How big were the biggest sauropod trackmakers?

You might have seen a story last week about some huge sauropod tracks discovered in Upper Jurassic deposits from the Jura plateau in France, near the town of Plagne. According to the news reports, the tracks are the largest ever discovered. Well, let’s see.

The Guardian (from which I stole the image above) says the prints are “up to 2 metres (6ft 6 in) in diameter”, but ScienceDaily says “up to 1.5 m in total diameter”. Not sure how ‘total diameter’ is different from regular diameter, but that’s science reporting for you. The BBC clarifies that, “the depressions are about 1.5m (4.9ft) wide”, which might be the key here (see below), but then mysteriously continues, “corresponding to animals that were more than 25m long and weighed about 30 tonnes.” I find it rather unlikely that a pes track 1.5 m wide indicates an animal only as big as Giraffatitan (hence this post).

So there’s some uncertainty with respect to the diameter of the tracks–half a meter of uncertainty, to be precise. But sauropod pes tracks are usually longer than wide, and a print 1.5 m wide might actually be 2 m long.

Not incidentally, Thulborn (1994) described some big sauropod tracks from the Broome Sandstone in Australia, with pes prints up to 1.5 m. Although the photos of the tracks are not as clear as one might wish, they do appear to show digit impressions and are probably not underprints.

I’ll feel a lot better about the Plagne tracks when the confusion about their dimensions is cleared up and when some evidence is presented that they also are not underprints. In any case, the only dimension with any orientation cited for the Plagne tracks is the 1.5 m width reported by the BBC, so we’ll go with that. So the Plagne tracks might only tie, but not beat, Thulborn’s tracks.

…Then again, Thulborn only said that the biggest tracks were up to 150 cm in diameter. What does that mean–length? Width? Are the tracks perfect circles? Does no one who works on giant sauropod tracks know how to report measurements? These questions will have to wait, because despite the passing of a decade and a half, the world’s (possibly second-) biggest footprints–from anything! ever!–have not yet merited a follow-up paper.

Nevertheless, for the remainder of this post we’ll accept that at least some sauropods were leaving pes prints a meter and a half wide. Naturally, it occurs to me to wonder how big those sauropods were. I don’t know of any studies that attempt to rigorously estimate the size of a sauropod from its tracks or vice versa, so in the finest tradition of the internet in general and blogging in particular, I’m going to wing it.

How Big?

First we need some actual measurements of sauropod feet. When Mike and I were in Berlin last fall (gosh, almost a year ago!), we measured the feet (pedes) of the mounted Giraffatitan and Diplodocus for this very purpose. The Diplodocus feet were both 59 cm wide, and the Giraffatitan feet were 68 and 73 cm wide. The Diplodocus feet are trustworthy, the Giraffatitan bits less so. Unfortunately, the pes is the second part of the skeleton of Giraffatitan that is less well known than I would like (after the cervico-dorsal neural spines). The reconstructed feet look believable, but “believability” is hard to calibrate and probably a poor predictor of reality when working with sauropods.

One thing I won’t go into is that Giraffatitan (HM SII) probably massed more than twice what Diplodocus (CM 84/94) did, but on the other hand G. bore more of its weight on its forelimbs. It would be interesting to calculate whether the shifted center of mass would be enough to even out the pressure exerted by the hindfeet of the two animals; Don Henderson may have done this already.

Anyway, let’s say for the sake of argument that the hindfeet of the mounted Giraffatitan are sized about right. The next problem is figuring out how much soft tissue surrounded the bones. In other words, how much wider was the fleshy foot–deformed under load!–than the articulated pes skeleton? I am of two minds on this. On one hand, sauropods probaby had a big heel pad like that of elephants, and it seems reasonable that the heel pad plus the normal skin, fat, and muscle might have expanded the fleshy foot considerably beyond the edges of the bones. On the other hand, the pedal skeleton is widest across the distal ends of the phalanges, and in well-preserved tracks like the one below the fleshy foot is clearly not much wider than that (thanks, Brian, for the photo!).

Bear in mind that a liberal estimate of soft tissue will give a conservative estimate of the animal’s size, and vice versa. Looking at the AMNH track pictured above, it seems that the width added by soft tissue could possibly be as little as 5% of the width of the pes skeleton. Skewing hard in the opposite direction, an additional 20% or more does not seem unreasonable for other animals (keep in mind this would only be 10% on either side of the foot). Using those numbers, Diplodocus (CM 84/94) would have left tracks as narrow as 62 cm or as wide as 71 cm. For Giraffatitan (HM SII) I’ll use the wider of the two pes measurements, because the foot is expected to deform under load and the 73 cm wide foot looked just as believable as the 68 cm foot (for whatever that’s worth). Applying the same scale factors (1.05 and 1.20) yields a pes track width of 77-88 cm.

These numbers are like pieces of legislation, or sausages: the results are more pleasant to contemplate than the process that produced them. They’re ugly, and possibly wrong. But they give us someplace to start from in considering the possible sizes of the biggest sauropod trackmakers. Something with a hindfoot track 1.5 meters wide would be, using these numbers, conservatively more than twice as big as (2.11x) the mounted Carnegie Diplodocus or 170% the size of the mounted Berlin Giraffatitan. That’s right into Amphicoelias fragillimus/Bruhathkayosaurus territory. The diplo-Diplodocus would have been 150 feet long, and even assuming a very conservative 10 tons for Vanilla Dippy (14,000L x 0.7 kg/L = 9800 kg), would have had a mass of 94 metric tons (104 short tons). The monster Giraffatitan-like critter would have been “only” 130 feet long, but with a 14.5 meter neck and a mass of 113 metric tons (125 short tons; starting from a conservative 23 metric tons for HM SII).

Keep in mind that these are conservative estimates, for both the size of the trackmakers and the masses of the “known” critters. If we use the conservative soft tissue/liberal animal size numbers, the makers of the 1.5 meter tracks were 2.4 times as big as the mounted Diplodocus or almost twice as big as the mounted Giraffatitan, in which case masses in the blue whale range of 150-200 tons become not just probable but inevitable.

Mike measuring Giraffatitan's naughty bits. Check out the hindfeet. Also note the sauropod vertebrae in the background--titular obligation fulfilled!

Too Big?

Going the other way, I can think of only a handful of ways that the “conservative” trackmaker estimates might still be too big:

First, the pes of Giraffatitan might have been bigger than reconstructed in the mounted skeleton. Looking at the photo above, I can image a pes 10% wider that wouldn’t do any violence to the “believability” of the mount. That would make the estimated track of HM SII 10% wider and the estimated size of the HM-SII-on-steroids correspondingly smaller. But that wouldn’t affect the scaled up Diplodocus estimate, and the feet of Giraffatitan would have to be a LOT bigger than reconstructed to avoid the reality of an animal at least half again as big as HM SII.

Second, the amount of soft tissue might have been greater than even the liberal soft tissue/conservative size estimate allows. But I think that piling on 20% more soft tissue than bone is already beyond what most well-preserved tracks would justify, so I’m not worried on that score. (What scares me more is the thought that the conservative estimates are too conservative, and the real trackmakers even bigger.)

Third, I suppose it is possible that sauropod feet scaled allometrically with size and that big sauropods left disproportionately big tracks. I’m also not worried about this. For one thing, when they’ve been measured sauropod appendicular elements tend to scale isometrically, and it would be weird if feet were the undiscovered exception. For another, the allometric oversizing of the feet would have to be pronounced to make much of a dent in the estimated size of the trackmakers. I find the idea of 100-ton sauropods more palatable than the idea of 70-ton sauropods with clown shoes.

