Here’s a frozen pig head being hemisected with a band saw.

The head in question, and the other bits we’ll get to later on in this post, both came from Jessie Atterholt’s Thanksgiving pig. As soon as Jessie knew she was cooking a pig for Thanksgiving, she had a plan for the head and the feet: cut ’em in half, skeletonize one half (like Mike did with his pig head), and plastinate the other. Jessie has her own plastination setup and you can see some of her work in her Instagram feed, here.

Here’s the freshly hemisected head. At one time or another, about four of us were involved in checking the alignment of the cut, with the intention of just missing the nasal septum (it can be easier to see some of the internal nasal anatomy if the septum’s all on one side). But we were all wrong–not only did the saw hit the nasal septum dead on, it hemisected the septum itself. Which I guess is the next-best possible outcome. The septum is the big expanse of white cartilage behind the nose and in front of the brain. You have one, too–it separates your left and right nasal cavities–but yours is a lot thinner.

Here’s the left half washed off and cleaned up a bit.

I was completely entranced by the little blood vessels inside the nasal septum, seen here as tiny traceries of red inside the blue-white cartilage. Also notice the frontal sinus above the septum and in front of the brain.

Here’s the right half in a postero-medial oblique view. Shown well here are the first two cervical vertebrae, plus part of the third, and the intervertebral joints. This was a young pig and the remains of growth plates are still visible between the different ossification centers of the vertebrae. If I get inspired (= if I get time) I might do a whole post on that.

It wasn’t my pig or my show, but Jessie made me a gift of two pig feet, and I got a little time on the saw. Here I’m using a plastic tool to push one of the pig’s hind feet through the saw.

We had been dithering over how best to prep the feet but the lure of the band saw proved irresistable: we hemisected all four. We’re planning to do half skeletonized/half plastinated preps for all of them, a forefoot and a hindfoot set for each of us.

Jessie and I were joined by two other WesternU anatomists, Thierra Nalley and Jeremiah Scott. Here Thierra is explaining to Jeremiah, who works on primate dentition and diet, that mammals have more parts than just teeth.

That’s a good segue to this video I shot, in which Thierra gives a quick tour of the hemisected pig head. All four of us have just come off of teaching human head and neck anatomy, so it was cool to see in another mammal the same structures we’ve just been dissecting in humans.

From 1:40 to 1:55 in the video Thierra and I are discussing the prenasal bone, something pigs have that we don’t. It’s the separate bone at the end of the snout in this mounted skeleton:

Darren discusses and illustrates the prenasal bone in this Tetrapod Zoology post.

Parting shots: many thanks to Ken Noriega and Tony Marino of WesternU’s College of Veterinary Medicine for their guidance, assistance, and expertise. Jessie covered this dissection as an Instagram story, here–I believe you have to be signed in to see it. Update: Jessie added a regular stream post, with lots of features labeled, here. I’ll probably have more to say about this pig and its bits in the future. Stay tuned!

For more hemisected heads and skulls, see:

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Please welcome Mirarce eatoni

November 13, 2018

Skeletal reconstruction of Mirarce by Scott Hartman (Atterholt et al. 2018: fig. 19). Recovered bones in white, missing bones in gray. The humerus is 95.9mm long.

Today sees the publication of the monster enantiornithine Mirarce eatoni (“Eaton’s wonderful winged messenger”) from the Kaiparowits Formation of Utah, by Jessie Atterholt, Howard Hutchinson, and Jingmai O’Connor. Not my critter, not my story, but it is SV-POW!-adjacent. (Just here for the paper? Here’s the link.)

Xiphoid process of sternum of Mirarce (Atterholt et al. 2018: fig. 5). Scale bar = 1cm.

As of this past summer, I knew that Jessie had a prehistoric monster coming out soon, and I knew that Brian Engh liked bringing prehistoric monsters to life, and I suspected that if the two reagents were combined, the rest of us might get something cool out of it.

Jessie and Brian talking about Mirarce, Utah for scale. July 13, 2018.

