November 12, 2013
It’s a strange time of year for me. Teaching and SVP are both behind me, my tenure dossier is in (I’ll find out how that goes next April, probably), and for the first time in a while, I’m not shepherding any pressing manuscripts through the valley of potential rejection. Urgency has dissipated. Flights of fancy are very in right now.
Take this post. I was supposed to be writing about intervertebral cartilage thickness in sauropods, but I got distracted and drew this instead. I am going through one of my periodic bouts of fascination with dodos, inspired by the awesome poster by Biedlingmaier et al. at SVP. So here’s an attempt. It’s based on this photo from Arkive:
with some details filled in from this plate from Strickland and Melville (1848):
and, to be honest, a very generous helping of artistic license. I don’t know from bird skulls so I may have the basioccipital wired to the nasals or some other godawful assault on sanity. I did it for fun, not for science.
If you want dodo science, I have
mixed great news. Crappily–and futilely–enough, Owen’s descriptive papers on the dodo are paywalled at Transactions of the Zoological Society of London. (Seriously, guys? After 140 years you still haven’t made your nut off those papers?) BUT you can get them for free from a couple of other places–see Sarah Werning’s comment below. And happily Strickland and Melville (1848) is available for free from the Internet Archive, and in a host of formats. I am sorely tempted to have a hardcopy printed through Lulu. For more on the dodo side of the Aves 3D project underway at the Claessens lab, of which the Biedlingmaier et al. poster is early fruit, check out the news stories here, here, and here, and keep your fingers firmly crossed for the coming year. I can say no more for now.
Röck döts inspired by a few hours of stippling, and copied and pasted, appropriately, from False Machine.
- Biedlingmaier, A., Leavitt, J., Monfette, G., Allan, D.G., and Claessens, L.P.A.M. 2013. Digital surface scanning and analysis of a cave specimen of the dodo (Raphus cucullatus). Journal of Vertebrate Paleontology, Program and Abstracts 2013, p. 87.
- Strickland, H.E., and Melville, A.G. 1848. The Dodo and Its Kindred; or the History, Affinities, and Osteology of the Dodo, Solitaire, and Other Extinct Birds of the Islands Mauritius, Rodriguez, and Bourbon. London: Reeve, Benham and Reeve.
November 10, 2013
That’s me on top of the Giraffatitan, Matt to the right, and Darren swinging from its wattle.
October 4, 2013
For a palaeontology blog, we don’t talk a lot about geology. Time to fix that, courtesy of my middle son Matthew, currently 13 years old, who made this helpful guide to the rock cycle as Geology homework.
September 25, 2013
This beauty is by Bryan Riolo, aka Algoroth on DeviantART, who also let me use his giant space Cthulhu for my Collect Call of Cthulhu over on Echo Station 5-7. Update: and here, belatedly, is a link to the piece on DA, with Bryan’s thoughts on it.
I love the sense of scale here, with paralititans striding through the surf, the chiaroscuro, and the sheer amount of stuff going on. It reminds me of William Stout’s murals, and lots of atmospheric classic paintings. Sure, there’s a theropod getting his guts rearranged, which I’m always up for, but that’s literally just a sidelight (or sidedark?) in this epic image. In short, I’m diggin’ the art in this paleoart.
For more sauropods stomping theropods, see:
- Genesis of an instant paleo-art classic
- Sauropods stomping theropods: a much neglected theme in palaeo-art
- Sauropods stomping theropods redux
- Brian Engh: Stomp time!
And if your definition of ‘stomping’ encompasses pooping on, vomiting at, and blowing away with sheer awesomeness, you may also enjoy:
September 17, 2013
I liked it, but I thought it could use some color, so I hacked a crude version in GIMP and sent it to Mark with a, “Hey, please put this on a t-shirt so I can throw money at you” plea. Lo and behold, he did just that.
You can get your own from Mark’s Zazzle store. And apparently he will have more sauropod-themed merch coming soon.
September 16, 2013
Because “here’s that Brian Engh sketch of a sauropod literally stomping the guts out of a theropod you ordered” was a bit ungainly for a post title.
Here we have Futalognkosaurus sporting some speculative soft tissues, smooshing some very non-speculative soft tissues out of SeriouslywhogivesacrapwhatitisImjustgladitsdyingvenator. If you just look at the theropod’s face and not the…other stuff, you can imagine that maybe it is laughing. “Oh, ha-ha, you found my tickle spot! Hahaha, stop it! HAHAHA TOO MUCH AAIIIIEEEE–” Schploorrchtbp!!
Futalognkosaurus is clearly saying, “…and I thought they smelled bad on the outside.”
Brian drew this just because we’ve been living up to our mandate lately and posting pictures of sauropod vertebrae. So clearly we gotta do more of that.
For more posts with Brian’s art, go here.
September 15, 2013
I thought I’d done a decent job of illustrating MB.R.2180:C5 last time, but Wedel was not satisfied, demanding ventral and right-lateral views as well as the provided right lateral, anterior, posterior and dorsal.
All right then: here you go!
Here once more, for comparison, is Janensch’s (1950) illustration of the same vertebra:
As you’ll see, I changed the composition of my version, now that I have a right lateral view, to more closely match the composite of Janensch’s figures. The third row of mine is now exactly the same composition as I used for his illustrations, so it’s easier to compare the two.
