September 20, 2015
Last time, we looked at some of Brian Engh’s preliminary sketches of pieces to illustrate our fighting-apatosaur hypothesis. But there’s more: some way into the process, Brian also came up with this very rough sketch, illustrating a different style of combat:
All the pictures in the previous post show various forms of ventral-to-ventral combat, but we’ve also been thinking about possibilities, and an important one is ventral-to-dorsal.
That could work in at least two ways. We can imagine a wresting match, where each animal tries to get its neck above its opponent’s, and to force it to the ground. There is precedent for this in the behaviour of various extant animals. (Or perhaps I should call it postcedent, since apatosaurs came first.)
But other extant animals have a much more violent combat style, based on striking blows rather than exerting steady force. Notably, giraffes do this, using their long necks as levers to crash their uncharismatic, highly fused mammalians heads into each other.
Could apatosaurs have done this? Not exactly: their heads were far too small to be effective clubs, and far too fragile to survive being used in this way. But the necks themselves would have been formidable weapons: we’re confident that apatosaurs striking blows would have done so with their necks, bringing them powerfully downwards on their adversaries.
Brian liked this idea enough to work the rough sketch above up into a completed drawing, which we also plan to include in the paper (and which, by the way, I unreservedly love):
So what style of combat did apatosaurs use? Ventral-on-ventral shoving? Wrestling to the ground? Striking downwards blows with the neck?
My best guess (and it’s only a guess, necessarily) is that among the half-dozen or so recognised species of apatosaurine, all these styles were likely in use. And this may explain the variation in cervical morphology that we see between species (though of course ontogeny and sexual dimorphism may also be at work).
In short, I think all of these scenarios are credible — and therefore perfectly legitimate subjects for palaeo-art *hint hint*.
September 19, 2015
In putting together our thoughts on how apatosaurs used their necks, we were motivated by genuine curiosity — which in Matt’s and my case, at least, goes back many years. (We briefly discussed the problem, if only to throw our hands up in despair, in our 2013 neck-anatomy paper.) We didn’t land on the combat hypothesis because it’s cool, but because it’s where the evidence points.
That said, it is cool.
Brian Engh is on the authorship for this paper largely because of his insights into extant animal behaviour. But there’s no denying that it’s a real bonus that he’s also an awesome artist. He’s been putting together sketches to illustrate our hypothesis for some time, partly with the goal of figuring out which compositions to work up into finished pieces. Here, with Brian’s permission, are some of those preliminary sketches.
First, a really nice sketch showing a ventral-to-ventral shoving match from down at ground level.
I really like this one, and would have been happy for it to be one of the anointed ones. I like the sense of huge beasts towering over the viewer. That said, I always love pencil sketches, often more than I do finished pieces, so I’m not too unhappy that the world gets to see this one in pencil-sketch form.
Next up, sketched more roughly, is a concept for a different form of combat in a different aspect. Here, we see two animals side by side, wrestling with both necks and tails.
I like the dynamism of this one, and especially that the one on the right is in the process of being pushed over. But there’s nothing in apatosaur tail morphology that particularly says “combat”, so I guess I’m not too unhappy that this one didn’t make the cut.
The third sketch shows two individuals rearing into into ventral-to-ventral push.
Matt and Brian liked this one the most, so it got worked up into a finished and coloured piece which will be one of the figures in the paper when we get around to submitting it. Here is the current version — as I understand it, Brian plans to revise it further before it’s done.
The craftsmanship here is superb, but I can’t help regretting that the dinosaurs are rearing less than in the sketch. I feel it’s lost some of the power of the concept sketch.
What you’re seeing here, folks, is a bona fide instance of co-authors disagreeing. Happens all the time, but you usually don’t see it, because it’s all resolved by the time the paper is submitted. Brian is the artist, and ultimately it’s for him to decide what to depict and how; but I’ll always be glad that we still have the pencil-sketch as well as the finished version.
September 15, 2015
Ten years ago today — on 15 September 2005 — my first palaeo paper was published: Taylor and Naish (2005) on the phylogenetic nomenclature of diplodocoids. It’s strange to think how fast the time has gone, but I hope you’ll forgive me if I get a bit self-indulgent and nostalgic.
I’d applied to join Portsmouth University on a Masters course back in April 2004 — not because I had any great desire to earn a Masters but because back in the bad old days, being affiliated to a university was about the only way to get hold of copies of academic papers. My research proposal, hilariously, was all about the ways the DinoMorph results are misleading — something that I am still working on eleven years later.
In May of that year, I started a Dinosaur Mailing List thread on the names and definitions of the various diplodocoid clades. As that discussion progressed, it became clear that there was a lot of ambiguity, and for my own reference I started to make notes. I got into an off-list email discussion about this with Darren Naish (who was then finishing up his Ph.D at Portsmouth). By June we thought it might be worth making this into a little paper, so that others wouldn’t need to do the same literature trawl we’d done.