Fourth, the meta-point, what if the Broome and Plagne tracks are underprints? I’ve seen some tracks-with-undertracks where the magnification of the apparent track size in the undertracks was just staggering. The Broom tracks have gotten one brief note and the Plagne tracks have not been formally described at all, so all of this noodling around about trackmaker size could go right out the window. Mind you, I don’t have any evidence that the either set are underprints, and at least for the Broome tracks the evidence seems to go the other way, I’m just trying to cover all possible bases.

Conclusions

So. Sauropods got big. As usual, we can’t tell exactly how big. Any one individual can leave many tracks but only one skeleton, so we might expect the track record to sample the gigapods more effectively than the skeletal record. Interestingly, the largest fragmentary skeletal remains (i.e., Amphicoelias and Bruhathkayosaurus, assuming they’re legit) and the largest tracks (i.e., Plagne and Broome) point to animals of roughly the same size.

It’s also weird that some of the biggest contenders in both categories have been so little published. I mean, if I had access to Bruhathkayosaurus or a track 1.5 m wide, you can bet that I’d be dropping everything else like a bad habit until I had the gigapod evidence properly written up. What gives?

Finally, IF the biggest fragmentary gigapods and the biggest tracks are faithful indicators of body size, they suggest that gigapods were broadly distributed in space and time (and probably phylogeny). I wonder if these were representatives of giga-taxa, or just extremely large individuals of otherwise vanilla sauropods. Your thoughts are welcome.

Epilogue: What About Breviparopus?

It’s past time someone set the record straight about damn Breviparopus. The oft-quoted track length of 115 cm is (A) much smaller than either the Broome or Plagne tracks, and (B) the combined length of the manus and pes prints together; I know, I looked it up (Dutuit and Ouazzou 1980). Why anyone would report track “length” that way is beyond me, but what is more mysterious is why anyone was taken in by it, since the width of 50 cm (pathetic!) is usually quoted along with the 115 cm “length”, indicating an animal smaller than Vanilla Diplodocus (track length is much more likely than width to get distorted by foot motions during locomotion) [This part is wrong; see the update below.]. But people keep stumbling on crap (thanks, Guiness book!) about how at 157 feet long (determined how, exactly?) Breviparopus was possibly the largest critter to walk the planet. Puh-leeze. If there’s one fact that everyone ought to know about Breviparopus, it’s that it was smaller than the big mounted sauropods at museums worldwide. The only thing super-sized about it is the cloud of ignorance, confusion, and hype that clings to the name like cheap perfume. Here’s the Wikipedia article if you want to do some much-needed revising.

UPDATE (Nov 17 2009): The width of the Breviparopus pes tracks is 90 cm, not 50 cm. The story of the 50 cm number is typically convoluted. Many thanks to Nima Sassani for doing the detective work. Rather than steal his thunder, I’ll point you to his explanation here. Point A above is still valid: Breviparopus was dinky compared to the Broome and Plagne trackmakers.

Parting Shot

You know I ain’t gonna raise the specter of a beast 1.7 times the size of HM SII without throwing in a photoshopped giant cervical. So here you go: me with C8 of Giraffatitan blown up to 170% (the vert, not me). Compare to unmodified original here.

References

• Dutuit, J.M., and A. Ouazzou. 1980. Découverte d’une piste de Dinosaure sauropode sur le site d’empreintes de Demnat (Haut-Atlas marocain). Mémoires de la Société Géologique de France, Nouvelle Série 139:95-102.
• Thulborn, R.A., T.Hamley and P.Foulkes. 1994. Preliminary report on sauropod dinosaur tracks in the Broome Sandstone (Lower Cretaceous) of Western Australia. Gaia 10:85-96.

Blogs, papers, and the brave new digital world: Matt’s thoughts

First off, thanks to everyone for reading, commenting on, and discussing the previous post. Seeing the diversity of opinions expressed has been interesting and gratifying for us, and we’ve learned a lot from you about how the blogosphere is changing science already. My own thoughts follow, Mike chimes in at the end, and Darren will probably have something to add soon, too.

The Intolerable Problem

Sometimes people push back on posts of mine they don’t like by telling me I’m out of bounds. Somehow, they say, I’ve crossed the boundary of what I’m allowed to write about. They are angry that I’m now writing about something outside my defined area.

I’m usually taken aback by this, because I didn’t realize I’d actually agreed to any boundaries.

Seth Godin, 2009, “Out of Bounds”

Several commenters have brought up what I call the Intolerable Problem, which is that people online can critique papers and present new evidence and arguments in a format that is impermanent and not peer-reviewed. It’s intolerable because on one hand such material is not currently (operative word) citable in most outlets, and on the other hand repeating it sans citation in peer-reviewed literature smacks of plagiarism (to some, but not to all). Although this material is potentially valuable it “doesn’t count” professionally (see exceptions below), which some professionals (not necessarily those who have commented here) regard as a fatal argument against posting it in the first place. But–and this is crucial–it’s only a problem for the tiny fraction of the audience who might want to cite the freely exchanged material. If you’re in that fraction, we value your attention and comments, but don’t assume we’re writing only for you, or to further our professional standing. We blog because we love this stuff, and even at a technical niche blog like SV-POW! the majority of readers probably don’t care at all whether the information is peer-reviewed or “counts” for professionals; they mostly care whether it’s right or not.

One obvious solution to the Intolerable Problem is to simply let people cite anything they want, including blog posts and DML posts. This is already starting to be implemented–see examples here and here and more discussion here. This runs into two problems: one is permanence (there is no guarantee that the cited post will be up forever, or that the author won’t revise it later in response to criticism [as I have done with this very post!]), which can already be solved using tools such as WebCite (thanks to Cameron Neylon for bringing this to our attention in a comment on the previous post).

The other problem is that citations serve two functions, which are to establish priority and to lend authority to an argument. Citing a blog post may establish priority, but some researchers will cavil at the idea that a blog post is an authoritative source (for varying combinations of researchers and blog posts). Whether they would be right to cavil I don’t know; in the end the market will decide. The market–that is, the desire to attain professional respect and avoid censure–will also dissuade authors from larding up their papers with citations to trivial or worthless online sources.

Those who are troubled by the free discussion of papers, evidence, and hypotheses online need to realize that:

• it’s been going on for a long time (15 years for the Dinosaur Mailing List);
• it’s only going to accelerate in the future;
• it’s not a problem for the vast majority of people participating in the discussions;
• any solution must involve accommodation to the reality of how people exchange information online (immediately, freely, globally, without prior filtering).

These discussions are not going to stop, and ignoring the output of such discussions (because they “don’t count”) will eventually become prohibitively expensive as those workers who insist on playing only by the old rules are outmaneuvered by others who find ways to use all available information regardless of its provenience or “respectability”.

Paper journals will die when online journals stop sucking

Most online publications are hampered by having to be identical to the dead-tree versions (no links, no embedded video, no rotating 3D PDF images, etc.). Eventually people will realize that it is counterproductive to keep hobbling the new medium to make it as slow, flat, and inefficient as the old medium. Once one journal takes the hobbles off, others will do the same rather than lose contributors to cutting-edge outlets. A few boutique journals may still produce flattened, gutted versions of the online publications on paper. People still fly biplanes, too. Paper-based journals will never be popular again and their existence will not stop people from doing whatever technology allows them to in the online venues.

