Hello, ladies!
March 28, 2019
To my shock, I find that we seem never to have posted Bob Nicholls’ beautiful sketch Hello, ladies! on SV-POW!. His recent tweet reminded me about this piece, so here it is!
Like so many classic sauropod sketches, this was executed during a mammal-tooth talk at SVPCA: this one back in 2013, the year of our first Barosarus talk. (Our second was in 2016.)
Bob’s sketch shows speculative sexual display behaviour. We have no direct evidence for (or against) such behaviour; but while we don’t believe sexual selection was the main reason for sauropods evolving long necks, it seems inevitable that long necks evolved for other purposes would be exapted for sexual display.
I always love Bob’s sketches — in fact, for most palaeoartists, I tend to like their sketches more than their finished pieces. Among the many things about this one that make me jealous is all the females in the background admiring the male: the economy of line where Bob can not only summon up a perfectly cromulent diplodocid head in a few strokes, but imbue it with a sense of being inquisitive about the display. It’s magical.
Whatever happened to that 2013 Barosaurus project?, you may ask.
Well, the first thing that happened is that after we submitted the abstract, entitled Barosaurus revisited: the concept of Barosaurus (Dinosauria: Sauropoda) is based on erroneously referred specimens, we realised that there was a tiny, tiny mistake in our work. So by the time I gave the talk at the actual conference, the title slide was this:
Then you will recall we did an efficient job of converting the conference presentation into a manuscript, which we submitted as a preprint less than a month after the conference. The preprint quickly garnered amazingly helpful comments, which we used to extensively revise the manuscript.
For reasons we don’t understand, there was a three-year delay before we got it submitted for peer-review in 2016; but when we did finally submit, we did it in the confident hope that it would sail through peer-review, having already been extensively reviewed and revised.
But it was not to be. When we got the reviews back, they asked for a ton of changes, and that process was just too dispiriting to face having already made a ton of changes based on the first set of comments just prior to the submission. So the tedious process got back-burnered, and the suddenly three more years passed.
The upshot is that I still need to handle the reviews on the 2nd version of the paper, and shove the blasted thing through the peer-review process. I will, to be frank, be glad to get it out of my POOP chute, so I can think about other things — not least, the 2016 Barosaurus project.
Walking around the mounted skeleton of Apatosaurus louisae
March 22, 2019
In case you haven’t gotten to do this, or need a refresher, or just want a little more Apatosaurus in your life. And honestly, who doesn’t? As with the previous Diplodocus walk-around, there’s no narration, just whatever ambient sound reached the mic. Go have fun.
How our week at the Carnegie Museum went
March 17, 2019
In a word, amazingly. After 6 days (counting public galleries last Sunday), 4300 photos, 55 videos, dozens of pages of notes, and hundreds of measurements, we’re tired, happy, and buzzing with new observations and ideas.
We caught up with some old friends. Here Mike is showing an entirely normal and healthy level of excitement about meeting CM 584, a specimen of Camarasaurus from Sheep Creek, Wyoming. You may recognize this view of these dorsals from Figure 9 in our 2013 PeerJ paper.
We spent an inordinate amount of time in the public galleries, checking out the mounted skeletons of Apatosaurus and Diplodocus (and Gilmore’s baby Cam, and the two tyrannosaurs, and, and…).
I had planned a trip to the Carnegie primarily to have another look at the Haplocanthosaurus holotypes, CM 572 and CM 879. I was also happy for the chance to photograph and measure these vertebrae, CM 36034, which I think have never been formally described or referred to Haplocanthosaurus. As far as I know, other than a brief mention in McIntosh (1981) they have not been published on at all. I’m planning on changing that in the near future, as part of the larger Haplocanthosaurus project that now bestrides my career like a colossus.
The real colossus of the trip was CM 555, which we’ve already blogged about a couple of times. Just laying out all of the vertebrae and logging serial changes was hugely useful.
Incidentally, in previous posts and some upcoming videos, we’ve referred to this specimen as Brontosaurus excelsus, because McIntosh (1981) said that it might belong to Apatosaurus excelsus. I was so busy measuring and photographing stuff that it wasn’t until Friday that I realized that McIntosh made that call because CM 555 is from the same locality as CM 563, now UWGM 15556, which was long thought to be Apatosaurus excelsus but which is now (i.e., Tschopp et al. 2015) referred to Brontosaurus parvus. So CM 555 is almost certainly B. parvus, not B. excelsus, and in comparing the specimen to Gilmore’s (1936) plates of CM 563, Mike and I thought they were a very good match.
Finding the tray of CM 555 cervical ribs was a huge moment. It added a ton of work to our to-do lists. First we had to match the ribs to their vertebrae. Most of them had field numbers, but some didn’t. Quite a few were broken and needed to be repaired – that’s what I’m doing in the above photo. Then they all had to be measured and photographed.
