December 23, 2014
Arriving as an early Christmas present, and coming in just a week before the end of what would otherwise have been a barren 2014, my paper Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs is out! You can read it on PeerJ (or download the PDF).
Yes, that posture is ludicrous — but the best data we currently have says that something like this would have been neutral for Diplodocus once cartilage is taken into account. (Remember of course that animals do not hold their necks in neutral posture.)
The great news here is that PeerJ moved quickly. In fact here’s how the time breaks down since I submitted the manuscript (and made it available as a preprint) on 4 November:
28 days from submission to first decision
3 days to revise and resubmit
3 days to accept
15 days to publication
TOTAL 49 days
Which of course is how it ought to be! Great work here from handling editor Chris Noto and all three reviewers: Matt Bonnan, Heinrich Mallison and Eric Snively. They all elected not to be anonymous, and all gave really useful feedback — as you can see for yourself in the published peer-review history. When editors and reviewers do a job this good, they deserve credit, and it’s great that PeerJ’s (optional) open review lets the world see what they contributed. Note that you can cite, or link to, individual reviews. The reviews themselves are now first-class objects, as they should be.
At the time of writing, my paper is top of the PeerJ home-page — presumably just because it’s the most recent published paper, but it’s a nice feeling anyway!
A little further down the front-page there’s some great stuff about limb function in ratites — a whole slew of papers.
Well, I’m off to relax over Christmas. Have a good one, y’all!
November 5, 2014
Last night, I submitted a paper for publication — for the first time since April 2013. I’d almost forgotten what it felt like. But, because we’re living in the Shiny Digital Future, you don’t have to wait till it’s been through review and formal publication to read it. I submitted to PeerJ, and at the same time, made it available as a preprint (Taylor 2014).
It’s called “Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs”, and frankly the results are weird. Here’s a taste:
A year back, as I was composing a blog-post about our neck-cartilage paper in PLOS ONE (Taylor and Wedel 2013c), I found myself writing down the rather trivial formula for the additional angle of extension at an intervertebral joint once the cartilage is taken into account. In that post, I finished with the promise “I guess that will have to go in a followup now”. Amazingly it’s taken me a year to get that one-pager written and submitted. (Although in the usual way of things, the manuscript ended up being 13 pages long.)
To summarise the main point of the paper: when you insert cartilage of thickness t between two vertebrae whose zygapophyses articulate at height h above the centra, the more anterior vertebra is forced upwards by t/h radians. Our best guess for how much cartilage is between the adjacent vertebrae in an Apatosaurus neck is about 10% of centrum length: the image above shows the effect of inserting that much cartilage at each joint.
And yes, it’s weird. But it’s where the data leads me, so I think it would be dishonest not to publish it.
I’ll be interested to see what the reviewers make of this. You are all of course welcome to leave comments on the preprint itself; but because this is going through conventional peer-review straight away (unlike our Barosaurus preprint), there’s no need to offer the kind of detailed and comprehensive comment that several people did with the previous one. Of course feel free if you wish, but I’m not depending on it.
Gilmore Charles W. 1936. Osteology of Apatosaurus, with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11:175–300 and plates XXI–XXXIV.
Stevens, Kent A., and J. Michael Parrish. 1999. Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284(5415):798–800. doi:10.1126/science.284.5415.798
Taylor, Michael P., and Mathew J. Wedel. 2013c. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs. PLOS ONE 8(10):e78214. 17 pages. doi:10.1371/journal.pone.0078214
August 21, 2014
I have often argued that given their long hindlimbs, massive tail-bases, and posteriorly-located centers of mass, diplodocids were basically bipeds whose forelimbs happened to reach the ground. I decided to see what that might look like.
Okay, now obviously I know that there are no trackways showing sauropods actually getting around like this. It’s just a thought experiment. But given how close the center of mass of Diplodocus is to the acetabulum, I’ll bet that this pose was achievable in life. If diplodocids had just pushed the CM a few cm farther back, they might have dispensed with forelimbs entirely, or done something different with them, like re-evolved grasping hands.
Image modified from Gilmore (1932: plate 6). Here’s a horizontal-necked bipedal Diplodocus and the original pose:
UPDATE the next day: I had forgotten that Niroot had already done a bipedal Apatosaurus, and a much more convincing one than mine. Go see it.
UPDATE the next week: Well, heck. Looks like the primary value of this post was so that people would remind me of all the other places the same idea has already been covered better. As you can see from the comment thread, Mike blogged about this at the WWD site, Scott Hartman drew it, and Heinrich Mallison showed that it was plausible. Sheesh, I suck.
- Gilmore, C. W. 1932. On a newly mounted skeleton of Diplodocus in the United States National Museum. Proceedings of the United States National Museum 81, 1-21.
This was inspired by an email Mike sent a couple of days ago:
Remind yourself of the awesomeness of Giraffatitan:
Now think of this. Its neck is 8.5m long. Knock of one measly meter — for example, by removing one vertebra from the middle of the neck — and you have 7.5 m.
