Hey sports fans, as the year winds down I bring you another podcast appearance. This time out I’m rolling with Mark Hallett, and we’re talking about sauropods through the lens of our still-plausibly-somewhat-newish book, The Sauropod Dinosaurs: Life in the Age of Giants, on the I Know Dino podcast. Many thanks to Sabrina and Garret for having us on the show. While you’re on that page, check out the nice preview of Mark’s 2018 dinosaur calendar, which is available at Pomegranate and Amazon.

The photo shows the Diplodocus carnegii cast mounted in the natural history museum in Vienna, one of Andrew Carnegie’s gifts to the world. A happy seasonal metaphor, sez me. Hope your new year is equally happy!

Advertisements

I have used this photo in loads of talks, but as far as I can tell, this is the first time I’ve put it up on SV-POW! (I am certain that, having said that, someone will find a previous instance – if so, consider this an extremely inefficient and lazy form of search.) The vert is OMNH 1670, the most complete and nicest dorsal of the giant Oklahoma apatosaurine, probably a D5 or D6. That’s me back in 2004. Photo by my then fellow grad student in the Padian lab, Andrew Lee. I’m 6’2″ and have normally-proportioned human arms, but if you’re trying to figure out the scale, that vert is 135cm tall, with an anterior centrum face 38cm tall by 46cm wide (partly reconstructed but probably accurate). See this post for more details and a fairly exhaustive list of measurements.

Here’s a stupid thing: roughly 2-3 times a year I go to the field or to a museum and get hundreds of SV-POW!-able photos. Then I get back to the world and catch up on all of the work that piled up while I was away. And by the time I’m done with that, whatever motivating spark I had – to get some of those photos posted and talk about the exciting things I figured out – has dissipated.

Case in point – this bitchin’ shark, prepped in ventral view, which I saw last month in the natural history museum in Vienna. Look at that fat, muscular tail – this shark is swole.

That’s dumb. And this blog is in danger of slipping into senescence, and irrelevance.

So here’s my New Year blog resolution for 2018: I’m getting us back to our roots. I, or we – I am taking this plunge without consulting with Mike (surprise, buddy!) – will post a new, never-posted-before photo, at least once a week, for the whole year. It may not always be a sauropod vertebra, but if often will be, because that’s what I have the most of, and the most to yap about. And I will try to write something interesting about each photo, without lapsing into the logorrhea that has too often made this blog too exhausting to contemplate (at least from this side of the keyboard).

Wish me luck!

This was an interesting exercise. It was my first time generating a poster to be delivered at a conference since 2006. Scientific communication has evolved a lot in the intervening decade, which spans a full half of my research career to date. So I had a chance to take the principles that I say that I admire and try to put them into practice.

It helped that I wasn’t working alone. Jann and Brian both provided strong, simple images to help tell the story, and Mike and I were batting ideas back and forth, deciding on what we could safely leave out of our posters. Abstracts were the first to go, literature cited and acknowledgments were next. We both had the ambition of cutting the text down to just figure captions. Mike nailed that goal, but my poster ended up being slightly more narrative. I’m cool with that – it’s hardly text-heavy, especially compared with most of my efforts from back when. Check out the text-zilla I presented at SVP back in 2006, which is available on FigShare here. I am happier to see, looking back, that I’d done an almost purely image-and-caption poster, with no abstract and no lit cited, as early as 1999, with Kent Sanders as coauthor and primary art-generator – that one is also on FigShare.

I took 8.5×11 color printouts of both my poster and Mike’s, and we ended up passing out most of them to people as we had conversations about our work. That turned out to be extremely useful – I had a 30-minute conversation about my poster at a coffee break the day before the posters even went up, precisely because I had a copy of it to hand to someone else. Like Mike, I found that presenting a poster resulted in more and better conversations than giving a talk. And it was the most personally relaxing SVPCA I’ve ever been to, because I wasn’t staying up late every night finishing or practicing my talk.

I have a lot of stuff to say about the conference, the field trip, the citability of abstracts and posters (TL;DR: I’m for it), and so on, but unfortunately no time right now. I’m just popping in to get this posted while it’s still fresh. Like Mike’s poster, this one is now published alongside my team’s abstract on PeerJ PrePrints.

I will hopefully have much more to say about the content in the future. This is a project that Jann, Brian, and I first dreamed up over a decade ago, when we were grad students at Berkeley. Mike provided the impetus for us to get it moving again, and kindly stepped aside when I basically hijacked his related but somewhat different take on ontogeny and serial homology. When my fall teaching is over, I’m hoping that the four of us can take all of this, along with additional examples found by Mike that didn’t make it into this presentation, and shape it into a manuscript. I’ll keep you posted on that. In the meantime, the comment field is open. For some related, previously-published posts, see this one for the baby sauropod verts, this one for CM 555, and this one for Plateosaurus.

Flying over Baffin Island on the way home.

And finally, since I didn’t put them into the poster itself, below are the full bibliographic references. Although we didn’t mention it in the poster, the shell apex theory for inferring the larval habits of snails was first articulated by G. Thorson in 1950, which is referenced in full here.

