As noted in the last post, Matt and I are off to spend a week at the Carnegie Museum from 11th-15th March. We expect to see many, many fascinating specimens there: far more than we’ll be able to do proper work on in the five days we have. So our main goal is to exhaustively document the most important specimens that we see, so we can work on them later after we’ve got home. I think of this as the “harvesting” phase of research, with the grinding and baking to follow.

I was going to write a checklist for myself, to ensure that I cover all the bases and we don’t find ourselves in six months’ time looking at our records and saying “I can’t believe we forgot to do X for this specimen” — because, believe me, we have spent far too much of our lives doing this already. But then I realised I should share it with the world, in case it’s helpful to others, too.

So here’s what to do when dealing with, for example, an apatosaurine cervical like this one. Let me know in the comments if I forgot anything!

BYU 20178, cervical vertebra from an apatosaurine sauropod. ventral view, anterior to the left. Note that the scalebar is held at approximately half the height of the vertebra; and that the catalogue card is in view and legible, giving a record who collected the specimen, when, and where.

Sketch the specimen, even if (like me) you are a terrible artist. The process of sketching forces you to really look at it — at each part of it in turn — and often results in you noticing something you would otherwise have missed. It would be worth doing this even if you immediately threw the sketch away: but don’t do that, because you’re going to want to …

Measure the specimen, using a tape measure, digital calipers or both as appropriate. You want to get at least all the measurements that you’ll include in a formal description — total length, total height, width across zygapophyses, etc. — but it’s often useful to also get other, more obscure measurements, just to make sure you’ve got your head around the shape. For example, in the vertebra above, you might measure the diagonal distances from the anteriormost projection of each cervical rib to to opposite side’s posterolateralmost part of the centrum. You record measurements in a table in your notebook, but some measurements are hard to describe: so just write them straight onto your sketch. To keep things straight, it can be useful to do the sketch in one colour and the measurements in another; or the sketch in pencil and the measurements in pen.

Now we come to photography. You want a lot of different kinds of photo, so lets consider them separately.

Take photographs of the specimen with its specimen label, ideally from several different aspects. This will make it easy to remember later which specimen is which. In a typical museum visit — especially a reconnaisance visit like our upcoming Carnegie trip — you’re going to see a lot of different specimens, and when you revisit your photos in six months it’ll be hard to keep them all straight. Make it easy on yourself. Also: the specimen label often contains other  useful information such as the quarry where the specimen was found. Capture that. Get a good close-up photo of the label alone, to ensure all the text is captured cleanly.

Take photographs from the cardinal directions. To illustrate a specimen nicely in a descriptive paper, you will at minimum want photos from anterior, posterior, dorsal, ventral and left and right lateral aspects (or as many of these are possible to obtain: you can’t always turn big specimens). Since these are the photos you’re likely to use in a publication, take extra care with these. Set up a plain-coloured background when possible so it’s easier to crop out later. Set up the best lighting you can. Take each photo several times so you can keep the best one. Use a tripod if you have one. (For much more on this, see Tutorial 8 on how to photograph big bones.)

Take photographs with a scalebar. This will give you a way to sanity-check your measurements later. Think carefully about scalebar placement. If you put it on top of the specimen so it obscures part of the fossil, be sure that’s not your only photo from that aspect: you won’t want to be left without good images of the whole bone. A scalebar placed on top of the specimen will appear larger than the same scalebar placed on the floor or the bench next to the specimen, thanks to perspective, which means your measurements are more trustworthy than photos of the scalebar. If you can easily arrange for it to be raised to half the total height of the specimen, you’ll get a more honest reading.

Photograph individual features of the bone with some kind of note. The reason I say “with some kind of note” is that I have hundreds of close-up photos of bits of sauropod vertebra which I evidently took in the hope of highlighting some specific bit of morphology, but I have no idea what morphology. Get a scrap of paper and scribble something like “big nutrient foramen”, draw an arrow on it, and place the scrap on the bone so that the arrow points at the feature. Take a photo; then remove the paper and take another photo. The first one is your note to yourself; the second is the raw material for an illustration that you might prepare later, highlighting the relevant feature in a more elegant way.