Note that this does not even refer to the economic argument against dead-tree publishing, which has already relocated encyclopedias and newspapers from ubiquity to marginality or extinction.

I’m surprised that the revolution isn’t farther along already. The cage is open.

Whither peer review and editing?

This is all part of the Big Flip in publishing generally, where the old notion of “filter, then publish” is giving way to “publish, then filter.” There is no need for Slashdot’s or Kuro5hin’s owners to sort the good posts from the bad in advance, no need for Blogdex or Daypop to pressure people not to post drivel, because lightweight filters applied after the fact work better at large scale than paying editors to enforce minimum quality in advance.

Clay Shirky, 2003, “The Music Business and the Big Flip”

PLoS ONE is already going gangbusters, without peer-review prior to publication in many cases. The only holdup there is that the post-hoc review by commenters is not working out quite like they’d hoped, because few people are commenting. Not everyone agrees that there is a dearth of commenting at PLoS ONE; the larger point is that people publish there a lot and the community treats those pubs like they count, even though in many cases they are essentially un-reviewed.

[Update: I misunderstood peer review at PLoS ONE. Papers may be reviewed externally by people unconnected to PLoS, or by one or more unpaid Academic Editors, or by a combination. I had thought of the review by Academic Editors only, which accounts for 13% of papers, as a form of internal review, but according to Bora (down in the comments) it should count as external review. If you're happy with that--and the system is not without its critics--then all papers at PLoS ONE are externally reviewed prior to publication; even if you're not, pre-publication review by someone is still in place across the board at PLoS ONE, and 87% of papers are externally reviewed by people unaffiliated with PLoS. Post-publication commenting supplements rather than replaces pre-publication review.]

People do comment on blogs, all the time. Post-hoc review will work, in fact already does work, just fine on blogs. I predict that PLoS ONE clones of the future (PLoS TWO?) will emulate whatever features of blogs make people willing to comment on them but not on PLoS ONE v1.0.

Alternatively, the paucity of post-hoc commenting at PLoS ONE could be taken as further evidence that journal-mediated peer review, whether before or after publication, is dying just off to a slow start. I think that editorial control is not far behind. Both are locally extinct in some parts of the science publishing ecosystem, since people are already citing blogs.

Q: But–but–but? What about protecting the sanctity of the process? What about about guaranteeing respectability? What about prestige?

A: Hey, those questions would make a terrific opinion piece for your local newspaper–oops, too late.

I don’t deny that editors and peer reviewers often make significant contributions to the quality of published work. I just think that people will learn to get along without them if doing so allows faster and easier exchange of information. That was never possible on paper; it’s long been possible here.

A priori peer review and editorial control were invented because publications were scarce (in the Econ 101 sense of being limited) and there needed to be a barrier to entry. Now publication is instant, free, and global. Error correction and the assignment of value will still happen, but they’ll happen after publication rather than before, and they’ll be distributed rather than centralized.

Creeping blogification

Clay Shirky described the problem for newspapers and the recording industry as the existence of “cheap perfect copies”. An expanded but by no means exhaustive list for science publication includes:

• cheap perfect copies
• editable (but also archivable)
• sharable
• linkable (both incoming and outgoing)
• globally distributed
• instantly
• for free
• without pre-publication filtering
• with multimedia embeds (as opposed to including video etc. separately in the suppl. info.)

Online open-access journals currently take advantage of all of those capabilities except the last two. Newsgroup posts cover all the bases except the last one (so do tweets, despite the severe length limitations).

What covers everything? Blog posts. Which have the added advantage that people will comment on them without being asked.

But that’s not the whole simple story.

The center cannot hold–or can it?

So we’re looking at total chaos, right–a world where anyone posts anything they want, no one has any control, and no one knows how to find the good stuff? Well, two out of three, at least. I’m not worried about that last point, for two reasons.

First, thanks to search engines, aggregators, tags, tweets, links, etc., we already have pretty good tools for finding the good stuff. Those direction finders will get better even as the map gets more complicated.

Second, prestige will always be a motivator, so people will always compete to get into exclusive venues. Nature is not going away, although I think that in the near future they will decouple their online and print publications so that the former can take advantage of all the possibilities the web offers.

If I have a really good idea backed up with lots of data, I’ll keep trying to get it into the most prestigious outlet I can. I won’t put my best stuff on a blog just because it’s faster and less encumbered. Blogs probably won’t replace journals, at least not anytime soon. Rather, the spectrum of publishing possibilities will expand; below the category of Least Publishable Unit we’ll add Most Bloggable Unit and so on down to Least Tweetable Unit, and the new categories will interpenetrate with the old over time.

How nice for me

Well, what a striking coincidence that Mr. Paleo Blogger looks into the ole digital crystal ball and sees “bloggy with a 90% chance of exactly-what-he’s-already-doing”.

I can’t claim to be either uninterested or unbiased in all of this. But I am new to actually thinking about the implications. I hadn’t been to most of the above links or had any of these thoughts as of a week ago. When Casey first e-mailed me six days ago, I replied:

If you’re curious, here’s the short short version of my thoughts: science bloggers critique published papers and blog about unpublished observations all the time. Our post-paper run of posts might be an extreme or even vulgar example, and it might fire more discussion about “what counts?”, but I don’t see it as being different in kind from what many science bloggers do. Papers are papers and blogs are blogs, and I never intended to blur the lines. If people feel that all the blog posts only count as “crap some guys wrote on the internet” and that they can be safely ignored, that’s fine with me. If they think the blog posts deserve some higher level of recognition a la “what counts?”, then I’m honored, but that’s extra value that others are investing in our blog, and not anything that we’ve knowingly sought. I suppose you could turn around and say that I’m trying to have my cake and eat it, too, first with all the pro-paper blogging and now with this “I’m innocent” schtick. I don’t know what the answer is, but I know that I’m too tired to figure it out tonight. All the more reason to have an open conversation about this stuff.

Now I realize that the lines between papers and blog posts are blurring, and whether we mean to or not, we SV-POW!sketeers are contributing (Darren’s doing double duty thanks to Tet Zoo). I still think that the investment of blog posts with respectability, value, citability, or whatever rests entirely with readers, and always will. Options range from treating posts like papers to treating them like bar conversations to treating them like spam. You decide.

Also, I tried to keep the writing above value-neutral but probably failed. It’s hard not to get a bit evangelistic about the potential advantages of online publication and online everything else, a tendency I call DISSUADE: Da Internet Shall Save Us All Dead-trees Excepted. Getting published in science hasn’t always been easy up until now, but the process has been relatively clear and familiar. And stable, on decadal and even centennial timescales. Everything about scientific publication is about to get much more fluid and much less clear, and it will probably stay that way for a long time, and it may stay that way forever. Not all of the changes will be for the better, and it may be hard to decide what’s better and what’s worse until we look back with some perspective. Mechanical looms were bad for weavers but good for everyone else. I think many of the changes discussed in this post and the previous comment thread are likely, and some are inevitable.