Literature Cited

 

Or, how a single lateral fossa becomes two foramina: through a finely graded series of intermediate forms. Darwin would approve. The ‘oblique lamina’ that separates the paired lateral foramina in C6 starts is absent in C2, but C3 through C5 show how it grows outward from the median septum. How do I know it grows outward, instead of being left behind during the pneumatization of the more posterior cervicals? Because with very few exceptions, all neosauropod cervicals start out with a single lateral fossa on each side, as illustrated in this post. But many of them end up with two or more foramina. Diplodocus is a nice example of this (from Hatcher 1901: plate 3):

I should clarify that the vertebrae above show that character transformation in this individual, at this point in its ontogeny. The vertebrae of CM 555 are about two-thirds the size of those of CM 3018, the holotype of A. louisae. In CM 3018, even C4 and C5 have completely divided lateral fossae, corresponding to the condition in C6 of CM 555.

As Mike and I discussed in our 2013 neural spine bifurcation paper, isolated sauropod cervicals require cautious interpretation because the morphology of the vertebrae changes so much along the series. The simple morphology of anterior cervicals reflects both earlier ontogenetic stages and more primitive character states. As Mike says, in sauropod necks, serial position recapitulates both ontogeny and phylogeny. So if you have a complete series, you can do something pretty cool: see the intermediate stages by which simple structures become complex.

If you’re thinking this might have something to do with my impending SVPCA poster, you’re right. Here’s the abstract.

For more on serially increasing complexity in sauropodomorph cervicals, see this post.

Here’s a dorsal vertebra of Camarasaurus in anterior view (from Ostrom & McIntosh 1966, modified by Wilson & Sereno 1998). It is one of the most disturbing things I have ever seen in a sauropod. It makes my skin crawl.

Here’s why: the centrum and the thing we habitually call the ‘neural arch’ aren’t fully fused, and as this modified version makes clear, the ‘neural arch’ is neither neural nor an arch. Instead of being bounded ventrally by the centrum and dorsally and laterally by the neural arch, the neural canal lies entirely below the synchondrosis between the not-really-an-arch and the centrum.

Why?! WHY WOULD YOU DO THAT, CAMARASAURUS? This is not ‘Nam. This is basic vertebral architecture. There are rules.

Look at c6 of Apatosaurus CM 555 here, behaving as all good vertebrae ought to. Neural arch be archin’, as the kids say.

And if you are seeking solace in the thought that maybe the artist just drew that Cam dorsal incorrectly, forget it. I’ve been to Yale and examined the original specimen. I’ve seen things, man!

Camarasaurus isn’t the only pervert around here. Check this out:

Unfused neural arch of a caudal vertebra of a juvenile Alamosaurus from Big Bend. And I mean, this is a neural arch. This may be the most neural of all neural arches, in that it contains the entire neural canal. It’s more of a neural…ring, I guess. That’s right, this Alamosaurus caudal is batting for the opposite team from the Cam dorsal above. And it’s a team that neither you nor I play on, because we have well-behaved normal-ass vertebrae with neural arches that actually arch, and then stop, like God and Richard Owen intended.

Scientifically, my question about these vertebrae is: well, that is, I mean to say, what!? I think they have damaged me in some fundamental way.

If you have anything more intelligent to add (or even less intelligent – consider the gauntlet thrown down!), the comment thread is open.

References

  • Ostrom, John H., and John S. McIntosh. 1966. Marsh’s Dinosaurs. Yale University Press, New Haven and London. 388 pages including 65 absurdly beautiful plates.
  • Wilson, J. A. and Paul C. Sereno. 1998. Early evolution and higher-level phylogeny of sauropod dinosaurs. Society of Vertebrate Paleontology, Memoir 5: 1-68.

Hey sports fans! I met David Lindblad at Beer ‘N Bones at the Arizona Museum of Natural History last month, and he invited me to talk dinosaurs on his podcast. So I did (LINK). For two hours. Some of what I talk about will be familiar to long-time readers – dinosaur butt-brains and the Clash of the Dinosaurs saga, for example. But I also just sorta turned off my inhibitions and let all kinds of speculative twaddle come gushing out, including the specter of sauropod polyphyly, which I don’t believe but can’t stop thinking about. David was a gracious and long-suffering host and let me yap on at length. It is more or less the kind of conversation you could have with me in a pub, if you let me do most of the talking and didn’t want to hear about anything other than dinosaurs.

Is it any good? Beats me – I’m way too close to this one to make that call. Let me know in the comments.

Oh, I didn’t have any visuals that really fit the theme so I’m recycling this cool image of speculative sauropod display structures by Brian Engh. Go check out his blog and Patreon and YouTube channel.

Anterior view. Dorsal is to the upper right. The neural spine and left transverse process are missing.

Here’s a closeup of the condyle. The outer layer of cortical bone is gone, allowing a glimpse of the pneumatic chambers inside the vert. The erosion of the condyle was probably inflicted post-excavation by relatively unskilled WPA workers, whose prep tools were limited to chisels, penknives, and sandpaper. Because the bones from the Kenton localities are roughly the same color as the matrix, the preparators sometimes did not realize that they were sanding into the bones until the internal structure was revealed. Bad for the completeness of this specimen, but good for pneumaticity junkies like me, because this baby is too big to be scanned by any but the largest industrial CT machines.

For other posts on the giant Oklahoma apatosaur, see: