Revising a poster
September 14, 2017
Yesterday, Matt and I showed our posters in a two-hour session at SVPCA, as two of about thirty. It was actually a hugely positive experience, and it’s left me wondering whether to prefer posters to talks at future conferences — one of us will write about it separately
My poster (left) and Matt’s (right), in their natural environment. Phil Mannion (Mammalia: Primates: Homoninae) for scale.
But it was eye-opening to road-test what I’d thought was a pretty good poster with real visitors. I quickly realised that the “Biconcavoposeidon” poster was missing two important things.
First, there’s an insert that shows schematic views of amphiplatyan, opisthocoelous, procoelous and amphicoelous vertebra. But it should show two or three of each kind of vertebra, in articulation, so that the insert shows not only the isolated shapes, but how they fit together (or how, in the case of biconcave centra, they do not fit together.)
The second problem: another insert shows — again in schematic form — how vertebrae articulate in amphibians and mammals. But I really needed a third part of that figure showing how the articulation works in birds. I kept needing to point to such an illustration, and I didn’t have one.
But all is not lost: I am not bound to an imperfect poster for all time. The poster is published as part of a PeerJ Preprint, and I can revise that preprint as often as I like. Which means I can revise the poster.
And that is what I plan to do. I’ll make both of the changes described above, and update the published version. The question then becomes: in my publications list, where the poster is explicitly tied to the presentation at SVPCA 2017, should I continue to point to the version that I actually used at the meeting? I am inclined to think so.
But wait: there’s more.
It turned out at the conference that Matt was right when he advised me that I should have made the anaglyph bigger, and placed it at the top of the poster, at eye-level. Instead, I had a sequence of visitors who had to painfully kneel down and peer myopically at the small, low-down version that I used. (Or, more often, they didn’t bother looking at the anaglyph at all — which is a shame, because it’s really informative.)
(Seriously, folks: buy yourself some dirt-cheap red/cyan glasses, and start making use of these incredibly useful, and very simple-to-make, visuals. Everyone who looked at the anaglyph, without exception, was startled at how much more informative it was than the regular image.)
But I am not going to re-organise the poster along those lines in the forthcoming revision. Why not? Because I don’t expect to present the new version at a conference, where eye-level is an issue. Instead, I expect it to stand as a research artefact in its own right, to be viewed on screens or printouts — and for those purposes, the present composition is better. That’s true especially because most people downloading the poster won’t have the red/cyan glasses necessary to view what would be centrepiece of the putative revision; but when presenting the poster at a conference, I can provide the glasses (and I did).
So I think I have now landed on the notion that a poster as a research artefact is a fundamentally different thing from a poster for presentation at a conference. I didn’t see that coming.
The “Biconcavoposeidon” poster is published
September 8, 2017
If you don’t get to give a talk at a meeting, you get bumped down to a poster. That’s what’s happened to Matt, Darren and me at this year’s SVPCA, which is coming up next week. My poster is about a weird specimen that Matt and I have been informally calling “Biconcavoposeidon” (which I remind you is not a formal taxonomic name).
Here it is, for those of you who won’t be at the meeting (or who just want a preview):
But wait — there’s more. The poster is now also formally published (Taylor and Wedel 2017) as part of the PeerJ preprint containing the conference abstract. It has a DOI and everything. I’m happy enough about it that I’m now citing it in my CV.
Do scientific posters usually get published? Well, no. But why not? I can’t offhand think of a single example of a published poster, though there must be some out there. They are, after all, legitimate research artifacts, and typically contain more information than published abstracts. So I’m happy to violate that norm.
Folks: it’s 2017. Publish your posters.
