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).

This is the second in a series of posts on our new paper about the expanded neural canals in the tail vertebrae of the Snowmass Haplocanthosaurus. I’m not going to talk much about Haplo in this post, though. Instead, I’m going to talk about chickens, and about how you can see a lot of interesting spinal anatomy in a living dinosaur for about two bucks.

You know by now that Academia Letters publishes peer reviews, which is one of the things that drew me to this fairly new journal. More on that in a later post, but in the meantime, the peer reviews for the Haplo paper are on the right sidebar here. I confess, I had a total forehead-slap moment when I read the opening lines of Niels Bonde’s review: 

This paper is interesting, and should be published and discussed by others with interest in dinosaur-bird relations. However, as these publications are also meant for the general public, I would recommend that 2 – 3 illustrations were added of the features mentioned for birds under nos. 3 – 6, because the general public (and many paleontologists) have no ideas about these structures, and what they look like.

The original submission only had figures 1 and 2. And this request is totally fair! If you are going to discuss six alternative hypotheses for some mysterious anatomical structure, it’s just responsible reporting to illustrate those things. That goes double if, as Niels Bonde noted, the anatomy in question is unfamiliar to a lot of people, even many paleontologists. Huxley’s quote after first reading Darwin’s Origin of Species flashed through my head: “How extremely stupid not to have thought of that.”

Slide 21 of my 2014 SVPCA talk on supramedullary diverticula in birds and other dinosaurs, illustrating pneumatic foramina in the roof, walls, and floor of the neural canal.

At the time I read that review, I already had images illustrating five of the six hypotheses. A juvenile ostrich synsacrum that Jessie Atterholt and I had CT scanned gave us three of them all by itself: the lumbosacral expansion of the spinal cord to run the hindlimbs, as in all limbed tetrapods and in some fish with sensitive fins; the transverse channels in the dorsal wall of the neural canal to accommodate the lumbosacral balance organ; and the paired troughs in the floor of the neural canal that house the ventral eminences of the spinal cord (Figure 4D in the image at the top of this post). I had good photos of pneumatic foramina in the walls and floor of the neural canal in a dorsal vertebra of a rhea from my 2014 SVPCA talk (Figure 4B), and some photos of small foramina, presumably for blood vessels rather than air spaces, in the floor of the neural canal in a caudal vertebra of Apatosaurus (Figure 4A).

What I did not have is a photo illustrating the fairly abrupt, dome-shaped space in the sacral neural canal that houses the glycogen body of birds. I mean, I had published images, but I didn’t want to wrestle with trying to get image reproduction rights, or with redrawing the images. Instead, I went to the grocery store to buy some chicken.

I don’t know how universally true this is, but IME in the US when you buy a quartered chicken, the vertebrae are usually nicely hemisected by the band saw that separated the left and right halves of the animals. So you can see the neural canal in both the dorsal and sacral parts of the vertebral column. Here are the hemisected dorsal vertebrae in the breast quarter from a sectioned rotisserie chicken:

That’s just how it came to lie on my plate, but it’s not in anatomical position. Let’s flip it over to sit upright:

And label it:

I could and probably should do a whole post just unpacking this image, but I have other fish to fry today, so I’ll just note a couple of things in passing. The big interspinous ligament is the same one you can see in transverse section in the ostrich dissection photos in this post and this one. Also, the intervertebral joints heading toward the neck, on the left of the image, have much thicker intervertebral cartilage than the more posterior dorsals. That’s because the posterior ones were destined to fuse into a notarium. You can see a diagram and a photograph of a chicken notarium in figures 4 and 5, respectively, here. And finally, the big takeaway here is that the neural canal is normal, just a cylindrical tube to hold the spinal cord.

The thigh quarter usually has the pelvis and the hemisectioned synsacrum attached. Here’s a lateral view of the left half of the pelvis and synsacrum:

And the same thing labeled:

And now flipped around so we can see it in medial view:

And now that image labeled:

And, hey, there are three of our alternative hypotheses on display: the long (many vertebral segments) lumbosacral expansion of the spinal cord, which is reflected in a gradually expanded neural canal in the synsacrum; the shorter, higher dome-shaped recess for the glycogen body; and finally the transverse spaces for the lumbosacral balance organ.