In September of 2004, I committed to the Portsmouth course, sending my tuition fees in a letter that ended:
On the way to SVPCA that year, in Leicester, I met Darren on the train, and together we worked through a printed copy of the in-progress manuscript that I’d brought with me. He was pretty happy with it, which meant a lot to me. It was the first time I’d had a legitimate palaeontologist critique my work.
At one of the evening events of that SVPCA, I fell into conversation with micro-vertebrate screening wizard Steve Sweetman, then on the Portsmouth Ph.D course, and he persuaded me to switch to the Ph.D. (It was my second SVPCA, and the first one where I gave a talk.) Hilariously, the heart of the Ph.D project was to be a description of the Archbishop, something that I have still not got done a decade later, but definitely will this year. Definitely.
On 7th October 2004, we submitted the manuscript to the Journal of Paleontology, and got an acknowledge of receipt<sarcasm>after just 18 short days</sarcasm>. But three months later (21st January 2005) it was rejected on the advice of two reviewers. As I summarised the verdict to Darren at the time:
It’s a rejection. Both reviewers (an anonymous one and [redacted]) say that the science is pretty much fine, but that there just isn’t that much to say to make the paper worthwhile. [The handling editor] concurs in quite a nice covering letter […] Although I think the bit about “I respect both of you a great deal” is another case of Wrong Mike Taylor Syndrome :-)
At this point, Darren and I spent a while discussing what to do: revise and resubmit (though one of the reviewers said not to)? Try to subsume the paper into another more substantial one (as one reviewer suggested)? Invite the reviewers to collaborate with us on an improved version (as the editor suggested)? Or just revise according to the reviewers’ more helpful recommendations and send it elsewhere? I discussed this with Matt as well. The upshot was that on 20th February Darren and I decided to send the revised version to PaleoBios, the journal of the University of California Museum of Paleontology (UCMP) — partly because Matt had had good experiences there with two of his earlier papers.
[Side-note: I am delighted to see that, since I last checked, PaleoBios has now made the leap to open access, though as of yet it says nothing about the licence it uses.]
Anyway, we submitted the revised manuscript on 26th May; and we got back an Accept With Minor Revisions six weeks later, having received genuinely useful reviews from Jerry Harris and Matt. (This of course was long before I’d co-authored anything with Matt. No handling editor would assign him to review one of my papers now.) It took us two days to turn the manuscript around with the necessary minor changes made, and another nine days of back and forth with the editor before we reached acceptance. A week later I got the proof PDF to check.
Back in 2005, publication was a very different process, because it involved paper. I remember the thrill of several distinct phases in the publication process — particularly sharp the first time:
- Seeing the page proof — evidence that I really had written a legitimate scholarly paper. It looked real.
- The moment of being told that the paper was published: “The issue just went to the printer, so I will send the new reprints […] when I get them, probably sometime next week.”
- Getting my copy of the final PDF.
- The day that the physical reprints arrived — funny to think that they used to be a thing. (They’re so Ten Years Ago now that even the SVPCA auction didn’t have many available for bid.)
- The tedious but somehow exhilarating process of sending out physical reprints to 30 or 40 people.
- Getting a physical copy of the relevant issue of the journal — in this case, PaleoBios 25(2).
I suppose it’s one of the sadder side-effect of ubiquitous open access that many of these stages don’t happen any more. Now you get your proof, then the paper appears online, and that’s it. Bam, done.
I’m kind of glad to have lived through the tail end of the old days, even though the new days are better.
To finish, there’s a nice little happy ending for this paper. Despite being in a relatively unregarded journal, it’s turned out to be among my most cited works. According to Google Scholar, this humble little taxonomic note has racked up 28 citations: only two fewer than the Xenoposeidon description. It’s handily outperforming other papers that I’d have considered much more substantial, and which appeared in more recognised journals. It just goes to show, you can never tell what papers will do well in the citation game, and which will sink without trace.
September 14, 2015
We’ve noted that the Taylor et al. SVPCA abstract and talk slides are up now up as part of the SVPCA 2015 PeerJ Collection, so anyone who’s interested has probably taken a look already to see what it was about. (As an aside, I am delighted to see that two more abstracts have been added to the collection since I wrote about it.)
It was my privilege to present a talk on our hypothesis that the distinctive and bizarre toblerone-shaped necks of apatosaurs were an adaptation for intraspecific combat. This talk was based on an in-progress manuscript that Matt is lead-authoring. Also on board is the third SV-POW!sketeer, the silent partner, Darren Naish; and artist/ethologist Brian Engh.