I did some heavy eavesdropping while the three of us were stomping around southern Utah looking for dinosaurs, so I got to hear Jessie and Brian batting ideas back and forth. By the end of our Utah trip Brian had sketches, and not long after, finished art (his post on Mirarce, including process sketches, is here). If you’ve seen one of my talks in the last month or so, you’ve gotten a teaser (with Jessie’s and Brian’s permission), and I know the piece got shown around a bit at SVP, too. You’ve waited long enough, here you go:

Not that the art is the whole story! Mirarce is a legitimately awesome find and Jessie and her coauthors poured a ton of work into the description. I’d tell you all about it, but much more capable and bird-fluent folks are on that already, and I have spinal cord and brainstem lectures to polish. So I’m gonna leave you with some links, which I’ll try to keep updated as different outlets get the story out:

Reference

Atterholt, J., Hutchinson, J.H.., and O’Connor, J.K. 2018. The most complete enantiornithine from North America and a phylogenetic analysis of the Avisauridae. PeerJ 6:e5910 https://doi.org/10.7717/peerj.5910

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.

 

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!

Here’s the story of my fascination with supramedullary airways over the last 20 years, and how Jessie Atterholt and I ended up working on them together, culminating with her talk at SVPCA last week. (Just here for the preprint link? Here you go.)

Müller (1908: fig. 12). Upper respiratory tract, trachea, and lungs in pink, air sacs and diverticula in blue. DSPM = diverticulum supramedullare.

Way back when I was working on my Master’s thesis at the University of Oklahoma and getting into pneumaticity for the first time, Kent Sanders found Müller (1908) and gave me a photocopy. This would have been the spring or summer of 1998, because we used some of Müller’s illustrations in our poster for SVP that year (Wedel and Sanders 1998). Müller’s description of pneumatic diverticula in the pigeon formed part of my intellectual bedrock, and I’ve referenced it a lot in my pneumaticity papers (complete list here).

One of the systems that Müller described is the diverticulum supramedullare, a.k.a. supramedullary diverticula, or, informally, supramedullary airways (SMAs). Traditionally these are defined as pneumatic diverticula that enter the neural canal and lie dorsal (supra) to the spinal cord (medulla), although O’Connor (2006) noted that in some cases the diverticula could completely envelop the spinal cord in a tube of air. I yapped about SMAs a bit in this post, and they’re flagged in almost every ostrich CT or dissection photo I’ve ever published, here on the blog or in a paper.

CT sections of a Giraffatitan cervical, with connections between the neural canal and pneumatic chambers in the spine highlighted in blue. Modified from Schwarz & Fritsch (2004: fig. 4).

Fast forward to 2006, when Daniela Schwarz and Guido Fritsch documented pneumatic foramina in the roof of the neural canal in cervical vertebrae of Giraffatitan. As far as I know, this was the first published demonstration of SMAs in a non-bird, or in any extinct animal. Lemme repeat that: Daniela Schwarz found these first!

OMNH 60718: too ugly for radio. This is an unfused neural arch in ventral view. Anterior is to the left. Neurocentral joint surfaces are drawn over with ladders; pneumatic foramina lie between them.

Shortly thereafter I independently found evidence of SMAs in a sauropod, in the form of multiple pneumatic foramina in the roof of the neural canal in an unfused neural arch of a basal titanosauriform (probably a brachiosaurid) from the Cloverly Formation of Montana. It’s a pretty roadkilled specimen and I was busy with other things so I didn’t get around to writing it up, but I didn’t forget about it, either (I rarely forget about stuff like this).

Then in 2013 I went to the Perot Museum in Dallas to see the giant Alamosaurus cervical series, and I also visited the off-site research facility where juvenile Alamosaurus from Big Bend is housed. When Ron Tykoski let me into the collections room, I was literally walking through the door for the first time when I exclaimed, “Holy crap!” I had spotted an unfused neural arch of a juvenile Alamosaurus on a shelf across the room, with complex pneumatic sculpting all over the roof of the neural canal.

Title slide for the 2014 SVPCA presentation.

The Big Bend and Cloverly specimens were the basis for my talk on SMAs at SVPCA in 2014, coauthored with Anthony Fiorillo, Des Maxwell, and Ron Tykoski. As prep for that talk, I visited the ornithology collections at the Natural History Museum of Los Angeles County, photographed a lot of bird vertebrae with foramina inside their neural canals, and shot this pelican video. That was four years ago – why no paper yet? It’s because I wanted one more piece of smoking-gun evidence: a CT scan of a bird that would show a direct communication between the SMAs and the air spaces inside a vertebra, through one or more foramina in the roof, wall, or floor of the neural canal.

A spectrum of pneumatic traces in the neural canals of birds, including complexes of large or small foramina, isolated foramina, and sculpting without foramina.