As a refresher, there’s nothing terribly special about the lumbosacral expansion of the spinal cord — you have one, labeled as the ‘lumbar enlargement’ in the above diagram. Where the spinal cord has adjacent limbs to run, it has more neurons, so it gets fatter, so the neural canal gets fatter to accommodate it. The cord itself doesn’t look very expanded in the chicken photo above, but that chicken has been roasted rotisserie-style, and a lot of lipids probably cooked out of the cord during that process. What’s more important is that the neural canal is subtly but unmistakably expanded, over the span of many vertebrae.

The lumbosacral spinal cord of a 3-week-old chick in dorsal view. The big egg-shaped mass in the middle is the glycogen body. Watterson (1949: plate 1).

That’s in contrast to the recess for the glycogen body, which is colored in blue in the chicken photo. Glycogen bodies, like the egg-shaped one in the young chicken in the image immediately above, tend not to go on for many vertebral segments. Instead they balloon up and subside over the space of just 4 or 5 vertebrae, so they leave a different skeletal trace than other soft tissues.

Finally, there are the transverse spaces for the lumbosacral balance organ, which I discussed in this post. Those are the things that look like caterpillar legs sticking up from the sacral endocasts in the above figure from Necker (2006). In life, the spaces are occupied by loops of meningeal membranes, through which cerebrospinal fluid can slosh around, which in turn puts pressure on mechanoreceptive cells at the edge of the spinal cord and gives birds a balance organ in addition to the ones in their heads. In the photo of the cooked chicken, the delicate meninges have mostly fallen apart, leaving behind the empty spaces that they once occupied.

I really liked that chicken synsacrum, and I wanted to use it as part of Figure 4 of the new paper, but it needed a little cleaning, so I simmered it for a couple of hours on low heat (as one does). And it promptly fell apart. At least in the US, most of the chickens that make it to table are quite young and skeletally immature. That particular bird’s synsacrum wasn’t syn-anything, it was just a train of unfused vertebrae that fell apart at the earliest opportunity. I had anticipated that might be an issue, so I’d gotten a lot of chicken, including a whole rotisserie chicken and four thigh quarters from the deli counter at the local supermarket. Happily this fried chicken thigh quarter had a pretty good neural canal:

And it cleaned up nicely:

And with a little cropping, color-tuning, and labeling, it was ready for prime time:

I didn’t label them in the published version, for want of space and a desire not to muddy the waters any further, but the jet-black blobs I have colored in the lower part of that image are the exit holes that let the spinal nerves out of the neural canal so they could go serve the hindlimbs, pelvic viscera, and tail. We have them, too.

At my local grocery store, a fried chicken thigh costs about $1.65 if you get it standalone, or you can buy in bulk and save. You get to eat the chicken, and everything else I’ve done here required only water, heat, soap, and a little time. The point is that if I can do this, you can do this, and if you do, you’ll get to see some really cool anatomy. I almost added, “which most people haven’t seen”, but given how much chicken we eat as a society these days, probably most people’s eyes have fallen on the medial surface of a cooked chicken thigh quarter at one time or another. Better to say, “which most people haven’t noticed”. But now you can. Go have fun. 

Way back in January of 2019, I finished up “Things to Make and Do, Part 25b” with this line: “I have one more thing for you to look for in your bird vertebrae, and that will be the subject of the next installment in this series. Stay tuned!” Here we are, 2.3 years later, and I’ve finally made good. So if there’s a promised post you’ve been waiting for, stick around, we may get to it yet.

References

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.

 

This is something I did over Thanksgiving break in 2019. I meant to blog about it sooner, but you know, 2020 and all. So here I am finally getting around to it. (Yes, I know the ruler in the above photo is the worst scale bar ever. I was, uh, making a point. Which you got. So go you!)

For reasons unknown to me, the strip of skin between the mid-snout and the ear on the right side of the head was already off when I took possession from the local butcher. But it did show the ear muscles to good advantage, as well as the parotid gland–the knobbly white thing between the eye and ear that looks like grits, or eggs, or white beans. You have a parotid gland in front of each of your ears, too (par-otid = “next to ear”), each with a duct that crosses the cheek to bring saliva into your mouth. If you push your tongue into the upper-lateral “corners” of your cheeks, you can feel the little papilla where the duct opens, and if you push against the papilla with your tongue you may feel a little saliva leak out. You also have paired submandibular and sublingual salivary glands, but those will have to wait for another day.

Here’s the head from the back, after I’d gotten the right ear off. The bluish-white hyaline cartilage over the occipital condyles is clearly visible about 2/3 of the way up from the bottom, with the faintly yellowish stump of the medulla oblongata in between, going up into the braincase. Tons of neck muscles are visible here, and maybe someday I or someone else will get around to labeling them in this photo–but it is not this day.

What was I doing here? Getting off the ears, and as much skin and subcutaneous fat as possible, in preparation for brining and smoking. I like this photo, the little piggy looks positively happy about having its skull prepped.

Right, into the bag with you then. I did the same brining and smoking routine that I did for my first smoked turkey back when–see this post for details.

And here we are about 15 hours later. Note how much the color of the meat has changed from the brining.

Time to extract the brain. I already showed a version of this photo in my post on the $1 brain-extractor (a.k.a. drain rooter, see this post), but it bears repeating: the brain is mostly lipids and if you cook the head with the brain still in it, the brain will turn into liquid fat and seep into the bones and you’ll spend the rest of your days trying to degrease the skull before you die, unloved and weeping, on a pile of rags. So no matter how you’re planning to cook the head, yoink the brain first.

Onto the grill, with a drip pan underneath, foil heat shields in place to keep the heat indirect, and foil-wrapped mesquite smoke bombs visible under the grill, right on top of the coals. This is about all I do with my grill anymore; smoking is really no more work than anything else and the results are pretty much to die for. YMMV.

Same shot an hour later and the smoking is coming along nicely. I ended up smoking this head for three hours, an hour and a half on each side. 

And into the roasting pan for a few minutes’ rest at the end of the cooking. And it was cooking, not just specimen prep–we ate this pig head in lieu of a turkey for Thanksgiving, and it was amazingly delicious. One thing to note in this photo is how the temporalis fascia has pulled away from the skull at the upper left, exposing some bare bone. This would be a problem later on.

Defleshing, both to get the edible meat off, and to get as much of the rest of the soft tissue off in preparation for simmering. In this anterior view, you can see that the right side of the animal’s forehead (viewer’s upper left) got exposed during the smoking process and the bone is stained brown. 

Even with the meat cooked all the way through, disarticulating the jaw took some doing, and then some follow-up meat removal. Check out the very round, almost hemispherical mandibular condyles, which fit up into the sockets of the temporomandibular joints. Birds and other reptiles mostly do it the opposite way, with rounded quadrates on the cranium that fit into articular sockets on the lower jaw.

Ready for simmering. Pro tip: if you need a really big metal pot in which to simmer skulls or other large osteological specimens, but you don’t want to go bankrupt, look for a tamale-steaming pot. They’re comparatively thin-walled and lightweight, but still plenty sturdy for just about any application you are likely to think of. 

Our kitty, Moe, helped with the clean-up of the roasting pan.

The first simmer. At this remove, I don’t remember how many rounds of simmering I did, but it was at least two, maybe three.

Post-simmer, I put the skull into a sink-full of warm, soapy water for a defleshing. Notable bits you can see on the right side of the photo are the ridged surface of the palate (about 7:00 on the plate), the long straight cartilage of the nasal septum (going vertically up the right side of the plate), and the incisors at the extreme upper right, sitting on the edge of the sink. Most of the incisors fell out during the wash, which was fine, because most of them were horribly stained from the smoking process and would require a lot of scrubbing and bleaching to get back to a nice and natural-looking white.

The condition after the first simmer. You can see that the supraorbital foramina, on the forehead between the eyes, still have goop in them. This was true of pretty much all of the nerve and blood vessel passages. It took a lot of time, some ingenuity, bamboo barbeque skewers, and running water this way and that to flush out all of that crud. And the bones are still weird colors at this stage, pre-whitening, especially the groady dark patches on the forehead. It wasn’t the areas of bone that were directly exposed to smoke that were the problem, it was the areas just adjacent where the periosteum cooked against the bone.

Same stage, left lateral view. Note the empty sockets for the incisors, and the infraorbital foramen (above the upper teeth and about a third of the way between eye socket and the nose), which on this side is divided in two by a strut of bone. There’s another gross dark patch on the back of the zygomatic arch. All of those took pretty aggressive scrubbing to remove.

Back into the pot for another simmer. The perforated plate at the bottom sits on a lip of metal about three inches above the bottom of the pot so you can steam tamales with this thing. I used it to keep the bones off the bottom of the pot so they’d have no chance of getting scorched.

Here’s a significant jump forward in time. By this point I’d degreased and whitened the skull by soaking it in dilute hydrogen peroxide (I use the cheap stuff from the dollar store down the street, and it works fine), applied glue to several of the skull sutures that were threatening to come apart, and epoxied the prenasal bone back into position between the nasal bones above and the premaxillary bones below. The prenasal bone is a pretty cool structure, you can see it in other views (including a cross-section!) in this post. I also glued the incisors back in at this stage.

Believe it or not, this was the largest skull I had ever prepped myself–the largest osteological preparation of any kind, in fact–and it was a lot more work than I anticipated. But the effort was worth it, and now I have a really cool pig skull on my bookcase. I’ll show the finished skull in a follow-up post (no, really, I will!). EDIT: And I did! 

For other posts on pig skulls, see:

Well, it’s time. Ten years and almost 5 months after Mike kicked off our “Things to Make and Do” section with his post on cleaning a pig skull, I am finally getting around to prepping a pig skull of my own. There will be a complete play-by-play coming, but for now I want to focus on what is usually the least-pleasant step in prepping a skull: extracting the brain. Aside from the relatively small and often tortuous passages for the cranial nerves, the braincase is a cul-de-sac, with a big glob of tissue (the brain and associated meninges and vessels) only accessible through a relatively small hole at the back of the head (the foramen magnum). Virtually every tutorial and how-to on prepping skulls has some section where the author advises you to basically swirl something around in there, get stuff out the best you can, and prepare to deal with a lot of nastiness along the way. So I had my antennae out for anything that might help, and in the local dollar store I ran across the beauty shown above.

I figured drain rooter = brain rooter, and I was only risking a buck, so I picked one up. It worked a trick: by putting the pig’s snout down the drain, running hot water into the foramen magnum to continually flush out the loose bits, and vigorously exploring the cranial cavity with the brain rooter, I was able to get the whole brain out in about 10 minutes. To be clear, all the tissue came out the foramen magnum; there would be no way to get it to come out the nose without breaking the ethmoid bone and destroying the nasal turbinates. I only put the head snout-down for ease of access. I had a great deal of control, and I could tell pretty well which areas were getting emptied out and which still needed work. All I missed was a small glob of meninges and dural venous sinuses, which came out easily after the first simmer.

Some specific advantages of the drain rooter as a brain extractor:

  • backward-pointing teeth to hook out the tissue
  • flexible plastic so you can go pretty hard with it without damaging the bone
  • super long so you’re not going to find a job too big for it, OR you can cut it to length
  • still works for unclogging drains
  • dishwasher safe
  • dirt cheap

Go have fun.

UPDATE: Turns out pigs have an insane amount of cartilage and mucosa in their nasal cavities, and the brain rooter is pretty good at getting that stuff out, too.

My friend and frequent collaborator Jessie Atterholt has her office in the next building over from mine. When you walk in, you see something that looks approximately like this. Not exactly like this, because I took these photos in February and she’s changed a few things (and I’m rubbish about getting stuff posted in a timely fashion).

The last time I showed an office full of amazing stuff like this, it was Peter Dodson’s. It will come as no surprise that Jessie was Peter’s student at UPenn before she went to Berkeley for her PhD.

The far case holds mostly books and skulls. Dr. A has her own plastination setup for making preserved organs and organisms, and the snake on the second shelf here is one that she prepped herself. One side of the snake still has the skin on, the other half has been skinned to show the muscles. This is crunch week for me so I don’t have time to ID all of the stuff, but alert readers should have no problem spotting some digitally-resurrected Haplocanthosaurus bits.

Mostly skulls on the middle rack. The sirenian skull on the second shelf and the cave bear on the fourth are both casts, but almost everything else is real bone. The bighorn sheep on the middle shelf is a natural mummy.

Here’s a close-up of the top shelf. Other than some 3D-printed human skull bones sitting in front of the brain slice on the left, everything here is real bone, including the lion, baboon, and human skulls, and the giraffe cervicals winding across the top. Jessie’s been collecting since she was a kid and the African megafauna are gifts from a globe-trotting family friend.

The upper shelves here have quite a few of Jessie’s plastinated specimens, both whole organisms and things like hearts and kidneys from various critters.

A close-up of some of Jessie’s coolest anatomical preparations. In back is an internal cast of the lungs and bronchial tree of a cat. The baby rattlesnake died after eating a proportionally gigantic lizard — I was dumb and forgot to flip the snake over to show the lizard inside, plastinated along with its predator. The ground squirrel on the right is another half-fleshed, half-skinned plastinate, and the mouse up front is a classic dissection presentation, preserved forever through plastination.

I’ve heard it said that the difference between a collector and a hoarder is curation. As someone who definitely lurks more on the hoarder end of that spectrum (to paraphrase Dave Barry, if you could see my office you’d be blinded or driven insane), I’m pretty darned jealous of both the breadth of Jessie’s collection, and the skill and taste with which it is displayed. She’s featured some of these specimens on her Instagram, which I strongly recommend.

When I started working on sauropods, I thought their vertebrae were cool but they were loaded with weird structures that I didn’t understand. Then I dissected my first ostrich neck and suddenly everything made sense: this was a muscle attachment, that was a pneumatic feature, this other thing was a ligament scar. Everyone who is interested enough to read this blog should give themselves the same “Aha!” moment. You don’t even have to eat the birds yourselves, lots of people don’t like bird necks and will give them away if you ask.

If you get a whole bird, the neck is usually included with the giblets. Around Thanksgiving and Christmas you can often find bundles of spare turkey necks at your grocer or butcher.

This spring I picked up some smoked turkey necks at the grocery store. I wanted to make turkey stew and I figured I might as well get some toys in the bargain. Here are some neck segments in the crock pot.

And here they are after a few hours of cooking. Time to separate the meat from the bones. That neck segment in the middle of the above photo is a pretty good match for the ostrich neck cross-section in this post.

Here are parts of three vertebrae with the long, multi-segment muscles removed, but with the shorter single-segment muscles still connecting them. Anterior is to the right; that’s a cervical ribs sticking out at the lower right “corner”.

Here’s a single intact cervical in left lateral view with most of the meat off, but ready for a long simmer to loosen the remaining crud. This is roughly the same orientation as the lateral view of Mike’s famous turkey cervical.

Meat goes back in the pot.

Bones go on to the next stage: simmering. One of the nice things about the stepwise process of cleaning bones is that you can stop at any point, put the bones in the freezer, and come back days or months later. This bowl of bones went into the freezer in exactly the state you see here, and I didn’t pull them out and finish cleaning them until last week.

If you have a pot-sized strainer, it makes things easier, especially for rinsing. These aren’t turkey vertebrae, these are the verts from my Thanksgiving ducks. But the principle and the process are the same.

After simmering for an hour or two, it’s time to pick off the loosened muscles, ligaments, cartilage, and so on. Here are two similar turkey cervicals after simmering, in dorsal view with anterior to the right. The one on the left has not been cleaned and has all kinds of crud stuck to it, including a big chunk of intervertebral ligament sticking out between the rami of the postzygapophyses. The one on the right has been through a first-pass cleaning.

What tools should you use? Whatever you have to hand. I like old toothbrushes for scrubbing off little bits of muscle and tendon, toothpicks for shoving spinal cord bits through the neural canal and for picking bits of meat out of hard-to-reach places, and the Mark 1 thumbnail for planing off articular cartilage, as shown here with the back end of a duck cervical.

Here’s the outcome of a cleaning session: on the left, the bowl I used for cleaning the vertebrae. In the top middle, the pile of gloop I pulled off. And on the right, a bowl of cleaned turkey and duck vertebrae, ready for degreasing.

Here are the vertebrae of a couple of ducks after soaking overnight in 3% hydrogen peroxide, the ordinary stuff you get at the drugstore or dollar store.

Here’s another bowl with turkey vertebrae. They were all at the bottom of the bowl when I went to bed, floating when I got up the next morning. This is pretty common with lightweight pneumatic vertebrae: the oxygen bubbling out of the hydrogen peroxide has gotten trapped in the internal air spaces and made the vertebrae buoyant.

After a night in the hydrogen peroxide, it’s time to rinse and dry the vertebrae. I put this mixed lot of turkey and duck verts on a plate with a paper towel and left them out on the kitchen counter. In the summertime, when it’s hot and dry, I might put them outside for a bit and they’d be dry in a couple of hours. Indoors in the winter it can take a couple of days for the vertebrae to get completely dry.

Here’s the same batch of vertebrae a couple of days later, clean and dry and ready for whatever comes next.

Which bird should you use? Bigger birds have vertebrae that are easier to clean, harder to damage, and more fun to look at, but use whatever you can get your hands on. This photo shows the axis, a middle cervical, and a posterior cervical from the turkey (top) and duck (bottom). Note that the duck was so young that the cervical ribs hadn’t fused and they fell off during the cleaning process.

If you’ve been following along, you have some nice clean bird vertebrae to play with. So what now — what should you do with them? That will the subject of an upcoming post (UPDATE: this one). Stay tuned!

Lots of museums have some version of this, but this is the nicest one I’ve seen myself.

Just back from the field. Will post photos soon. Putting this up to meet the weekly posting requirement.

I’ve known who Peter Doson was since I was nine years old. A copy of The Dinosaurs by William Stout and William Service, with scientific content by Peter, showed up at my local Waldenbooks around the same time as the New Dinosaur Dictionary – much more on The Dinosaurs another time. Then when I started doing research as an undergrad at the University of Oklahoma, Peter’s chapter on sauropod paleobiology in The Dinosauria (Dodson 1990) was one of the first things I read. At the SVP banquet in 2000, I ran into Peter and he shook my hand and said, “Sauroposeidon rocks!” I managed not to swoon – barely.

When I was in Philadelphia this March, Peter invited me to the UPenn vet school for an afternoon. He gave me a tour of the building with its beautiful lecture halls and veterinary dissection lab, and then we spent a couple of hours rummaging around in his office. That was one of the highlights of the trip, because it turns out that Peter and I are both comparative anatomy junkies. He’s been at it for longer, and he has more regular access to dead critters and more space to display them, so his collection puts mine to shame. But he kindly let me play with study whatever I wanted.

 

In fact, he went farther than that: he quizzed me. A lot. I take it that it’s a right of passage for people coming through Peter’s office. It was an enjoyable challenge, and I got photos of a few quiz items so you can play, too. This transversely-sectioned skull was one of the first mystery specimens. I figured it out pretty quickly, for reasons I’ll reveal in a future post. Can you? Post your IDs in the comments.

I don’t remember all of the quiz items. One of them was the dark skull lying upside down behind the ratite skeleton in the photo up top. I had to figure that one out without picking it up, so you have about as much information as I did. We’ll call that one quiz item #2. Embiggenate for all the clues you’ll need.

This wasn’t a quiz item, just something cool: the skull of a large dog with the top of the cranium removed. In the paired cavities at the top, we’re looking down through the frontal sinuses to see the respiratory turbinates in the nasal cavities. The single large space behind is the braincase. At the very front, in the shadowed recess, you can see the cribriform plate of the ethmoid bone, perforated with dozens of holes to let the olfactory nerve endings through from the back of the nasal cavities. We have the same thing on a smaller scale a centimeter or two behind our brows, and oriented horizontally. But what really drew my attention were the linear arrays of paired foramina arcing across the floor of the braincase – holes to let cranial nerves and the internal jugular veins out of the skull, and the internal carotid arteries in. We have the same structures in our heads, of course, but the layout isn’t as neat – our big brains, bent forward at such a sharp angle from the spinal cord, have squished things around a bit.

Here are more skulls, garnished with a human femur and a ratite pelvis and synsacrum. Peter quizzed me on the Archaeoceratops (front) and Auroraceratops (back) skulls on the far right. I IDed them correctly, but only because I spent some quality time with the Alf Museum’s casts when I was reconstructing the skull of Aquilops. On the far left is an alligator skull with injected arteries, which is definitely worth a closer look.

Here’s a dorsal view of the injected alligator skull. The arteries have been injected with red resin, and then all of the soft tissue has been macerated away, leaving just the bone and the internal cast of the arterial tree. Some of the midline bone has been removed here to reveal the courses of the cerebral, ethmoid, and nasal arteries. Also note the artery looping around in the left supratemporal fenestra.

Here’s a look into the right side of the back of the skull, where the lateral wall of the braincase has been Dremeled away to show the course of the internal carotid artery. It’s a very cool demonstration of a bit of anatomy that I had never seen before. For more on cranial blood vessels in crocs, check out the obscenely well-illustrated recent paper by Porter et al. (2016).