Set against the shiny digital future is the inertia of the academy and those of us who roost there. I’m not going to stop publishing papers in dead-tree journals (although I will never publish in a journal that doesn’t provide PDFs to authors). Heck, I’m not even going to stop publishing in closed-access journals, some of which are run by societies I admire and want to participate in (after all, everything is open anyway). At the same time I will keep blogging, and while I will frequently bring up technical stuff I don’t want to publish more formally (at least not yet), I will try not to deliberately blur the lines any more than I already have. I don’t need to; the web is already blurring them faster than most of us can keep up.

Hang on.

Oh, about that mystery vert…

Metapophyses, I haz them

…at the end of the post Necks Lie. Nima called it–good spot on the split neural spine. It’s a mid-cervical of Barosaurus, AMNH 6341, in the big bone room (well, one of many big bone rooms) at the American Museum of  Natural History in New York. A cast of this vertebra makes up part of the neck in the awesome mounted skeleton in the museum rotunda. Here’s that skeleton, with Mike for scale.

Thanks for slogging through all this. We’ll get back to perforated postcentrodiapophyseal laminae, sacralized caudal transverse processes, and the air space proportions of pneumatic vertebrae soon.

Addendum (from Mike)

Matt is much more ready than I am to throw away peer-review, editorial control, and journals in general.  Sometimes, the reasons that things are the way they are, are good ones; it’s not in the interests of professional iconoclasts like Clay Shirky and Cory Doctorow to point that out or to discuss the strengths of how things are today, but that doesn’t mean we have to accept their arguments as uncritically as (say, to pick a name out of the air completely at random) Matt.

Anyway, happily, G. K. Chesterton foresaw the abolition of journals in favour of blogs, and commented thus:

Suppose that a great commotion arises in the street about something, let us say a lamp-post, which many influential persons desire to pull down. A grey-clad monk, who is the spirit of the Middle Ages, is approached upon the matter, and begins to say, in the arid manner of the Schoolmen, “Let us first of all consider, my brethren, the value of Light. If Light be in itself good–” At this point he is somewhat excusably knocked down. All the people make a rush for the lamp-post, the lamp-post is down in ten minutes, and they go about congratulating each other on their unmediaeval practicality. But as things go on they do not work out so easily. Some people have pulled the lamp-post down because they wanted the electric light; some because they wanted old iron; some because they wanted darkness, because their deeds were evil. Some thought it not enough of a lamp-post, some too much; some acted because they wanted to smash municipal machinery; some because they wanted to smash something. And there is war in the night, no man knowing whom he strikes. So, gradually and inevitably, to-day, to-morrow, or the next day, there comes back the conviction that the monk was right after all, and that all depends on what is the philosophy of Light. Only what we might have discussed under the gas-lamp, we now must discuss in the dark.

- Heretics (1905).

Blog posts, papers, and the brave new digital world: your thoughts are welcome

A new perspective, or the same old thing?

Brachiosaurus and friends from here (hat tip to Ville Sinkkonen).

In an e-mail with explicit permission to quote, our colleague Casey Holliday sent the following thoughts about our new paper and the subsequent ten days of related blogging:

I don’t know guys. I like your blogs, and your papers are fine. And I liked this paper. And I’m a fan.  But it looks to me that you blogged about far more data, in- or not in support of your paper than you actually presented in your paper. So,…wtf? The posts on Dinomorph far exceeded your (or any) published rebuke. Your explanation (and honorable erred parts) of the semicircular canal data also exceeded that actual published part too, with extra photos, description etc. (is that error going to be OA published too?) Also additional pix of necks (e.g., Nigersaurus), and not only from sauropods that would have
potentially bettered the original pub. So what’s fair? Why weren’t
these data also included in the publication? Maybe it’s not my business and was taken up in review…I don’t know. Frankly, none of this blog stuff really counts in the peer-reviewed world of “real” publications. Its not like this blogging and comments all count as Supplementary Data either. But also, I’m obviously here commenting on it, so also crossing into the fray…But who really cares about all this discussion? Its no different than the DML or any other noise in the internet world (or is it). Similar to what Paul Barrett was posting on Tet Zoo…what counts? Why take up arguments here, when they should (maybe?likely?) be taken up more formally and privately.

If you’re going to air all this additional data and unreviewed
opinion, then I think this discussion is important.

I think this phenomenon of the sauropod neck paper is really
interesting. We have 3 scientists that published a paper, and then, thanks to their current blogosphere cred, basically unleashed a hype not seen in this way previously that I can remember. Maybe that’s the interesting part? and kudos. But interestingly…we’re seeing this intersection of traditional publication (OA or not), blogosphere description, and perhaps, almost certainly, excellent self-promotion.

I’m still a fan. I think this paper is generally solid. But I’m
particularly interested in this phenomenon and hope this is a fair
place to raise it.

The comment field is open, and we SV-POW!sketeers are going to refrain from commenting for a couple of days to let the conversation develop unfettered.

We are genuinely curious to know what you think.

Neck posture, yet again: T. rex’s neck is pathetic

Here at SV-POW! Towers, we often like to play Spot The T. rex — a simple drinking game that can be played whenever you have supply of palaeontology-related news reports.  Each player in turn takes a report off the stack, and if T. rex is mentioned anywhere in the report, the player drinks.  We lay in a lot of beer when we play this game, because as it turns out, T. rex is nearly always mentioned (and nearly always spelled “T-Rex”, no italics, no full stop, gratuitous hyphen, capitalised trivial name).  For example, suppose someone publishes an innocent paper arguing that a particular Eocene clam was an obligate scavenger: then the story in the press will be “… just as has been argued for the terrifying T-Rex, which had teeth like steak knives”.  Or if someone names a new Miocene rodent, it will be introduced as “… which lived 50 million years after the terrifying T-Rex, which had teeth like steak knives”.   (Drink twice if the steak knives are mentioned.  Three times if they are described as “banana-sized”.)

So we didn’t feel our neck-posture paper was real until it had somehow been tied in with T-Rex.  Happily, the Great North Museum came to the rescue: by coincidence, they unveiled their T. rex cast the weekend before the paper came out, and the Sunday Sun wanted our opinion on the way the neck had been mounted.  Here’s their mount (not quite ready to exhibit):

Tyrannosaurus rex mounted skeleton at the Great North Museum. From journallive.co.uk

Of course, everything we said about the necks of sauropods in the paper also applies to every other extinct land vertebrate — we only concentrated on sauropods because (A) they are the group whose neck posture has been claimed to depart from the tetrapod norm, and (B) they are cool.  In particular, non-avian theropods such as T. rex are in the same extant phylogenetic bracket as sauropods are (i.e. birds plus crocs), so we’d expect strong extension at the base of the neck and strong flexion at the head joint in habitual pose.

So I replied that “the Newcastle mount has the neck and torso in more of a straight line [than a Vidal-compliant posture], which would probably not have been the habitual pose.  It looks to me as though this animal is crouching down to take a drink”, and I’m pleased that the resulting news story included a rather gracious response from the GNM curator.

I don’t know whether the notoriously litigious Disney corporation would be so mellow, though, regarding their truly horrible mount of a cast of “Sue”:

Tyrannosaurus rex "Sue" cast, at Animal Kingdom, Walt Disney World, Florida. From wwarby's Flickr photostream.

I’m really not sure what the people who mounted this were getting at: unlike the Great North Museum mount, the legs are erect, so it’s not going into or coming out of a crouch; and it’s not going into a drinking posture, because the head is pointing straight forward.  But for some reason, it’s below shoulder height.