Here is our case, briefly summarised from five key slides. First, let’s take a look at what is distinctive in the morphology of apatosaur cervicals:
Here I’m using Brontosaurus, which is among the more extreme apatosaurs, but the same features are seen developed to nearly the same extent in Apatosaurus louisae, the best-known apatosaur, and to some extent in all apatosaurs.
Now we’ll look at the four key features separately.
First, the cervicals ribs of sauropods (and other saurischians, including birds) anchored the longus colli ventralis and flexor colli lateralis muscles — ventral muscles whose job is to pull the neck downwards. By shifting the attachments points of these muscles downwards, apatosaurs enabled them to work with improved mechanical advantage — that is, to bring more force to bear.
Second, by redirecting the diapophyses and parapophyses ventrally, and making them much more robust than in other sauropods, apatosaurs structured their neck skeletons to better resist ventral impacts.
Third, because the low-hanging cervical ribs created an inverted “V” shape below the centrum, they formed a protective cradle for the vulnerable soft-tissue that is otherwise exposed on the ventral aspect of the neck: trachea, oesophagus, major blood vessels. In apatosaurus, all of these would have been safely wrapped in layers of connective tissue and bubble-wrap-like pneumatic diverticula. The presence of diverticula ventral to the vertebral centrum is not speculative – most neosauropods have fossae on the ventral surfaces of their cervical centra, and apatosaurines tend to have foramina that connect to internal chambers as well (see Lovelace et al. 2007: fig. 4, which is reproduced in this post).
Fourth, most if not all apatosaurs have distinctive ventrally directed club-like processes on the front of their cervical ribs. (It’s hard to tell with Apatosaurus ajax, because the best cervical vertebra of that species is so very reconstructed.) How did these appear in life? It’s difficult to be sure. They might have appeared as a low boss; or, as with rhinoceros horns, they might even have carried keratinous spikes.
Putting it all together, we have an animal whose neck can be brought downwards with great force; whose neck was mechanically capable of resisting impacts on its ventral aspect; whose vulnerable ventral-side soft-tissue was well protected; and which probably had prominent clubs or spikes all along the ventral aspect of the neck. And all of this was accomplished at the cost of making the neck a lot heavier than it would have been otherwise. Off the cuff, it seems likely that the cervical series alone would have massed twice as much in apatosaurines as in diplodocines of the same neck length.
Doubling the mass of the neck is a very peculiar thing for a sauropod lineage to do – by the Late Jurassic, sauropods were the leading edge of an evolutionary trend to lengthen and lighten the neck that had been running for almost 100 million years, through basal ornithodirans, basal dinosauromorphs, basal saurischians, basal sauropodomorphs, and basal sauropods. Whatever the selective pressures that led apatosaurines to evolve such robust and heavy necks, they must have been compelling.
The possibility that apatosaurs were pushing or crashing their necks ventrally in some form of combat accounts for all of the weird morphology documented above, and we know that sexual selection is powerful force that underlies a lot of bizarre structures in extant animals, and probably in extinct ornithodirans as well (see Hone et al. 2012, Hone and Naish 2013).
What form of combat, exactly? There are various possibilities, which we’ll discuss another time. But I’ll leave you with Brian Engh’s beautiful illustration of one possible form of combat: a powerful impact of one neck brought down onto the dorsal aspect of another.
We’re aware that this proposal is necessarily somewhat speculative. But we’re just not able to see any other explanation for the distinctive apatosaur neck. Even if we’re wrong about the ventrolateral processes on the cervical ribs supporting bosses or spikes, the first three points remain true, and given how they fly in the face of sauropods’ long history of making their necks lighter, they fairly cry out for explanation. If anyone has other proposals, we’ll be happy to hear them.
- Hone, D. W., Naish, D., & Cuthill, I. C. (2012). Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs?. Lethaia 45(2):139-156.
- Hone, D. W. E., & Naish, D. (2013). The ‘species recognition hypothesis’ does not explain the presence and evolution of exaggerated structures in non‐avialan dinosaurs. Journal of Zoology 290(3):172-180.
- Lovelace, D. M., Hartman, S. A., & Wahl, W. R. (2007). 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.
September 10, 2015
Wouldn’t it be great if, after a meeting like the 2015 SVPCA, there was a published set of proceedings? A special issue of a journal, perhaps, that collected papers that emerge from the work presented there.
Of course the problem with special issues, and edited volumes in general, is that they take forever to come out. After the Dinosaurs: A Historical Perspective conference on 6 May 2008, I got my talk on the history of sauropod research written up and submitted on 7 August, just over three months later. It took another five and a half months to make it through peer-review to acceptance. And then … nothing. It sat in limbo for a year and nine months before it was finally published, because of course the book couldn’t be finalised until the slowest of the 50 or so authors, editors and reviewers had done their jobs.