In 2017, Jessie Atterholt taught in our summer anatomy course at WesternU as an adjunct (her full-time employment was at the Webb Schools in Claremont, home of the Alf Museum). Jessie and I had been acquainted for a few years, but we’d never had the opportunity to really talk science. As we chatted between dissections, I learned that she had a huge warchest of CT scans of whole birds from her dissertation work at Berkeley (we’d missed each other by a few years). My antennae twitched: one nice thing about SMAs is that, being bounded by bone, they can’t collapse after death, unlike more peripheral diverticula. And air is jet black on CT scans, so SMAs are easy to spot even on comparatively low-res scans. All you need is one or two black pixels. I proposed a collaboration: we could use her CT scans to survey the presence and distribution of SMAs in as many birds as possible.

Vertebral diverticula in two sagittally-exploded cervical vertebrae of a turkey. Anterior is to the left, #5 is the SMA. Cover (1953: fig. 2). Yes, I know this is gross – if anyone has a cleaner scan, I’m interested.

You might think that such a survey would have been done ages ago, but it’s not the case. A few authors have mentioned supramedullary airways, and O’Connor (2006) gave a good description of some of the variation in SMAs in extant birds as a whole. But the only detailed accounts to illustrate the morphology and extent of the SMAs in a single species are Müller (1908) on the common pigeon and Cover (1953) on the domestic turkey. I’d seen what I suspected were traces of SMAs in the vertebrae of many, mostly large-bodied birds, and I’d seen them in CTs of ostriches and hummingbirds, and in ostriches and turkeys in dissection. But Jessie was offering the chance to see both the SMAs and their osteological traces in dozens of species from across the avian tree.

SMAs in a micro-CT of a female Anna’s hummingbird, Calypte anna. Scale bars are in mm.

Real life intervened: we were both so busy teaching last fall that we didn’t get rolling until just before the holidays. But the project gradually built up steam over the course of 2018. One story that will require more unpacking later: everything I’ve written on this blog about neural canals, Haplocanthosaurus, or CT scanning in 2018 is something serendipitously spun out of the SMA survey with Jessie. Expect a lot more Atterholt and Wedel joints in the near future – and one Atterholt et al. (minus Wedel) even sooner, that is going to be big news. Watch this space.

It didn’t hurt that in the meantime Jessie got a tenure-track job teaching human anatomy at WesternU, to run the same course she’d taught in as an adjunct last year, and started here at the beginning of June. By that time we had an abstract on our findings ready to go for this year’s SVP meeting. Alas, it was not to be: we were out in the field this summer when we learned that our abstract had been rejected. (I have no idea why; we’ve increased the taxonomic sampling of SMAs in extant birds by a factor of six or so, most of our important findings are in the abstract, and we mentioned the relevance to fossils. But whatever.)

We were bummed for a day, and then Jessie decided that she’d submit the abstract to SVPCA, only slightly chopped for length, and go to Manchester to present if it was accepted – which it was. Unfortunately I’d already made other plans for the fall, so I missed the fun. Fortunately the SVPCA talks were livestreamed, so last Friday at 1:30 in the morning I got to watch Jessie give the talk. I wish the talks had been recorded, because she knocked it out of the park.

Title slide for the 2018 SVPCA presentation.

And now everything we’re in a position to share is freely available at PeerJ. The SVPCA abstract is up as a PeerJ preprint (Atterholt and Wedel 2018), the longer, rejected SVP abstract is up as a supplementary file (because it has a crucial paragraph of results we had to cut to make the length requirement for SVPCA, and because why not), and our slideshow is up now, too. I say ‘our’ slideshow but it’s really Jessie’s – she built it and delivered it with minimal input from me, while I held down the sauropod side of our expanding empire of neural canal projects. She has the paper mostly written, too.

Oh, and we did get the smoking-gun images I wanted, of SMAs communicating with pneumatic spaces in the vertebrae via foramina in the neural canal. Often these foramina go up into the neural arch and spine, but in some cases – notably in pelicans and the occasional ratite – they go down into the centrum. So I now have no excuse for not getting back to the sauropod SMA paper (among many other things).

We’re making this all available because not only are we not afraid of getting scooped, we’re trying to get the word out. SMAs are phylogenetically widespread in birds and we know they were present in sauropods as well, so we should see some evidence of them in theropods and pterosaurs (because reasons). I made such a nuisance of myself at the recent Flugsaurier meeting, talking to everyone who would listen about SMAs, that Dave Hone went and found some pneumatic foramina in the neural canals of Pteranodon vertebrae during the conference – I suspect just to shut me up. That’ll be some kind of Hone-Atterholt-Wedel-and-some-others joint before long, too.