Supersaurus’s neck was probably TWICE that long.
I replied that I was indeed freaked out, and that it had given me an idea for a post, which you are now reading. I didn’t have a Giraffatitan that was sufficiently distortion-free, so I used my old trusty Brachiosaurus. The vertebra you see there next to Mike and next to the neck of Brachiosaurus is BYU 9024, the longest vertebra that has ever been found from anything, ever.
Regarding the neck length of Supersaurus, and how BYU 9024 came to be referred to Supersaurus, here’s the relevant chunk of my dissertation (Wedel 2007: pp. 208-209):
Supersaurus is without question the longest-necked animal with preserved cervical material. Jim Jensen recovered a single cervical vertebra of Supersaurus from Dry Mesa Quarry in western Colorado. The vertebra, BYU 9024, was originally referred to “Ultrasauros”. Later, both the cervical and the holotype dorsal of “Ultrasauros” were shown to belong to a diplodocid, and they were separately referred to Supersaurus by Jensen (1987) and Curtice et al. (1996), respectively.
BYU 9024 has a centrum length of 1378 mm, and a functional length of 1203 mm (Figure 4-3). At 1400 mm, the longest vertebra of Sauroposeidon is marginally longer in total length [see this post for a visual comparison]. However, that length includes the prezygapophyses, which overhang the condyle, and which are missing from BYU 9024. The centrum length of the largest Sauroposeidon vertebra is about 1250 mm, and the functional length is 1190 mm. BYU 9024 therefore has the largest centrum length and functional length of any vertebra that has ever been discovered for any animal. Furthermore, the Supersaurus vertebra is much larger than the Sauroposeidon vertebrae in diameter, and it is a much more massive element overall.
Neck length estimates for Supersaurus vary depending on the taxon chosen for comparison and the serial position assumed for BYU 9024. The vertebra shares many similarities with Barosaurus that are not found in other diplodocines, including a proportionally long centrum, dual posterior centrodiapophyseal laminae, a low neural spine, and ventrolateral flanges that connect to the parapophyses (and thus might be considered posterior centroparapophyseal laminae, similar to those of Sauroposeidon). The neural spine of BYU 9024 is very low and only very slightly bifurcated at its apex. In these characters, it is most similar to C9 of Barosaurus. However, theproportions of the centrum of BYU 9024 are more similar to those of C14 of Barosaurus, which is the longest vertebra of the neck in AMNH 6341. BYU 9024 is 1.6 times as long as C14 of AMNH 6341 and 1.9 times as long as C9. If it was built like that of Barosaurus, the neck of Supersaurus was at least 13.7 meters (44.8 feet) long, and may have been as long as 16.2 meters (53.2 feet).
Based on new material from Wyoming, Lovelace et al. (2005 [published as Lovelace et al. 2008]) noted potential synapomorphies shared by Supersaurus and Apatosaurus. BYU 9024 does not closely resemble any of the cervical vertebrae of Apatosaurus. Instead of trying to assign its serial position based on morphology, I conservatively assume that it is the longest vertebra in the series if it is from an Apatosaurus-like neck. At 2.7 times longer than C11 of CM 3018, BYU 9024 implies an Apatosaurus-like neck about 13.3 meters
(43.6 feet) long.
Bonus comparo: BYU 9024 vs USNM 10865, the mounted Diplodocus longus at the Smithsonian, modified from Gilmore 1932 (plate 6). For this I scaled BYU 9024 against the 1.6-meter femur of this specimen.
If you’d like to gaze upon BYU 9024 without distraction, or put it into a composite of your own, here you go:
- Gilmore, C. W. 1932. On a newly mounted skeleton of Diplodocus in the United States National Museum. Proceedings of the United States National Museum 81, 1-21.
- Lovelace, David M., Scott A. Hartman and William R. Wahl. 2008. Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional, Rio de Janeiro, 65 (4): 527-544.
- Wedel, M.J. 2007. Postcranial pneumaticity in dinosaurs and the origin of the avian lung. PhD dissertation, University of California, Berkeley, Department of Integrative Biology, 303 pp.
June 18, 2014
Check out this beautiful Lego Diplodocus:
(Click through for the full image at full size.)
I particularly like the little touch of having of bunch of Lego Victorian gentleman scientists clustered around it, though they’re probably a bit too big for the skeleton.
This is the work of MolochBaal, and all rights are reserved. You can see five more views of this model in his Flickr gallery. I especially admire how he’s managed to get the vertebral transitions pretty smooth, the careful use of separate radius/ulna and tibia/fibula, and the use of a transparent brick in the skull to represent the antorbital fenestra.
The forefeet are wrong — their toes should not be splayed out — but you can’t blame MolochBaal for that, as he was copying the mounted CM 84/94 cast in the Madrid museum.
I need to be sleeping, not blogging, so here are just the highlights, with no touch-ups and minimal commentary.
I don’t know what these real street signs were doing sitting on the ground when I walked to the museum this morning, but it was a good omen for the conference.
Home base for this part of the conference. We head to Green River, Utah, on Friday for the Early Cretaceous half.
I had never seen this on exhibit. This is not the Brachiosaurus scapulocoracoid formerly referred to “Ultrasauros”, this is the other big scap from Dry Mesa, from the giant diplodocid Supersaurus.
This is not Dinosaur Baptist Church–it is a cathedral of an entirely different order.
And that order is Sauropoda.
The sauropod bones are entombed in a matrix consisting of super-hard sandstone and non-sauropod bits.
I got about 150 photos of the Wall, but only because I ran out of time. You probably already know what I’m going to attempt with them. (If not, here’s a hint.)
Jim Kirkland (center left) literally walked us through the Morrison and Cedar Mountain Formations at this set of exposures north of the visitor center. The reddish stuff on the lower left is Morrison, and after that it’s CMF all the way up this ridge and next two behind it.
A cast of Diplodocus carnegii at the Utah Field House of Natural History State Park Museum, signalling that we’ve come to end of this tail–er, tale.
Further updates as time and opportunity allow. If you tweet about the conference, please use #MMFC14!
March 1, 2014
Christine Argot of the MNHN, Paris, drew our attention to this wonderful old photo (from here, original caption reproduced below):
I found a different version of what seems to be the same photo (greyscaled, lower resolution, but showing more of the surrounding area) here:
What we have here is a truly bizarre mount of Diplodocus — almost certainly one of the casts of the D. carnegii holotype CM 84 — with perfectly erect, parasagittal hind-limbs, but bizarrely everted elbows.
There are a few mysteries here.
First, where and when was this photo taken? Christine’s email described this as a “picture of a Diplodocus cast taken in St. Petersburg around 1920″, and the caption above seems to confirm that location; but then why is it copyright the Paleontological Museum, Moscow? Since the web-site in question is for a Swedish museum, it’s not forthcoming.
The second photo is from the web-site of the Borisyak Paleontological Institute in Moscow, but that site unfortunately provides no caption. The juxtaposition with two more modern Diplodocus-skeleton photos that are from its own gallery perhaps suggest that the modern mount shown in the more recent photographs is a re-pose of the old mount in the black-and white photo. If so, that might mean that the skeleton was actually in Moscow all along rather than St. Petersburg, or perhaps that it was moved from St. Petersburg to Moscow and remounted there.
Does anyone know? Has anyone out there visited the St. Petersburg museum recently and seen whether there is still a Diplodocus skeleton there? If so, is it still mounted in this bizarre way? Better yet, do you have photos?
The second question of course is why was this posture used? This pose makes no sense for several reasons — one of which is that even if Diplodocus could attain this posture it would only serve to leave the forefeet under the torso in the same position as erect forelimbs would have them. The pose only makes any kind of sense at all if you imagine the animal lowering its torso to drink; but given that it had a flexible six-meter-long neck, that hardly seems necessary.
Of course Diplodocus does have a history of odd postures: because of the completeness of the D. carnegii holotype, it became the subject of the Sauropod Posture Wars between Tornier, Hay and Holland in the early 20th Century. Both Tornier (1909) and Hay (1910) favoured a sprawling posture like that of lizards (see images above and below), and were soundly refuted by Holland
But the Tornier and Hay postures bear no relation to that of the mounted skeleton in the photographs above: they position the forefeet far lateral to the torso, and affect the hindlimbs as well as the forelimbs. So whatever the Russian mount was doing, I don’t think it can have been intended as a representation of the Tornier/Hay hypothesis.
But it gets even weirder. Christine tells me that “I’m aware of […] the tests that Holland performed on the Russian cast to get rid of the hypothesis suggesting a potential lizard-like posture. So I think that he would have never allowed such a posture for one of the casts he mounted himself.” Now I didn’t know that Holland had executed the mounting of this cast. Assuming that’s right, it makes it even more inexplicable that he would have allowed such a posture.
Or did he?
Christine’s email finishes by asking: “What do you think? do you think that somebody could have come behind Holland to change the position? do you know any colleague or publication who could mention this peculiar cast and comment its posture?”
Can anyone help?
- Hay, Oliver. P. 1910. On the manner of locomotion of the dinosaurs, especially Diplodocus, with remarks on the origin of birds. Proceedings of the Washington Academy of Sciences 12(1):1-25.
- Holland, W. J. 1910. A review of some recent criticisms of the restorations of sauropod dinosaurs existing in the museums of the United States, with special reference to that of Diplodocus carnegiei in the Carnegie museum. American Naturalist 44:259-283.
- Nieuwland, Ilja. 2010. The colossal stranger. Andrew Carnegie and Diplodocus intrude European Culture, 1904–1912. Endeavour 34(2):61-68.
- Tornier, Gustav. 1909. Wie war der Diplodocus carnegii wirklich gebaut? Sitzungsbericht der Gesellschaft naturforschender Freunde zu Berlin 4:193– 209.