Here’s how it should be done:

Tyrannosaurus rex at the American Museum of Natural History. Photo by Mike Taylor

It’s good to see that the biggest natural history musuem in the world is ahead of the curve, and has its T. rex mount in a pose consistent with how other land vertebrates habitually hold their necks.

I leave you with the news the T. rex’s neck is pathetic.  Here is the skull and neck of that same AMNH mount, composited with a single cervical vertebra (C8) of Sauroposeidon.  Please note that the Sauroposeidon cervical is way longer than the whole T. rex neck.

T. rex's neck is pathetic

No references today!

[You don't need to be told the reference for Taylor et al. (2009) again, do you?]

Range of motion in intervertebral joints: why we don’t trust DinoMorph

Wait, what?  So let’s assume for a moment that you accept our contention (Taylor et al. 2009) that, since extant terrestrial tetrapods habitually hold their necks in maximal extension, sauropods did the same.  That still leaves the question of why we have the neck of our Diplodocus reconstruction at a steep 45-degree angle rather than the very gentle elevation that Stevens and Parrish’s (1999) DinoMorph project permits.

As a reminder, here is fig. 6A of Stevens (2002), a paper on the computer science behind DinoMorph which used exactly the same models as the 1999 study but which conveniently illustrates them in lateral view:

Stevens (2002: fig. 6A), illustrating the fully extended, neutral and fully flexed poses attainable by Diplodocus according to the original DinoMorph model

As you’ll see, not only does the neutral pose show the characteristic subhorizontal neck with the drooping end, but even the maximally extended pose barely gets the head above the level of the back.  In the most recent version of his Diplodocus model, Kent has slightly changed the angle at which the neck leaves the torso, due to a reconfiguration of the pectoral girdle, but this still leaves the neck very low.

So why did we do this?

Diplodocus carnegii head, neck and anterior torso, right lateral view, articulated in habitual posture as hypothesised by Taylor et al. (2009). Skull and vertebrae from Hatcher (1901).

Doesn’t the DinoMorph model show that the posterior cervicals just can’t do this?

Well, maybe not.

Remember that the precursor to the DinoMorph project was John Martin’s (1987) paper on the mounting of the Rutland cetiosaur at the Leicester City Museum, in which he calculated neutral pose and the extreme extended and flexed poses by manipulating actual bones without the benefit of a computer.  Martin ended up with a similar result to that Stevens and Parrish were later to get:

Martin (1987:fig. 2) showing claimed limits of extension of and flexion in the neck of the Rutland cetiosaur

But when Matt and I looked at the actual mounted skeleton a few years back, what we saw didn’t fit with this at all:

Rutland cetiosaur, anterior part of neck in right lateral view, showing extreme disarticulation between the cotyle of C4 and condyle of C5

Check out that huge gap between the centra of the fourth and fifth cervicals!  There’s no way to avoid this without putting a comically extreme downward kink in the neck at this point.  And there are similar gaps at other points along the neck, including some near the neck-base that would require a strong upward kink in order to articulate both the centra and the zygapophyses simultaneously.

Are we saying that in life, this specimen did have strong kinks in the neck?  No, we’re not (despite the pleasant coincidence that this would force the neck into an extreme version of the elevated pose we’re advocating).  What we’re saying is that sauropod cervicals are rarely — I’d go so far as to say never — preserved undistorted, and so you just can’t rely on how they seem to articulate, at least not for quantitative analyses.  This post-mortem distortion should not be too surprising: unlike femora and other such solid bones, remember that the cervicals were highly pneumatic and composed primarily of laminae, which would be subject to all sorts of taphonomic and diagenetic distortion.  In the extreme case of Sauroposeidon, the cervicals, which were up to 140 cm in length, “are of extremely light construction, with the outer layer of bone ranging in thickness from less than 1 mm (literally paper-thin) to approximately 3 mm” (Wedel et al. 2000:110-111) — it’s astonishing that they are not much more smushed up than they are.

So Martin’s cetiosaur seems too distorted to give meaningful articulation results, but what about the specimens that Stevens and Parrish used for the DinoMorph paper?  Well, the Apatosaurus model is certainly based on questionable material.  As pointed out by Upchurch (2000):

A second difficulty with Stevens and Parrish’s analysis is that their data for Apatosaurus was derived from a single specimen in the Carnegie Museum (CM 3018). This generally well preserved specimen has suffered severe damage at the base of the neck, and the three most posterior cervicals are thus represented by plaster models that cannot provide reliable anatomical data (Gilmore 1936, pers. obs.). Although Stevens and Parrish acknowledge that the morphology of the posterior cervicals is particularly influential in determining the nature of the feeding envelope, they do not mention this problem, and it is not clear how this gap in the data was addressed in their analyses. This deficit could have had a profound impact on Stevens and Parrish’s conclusions.

And Gilmore’s observations are really rather damning: as well as the account of the damaged neck-base, he also noted (p. 195) that “the type of A. louisae [i.e. CM 3018] lacks most of the spine tops, only those of cervicals eight, ten and twelve being complete”.  (You would NEVER guess this from Gilmore’s Plate XXIV, which shows all of the cervicals but C5 essentially complete.)  So all in all, the DinoMorph study’s Apatosaurus is not one I’d want to build an argument on.

What about the Diplodocus carnegii holotype CM 84, which is the Diplodocus used in the DinoMorph papers?  That’s just about the best preserved sauropod skeleton in the world, right?  Well, yes.  But even that is distorted enough that the neck can’t be articulated without some sleight of hand.  I don’t have good photos of the mounted neck, unfortunately (and probably won’t have until someone at the NHM gives me a stepladder and access to the holy of holies that surrounds the mount), but I did have the experience of photoshopping the cervcial vertebra illustrations from Hatcher (1901: plate III)  in an attempt to get them into a good pose, and I found that even these don’t really fit properly:

Diplodocus carnegii holotype CM 84, partial neck (cervicals 6-9) in right lateral view, composed from elements in Hatcher (1901: plate III)

You’ll see that, while the condyles are sat nicely in the cotyles, the zygapophyses are not at all well articulated: in particular, the C7-C8 and C8-C9 junctions have the prezygs shoved much too far forward, so that a double downward kink would be necessary to accomodate these articulations without pulling the condyles out of the cotyles.

Finally, while Matt and I were in Berlin last November, as part of the excursion associated with the awesome all-sauropod-gigantism-all-the-time workshop, we got to play with the superbly preserved set of anterior brachiosaur cervicals HMN SI, and we tried to articulate the real bones.  We had to stop for fear of breaking them, because they simply would not fit nicely together.

In conclusion, the distortion of all sauropod cervicals renders them poor subjects for quantitative analysis such as that of the DinoMorph project.  While the approach of Stevens and Parrish is a real and valuable contribution to rigour in the analysis of posture, the output of DinoMorph is a hypothesis to be tested by other lines of evidence rather than a firmly established fact.  (That last bit was quoted verbatim from our paper.)

I’ve gone on much longer than I intended to in what was supposed to be a quick-and-easy post, so I’ll leave it here.  In order to keep the recent paper short and snappy, we didn’t go into this in much detail, summarising down to a mere 88 words (Taylor et al 2009: 216-217), so maybe this will bear repeating (in more rigorous form) in a future publication.