Do a video walkaround with narration. For some reason, we didn’t start doing this until very recently, but it’s a great way to get a rough-and-ready reminder of important aspects of the specimen. You can just do this with a phone, moving it around the specimen, pointing to interesting bits and saying things about them. Here’s an example of Matt pointing out some features of the preserved cervical vertebrae of Suuwassea, and here he is again pointing out how pelican vertebrae are made of nothing.

Take a shedload of undifferentiated photos from every possible angle. Your goal here is that you’ll be able to use photogrammetry later to make a 3D model of the fossil. I admit to my shame that I’ve still never successfully done this — but thanks to the kindness of my good friend Heinrich Mallison, who is an expect in this area, I do have some fine models, including the Xenoposeidon model that was published as a supplementary file to my 2018 paper. Even if you don’t have access to someone as helpful as Heinrich, it’s worth getting these comprehensive photo-sets because photogrammetry software is likely to get progressively easier to use. Hopefully in a couple more years there will be nothing to it but loading a bunch of photos and pressing a button.


Up till here, we’ve been concentrating on gathering information about the specimen in a form that we’ll be able to return to later and use in comparisons and illustrations. But we can do more than that now we’re here with the physical specimen:

Look at the bone texture. Figure out how much of it is real, and how much is reconstructed — a particular problem with older specimens. Keep an eye out for rugosities for muscle and ligament attachments, smooth areas and pockets for pneumatic diverticula (or fat pads in boring mammal verts), and any odd growths that might be ossified soft tissues or pathological reactive bone growth. These kinds of things are often much easier to see in the actual specimens than in even the very best photographs.

Check for areas where the specimen is under-prepared. It’s very common for a neural canal to remain filled with matrix — and easy to spot, so in a sense not a problem. But how often is a pneumatic feature obscured because it’s still full of matrix? This is probably part of the reason that caudal pneumaticity so often goes unobserved, and it will very often obscure foramina within the neural canal. Similarly, I don’t know whether the huge club on the end of the right cervical rib of NHMUK PV R173b (formerly BMNH R173b) is pathological bone or a mineral concretion, because all I have to go from is my lame photos. I should have figured that out while I was with the actual specimen.

Discuss the specimen with a friend. I just can’t overstate how important this is. When Matt and I visit a collection together, we discover much, much more than twice as much as either of us would alone. Isaac Asimov is said to have observed “The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka!” (I found it!) but “That’s funny …””. Whether or not he ever actually said it (it’s not in any of his written works) it’s certainly true that the key moment in investigating a specimen is frequently when one person says “Hey, take a look at this”. Two minds can spark off each other in a way that a single mind can’t.


Last of all, it’s worth giving a little bit of thought to the possibility that you’ll one day be doing publicity for this specimen. So:

Get someone to take photos of you with the specimen. You’ll need them for press releases and media packs. I’ve only once in my life been in physical proximity with the Brontomerus specimen: during the three-day 2007 visit when I did much of the descriptive work for the paper. Idiotically, although I was there with three colleagues (Matt, Randy Irmis and Sarah Werning), I didn’t get anyone to take a photo of me with the material. So when we needed a photo for the publicity:

The Brontomerus mcintoshi holotype specimen OMNH 27761-27800, 61248 and 66429-66432 with the authors of the paper that described it. Back row (L to R): Mike Taylor, Matt Wedel, Rich Cifelli.

There was no good way to get it. I certainly wasn’t going to fly back out to the USA just to get a photo. So we got our Emmy award-winning special-effects-wizard friend Jarrod Davis to photoshop me into a photo that the museum had been able to take of Matt and Rich. (You can see the evidence here and here if you want to see how it was done. And, yes, before he could even start composing me in, Jarrod had to rescue a ludicrously under-exposed base image.)

Much better to avoid such nonsense. Get good photos of you with the specimens, like the one at the top of the Sauropocalypse post, and then if you ever need ’em you’ve got ’em.

 

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Hot news! Matt and I will be spending the week of 11th-15th March at the Carnegie Museum in Pittsburgh: the home of the world’s two most definitive sauropods!

The Carnegie Diplodocus, CM 84, is the original from which all those Diplodocus mounts around the globe were taken, and so by far the most-seen sauropod in the world — almost certainly the most-seen dinosaur of any kind.

Diplodocus carnegii mounted holotype specimen CM 84 at the Carnegie Museum, Pittsburgh. Photo by Scott Robert Anselmo, CC By-SA. From Wikimedia.

Like most dinosaur-loving Brits, I grew up with this specimen, in the form of the cast that until recently graced the central hall of the Natural History Museum in London. It defined my concept of what a sauropod is. But I’ve never seen the original before, and I am stoked about it.

Also like most Brits — and American dinophiles often find this hard to believe — I never saw an Apatosaurus skeleton, or indeed any Apatosaurus material, when I was growing up, or even for several years after I started functioning as a palaeontologist. We just don’t have the material over here, so when I saw the mounted Brontosaurus holotype at the Yale Peabody Museum in 2009, it was a big moment for me.

But now, for the first time, I am going to see the definitive apatosaurine specimen, the Apatosaurus louisae holotype CM 3018!

Apatosaurus louisae mounted holotype specimen CM 3018 at the Carnegie Museum, Pittsburgh. Photo by Tadek Kurpaski, CC By. From Wikimedia.

(And I know this is not exactly a new observation here on SV-POW!, but: check out that neck! it’s insane!)

And of course the two big, glamorous mounted sauropods are only the tip of the iceberg. The Carnegie Museum has a ton of awesome material in collection, including Hatcher’s Haplocanthosaurus specimens, the much-loved juvenile apatosaurine cervical sequence CM 555, the Barosaurus cervical sequence CM 1198, and much much more.

We are going to be drowning in sauropods!

I’ll have more to say about this trip shortly, but I just want to close today’s post by saying two things:

First: those of you familiar with the collections at the Carnegie, what are the things that Matt and I should definitely not miss? What will we kick ourselves if we come come without having seen?

And finally: a big thank you to my wife, Fiona, who is finishing up a masters in March and definitely doesn’t need me to be out of the country and unable to help for a week of that final month. She is a marvel, and is sending me anyway.

 

We’ve posted a lot here about how crazy the cervical vertebrae of apatosaurines are (for example: 1, 2, 3), and especially the redonkulosity of their cervical ribs. But I think you will agree with me that this is still an arresting sight:

That’s MWC 1946, a mid-cervical from the Mygatt-Moore Quarry that was figured by Foster et al. (2018: fig. 18 A-B) and referred with the rest of the Mygatt-Moore apatosaur material to Apatosaurus cf. louisae (entirely correctly, in my view). This is a ventral view, with the condyle down by the scale bar.

Here’s the same thing cropped from the background to emphasize its unbelievableness:

and mirrored and restored a bit in GIMP to give a taste of its probable appearance in life (if you had an apatosaur, an x-ray machine, and a lot of confidence about not getting stepped on):

For obvious reasons, my nickname for this specimen is the Brontosmasher.

Keep in mind that the centrum was full of air in life, whereas the cervical ribs and the bony struts that support them are just huge slabs of bone. I strongly suspect that the volume of bone in the cervical ribs and their supporting struts is vastly more than in the centrum and neural arch. I will soon have the ability to test that hypothesis–I have this specimen on loan from Dinosaur Journey for CT scanning and 3D modeling. Watch this space.

Many thanks to Julia McHugh at Dinosaur Journey for access to the specimen and assistance during my frequent visits.