To my chagrin, that’s all the good photos I got from Peter’s office – we were too busy passing specimens back and forth and frankly geeking out like a couple of kids. One of my favorite specimens from his office was the mounted foot skeleton of a horse, which Jessie Atterholt had prepared for him when she was his student at UPenn. It’s such a cool preparation that it captured my imagination, and when I got back I warned Jessie that if she didn’t get her own articulated horse foot posted soon, I was going to make something similar for myself and steal her thunder. A couple of months later, her horse foot is up on Instagram – I featured it in this post – and my cow foot is still sitting in pieces, waiting for me to put it together. Here’s a shot of Jessie’s, to hopefully prod me into action:

I didn’t get all of Peter’s quiz questions correct. I knew that the endocast of the pharyngeal pouch in a horse was an endocast, but of what I didn’t know, although I did correctly identify the hyoid apparatus of a horse, mounted separately. And there was a partial cetacean jaw that I misidentified as a shark (in my defense, it was from one of the small, short-faced weirdos). Still, Peter said that I’d done as well as anyone else ever had. That was nice to hear, but I was already happy to have gotten to see and talk about so many cool things with a fellow connoisseur. Thanks, Peter, for a wonderful afternoon, and for permission to post these pictures. I am looking forward to a rematch!

References

  • Dodson, P. 1990. Sauropod paleoecology. In: D.B. Weishampel, P. Dodson, P., & H. Osmolska, (eds), The Dinosauria, 402-407. University of California Press, Berkeley.
  • Porter, W.R., Sedlmayr, J.C. and Witmer, L.M., 2016. Vascular patterns in the heads of crocodilians: blood vessels and sites of thermal exchange. Journal of Anatomy 229(6): 800-824.
  • Stout, W., Service, W., and Preiss, B. 1984. The Dinosaurs: A Fantastic View of a Lost Era. Bantam Dell Publishing Group, 160pp.

Exploded turtle skulls are cool, but what about exploding the entire turtle? (Not that way.) Folks at the Naturhistorisches Museum Wien roll hard. Or did – I assume these exhibits are old. Thankfully no museum studies doofus has insisted they be taken down and replaced with an interactive 3D display on what it feels like to be a sea turtle. Kudos to the current management for keeping the natural history museum filled with natural history.

I didn’t get back far enough from them to photograph all of the labels, mostly because I had like 90 minutes to jet through roughly 13,792 halls of amazing things. But this one is a loggerhead, Caretta caretta. Identifying the others is left as an exercise for the reader.

Or better yet, make your own, if you can procure a dead turtle.

This will be a short and mostly navel-gaze-y collection of links.

Back in November, 2016, I posted here about my “Twelve Steps to Infinity” article in Sky & Telescope magazine. That one covered 12 objects in the winter sky and corresponding events in Earth history when the light we see now left those objects. I’ve now done a similar but larger article for the summer sky, titled “Fifteen Steps to Forever”, which is out in the June issue of Sky & Tel. Also, the June issue has not one but three articles on space rocks and their terrestrial traces: one on where we are as a species in assessing the impact threat (timely since I was just talking about that), one on how to see impact craters from commercial airliners (awesome!), and one on upcoming asteroid sample-return missions being prepped by the Japanese space agency and NASA. Confusingly, the June issue will be on newsstands during the month of May, so if you want to check it out, now’s the time.

More recently, in the unexpectedly popular tungsten cube post I wrote:

There are a couple of objects in my collection that give me more pleasure than any of the rest. One is a piece of shrapnel from the Sikhote-Alin meteorite – more about that another time, perhaps.

“Another time” has come – in the wake of my impact talk, I’m slowly going through my (small) meteorite collection over at 10 Minute Astronomy. I just covered my Sikhote-Alin chunk, in what I immodestly think is one of my better posts. Go see if you agree.

Finally, you presumably came here in hopes of seeing the anatomy from something, so here you go. My friend and colleague Jessie Atterholt is on Instagram as @theladyanatomica and she has been posting some pretty sweet photos and videos, mostly of specimens she prepared herself. I’m highlighting her work now because she just posted a video of her horse foot mount, which is free-standing with the help of a single rod, but which breaks almost all the way down thanks to metal pins and magnets. It’s one of my favorite anatomical preparations of all time and something I both envy and covet. Peter Dodson has one in his office – Jessie made it for him when she was his student at UPenn. Seeing it when I was in Philadelphia in March re-fired my interest in such things – if you’ve noticed an uptick in posts about anatomical specimens in the last few weeks, Peter and (mostly) Jessie are to blame. With any luck, I’ll have something similar of my own to post on in the not-too-distant future. In the meantime, go check out Jessie’s work at the link above.