usually lean inward by 30-45 degrees from their articulations with the ilia, so they can meet on the midline, but when people illustrate the “lateral view” of a sauropod pubis or ischium, it’s often the ventro-lateral aspect that is face-up when the element is lying on a shelf or a pallet. Photographic lateral does not equal biological lateral for those elements. Similarly, if I’m trying to answer biological questions about vertebrae (see below), I need to know something about their orientation in the body, not just how they sit comfortably on a pallet.

The other way that vertebrae are commonly oriented is according to what we might call the “visual long axis” of the centrum—so for example, dorsoventrally tall but craniocaudally short proximal caudals get oriented with the centrum ‘upright’, whereas dorsoventrally short but craniocaudally long distal caudals get oriented with the centrum ‘horizontal’, even if they’re in the same tail and doing so makes the neural canals or articular faces be oriented inconsistently down the column. (I’m not going to name names, because it seems mean to pick on people for something I just started thinking about myself, but if you go plow through a bunch of sauropod descriptions, you’ll see what I’m talking about.)

Are there biological questions where this matters? You bet! There are some questions that we can’t answer unless we have the vertebrae correctly oriented first. One that comes to mind is measuring the cross-sectional area of the neural canal, which Emily Giffin did a lot of back in the 90s. Especially for the Snowmass Haplocanthosaurus, what counts as the cross-sectional area of the neural canal depends on whether we are looking at the verts orthogonal to their articular faces, or in alignment with the course of the canal. I think the latter is pretty obviously the way to go if we are measuring the cross-sectional area of the canal to try and infer the diameter of the spinal cord—we’d want to see the canal the same way the cord ‘sees’ it as it passes through—but it’s less obvious if we’re measuring, say, the surface area of the articular face of the vertebra to figure out, say, cartilage stress. It doesn’t seem unreasonable to me that we might want to define a ‘neural axis’ for dealing with spinal-cord-related questions, and a ‘biomechanical axis’ for dealing with articulation-related questions.

Caudal 3 of the Snowmass Haplocanthosaurus, hemisected 3D model.

With all that in mind, here are some points.

To me, asking “how do we know if a vertebra is horizontal” is an odd phrasing of the problem, because “horizontal” doesn’t have any biological meaning. I think it makes more sense to couch the question as, “how do we define cranial and caudal for a vertebra?” Normally both the articular surfaces and the neural canal are “aimed” head- and tail-wards, so the question doesn’t come up. Our question is, how do we deal with vertebrae for which the articular surfaces and neural canal give different answers?

For example. Varanus komodoensis caudal.

(And by the way, I’m totally fine using “anterior” and “posterior” for quadrupedal animals like sauropods. I don’t think it causes any confusion, any more than people are confused by “superior” and “inferior” for human vertebrae. But precisely because we’re angling for a universal solution here, I think using “cranial” and “caudal” makes the most sense, just this once. That said, when I made the image above, I used anterior and posterior, and I’m too lazy now to change it.)

I think if we couch the question as “how do we define cranial and caudal”, it sets up a different set of possible answers than Mike proposed in the first post in this series: (1) define cranial and caudal according to the neural canal, and then describe the articular surfaces as inclined or tilted relative to that axis; (2) vice versa—realizing that using the articular surfaces to define the anatomical directions may admit a range of possible solutions, which might resurrect some of the array of possible methods from our first-draft abstract; (3) define cranial and caudal along the long axis of the centrum, which is potentially different from either of the above; (4) we can imagine a range of other possibilities, like “use the zygs” or “make the transverse processes horizontal” (both of which are subsets of Mike’s method C) but I don’t think most of those other possibilities are sufficiently compelling to be worthy of lengthy discussion.

IF we accept “neural canal”, “articular surfaces”, and “centrum long axis” as our strongest contenders, I think it makes most sense to go with the neural canal, for several reasons:

  • In a causative sense, the neural tube/spinal cord does define the cranial/caudal axis for the developing skeleton. EDIT: Actually, that’s a bit backwards. It’s the notochord, which is later replaced by the vertebral column, that induces the formation of the brain and spinal cord from the neural plate. But it’s still true that the vertebrae form around the spinal cord, so it’s not wrong to talk about the spinal cord as a defining bit of soft tissue for the developing vertebrae to accommodate.
  • The neural canal works equally well for isolated vertebrae and for articulated series. Regardless of how the vertebral column is oriented in life, the neural canal is relatively smooth—it may bend, but it doesn’t kink. So if we line up a series of vertebrae so that their neural canals are aligned, we’re probably pretty close to the actual alignment in life, even before we look at the articular surfaces or zygs.
  • The articulated tails of Opisthocoelicaudia and big varanids show that sometimes the articular surfaces simply are tilted to anything that we might reasonably consider to be the cranio-caudal axis or long axis of the vertebra. In those cases, the articular surfaces aren’t orthogonal to horizontal OR to cranio-caudal. So I think articular surfaces are ruled out because they break down in the kinds of edge cases that led us to ask the question in the first places.