Reference

  • Foster, J.R., Hunt-Foster, R.K., Gorman, M.A., II, Trujillo, K.C., Suarez, C.A., McHugh, J.B., Peterson, J.E., Warnock, J.P., and Schoenstein, H.E. 2018. Paleontology, taphonomy, and sedimentology of the Mygatt-Moore Quarry, a large dinosaur bonebed in the Morrison Formation, western Colorado—implications for Upper Jurassic dinosaur preservation modes: Geology of the Intermountain West 5: 23–93.

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.

 

We all know that apatosaurines have big honkin’ cervical ribs (well, most of us know that). But did they also have unusually large neural spines?

The question occurred to me the other day when I was driving home from work. I was thinking about C10 of CM 3018, the holotype of Apatosaurus louisae, and I thought, “Man, that is a lot of neural spine right there.”

Why was I thinking about C10, particularly? I traced and also stacked Gilmore’s (1936) drawing for my 2002 paper with Kent Sanders, and recycled the trace for my 2007 prosauropod paper, and recycled the stack-o-C10s for my 2013 PeerJ paper with Mike. So for better or worse C10 is my mental shorthand for A. louisae, the same way that their respective C8s seem to capture the essence of Giraffatitan and Sauroposeidon.

I decided that the quick-and-dirty solution was to compare the vertebrae of A. louisae with those of Diplodocus carnegii, the default reference diplodocid, and see how they stacked up. With the cotyles scaled to the same vertical diameters, this is what we get for C9 and C10 of CM 3018 (lighter gray, background, traced from Gilmore 1936) vs CM 84/94 (darker gray, foreground, traced from Hatcher 1901):

The A. louisae verts are a hair taller, proportionally, than those of D. carnegii, but not by much. The difference is trivial compared to the differences in centrum length and cervical rib size.

So where did I get this apparently erroneous impression that Apatosaurus had giant neural spines? Maybe it’s not that the neural spines of apatosaurines in particular are so large, but rather than diplodocids of all types have large neural spines compared to non-diplodocids. Here are the same vertebrae compared for D. carnegii (dark gray, background) and Camarasaurus supremus (black, foreground, traced from Osborn and Mook 1921):

I deliberately picked the longest C9 in the AMNH collection, and the least-distorted C10. The first surprise for me was how well this C. supremus C9 hangs with D. carnegii in terms of proportions. That is one looooong Cam vert. In any other sauropod, it would probably be beautiful. But because it’s Camarasaurus it attained its length in the most lumpen possible way, with the diapophysis way up front, the neural spine apex way at the back, and in the middle just…more vertebra. Like a stretch limo made from a Ford Pinto, or Mike’s horrifying BOBA-horse.

Inevitable and entirely justified Cam-bashing aside, it’s striking how much smaller the whole neural arch-and-spine complex is in C. supremus than in D. carnegii. And remember that D. carnegii is itself a bit smaller than Apatosaurus, spine-wise. Is this maybe a diplodocoid-vs-macronarian thing, at least in the Morrison? Here’s the C10 stack with Brachiosaurus included, represented by BYU 12867 (which I think is probably a C10 based on both centrum proportions and neural spine shape – see Wedel et al. 2000b for details), and with labels added because it’s getting a little nuts:

I like this; it shows a lot. Here are some things to note:

  • The diplodocids don’t just have taller neural spines, their pre- and postzygapophyses are also higher than in the macronarians. That’s gotta mean something, right? All else being equal, putting the zygs farther from the intervertebral joints would reduce the flexibility of the neck. Maybe diplodocoids could get away with it because they had more cervicals, or maybe their necks were stiffened for some reason.
  • The zygs being set forward of their respective centrum ends in the macronarians really comes through here.
  • The Brachiosaurus vert isn’t that different from a stretched (and de-uglified) Cam vert, with a slightly higher neural spine to help support the longer neck. (Maybe this is why Cam inspires such visceral revulsion: it reads as a failed brachiosaur.)
  • This emphasizes the outlier status of Apatosaurus in the cervical rib department. It bears repeating: the cervical ribs of Camarasaurus are certainly wide, but they’re not nearly as massive or ventrally expanded as in apatosaurines.