References

• Gilmore, C.W.  1936.  Osteology of Apatosaurus with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11: 175-300.
• Hatcher, J.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.
• Martin, J. 1987. Mobility and feeding of Cetiosaurus (Saurischia, Sauropoda) ­ why the long neck? In: P.J. Currie and E.H. Koster (eds.), Fourth Symposium on Mesozoic Terrestrial Ecosystems, Short Papers, 154­-159. Box-tree Books, Drumheller, Alberta.
• Stevens, K.A. 2002. DinoMorph: Parametric modeling of skeletal structures.  Senckenbergiana lethaea 82(1): 23-34.
• Stevens, K.A. and Parrish, J.M. 1999. Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284: 798­-800. [Free subscription required]
• Taylor, M.P., Wedel, M.J. and Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54(2): 213-220.
• Wedel, M.J., Cifelli, R.L. and Sanders, R.K. 2000. Sauroposeidon proteles, a new sauropod from the Early Cretaceous of Oklahoma. Journal of Vertebrate Paleontology 20, 109-114.

end

Sauropod neck posture: the world responds

[I wrote this in the cafe on the ground floor of the BBC's Millbank studios, where I spent much of yesterday, just before I headed off for Paddington and the train home.  I have lightly edited it since the original composition.]

It’s been a day spent doing publicity for the new SV-POW! paper on sauropod neck posture.

Two sauropod neck postures for the price of one: Diplodocus (foreground, low neck) and Brachiosaurus (background, high neck) at the Humboldt Museum fur Naturkunde, Berlin.

Overall, there’s been a little less interest than we were able to rustle up for Xenoposeidon, but we nevertheless got a live TV interview on Channel 4 News, plus radio interviews on BBC Radio 4’s Today programme, BBC Scotland, BBC Radio Solent (twice) and finally BBC Wales (which turned out to be my favourite).  In the mean time, Darren was being interviewed on BBC Radio 5 Live.  So a very BBC-centric day, with Channel 4 the only independent to take up the story.  (That contrasts with Xeno, when I seemed to spend the whole day doing interviews on the mobile phone for various independent radio stations as I was rushing between studios for the big boys.)

We got pretty good coverage in print, too.  I bought all the national dalies and went through looking for sauropod-neck news.  There was a good third-of-a-page story in Guardian (thanks to their fine science reporter Ian Sample who also did such a good job on Xeno), and smaller spots in the Times and Independent.  The Telegraph, oddly, in included a nice photo of the NHM Diplodocus with an inset of Mark Witton’s artwork, but accompanied it with no text other than a 38-word caption. Go figure.  There were brief mentions in the early editions of the Mirror and Sun, although they dropped out in later editions; I couldn’t find anything in the Mail, the Express or the Star — I think that’s everything.  There was a nice bonus in Metro, London’s free daily, which had half a page on the story including a nice big photo of the Berlin brachiosaur, with me by its elbow for scale.

As I write this, I’ve not been able to check on the net and see what the online coverage has been like, beyond a very quick informal scan this morning before I left the house I was staying at for the first radio interview.  I did find a story in the Times that was considerably more detailed that what made it into the print edition, so the same may have been true of other papers, too.  I’ll see what Google News digs up for me when I get home.  [Update: we're tracking Internet coverage on this page.]

A few themes emerged as the sequence of interviews progressed.  Most predictably, lots of interviewers wondered whether this meant that the NHM would have to remount its Diplodocus skeleton.  Not at all: the pose that it’s in is still a perfectly valid one, which it would have gone through in the transition between drinking and browsing poses; it’s just not what we think would have been the habitual pose.  Paul Barrett was quoted for the counter-view in several of the printed reports, and made that point (though usually it was reported in truncated form).  The BBC web-site’s coverage was unusually good in carefully reporting what we’d actually told everyone, that the mounted pose is one that would have been adopted from time to time, so hopefully no-one at the NHM will come away from thinking we were getting at them.

Another recurring theme was whether Seymour’s blood-pressure argument was good evidence that our proposed habitual posture is wrong.  I didn’t want to say too much about this, because our thoughts on the subject are still in the process of approaching their final form and are not ready to be published, but hopefully I was able to say enough to satisfy the interviewers and listeners without giving it all away.

Another point that I tried to make when given the opportunity is that we don’t see this paper as closing the debate and settling the issue of posture once and for all — as if that could ever happen for any palaeobiological controversy.  What we hope we’ve done is at least to reopen the debate and the end the unchallenged reign of the DinoMorph-compliant hangdog pose.  Needless to say, plenty of work remains to be done on the issue of neck posture, and there are now at least two published arguments in favour of each candidate posture. The time may be ripe for a review article.  For now, though, we confidently expect a published response from Kent “DinoMorph” Stevens, who we’ve discussed our work with at some length, and who has had a preprint for a few weeks now so that he could get working on it!  Ah, the cut and thrust of debate — bring it on!

Update (later the same evening)

I have finally managed to make an MP3 of the last interview — the second one with BBC Radio Solent, with Sasha Twining who was standing in on the Steve Harris Show.

And a plea for help: although the Channel 4 News interview is still available on Channel 4’s own site, I know it won’t last for long — probably no more than a week — so if anyone is able to make an MPEG, AVI, FLV or similar of these, please please do, and send it my way.  Thanks!

Sauropods held their necks erect … just like rabbits

Welcome, one and all, to Taylor, Wedel and Naish (2009), Head and neck posture in sauropod dinosaurs inferred from extant animals.  It’s the first published paper by the SV-POW! team working as a team, published in Acta Palaeontologica Polonica, and freely available for download here.

Far, far back in the uncharted depths of history, silly people like Osborn and Mook (1921:pl. 84), Janensch (1950b: pl. 8) and Paul (1988:fig. 1), who didn’t know any better, used to depict sauropods with their necks held strongly elevated.

The classic reconstruction of Brachiosaurus brancai, from Janensch (1950b: plate VIII. (For some reason, WordPress doesn't allow italics in these captions, hence the roman-font taxonomic names.)

All that began to change with Martin’s (1987) short paper in the Mesozoic Terrestrial Ecosystems volume, and was then turned upside-down by Stevens and Parrish’s (1999) seminal paper in Science: two and a half pages that transformed the way the world looked at sauropods.

The subhorizontally mounted neck of the Rutland Cetiosaurus skeleton at the Leicester City Museum, in right posterolateral view.

The median part of the subhorizontally mounted neck of the Rutland Cetiosaurus skeleton at the Leicester City Museum, in left lateral view. Mike Taylor for scale.

John Martin looked at the cervical vertebrae of the Rutland specimen of Cetiosaurus oxoniensis, and concluded that the joints between them couldn’t be as flexible as people thought.  He reconstructed that animal’s neck in a low, near-horizontal pose, and with a very narrow range of movement that didn’t allow it to raise its head far above shoulder level.  Stevens and Parrish brought more rigour to this approach by modelling the cervical articulations of two sauropods (Diplodocus carnegii and Apatosaurus lousiae) using a computer program of their own devising, DinoMorph.  And as most SV-POW! regulars will probably know, they got results similar to Martin’s, showing neutral positions for both animals that were well below horizontal, and finding restricted ranges of motion.  (“neutral pose” here means that the vertebra are aligned such that the zygapophyses overlap as much as possible.)

Diplodocus carnegii, DinoMorph computer model , showing neutral neck posture, and limits of dorsal and ventral flexibility. From Stevens (2002:fig. 6a). (Note that Stevens's more recent models show a slightly higher neck due to its leaving the torso at a less steep angle.)