Anyway, point is, SMAs are cool, and you now have everything you need to go find them in more critters. Jessie and I are happy to collaborate if you’re interested – if nothing else, we have the background, lit review, and phylogenetic sampling down tight – but we don’t own SMAs, and we’ll be nothing but thrilled when your own reports start rolling in. Unexplored anatomical territory beckons, people. Let’s do this.

References

John Yasmer, DO (right) and me getting ready to scan MWC 8239, a caudal vertebra of Diplodocus on loan from Dinosaur Journey, at Hemet Valley Imaging yesterday.

Alignment lasers – it’s always fun watching them flow over the bone as a specimen slides through the tube (for alignment purposes, obviously, not scanning – nobody’s in the room for that).

Lateral scout. I wonder, who will be the first to correctly identify the genus and species of the two stinkin’ mammals trailing the Diplo caudal?

A model we generated at the imaging center. This is just a cell phone photo of a single window on a big monitor. The actual model is much better, but I am in a brief temporal lacuna where I can’t screenshot it.

What am I doing with this thing? All will be revealed soon.

Preserved bits of the Snowmass Haplocanthosaurus, MWC 8028, with me for scale. Modified from Wedel (2009: fig. 10), but not much – MWC 8028 was about the same size as CM 879.

Let’s say you had a critter with weird neural canals and super-deeply-dished-in centrum-ends, and you wanted to digitally rearticulate the vertebrae and reconstruct the spinal cord and intervertebral cartilages, in a project that would bring together a bunch of arcane stuff that you’d been noodling about for years. Your process might include an imposing number of steps, and help from a LOT of people along the way:

1. Drive to Dinosaur Journey in Fruita, Colorado, to pick up the fossils and bring them back to SoCal. (Thank you Paige Wiren, John Foster, and Rebecca Hunt-Foster for an excuse to come to the Moab area, thank you Brian Engh for the awesome road trip, and thank you Julia McHugh for access to specimens and help packing them up!).

2. Take the fossils to the Hemet Valley Medical Center for CT scanning. (Thank you John Yasmer and team.)

3. Find a colleague who would help you generate 3D models from the CT scans. (Thank you Thierra Nalley.)

4. Talk it over with your university’s 3D vizualization team, who suggest a cunning plan: (Thank you Gary Wisser, Jeff Macalino, and Sunami Chun at WesternU.)

5. They print the best-preserved vertebra at 75% scale. (50% scale resin print shown here.)

6. You and a collaborator physically sculpt in the missing bits with some Super Sculpey. (Thank you Jessie Atterholt for sculpting, and thank you Jeremiah Scott for documenting the process.)

(7.) The 3D-viz team use their fancy optical scanner (basically a photogrammetry machine) to make:

  • a second-generation digital model (digital)
  • from the sculpted-over 3D print (physical)
  • of the first-generation digital model (digital)
  • made from the CT scans (digital)
  • of the original fossil material (physical).

(8.) With some copying, pasting, and retro-deforming, use that model of the restored vert as a template for restoring the rest of the vertebrae, stretching, mirroring, and otherwise hole-filling as needed. (Prelim 2D hand-drawn version of caudal 1 shown here.)

(9.) Test-articulate the restored vertebrae to see if and how they fit, and revise the models as necessary. (Low-fi speculative 2D version from January shown here.)

(10.) Once the model vertebrae are digitally rearticulated, model the negative spaces between the centra and inside the neural canals to reconstruct the intervertebral cartilages and spinal cord.

(11.) Push the university’s 3D printers to the limit attempting to fabricate an articulated vertebral series complete with cartilages and cord in different colors and possibly different materials, thereby making a third-generation physical object that embodies the original idea you had back in January.

(12.) Report your findings, publish the CT scans and 3D models (original and restored), let the world replicate or repudiate your results. And maaaybe: be mildly astonished if people care about the weird butt of the most-roadkilled specimen of the small obscure sauropod that has somehow become your regular dance partner.

We did number 6 yesterday, so just counting the arbitrarily-numbered steps (and ignoring the fact that 7-12 get progressively more complicated and time-consuming), we’re halfway done. Yay! I’ll keep you posted on how it goes from here.