References
- Taylor, Michael P., and Mathew J. Wedel. 2017. A unique Morrison-Formation sauropod specimen with biconcave dorsal vertebrae. p. 78 in: Abstract Volume: The 65th Symposium on Vertebrate Palaeontology and Comparative Anatomy & The 26th Symposium on Palaeontological Preparation and Conservation. University of Birmingham: 12th–15th September 2017. 79 pp. PeerJ preprint 3144v2. doi:10.7287/peerj.preprints.3144v2/supp-1
“Biconcavoposeidon”
August 15, 2017
Here is a fascinating sequence of five consecutive posterior dorsal vertebra — AMNH FARB 291 from the”Big Bone Room” at the AMNH:
AMNH FARB 291, five consecutive posterior dorsal vertebrae of a probably brachiosaurid sauropod, in right lateral view. The vertebrae are embedded in a plaster block, which has been desaturated in this image.
Matt and I first saw this specimen back in February 2009, when we were mostly there to look at “Apatosarus” minimus (and then again in 2012). As soon as our eyes lit on it, we couldn’t help but be captivated by its bizarre biconcave centra. We immediately started flippantly referring to it as “Biconcavoposeidon” — the ugliest name we could come up with — and in our subsequent discussions the name has stuck (often abbreviated to “BCP”).
- Taxonomic note: for avoidance of doubt, “Biconcavoposeidon” is not and will never be a formal taxonomic name, only an informal specimen nickname. If at some future point we conclude that this specimen represents a new taxon, and name it, we will definitely not use the name “Biconcavoposeidon”. If you ever use the name, please do not set it in italics.
As you can see in this front view, the specimen is sheared: the upper part of the vertebrae have been displaced to their left (which is the right as we see it in this image):
AMNH FARB 291, most anterior of five consecutive posterior dorsal vertebrae of a probably brachiosaurid sauropod, in anterior view.
Apart from the shearing, though, and the truncation of the neural spines shortly above the transverse processes, the specimen is in pretty good nick. Crucially, it’s not been “restored” in plaster to conceal what is and is not real bone — unlike many specimens of that era. It came out of the Bone Cabin quarry in 1898, back when scientific information was routinely discarded in order to obtain a more beautiful-looking specimen.
This is the specimen that I’ll be presenting at SVPCA this year — though only as a poster, unfortunately: there’s no talk for me, Matt or Darren this year. We’ve posted our abstract (including the illustration above) to the nascent PeerJ collection for SVPCA 2017, and we’re looking forward to seeing more of the materials from that conference — abstracts, then manuscripts, then papers — appearing in the collection.
So far as we know, there’s no other sauropod specimen with biconcave posterior dorsal vertebrae. (And, no, Amphicoelias is not an exception, despite its name.) But have we missed any?
Some further thoughts on Patagotitan
August 10, 2017
A bunch of stuff, loosely organized by theme.
Media
First up, I need to thank Brian Switek, who invited me to comment on Patagotitan for his piece at Smithsonian. I think he did a great job on that, arguably the best of any of the first-day major media outlet pieces. And it didn’t go unnoticed – his article was referenced at both the Washington Post and NPR (and possibly other outlets, those are the two I know of right now). I don’t think my quotes got around because they’re particularly eloquent, BTW, but rather because reporters tend to like point-counterpoint, and I was apparently the most visible counterpoint. They probably would have done the same if I’d been talking complete nonsense (which, to be fair, some people may think I was).
Paleobiology vs Records
The most commonly reproduced quote of mine is this one, originally from Brian’s piece:
I think it would be more accurate to say that Argentinosaurus, Puertasaurus and Patagotitan are so similar in size that it is impossible for now to say which one was the largest.
That may seem at odds with the, “Well, actually…[pushes glasses up nose]…Argentinosaurus was still biggest” tack I’ve taken both in my post yesterday and on Facebook. So let me elaborate a little.
There is a minor, boring point, which is that when I gave Brian that quote, I’d seen the Patagotitan paper, but not the Electronic Supplementary Materials (ESM), so I knew that Patagotitan was about the same size as the other two (and had known for a while), but I hadn’t had a chance to actually run the numbers.
The much more interesting point is that the size differences between Argentinosaurus, Puertasaurus, and Patagotitan are astonishingly small. The difference between a 2.5m femur and a 2.4m one is negligible, ditto for vertebrae with centra 59cm and 60cm in diameter. OMNH 1331, the biggest centrum bit from the giant Oklahoma apatosaur, had an intact max diameter of 49cm, making it 26% larger in linear terms than the next-largest apatosaur. The centra of these giant South American titanosaurs are more than 20% bigger yet than OMNH 1331, just in linear terms. That’s crazy.