The DinoMorph posture was quickly adopted as orthodox, and got a lot of exposure in the BBC’s classic CGIumentary, Walking With Dinosaurs: episode 2, Time of the Titans, was primarily about Diplodocus, and under Stevens’s consultancy showed them as having obligate low posture throughout the show.

A still from Walking With Dinosaurs, episode 2, Time of the Titans, showing Diplodocus in a DinoMorph-compliant posture with a low, horizontal neck. Image copyright the BBC.

The new horizontal-neck orthodoxy was also reinforced by an exhibition at the American Museum of Natural History featuring a physical metal sculpture of a DinoMorph model:

Physical DinoMorph model at the AMNH, with horizontal-neck advocate Kent Stevens. Photograph by Rick Edwards, AMNH

This brings us pretty much up to date: there’s been very little in the way of published dissent between 1999 and now, and a couple more Stevens and Parrish papers have reinforced their contention.  Upchurch (2000) published a half-page response to the DinoMorph paper, and Andreas Christian has put out a sequence of papers arguing for an erect neck posture in Brachiosaurus brancai on the basis that this best equalises stress along the intervertebral joints (e.g. Christian and Dzemski 2007), but otherwise all dissent from the DinoMorph posture has been limited to unpublished venues: for example, Greg Paul has posted several messages on the Dinosaur Mailing List disputing the low-necked posture, but has yet to put any of his arguments in print.

But enough of this dinosaury stuff.  Let’s look at a nice, cuddly bunny:

Now here’s the thing: you wouldn’t guess by looking at it, but that rabbit has a vertical neck.  In fact, it’s more than vertical: it’s so upright that it bends back on itself.  Don’t believe me?  Then take a look at this X-ray of an unrestrained awake rabbit:

Unrestrained awake rabbit, left lateral view, in X-ray, showing vertical neck. From Vidal et al. (1986:fig. 4B)

Amazing.

Can it be that rabbits have unusual cervical vertebrae, such that when you articulate them in neutral pose they curve strongly upwards?  No: and to prove it, here is (ahem) Taylor, Wedel and Naish (2009: fig. 1):

Taylor et al. (2009: fig. 1), reversed for easy comparison with the previous two images: skull and cervical skeleton of the Cape hare (Lepus capensis) in neutral pose and in maximal extension

(Yes, this is a hare rather than a rabbit, but it’s close enough for government work.)  What we found was that it was only possible to get the cervical skeleton anywhere near the habitual life posture by cranking all the proximal cervical joints up as far as they could physically go.  In fact, it seems that some of the joints in the live animal flex more than the dry bones can — presumably due to intervertebral cartilage moving the centra further apart.

And this is fully in accord with the findings of Vidal et al. (1986), who X-rayed a selected of life animals (human, monkey, cat, rabbit, rat, guinea pig, chicken, monitor lizard, frog) and found that the neck is inclined in all but the frog.  Furthermore, in all the mammals and reptiles, they found that:

• the cervical column is elevated nearly to the vertical during normal functioning;
• the middle part of the neck is habitually held relatively rigid;
• the neck is maximally extended at the cervico-dorsal junction and maximally flexed at the cranio-cervical junction; and
• it is the cranio-cervical and cervico-dorsal junctions that are primarily involved in raising and lowering the head and neck.

(In life, these facts are obscured from view by soft tissue.)

We also looked at unpublished live-alligator X-rays (thanks to Leon Claessens for access to these) and found that even in these ectothermic sprawlers, the neck is habitually elevated above neutral pose.  Published X-rays of turtles and even (slightly) salamanders also showed the same tendency.

So what does this mean for sauropods?  Simply, unless they were different from all extant terrestrial amniotes, they did not habitually hold their necks in neutral position, but raised well above horizontal.  And if they resembled their closest relatives, the birds — and the only other homeothermic and erect-legged group, the mammals — then their necks were strongly inclined.  As in, all the proximal cervicals were habitually cranked into the most erect positions they could attain.  Kind of like this:

Diplodocus carnegii head, neck and anterior torso, right lateral view, articulated in habitual posture as hypothesised by Taylor et al. (2009). Skull and vertebrae from Hatcher (1901).

Which is a looong way form the DinoMorph posture that we were all getting used to but couldn’t learn to love.  What do you know?  Turns out that Osborn and Mook, and Janensch, were right after all.

So that, in a nutshell, is the contention of the first SV-POW! paper: that sauropods held their heads up high.  That’s not to say that they couldn’t bring them lower when they wanted to — of course they could, otherwise they’d have been unable to drink — but we believe the evidence from extant animals says that they spent the bulk of their time with their heads held high.

I leave you with this rather beautiful piece that noted pterosaurophile Mark Witton drew to illustrate our favoured posture.  Enjoy!

Diplodocus herd -- mostly with necks in habitual raised posture, with one individual drinking. By Mark Witton.

Stay tuned for more on neck posture …

Update

For more cool stuff about the paper, including blog and media coverage and the chance to hear Mike on BBC Radio(!), see our page about the paper on the sidebar.

References

• Christian, A. and Dzemski, G. 2007. Reconstruction of the cervical skeleton posture of Brachiosaurus brancai Janensch, 1914 by an analysis of the intervertebral stress along the neck and a comparison with the results of different approaches. Fossil Record 10: 38-­49.
• Janensch, W. 1950b. Die Skelettrekonstruktion von Brachiosaurus brancai. Palaeontographica (Supplement 7): 97-­103.
• Martin, J. 1987. Mobility and feeding of Cetiosaurus (Saurischia, Sauropoda) ­ why the long neck? In: P.J. Currie and E.H. Koster (eds.), Fourth Sympo- sium on Mesozoic Terrestrial Ecosystems, Short Papers, 154­-159. Box- tree Books, Drumheller, Alberta.
• Osborn, H.F. and Mook, C.C. 1921. Camarasaurus, Amphicoelias, and other sauropods of Cope. Memoirs of the American Museum of Natural History, new series 3: 246­-387.
• Paul, G.S. 1988. The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world’s largest dinosaurs. Hunteria 2 (3): 1­-14.
• Stevens, K.A. and Parrish, J.M. 1999. Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284: 798­-800. [Free subscription required]
• Taylor, M.P., Wedel, M.J. and Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54(2): 213-220.
• Upchurch, P. 2000. Neck posture of sauropod dinosaurs. Science 287: 547b.
• Vidal, P.P., Graf, W., and Berthoz, A. 1986. The orientation of the cervical vertebral column in unrestrained awake animals. Experimental Brain Research 61: 549­-559.

The land of the free papers redux

There is almost too much coolness going on right now. Here’s a brief rundown.

SV-POW! on Tour

Mike and I just got back to our respective homes from the AMNH, where we spent a crazy day in the big bone room and received illumination at the shrine of Barosaurus (above). We came back armed with a gig or so of cool pictures, some of which you’ll see here in the near future and some of which we’ll put off showing you until the relevant papers come out (hopefully!).

Sauropods on TV

When I checked e-mail Thursday night I found out that I had been on TV and not known it. The US-based Discovery Channel spinoff Animal Planet is running an 8 episode series called Animal Armageddon, about the great mass extinctions. I’m in the two episodes devoted to the KT. I expected that they would run the episodes in the same order as the extinctions occurred, but they’re not, which I would have known had I checked the handy-dandy episode guide here (there’s one at the Animal Planet website, too, but all their animated geegaws make both me and my computer nauseated). Why is this relevant here? Because some of my talking-head time was given over to Alamosaurus, which will be on this week’s episode if it survived the cutting room floor. Tune in Thursday, March 5, at 9 PM Eastern/Pacific to find out.