It’s amazing how useful it was to be able to reassociate the vertebrae with their ribs. We only did the full reassembly for c6, in part because it was the most complete and perfect of all of the vertebrae, and in part because we simply ran out of time. As Mike observed in his recent post, it was stunning how the apatosaurine identity of the specimen snapped into focus as soon as we could see a whole cervical vertebra put back together with all of its bits.
We also measured and photographed the limb bones, including the bite marks on the radius (above, in two pieces) and ulna (below, one piece). Those will of course go into the description.
And there WILL BE a description. We measured and photographed every element, shot video of many of them, and took pages and pages of notes. Describing even an incomplete sauropod skeleton is a big job, so don’t expect that paper this year, but it will be along in due course. CM 555 may not be the most complete Brontosaurus skeleton in the world, but our ambition is to make it the best-documented.
In the meantime, we hopefully left things better documented than they had been. All of the separate bits of the CM 555 vertebrae – the centra, arches, and cervicals ribs – now have the cervical numbers written on in archival ink (with permission from collections manager Amy Henrici, of course), so the next person to look at them can match them up with less faffing about.
We have people to thank. We had lunch almost every day at Sushi Fuku at 120 Oakland Avenue, just a couple of blocks down Forbes Avenue from the museum. We got to know the manager, Jeremy Gest, and his staff, who were unfailingly friendly and helpful, and who kept us running on top-notch food. So we kept going back. If you find yourself in Pittsburgh, check ’em out. Make time for a sandwich at Primanti Bros., too.
We owe a huge thanks to Calder Dudgeon, who took us up to the skylight catwalk to get the dorsal-view photos of the mounted skeletons (see this post), and especially to Dan Pickering, who moved pallets in collections using the forklift, and moved the lift around the mounted skeletons on Tuesday. Despite about a million ad hoc requests, he never lost patience with us, and in fact he found lots of little ways to help us get our observations and data faster and with less hassle.
Our biggest thanks go to collections manager Amy Henrici, who made the whole week just run smoothly for us. Whatever we needed, she’d find. If we needed something moved, or if we needed to get someplace, she’d figure out how to do it. She was always interested, always cheerful, always helpful. I usually can’t sustain that level of positivity for a whole day, much less a week. So thank you, Amy, sincerely. You have a world-class collection. We’re glad it’s in such good hands.
What’s next? We’ll be posting about stuff we saw and learned in the Carnegie Museum for a long time, probably. And we have manuscripts to get cranking on, some of which were already gestating and just needed the Carnegie visit to push to completion. As always, watch this space.
References
- McIntosh JS. 1981. Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the collections of Carnegie Museum of Natural History. Bulletin of Carnegie Museum of Natural History 18:1-67
- (2015) A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda) PeerJ3:e857 https://dx.doi.org/10.7717/peerj.857
Walking around the mounted skeleton of Diplodocus carnegii
March 17, 2019
This is what it’s like. The lack of narration is deliberate. We have other videos, which we’ll post at other times, with lots of yap. This one is just for reference, in case later on we need to know what the ischia look like in posterior view, or how the scapulocoracoid is curved, or whatever.
The Apatosaurus louisae walk-around video will be up in the near future. And a similar thing for both skeletons from the second floor balcony. Watch this space!
Everything’s better with cervical ribs
March 15, 2019
You’ll remember that we’ve been playing with CM 555, a subadult apatosaurine of indeterminate species, though John McIntosh assigned it to Brontosaurus (then Apatosaurus) excelsus. At the start of the week, we had the centra and neural arches of cervicals 1-14, plus there were some appendicular elements on a shelf that we’d not yet gone to. But then today, Matt found this drawer:
It contained a nice selection of cervical ribs that were part of the same specimen. Jackpot!
[You might notice that some of them have the specimen number 584 written on them. The history is that CM 555 and CM 584 came out of the same quarry, but most of the bones were initially thought to belong to a camarasaur which was designated CM 584. John McIntosh (1981:25) identified them as belonging to an apatosaurine, and they are now considered to be part of CM 555. The limb bones are catalogued separately as CM 556, but recognised as likely belonging to the same individual.]
Most of these ribs had field numbers written on them which were able to use to associate them with individual cervicals; and those that lacked these numbers, we could associate anyway, because the options were limited to a relatively small number of gaps. The upshot is that we know which vertebra each of these belongs to.
We have both ribs of C6, which is probably the best preserved single vertebra — centrum and arch — so I was able to rebuild the vertebra from its component parts. Matt was impressed:
And to be fair, I was pretty darned impressed myself:
Truly, this is a beautiful specimen. It was already pretty lovely, but putting the cervical ribs in place changed everything. It was totally transformed from a nice diplodocid cervical to an absolutely rock-solid slam-dunk apatosaurine — one to make grown men weep.