It’s also crazy that these three in particular – Argentinosaurus, Puertasaurus, and Patagotitan – are so similar in size. Dinosaur developmental programs were ‘messy’ compared to those of mammals, both in having weird timings for things like onset of reproduction, and in varying a lot among closely related taxa. Furthermore, sauropod population dynamics should have been highly skewed toward juveniles and subadults. So is the near-equality in size among Argentinosaurus, Puertasaurus, and Patagotitan just a coincidence, or does it mean that something weird was going on? There’s really no third option. I mean, even if some kind of internal (biomechanical or physiological) or external (ecological, food or predation) constraint forced those three to the same adult body size, it’s weird then that we’re finding only or at least mostly near-max-size adults. (If the available specimens of these three aren’t near-max-size, then any hypothesis that they’re forced to the same size by constraints is out the window, and we’re back to coincidence.)
BUT
With all that said, the title of “world’s largest dinosaur” is not handed out for effort expended, number of specimens collected, skeletal completeness, ontogenetic speculation, or anything other than “the dinosaur with the largest measured elements”. And that is currently Argentinosaurus. So although for any kind of paleobiological consideration we can currently consider Argentinosaurus, Puertasaurus, and Patagotitan to all be about the same size – and Alamosaurus, Paralititan, Notocolossus, and probably others I’ve forgotten should be in this conversation – anyone wanting to dethrone Argentinosaurus needs to actually show up with bigger elements.
So, if you’re interested in paleobiology, it’s fascinating and frankly kind of unnerving that so many of these giant titanosaurs were within a hand-span of each other in terms of size. Patagotitan is one more on the pile – and, as I said yesterday, exciting because it’s so complete.
But if you want to know who holds the crown, it’s still Argentinosaurus.
Humeri
In a comment on the last post, Andrea Cau made an excellent point that I am just going to copy here entire:
Even Paralititan stromeri humerus is apparently larger than Patagotitan humerus (169 cm vs 167.5 cm). I know humerus length alone is bad proxy of body size, but at least this shows that even in that bone Patagotitan is just another big titanosaur among a well known gang of titans, not a supersized one.
That made me want to start a list of the longest sauropod humeri. Here goes – if I missed anyone or put down a figure incorrectly, I’m sure you’ll let me know in the comments.
- Giraffatitan: 213cm
- Brachiosaurus: 203cm
- Ruyangosaurus: 190cm (estimated from 135cm partial)
- Turiasaurus: 179cm
- Notocolossus: 176cm
- Paralititan: 169cm
- Patagotitan: 167.5cm
- Dreadnoughtus: 160cm
- Futlognkosaurus: 156cm
Admittedly the Patagotitan humerus is from a paratype and not from the largest individual, but that is true for some others on the list, including Giraffatitan. And we have no humeri from Argentinosaurus, Puertasaurus, and some other giants.
Dorsal Vertebrae
A couple of further thoughts on how the dorsal vertebrae of Patagotitan compare to those of Argentinosaurus. First, now that I’ve had some time to think about it, I have a hard time seeing how the dorsal polygon method used by Carballido et al. in the Patagotitan paper has any biological meaning. In their example figure, the polygon around the Puertasaurus vertebra is mostly full of bone, and the one around Patagotitan has a lot of empty space. It’s easy to imagine an alternative metric, like “area of the minimum polygon actually filled by bone”, that would lead to a different ‘winner’. But that wouldn’t mean much, either.