So far, pretty interesting. I’d like to add Barosaurus and Haplocanthosaurus to round out the “big six” Morrison sauropods. I known Haplo has big, tall, almost apatosaurine neural spines (as shown above, with arrows highlighting the epipophyses), but for Baro I’d have to actually do the comparison to see where it falls out.

The idea of bringing in Barosaurus also forces the question, previously glossed over, of how legit it is to compare C10s of all these animals when their cervical counts differed. C. supremus is thought to have had 12 vertebrae in its neck, Brachiosaurus 13 (based on Giraffatitan), A. louisae and D. carnegii 15, and Barosaurus probably 16. It would be more informative to graph neural spine height divided by cotyle diameter along the column for all of these critters, plus Kaatedocus and Galeamopus. But that’s a lot of actual work, and as much fun as it sounds (really, I’d rather be doing that), I have summer teaching to prep for and field gear to wrangle. So I’ll have to revisit this stuff another time.

References

Last Wednesday, May 9, Brian Engh and I bombed out to Utah for a few days of paleo adventures. Here are some highlights from our trip.

We started at a Triassic tracksite on Thursday. But I’m not going to post any pictures of the tracks – those will be coming to a Brian Engh joint near you in the future. Instead, I’m going to talk about this little male collared lizard whose territory included the tracksite. He was fearless – didn’t want to run off and leave us yahoos wandering around his patch of desert unsupervised. Brian tickled his chin at one point.

Getting this close to him is how I got shots like this one:

Click through to the big version, it’s worth it.

One more shot of a couple of cool desert dwellers. I was so fixated on the lizard that I didn’t realize until later that Brian was in the frame, taking a much-needed hydration break.

On Friday we had a temporary breaking of the fellowship. I went to Fruita, Colorado, to visit the Dinosaur Journey museum. You’ve seen photos from DJ here before, from the 2014 Mid-Mesozoic Field Conference and the 2016 Sauropocalypse. Here’s an apatosaur pubis with some obvious bite marks on the distal end. This is on display next to a similarly-bitten ischium, which is shown in the MMFC14 post linked above.

Here’s a big apatosaur cervical, in antero-ventral view, with a dorsal rib draped over its left side. The cervical ribs are not fused in this specimen, so it was probably still growing. Here’s a labeled version:

The short centrum and nearly-vertical transverse processes indicate that this is a pretty posterior cervical, possibly a C13 or thereabouts. This specimen was over the fence in the exhibit area and I couldn’t throw a scale bar at it, but I’d describe it as “honkin'”. Like most of the apatosaur material at DJ, this vert is from the Mygatt-Moore Quarry.

Of course the real reason I was at Dinosaur Journey was to see the Snowmass Haplocanthosaurus that John Foster and I described back in 2014. You may remember that its caudal vertebrae have wacky neural canals. You may also have noticed a recent uptick in the number of posts around here about wacky neural canals. The game is afoot.

But as cool as they were, the Triassic tracks, the collared lizard, and even the Snowmass Haplo were only targets of opportunity. Brian and I had gone to Utah for this:

That photo was taken by Paige Wiren of Salt Lake City, on the day that she discovered that bone eroding out of a riverbank, just as you see it.

Here’s Paige with the element, which proved to be the left femur of an apatosaurine sauropod. It’s face down in these photos, so we’re looking at the medial side. The articular head is missing from the proximal end – it should be facing toward Paige’s right knee in the above photo – but other than that and a few negligible nicks and dings, the femur was complete and in really good shape.