Here it is in right posterolateral view, just generally being awesome.
References
- McIntosh, John S. 1981. Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the collections of Carnegie Museum of Natural History. Bulletin of the Carnegie Museum 18:1–67.
Neck ontogeny in Tyrannosaurus rex
March 14, 2019
Having spent much of the last few days playing with the cervical vertebrae of a subadult apatosaur, and trying to make sense of those of the mounted adult, neck ontogeny is much on our minds. Here’s an example from the less charismatic half of Saurischia.
I was forcibly struck, when seeing a cast of Jane the juvenile Tyrannosaurus in the museum gift-shop, by how weedy its neck is:
This being the Carnegie Museum, it was with us the work of a moment to scoot across to the Cretaceous gallery and compare with the neck of an adult, CM 9380:
As you can see, the transformation of the neck is every bit as dramatic as that of the skull, as a slender animal optimised for pursuit grows into a total freakin’ monster.
Someone ought to quantify this. I’m talking to you, theropod workers! (We’ll be busy over here with sauropods.)
Here are the full, uncropped and uncorrected, versions of the photos that I extracted the above from:
This is truly a magnificent museum.
Mounted sauropods in dorsal view!
March 13, 2019
Mike’s and Matt’s excellent adventure in Pittsburgh continues! Today was Day 4, and just as yesterday offered us a unique opportunity to see the mounted Dipodocus and Apatosaurus skeletons up close on a lift, so today we got to look the two mounts from directly above!
Thanks to our host Amy Henrici and to Calder Dudgeon, we were able to go up to the maintenance balconies above the dinosaur hall, and from there we were able to see this:
It was a little bit scary up there: here’s Matt’s vertical panorama photo of me. Just below the balcony I’m standing on you can see another, which is actually far below up but further back. Below that is the main balcony that overlooks the hall. And below that, the hall itself, showing Diplodocus from above:
We think this is a first: we don’t know of any published photos of mounted sauropods from above — but now, there are some. Let’s take a closer look at the torsos:
Diplodocus carnegii holotype CM 84, torso, in dorsal view, anterior to right.
Apatosaurus louisae holotype CM 3018, torso, in dorsal view, anterior to left.
You can immediately see from here that Apatosaurus is a much broader animal than Diplodocus. That much, we could have guessed. What’s more interesting is that Apatosaurus seems to be slightly broader at the shoulders than at the hips, whereas the opposite is the case in Diplodocus.
This observation left us wondering what’s known about the relative widths of the forelimb and hindlimb articulations in extant animals. What, from the modern bestiary, has hips broader than its shoulders, and what has shoulders wider than its hips? We have no idea. Does anyone know if this has been studied, or better yet summarised?
Four huge beasts
March 13, 2019
Left to right: Allosaurus fragilis, Apatosaurus louisae, Homo sapiens, Diplodocus carnegii.
Derrrrr
March 13, 2019
Separated at birth.
Left: Apatosaurus lousiae holotype CM 2018, cast skull associated with specimen. Right: Matt Wedel. Scientists have long wondered how such a bloated beast could etc. etc.
Behold! The glory that is CM 555
March 12, 2019
Matt and I have completed Day 2 of our excursion to the Carnegie Musuem in Pittsburgh. Day 1 was spent in the public galleries, because collections aren’t open on Sunday, but today we got into the Big Bone room.
One of our targets was CM 555, a very nice nearly complete neck (C1-C14) from a subadult apatosaurine — quite possibly Brontosaurus excelsus, which is what John McIntosh catalogued it as, though I am not yet 100% convinced it’s the same thing as YPM 1980, the holotype of that species.
We were able to lay out the full sequence on the floor, on styroforam sheets, and spend quality time just looking at it and thinking about it. I don’t just mean documenting it for later analysis, but making use of that precious time right there with the physical specimen to think through together what it’s telling us. We have a bunch of new insights, which we’ll share when we’re not completely exhausted.
Here’s Matt with the first six cervicals. C1 (the atlas) is as usual an unprepossessing lump, but then things get interesting. C2 to C6 are all unfused, so the centra and neural arches are separate.
Behind C6, the arches are fused to the centra (though the fusion lines are still apparent in C7 and C8). This is a nice example of how, in sauropods, serial position recapitulates ontogeny — one of the great confounding factors when studying isolated vertebrae.
We’ve learned a lot already from CM 555. Tomorrow will be spent with the two big mounted diplodocids (Diplodocus carnegii CM 84 and Apatosaurus louisae CM 3018). We’ll let you know how it goes. I predict: awesome.
Sauropod Vertebra Picture of the Week 