Opistocoelicaudia caudals 6-8, stereopair, Borsuk-Bialynicka (1977:plate 5).

“Orient vertebrae, isolated or in series, so that their neural canals define the cranio-caudal axis” may seem like kind of a ‘duh’ conclusion (if you accept that it’s correct; you may not!), but as discussed up top, often vertebrae from a single individual are oriented inconsistently in descriptive works, and orientation does actually matter for answering some kinds of questions. So regardless of which conclusion we settle on, there is a need to sort out this problem.

That’s where I’m at with my thinking. A lot of this has been percolating in my hindbrain over the last few weeks—I figured out most of this while I was writing this very post. Is it compelling? Am I talking nonsense? Let me know in the comments.

Well, that didn’t take long. Earlier today, my subterranean hacker collective released thousands of emails exchanged by Mike Taylor and Brian Engh, which touched on numerous issues of national and global security. Of most interest to SV-POW! readers will be this correspondence from just a few hours ago:

– – – – – – – – – – – – – – – – – – – – – – – –

Mike: Artwork attached. [Scroll down to see Mike’s submission.–MJW]

Brian: NAILED IT.

I haven’t been responding here to entrants but i feel pretty safe calling this one the winner already. Thank you for submitting. We can now sit back and laugh as all the other feeble entrants squabble knowing that you’ve already got this one in the bag.

Mike: Thanks, Brian. I hesitated before submitting this, thinking it might not be fair to up-and-coming artists who need the win more than I do; but in the end, I decided that was patronising. If they’re going to win the prize, they have to beat me on merit. You never know: it could happen.

– – – – – – – – – – – – – – – – – – – – – – – –

So, it looks like Brian has made his decision and the contest is effectively over. Although Mike says that someone else winning the contest “could happen”, Brian’s already signaled his intention to “laugh as all the other feeble entrants squabble”, which hardly sounds like he’s going to be giving anyone else a fair shake.

In Brian’s defense, the art that Mike submitted is glorious:

So complex and subtle is this work, so playful in its blending of traditional and cutting-edge thinking, so packed with detail, life history, and sheer emotion, that I feel certain that it will usher in a new era of paleoart as the dominant aesthetic expression on this planet.

Still, I don’t see how #TheSummonENGH2018 is going to survive the inevitable scandal of having a winner secretly chosen on the second day of the contest. I’m torn between towering admiration for my friends and colleagues, and fear for the rifts this may cause in the paleoart community.

I’ve reached out to representatives of both Mike and Brian for comment, and I’ll keep you updated on this developing story as more information becomes available.

My good friend, frequent collaborator, and fellow adventurer Brian Engh has won the John J. Lanzendorf Paleoart Prize for 2D paleoart (there are also categories for 3D paleoart and scientific illustration). He’s in august company; previous Lanzendorf winners include luminaries like John Gurche, Michael Skrepnick, Mark Hallett, Todd Marshall, and Julius Csotonyi (among many others–see the complete list of previous winners here). Naturally I’m happy as heck for Brian, and immensely proud of him, not only for the award, but also for what he’s doing now. Usually when we say “pay it forward” we mean metaphorically, but Brian is literally going to pay it forward. He’s created his own paleoart contest, the SummonENGH 2018, and he will award half of his October Patreon take to the winner.

He lays out the rules on his blog and in this video:

There’s a Facebook group, here, and a hashtag: #TheSummonEngh2018 (Facebook, Twitter).

Why do I think this is cool? It’s no exaggeration to say that I am a paleontologist today because I was exposed to mind-bending paleoart from a young age. Brian cares about paleoart–he cares about making better paleoart, himself, and he cares about making paleoart better, for everyone. And now he’s putting his money where his mouth his and doing something to hopefully bring more visibility to the paleoart community, and help move the field forward. That’s admirable, and I’m happy to support the cause.

Also, when we visited the Aquilops display at Dinosaur Journey this summer, we were lucky enough to capture this single frame showing a 100% real paleo-energy discharge. I definitely felt something at the time, but I didn’t know the full extent of what had happened until Brian sorted through our photos after the trip. Apparently this was all fated to happen–some kind of transdimensional chronoparticle emission linking past and future–and who am I to argue with fate?

Now, go summon monsters!