Something that probably does have a real and important biomechanical meaning is the surface area of the articular face of the centrum, because that’s the area of bone that has to bear the compressive load, which is directly related to the animal’s mass. The biggest Patagotitan centrum is that of MPEF-PV 3400/5, which is at least a local maximum since has smaller centra both ahead and behind. The posterior face measures 59cm wide by 42.5cm tall. Abstracted as an ellipse, which may not be perfectly accurate, those measurements give a surface area of (pi)(29.5)(21.25)=1970 cm^2. For Argentinosaurus, the largest complete centrum has a posterior face measuring 60cm wide by 47cm tall (Bonaparte and Coria 1993: p. 5), giving an elliptical surface area of (pi)(30)(23.5)=2210 cm^2. (I’d use hi-res images of the centra to measure the actual surface areas if I could, but AFAIK those images either don’t exist or at least have not yet been made public, for either taxon.) So although the Argentinosaurus dorsal seems like it is only a bit bigger in linear terms, it’s 12% larger in surface area, and that might actually be a meaningful difference.
Cervical Vertebrae
One thing I haven’t commented on yet – Patagotitan is the newest member of the “world’s longest vertebrae” club. The longest Patagotitan cervical, MPEF-PV 3400/3, is listed in the ESM as having a centrum length of 120cm, but it’s also listed as incomplete. In the skeletal recon in the paper, the centrum is colored in as present, but the neural spine is missing. So is the centrum complete in terms of length? I don’t think it’s clear right now.
Anyway, here’s the current rundown of the longest cervical centra of sauropods (and therefore, the longest vertebrae among animals):
- BYU 9024, possibly referable to Supersaurus or Barosaurus: 137cm
- Price River 2 titanosauriform: 129cm
- OMNH 53062, Sauroposeidon holotype: 125cm
- KLR1508-77-2, Ruyangosaurus giganteus referred specimen: 124cm
- MPEF-PV 3400/3, Patagotitan holotype: 120cm (+?)
- MPM 10002, Puertasaurus holotype: 118cm
You may be surprised to see the Price River 2 cervical in there. It was reported in an SVP abstract a few years ago (I’ll dig up that ref and update this post), and Mike and I saw it last year on the Sauropocalypse. We measured the centrum at 129cm, making it just a bit longer than the longest centrum of Sauroposeidon, and therefore the second-longest vertebra of anything ever.
Aside – I’m probably getting a reputation as a big ole meanie when it comes to debunking “world’s largest dinosaur” claims. If I’m willing to take the lead in kicking my own dinosaur down the ladder, don’t expect me to be kind to yours. I follow where the numbers lead.
Now, here’s an interesting thing – now that Sauroposeidon is coming out as a basal titanosaur, rather than a brachiosaur, it might not have been a skinny freak. The 120cm cervical of Patagotitan makes the 125cm cervical of Sauroposeidon and the 129cm cervical from Price River 2 look even more tantalizing. Maybe it’s super-giant sauropods all the way down.
Two new sauropods in PeerJ today: Galeamopus pabsti (sp. nov) and Vouivria damparisensis (gen. et sp. nov.)
May 2, 2017
The best-preserved presacral vertebra of Vouivria damparisensis (Mannion et al. 2017: fig. 10).
New goodies out today in PeerJ: Tschopp and Mateus (2017) on the new diplodocid Galeamopus pabsti, and Mannion et al. (2017) redescribe and name the French ‘Bothriospondylus’ as Vouivria damparisensis.
C7 of Galeamopus pabsti (Tschopp and Mateus 2017: fig. 24).
Both papers are packed with interesting stuff that I simply don’t have time to discuss right now. Possibly Mike and I will come back with subsequent posts that discuss these critters in more detail. We both have a connection here besides our normal obsession with well-illustrated sauropods – Mike reviewed the Galeamopus paper, and I reviewed Vouivria. Happily, both sets of authors chose to publish the peer-review histories, so if you’re curious, you can go see what we said.
For now, I’ll just note that C7 of Galeamopus pabsti, shown above, is intriguingly similar in form to Vertebra ‘R’ of YPM 429, the ‘starship’ Barosaurus cervical (illustrated here). Mike and I spent a lot of time puzzling over the morphology of that vert before we convinced ourselves that much of its weirdness was due to taphonomic distortion and a restoration and paint job that obscured the fact that the metapophyses were missing. Given our ongoing project to unravel the wacky morphology of Barosaurus, I’m looking forward to digging into the morphology of G. pabsti in more detail.