Paige did the right thing when she found the femur: she contacted a paleontologist. Specifically, she asked a friend, who in turn put her in touch with Carrie Levitt-Bussian, the paleontology Collections Manager at the Natural History Museum of Utah. Based on Paige’s photos and maps, Carrie was able to identify the element as a dinosaur femur, probably sauropod, within the territory of the BLM Hanksville Field Office. John Foster, the Director of the Museum of Moab, has a permit to legally collect vertebrate fossils from that area, and he works on sauropods, so Carrie put Paige in touch with John and with ReBecca Hunt-Foster, the district paleontologist for the BLM’s Canyon Country District in Utah.

Now, I know there’s a lot of heated rhetoric surrounding the Bureau of Land Management, but whatever your political bent, remember this: those are our public lands. Therefore the fossils out there are the collective property of all of us, and we should all be upset if they get poached or vandalized. Yes, that is a big problem – the Brontomerus type quarry was partially poached before the bones we have now were recovered, and vandalism at public fossil sites in Utah made the national news while we were out there.

So that’s what we went to do: salvage this bone for science and education before it could be lost to erosion or asshats. Brian and I were out there to assist John, ReBecca, and Paige, who got to see her find come out of the ground and even got her hands dirty making the plaster jacket. Brian and John headed out to the site Friday morning and met up with Paige there, and ReBecca and I caravanned out later in the day, after I got back from Fruita.

But I’m getting ahead of myself a bit. We didn’t have to jacket the whole thing. It had naturally broken into three pieces, with thin clay infills at the breaks. So we just slid the proximal and middle thirds away as we uncovered them, and hit any loose-looking pieces with consolidant. The distal third was in more questionable shape, so we did make a partial jacket to hold it together.

We also got to camp out in gorgeous country, with spectacular (and welcome) clouds during the day and incredible starry skies at night.

We floated the femur out of the site using the Fosters’ canoe at the end of the day on Saturday, and loaded up to head back to Moab on Sunday. At one point the road was empty and the sky was not, so I stood on the center line and took some photos. This one is looking ahead, toward I-70 and Green River.

And this one is looking behind, back toward Hanksville.

Here are John and Brian with the femur chunks in one of the back rooms of the Museum of Moab. The femur looks oddly small here, but assembled it was 155 cm (5’1″) long and would have been 160 (5’3″) or more with the proximal head. Smaller than CM 3018 and most of the big mounted apatosaurs, but nothing to sneeze at.

What happens to it next? It will be cleaned, prepped, and reassembled by the volunteers and exhibit staff at the Museum of Moab, and eventually it will go on public display. Thousands of people will get to see and learn from this specimen because Paige Wiren made the right call. Go thou and do likewise.

That was the end of the road for the femur (for now), but not for Brian and me. We had business in Cedar City and St. George, so we hit the road Sunday afternoon. Waves of rainclouds were rolling east across Utah while we were rolling west, with breaks for sunlight in between. I miiiight have had to swerve a couple of times when all the scenery distracted me from driving, and I definitely made an obnoxious number of stops to take pictures.

I don’t remember which scenic overlook this was, but it was a pretty darned good view. This is another one that will reward embiggening – check out those mesas marching off into the distance.

In Cedar City we were guests of Andrew R.C. Milner, Site Paleontologist and Curator at the St. George Dinosaur Discovery Site at Johnson Farm (SGDS). We spent most of Monday at SGDS, getting our minds comprehensively blown by the amazing trace and body fossils on display. It was my first time visiting that museum, but it sure as heck won’t be the last.

I didn’t take nearly enough photos in St. George – too busy helping Brian do some filming for a future project – but I did get this gem. This is a Eubrontes track, from a Dilophosaurus-sized theropod. This is a positive track, a cast of the dinosaur’s foot made by sandy sediment that filled the natural mold formed when the dino stepped into mud. The high clay content of the mud recorded the morphology of the foot in fine detail, including the bumps of individual scales on the foot pads. The vertical streaks were cut into the side of the track by similar scales as the animal’s foot pushed into the mud.

The full story of the Johnson Farm tracks and trackmakers is beautifully told in the book Tracks in Deep Time: The St. George Dinosaur Discovery Site at Johnson Farm, by Jerry Harris and Andrew Milner. I hadn’t read it before, so I picked up a copy in the gift shop and I’ve been devouring it. As a professional scientist, educator, and book author myself, I’m jealous of what Jerry and Andrew produced – both the text and the abundant full-color illustrations are wonderfully clear, and the book is well-produced and very affordable.

From St. George we hit the road home, and rolled into Claremont just before midnight on Monday. It was a whirlwind tour – 1800 miles, three museums, and two fossil sites in six days – and my brain is still fizzing with all of the things we got to see and do.

One of the many pros of having a professional artist as a friend is that minimal hospitality, like letting him crash on my couch, is sometimes rewarded with original art. Brian was already gone when I got up Tuesday morning, but this was waiting for me on the dining room table. (Want your own? Help Brian make more monsters here.)

I owe plenty of thanks myself: to the Foster and Milner families for their near-maximal hospitality, to Julia McHugh of Dinosaur Journey for assistance in collections, to Diana Azevedo, Jalessa Spor, Jerry Harris, and the rest of the SGDS staff for being such gracious hosts, to Brian for being such a great friend and traveling companion, and most of all to Paige Wiren for finding the apato femur and helping us save it for science. You’re all top-notch human beings and I hope our paths cross again soon.

Back in the spring of 1998, Kent Sanders and I started CT scanning sauropod vertebrae. We started just to get a baseline for the Sauroposeidon project, but in time the data we collected formed the basis for my MS thesis, and for a good chunk of my dissertation as well. Mostly what we had available to scan was Morrison material. Between imperfect preservation, inexpert prep (by WPA guys back in the ’30s), and several moves over the decades, most of the verts from the Oklahoma Morrison have their neural spines and cervical ribs broken off. One of the first things I had to figure out was how to tell broken vertebrae of Camarasaurus from those of Apatosaurus (at the time; Brontosaurus is back in contention now). Here’s a thing I made up to help me sort out cervical centra of Camarasaurus and whatever the Oklahoma apatosaurine turns out to be. It’s a recent production, but it embodies stuff from my notebooks from 20 years ago. Should be useful for other times and places in the Morrison as well, given the broad spatiotemporal overlap of Camarasaurus and the various apatosaurines.

For a related thing in the same vein, see Tutorial 30: how to identify Morrison sauropod cervicals.

More elephant seals soon, I promise.

UPDATE 20 Feb 2018

Ken Carpenter sent this by email, with a request that I post it as a comment. Since it includes an image, I’m appending to the post, because it makes an important point that I neglected to mention.

Camar post cerv

Ken: Sorry, Matt. Not so easy. The last cervical of Camarasaurus from the Cleveland Lloyd Quarry is more apatosaurine-like than Camarasaurus-like based on your posting. Note the position of both zygapohyses with both ends of the centrum.

My response: Yes, good catch. I meant to say in the post that my distinguishing characters break down at the cervico-dorsal transition. Even so, in this Cleveland Lloyd vert the postzyg is still forward of a line drawn directly up from the cotyle. I’ve never seen that in an apatosaurine–going into the dorsal series, the postzygs tend to be centered over a line projected up from the rim of the cotyle. (If anyone knows of counterexamples, speak up!)

For distinguishing cervico-dorsals, apatosaurines tend to have much taller neural spines than Camarasaurus, and this carries on through the rest of the dorsal series. In apatosaurine dorsals, the height of the spine above the transverse processes always equals or exceeds the height of the arch below the transverse processes. In Camarasaurus, the height of the dorsal neural spines is always less than or equal to the height of the arch. The shapes of the spines are fairly different, too. Maybe that will be the subject of a future post.