There has to be a better way, doesn’t there?
Rhetorical question, there. There is a better way, and unsurprisingly to regular readers, it’s PeerJ that has pioneered it. In PeerJ Collections, papers can be added at any time, and each one is published as it’s ready. Better still, the whole lifecycle of the paper can (if the authors wish) be visible from the collection. You can start by posting the talk abstract, then replace it with a preprint of the complete manuscript when it’s ready, and finally replace that with the published version of the paper once it’s been through peer-review.
Take a look, for example, at the collection for the 3rd International Whale Shark Conference (which by the way was held at the Georgia Aquarium, Atlanta, which has awesome whale sharks on view.)
As you can see from the collection (at the time of writing), only one of the constituent papers — Laser photogrammetry improves size and demographic estimates for whale sharks — has actually been published so far. But a dozen other papers exist in preprint form. That means that the people who attended the conference, saw the talks and want to refer to them in their work have something to cite.
The hot news is that Mark Young and the other SVPCA 2015 organisers have arranged for PeerJ to set up an SPPC/SVPCA 2015 Collection. I think this is just marvellous — the best possible way to make a permanent record of an important event.
The collection is very new: at the time of writing, it hosts only five abstracts (one of them ours). We’re looking forward to seeing others added. Some of the abstracts (including ours) have the slides of the talk attached as supplementary information.
Although I’m lead author on the talk (because I prepared the slides and delivered the presentation), this project is really Matt’s baby. There is a Wedel et al. manuscript in prep already, so we hope that within a month or two we’ll be able to replace the abstract with a complete manuscript. Then of course we’ll put it through peer-review.
I hope plenty of other SVPCA 2015 speakers will do the same. Even those who, for whatever reason, don’t want to publish their work in PeerJ, can use the collection as a home for their abstracts and preprints, then go off and submit the final manuscript elsewhere.
September 9, 2015
As we’ve previously noted more than once here at SV-POW!, apatosaurine cervicals really are the craziest things. For one thing, they are the only dinosaur bones to have inspired the design of a Star Wars spaceship.
One result of this very distinctive cervical shape, with the ribs hanging down far below the centra, was that the necks of apatosaurines would have been triangular in cross-section, rather than tubular as often depicted. (The Apatosaurus maquette that Matt reviewed gets this right.)
Here’s how I conveyed this in two slides of my SVPCA talk:
Although apatosaurs take this to the extreme, the same was essentially true of all sauropod necks. The ventrolateral position of the cervical ribs would have lent the necks a rounded triangular shape, or diamond-shaped in the case of less extreme sauropods whose neck soft-tissue hung below the cervical ribs.
August 11, 2015
Back in 2012, when Matt and I were at the American Museum of Natural History to work on “Apatosaurus” minimus, we also photographed some other sacra for comparative purposes. One of them you’ve already seen — that of the Camarasaurus supremus holotype AMNH 5761. Here is another:
(Click through for glorious 3983 x 4488 resolution.)
This is AMNH 3532, a diplodocid sacrum with the left ilium coalesced and the right ilium helpfully missing, so we can see the structure of the sacral ribs. Top row: dorsal view, with anterior to the left; middle row, left to right: anterior, left lateral and posterior views; bottom row: right lateral view.
As a matter of fact, we’ve seen this sacrum before, too, in a photo from Matt’s much earlier AMNH visit. But only from a left dorsolateral perspective.
When we first saw this, it didn’t even occur to us that it could be anything other than good old Diplodocus. And indeed it’s a pretty good match for the same area in the CM 84/94 cast in the Museum für Naturkunde Berlin (this image extracted from Heinrich Mallison’s beautiful giant composite):
And the general narrowness of the AMNH sacrum says Diplodocus to me. But what is that expectation of narrowness based on? When I compared the AMNH specimen with Hatcher’s (1901) ventral-view illustration in his classic Diplodocus monograph, I had second thoughts:
That is a much wider sacrum than I’d expected from Diplodocus.
So what is going on here? Is Diplodocus a fatter-assed beast than I’d realised? I am guessing not, since my expectation of narrowness has been built up across years of looking at (if not necessarily paying much attention to) Diplodocus sacra.
So could it be that CM 94, the referred specimen that Hatcher used to make up some of the missing parts of the CM 84 mount, is not Diplodocus?
Well. That is certainly now how I expected to finish this post. Funny how blogging leads you down unexpected paths. It’s a big part of why I recommend blogging to pretty much everyone. It forces you to think down pathways that you wouldn’t otherwise wander.
- Hatcher, Jonathan B. 1901. Diplodocus (Marsh): its osteology, taxonomy and probable habits, with a restoration of the skeleton. Memoirs of the Carnegie Museum 1:1-63 and plates I-XIII.