I’ll surely irritate Mike by saying this, but my favorite figure in either paper is this one, Figure 4 from Tschopp and Mateus (2017). I can’t remember ever seeing an exploded skull diagram like this for a sauropod before, but it’s extremely helpful and I love it.
And that’s all for now. Go read these papers – they’re both substantial contributions with intriguing implications for the evolution of their respective clades. Congratulations to both sets of authors for producing such good work.
References
- (2017) The earliest known titanosauriform sauropod dinosaur and the evolution of Brachiosauridae. PeerJ 5:e3217 https://doi.org/10.7717/peerj.3217
- (2017) Osteology of Galeamopus pabsti sp. nov. (Sauropoda: Diplodocidae), with implications for neurocentral closure timing, and the cervico-dorsal transition in diplodocids. PeerJ 5:e3179 https://doi.org/10.7717/peerj.3179
A quick stop at the Oklahoma Museum of Natural History
December 21, 2016
I’m back in Oklahoma for the holidays, and anytime I’m near Norman I pop in to the OMNH to see old friends, both living and fossil. Here’s the Aquilops display in the hall of ancient life, which has been up for a while now. I got some pictures of it when I was here back in March, just never got around to posting them.
Aquilops close up. You can’t see it well in this pic, but on the upper right is a cast of the Aquilops cranium with a prosthesis that shows what the missing bits would have looked like. That prosthesis was sculpted by – who else? – Kyle Davies, the OMNH head preparator and general sculpting/molding/casting sorceror. You’ve seen his work on the baby apatosaur in this post. I have casts of everything shown here – original fossil, fossil-plus-prosthesis, and reconstructed 3D skull – and I should post on them. Something to do in the new year.
The Aquilops display is set just opposite the Antlers Formation exhibit, which has a family of Tenontosaurus being menaced by two Deinonychus, and at the transition between Early and Late Cretaceous. The one mount in the Late Cretaceous area is the big Pentaceratops, which is one of the best things in this or any museum.
Evidence in support of that assertion. Standing directly in front of this monster is a breathtaking experience, which I highly recommend to everyone.
It’s just perfect that you can see the smallest and earliest (at least for now) North American ceratopsian adjacent to one of the largest and latest. Evolution, baby!
I didn’t only look at dinosaurs – the life-size bronze mammoth in the south rotunda is always worth a visit, especially in holiday regalia.
No holiday post about the OMNH would be complete without a shot of “Santaposeidon” (previously seen here). I will never get tired of this!
The chances that I’ll get anything else posted in 2016 hover near zero, so I hope you all have a safe and happy holiday season and a wonderful New Year.
How horrifying was the neck of Barosaurus?
September 16, 2016
Suppose that I and Matt were right in our SVPCA talk this year, and the
“Supersaurus” cervical BYU 9024 really is the C9 of a gigantic Barosaurus. As we noted in our abstract, its total length of 1370 mm is exactly twice that of the C9 in AMNH 6341, which suggests its neck was twice as long over all — not 8.5 m but 17 m.
How horrifying is that?
I realised one good way to picture it is next to the entire mounted skeleton of Giraffatitan at the Museum für Naturkunde Berlin. That skeleton is 13.27 m tall. At 17 m, the giant barosaur neck would be 28% longer than the total height Giraffatitan.
Giraffatitan brancai mounted skeleton MB.R.2181 at the Museum für Naturkunde Berlin, with neck of Barosaurus ?lentus BYU 9024 at the same scale. Photo by Axel Mauruszat, from Wikipedia; drawing from Scott Hartman’s Supersaurus skeleton reconstruction.
Yes, this looks ridiculous. But it’s what the numbers tell us. Measure the skeleton’s height and the neck length off the image yourself if you don’t believe me.
(Note, too, that the size of the C9 in that big neck is about right, compared with a previous scaled image that Matt prepared, showing the “Supersaurus” vertebra in isolation alongside the Chicago Brachiosaurus.)
