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!


  • 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.

This is one of my favorite things I’ve made so far! It is a horse toe that I skeletonized and articulated, after some vet students dissected and studied it. What’s super cool is that the bones are attached with magnets and small metal rods, so they can all come apart and be put back together again! . #horse #evolution is one of my favorite evolutionary stories. It is super well documented in the fossil record, and we know lots of cool stuff about how it occurred. The first horses were the size of small dogs, and originated in North America! As they evolved to live on open plains and eat grass, horses underwent several evolutionary trends, including larger body size and a reduction of toes (this helps them run faster). This leaves us with modern horses, which actually only walk around on ONE TOE (or finger) per foot!! . So this is one single toe (the third digit, or middle finger to be exact). The upper bone is a remnant of the foot bones, and the lower three are phalanges of the digit. You can also see several large sesamoids on the back (these are accessory ossifications that usually occur within a ligament). . #horsesofinstagram #horseevolution #horsetoe #bones #skeleton #science #evolutionarybiology #womeninscience #ladyscientist #teachersofinstagram #horsebones #scienceart

A post shared by Jessie Atterholt (@theladyanatomica) on

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.

Saw this gem back in the herpetology collections at the Academy of Natural Sciences in Philadelphia and thought, “Someone up and Beauchened a turtle head.” (My inner monologue is a tennis match between an arch language pedant and an unreconstructed hick with a penchant for folksy archaisms.)

What a sweet mount – there should be one of these for every critter in the museum. There should be a Hall of Exploded Skulls, and a Curator of Exploded Skulls. Would that be too much, or not enough? Both hypotheses remain untested. Someone should fix that.

Many, many thanks to Ted Daeschler for showing me all the awesome stuff at the Academy of Natural Sciences – or, if not all, as much as we could cram into two hours.

Marten skull on top, opossum on bottom. Internal (medial) view of the right half of each skull.

These have been in my collection for ages, I just hadn’t gotten around to posting pictures. I don’t remember where I got them, but they were definitely purchased rather than collected. It’s funny, I remember the origin story of almost every bone and skull I’ve collected myself, but stuff I’ve bought tends to slide out of recollection.

I assume the marten is the American marten, Martes americana, but I haven’t keyed it out. The opossum is definitely Didelphis virginiana.

I think the opossum skull was already hemisected when it came to me – at least, I can’t find the other half. The marten I did myself, with a Dremel. In part because I wanted to compare the size and shape of the braincases. As you can see from the photos, the marten had a big wrinkly brain that left impressions on the inside of the skull, and these are visible externally through the thin walls of the braincase.

Now, I am an opossum fan, but I will be the first to admit that the osteological evidence does not imply a lot of brainpower for North America’s only resident marsupial. Apparently its brain was small and smooth, untroubled by any thoughts more complicated than trash can access. Images of opossum brains online confirm that impression (or maybe lack of impression, since we’re talking about braincases here).

And yet, opossums are still around, thriving in the face of placentals with our wrinkly brains, high metabolisms, regular garbage collection, and whatnot. Long may they scurry.