Free Papers That Are Actually Free

Finally, what about the titular free papers? SV-POW! and Tet Zoo regular Ville Sinkkonen turned up some goodies at the Biodiversity Heritage Library and passed them on to me, and now I am passing them on to you:

Holland, W.J. 1915. A new species of Apatosaurus. Annals of the Carnegie Museum 10:143-145. [page] [PDF]

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(18)1-21. [page] [PDF]

Young, D. 1975. Brachiosaurus, the biggest dinosaur of them all. Field Museum of Natural History Bulletin 46(1):3-9. [page] [PDF]

Jensen, J.A. 1987. New brachiosaur material from the Late Jurassic of Utah and Colorado. Great Basin Naturalist 47:592-608. [page] [PDF]

These are far from the only sauropod papers at the BHL; in fact, they are just the tip of the iceberg. I’m listing these four specific papers because they’re the ones Ville sent and because they exist as stand-alone PDFs. For others that you find, you can either download a PDF of the entire volume in which the paper was published, or use a nifty online PDF generator to make a PDF of just the pages you want. Click the “Download/About this book” tab on the bar above the page viewer and then “Select pages to download”. User-generated PDFs will be hosted by the BHL for a while but not forever. Ville reports that the ones listed above should be good for 30 days (through the end of March 2009); after that you’ll have to make your own. Which is not onerous at all, considering how much literature is being made available for free here. The glass is not just half full, it is running over. Go slake your thirst for obscure sauropod papers, and don’t forget to hoist a metaphorical glass to Ville, or a real one if you get the chance!

The sauropods of Star Wars: Special Edition

I ended the last post with this teaser:

There is another sauropod (sort of) in Episode IV (sort of), but I’ll wait a week before I blab about that one. I wonder if anyone will guess what it is in the meantime?

The mystery lasted all of a single comment. Several of you got it right, but the title of First (w00t w00t LOL!!1!!11!!) goes to Paul and his terse, “Would it be a ronto?”

It is apparently no secret that the Rontos briefly glimpsed in A New Hope: Special Edition and The Phantom Menace are morphed versions of the Brachiosaurus from Jurassic Park.

Here’s the official line, from the Star Wars Databank entry:

The rontos added into the Mos Eisley scenes for the Special Edition release of A New Hope are entirely computer-generated. It was a cousin of sorts to the digital models crafted for Jurassic Park; the ronto used a brachiosaur as a starting point with enough modification to make it distinctly Star Wars. Throughout the making of the sequence, the ILM animators referred to the otherwise nameless creature as a “bronto.” When asked to name the animal, George Lucas dropped the ‘b’ from the name, and thus the ronto was christened.

So now you know.

Rontos are apparently allergic to photography (possibly related to Nessie?), as I found just about zip for decent images in my exhaustive 10-minute web search.

I did learn that there is a competitive rib-eater named Ronto, who got a beat-down from Joey Chestnut, who ate 8.4 lbs of ribs in 12 minutes. Someday I will do a post about all the wacky search terms that bring people to SV-POW! “Basement” is always in the top 20, which must be a surprise for those folks who just want to remodel their cellar.

ANYWAY, the link to Brachiosaurus, no matter how tenuous, gives me an excuse to post this:

Next week we’ll get back to science. Almost certainly.

The sauropods of Star Wars

I’m sure Mike will deride this as sordid linkbait, but what the heck. I’ve been meaning to blog about the sauropods of Star Wars for a while now, and I was finally spurred into action by this comment over at TetZoo.

The first (and best) sauropod of Star Wars will be no surprise to anyone with reasonably sharp eyes and rudimentary knowledge of sauropod osteology: the Krayt dragon skeleton that C-3PO walks past on Tatooine is composed mainly of cast sauropod vertebrae.

You can see that the monster’s cervicals have big cervical rib loops. The deeply bifurcated neural spines mean that they are either from a diplodocid or Camarasaurus. Some of them are also fairly long and low-spined, especially those close to the head, which rules out Camarasaurus. I find the purely fictional skull pretty unconvincing next to the real (cast) sauropod vertebrae.

Moving on down the series, we see that all of the dorsals have high neural spines, some of which are deeply bifurcated, which again is consistent with diplodocids but not with Camarasaurus, whose bifurcated spines are all short (and fairly ugly).  The vertebrae also have broad transverse processes that give them a ‘t’ shape. You can see that whoever laid out the dorsals scrambled their order (perhaps deliberately) so that the deeply cleft vertebra in the middle is bordered ahead and behind by verts with little or no bifurcation of the neural spine. In articulated diplodocids, the neural spine cleft first appears in the anterior cervicals, grows larger and deeper through the rest of the neck, and then disappears around the middle of the dorsal series.

So which diplodocid is it? My vote is Diplodocus, probably a cast of the mounted Carnegie skeleton like the one shown here in London’s Natural History Museum (this particular mount turns up here at SV-POW! quite frequently). The cervical rib loops of the anterior cervicals attach near the bottoms of the centra instead of hanging far below them as in Apatosaurus. Also, you can see below that the cervical ribs loops of the posterior cervicals are narrow, as in Diplodocus, but not Apatosaurus (images of Diplodocus cervicals are from Hatcher’s 1901 monograph).

The final piece of evidence for the Diplodocus ID is a closeup of part of one of the vertebrae. According to Wookieepedia (from which I stole the Ep IV screencap I’ve used throughout this post) Lucas and crew left the prop skeleton out in the desert when they were done shooting back in the 70s, and rediscovered it when they returned to Tunisia to film the Tatooine sequences for Attack of the Clones. I don’t know if the skeleton was scavenged by prop hunters before, during, or after the ATOC filming, but pieces of the skeleton turn up on movie prop sites, including the one shown here:

This is a cervical rib of a sauropod, and it looks to me more like the slender ribs of Diplodocus than the massive ribs of Apatosaurus. I could be wrong about the genus, but if the bones in the movie don’t belong to Diplodocus they have to be Apatosaurus, and the balance of the evidence points to Diplodocus.

Oddly enough, Wikipedia states that, “The artificial skeleton used for the movie was left there after filming and still lies in the Tunisian desert. During filming of Attack of the Clones, the site was visited by the crew and the skeleton was still found there. The skull used resembles that of a Diplodocus, a herbivorous dinosaur related to the Apatosaur” (emphasis added). Good call, Wiki-trolls.

The “Krayt dragon” locality has been visited, and blogged about, by paleontologist and paleo-blogger Michael Ryan.

One more thing: Diplodocus and Apatosaurus both have 25 presacral vertebrae. The photo above is not crisp enough to determine precisely how many vertebrae are in the cervical+dorsal regions, but it’s more than 25. Also, none of the dinky anterior cervicals of Diplodocus are visible. So I think they must have gotten two sets of presacrals (possibly two whole columns) and used only the bigger vertebrae. I wonder what happened to the verts they didn’t use…I’d give a non-essential organ for a cast Diplodocus cervical.

That’s it for this one. There is another sauropod (sort of) in Episode IV (sort of), but I’ll wait a week before I blab about that one. I wonder if anyone will guess what it is in the meantime?