September 15, 2013
Janensch’s (1950) paper on the vertebral column of Giraffatitan (which he called Brachiosaurus brancai, wrongly as it turns out) is in many ways a superb piece of work. Together with a separate paper on the skull of Giraffatitan and other Tendaguru sauropods (Janensch 1935-6), and yet another on their limbs and girdles (Janensch 1961), it makes up one of the most comprehensive descriptions ever published of any sauropod.
But limitations of the era meant that he wasn’t able to illustrate the vertebrae to the level that we’d hope to see today — certainly nothing like the glorious job Tschopp and Matteus (2012) did on Kaatedocus. As a result, all you get is smallish black-and-white drawings like this one, of C5 of MB.R.2180 (previously known as S I):
As it happens, Matt and I need a dorsal-view brachiosaur vertebra for a paper we’re working on. So I finally got my GIMP on and prepared a nice, high-resolution multiview illustration from the photos that Matt and I took back in 2008. Here it is:
As always, click through for the full-size version, which is 3781 by 2008.
We have here the same vertebra as above: MB.R.2180:C5. On the top row, the long-awaited dorsal view, with anterior to the left; on the bottom row (from left to right): anterior, left lateral and posterior views.
You’ll notice that I’ve illustrated the left side rather than the right that Janensch used. We have photos from both sides, but none of the right-side images came out as cleanly as this one. The anterior and posterior views are pleasantly familiar from Janensch’s figures — although my posterior one is evidently from a slightly more elevated aspect, hence the obscured upper parts of the transverse processes. I also note that Janensch rather sneakily restored the broken parts on both sides of the neurapophysis, and threw in some more prominent spinopostzygapophyseal lamine than the fossil really justifies.
Let’s look more closely at that crucial dorsal view:
It’s now apparent just how narrow brachiosaur cervicals are — at least, those as anterior as C5. You can also see how neatly the spinoprezygapophyseal and spinopostzygapophyseal laminae converge in an “X” shape to form the neurapophysis; and how the prezygapophyseal rami are drawn out almost to a point, with relatively small facets.
- Janensch, W. (1935-36). Die Schadel der Sauropoden Brachiosaurus, Barosaurus und Dicraeosaurus aus den Tendaguru-Schichten Deutsch-Ostafrikas. Palaeontographica (Suppl. 7) 2:147-298.
- Janensch, Werner. 1950. Die Wirbelsaule von Brachiosaurus brancai. Palaeontographica (Suppl. 7) 3:27-93.
- Janensch, Werner. 1961. Die Gliedmaszen und Gliedmaszengurtel der Sauropoden der Tendaguru-Schichten. Palaeontographica (Suppl. 7) 3:177-235.
- Tschopp, Emanuel, and Octávio Mateus. 2012. The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs. Journal of Systematic Palaeontology. doi:10.1080/14772019.2012.746589
September 11, 2013
We’ve blogged a lot of Bob Nicholls‘ art (here, here, and here) and we’ll probably continue to do so for the foreseeable future. We don’t have much choice: he keeps drawing awesome things and giving us permission to post them. Like this defiantly shaggy Apatosaurus, which was probably the star of the Morrison version of Duck Dynasty. Writes Bob:
On my way home at the airport I did a sketch of your giant Apatosaurus* – see attachment. My thought was that massive thick necks were probably pretty sexy things to apatosaurs, so maybe sexually mature individuals used simple feathers (stage 1, 2 or 3?) to accentuate the neck profile. The biggest males would of course have the most impressive growths so in the attached sketch your giant has one of the biggest beards in Earth’s history! What do you think of this idea?
Well, I think it’s awesome. And entirely plausible, for reasons already explained in this post.
“Now, wait,” you may be thinking, “I thought you guys said that sauropod necks weren’t sexually selected.” Actually we made a slightly different point: that the available evidence does not suggest that sexual selection was the primary driver of sauropod neck elongation. But we also acknowledged that biological structures are almost never single-purpose, and although the long necks of sauropods probably evolved to help them gather more food, there is no reason that long necks couldn’t have been co-opted as social billboards. This seems especially likely in Apatosaurus, where the neck length is unremarkable** but the neck fatness is frankly bizarre (and even inspired a Star Wars starfighter!).
I also love the “mobile ecosystem” of birds, other small dinosaurs, and insects riding on this Apatosaurus or following in its train. It’s a useful reminder that we have no real idea what effect millions of sauropods would have on the landscape. But it’s not hard to imagine that most Mesozoic terrestrial ecosystems were sauropod-driven in a thousand cascading and ramifying chains of cause and effect. I’d love to know how that worked. At heart, I’m still a wannabe chrononaut, and all my noodlings on pneumaticity and sauropod nerves and neural spines and so on are just baby steps toward trying to understand sauropod lives. Safari by way of pedantry: tally-ho!
For other speculative apatosaurs, see:
** Assuming we can be blasé about a neck that is more than twice as long (5 m) as a world-record giraffe neck (2.4 m), for garden variety Apatosaurus, or three times that length for the giant Oklahoma Apatosaurus (maybe 7 m).
September 9, 2013
I was at the Oklahoma Museum of Natural History in March to look at their Apatosaurus material, so I got to see the newly-mounted baby apatosaur in the “Clash of the Titans” exhibit (more photos of that exhibit in this post). How much of this is real (i.e., cast from real bones, rather than sculpted)? Most of the vertebral centra, a few of the neural arches, some of the limb girdle bones, and most of the long bones of the limbs. All of the missing elements–skull, neural arches, ribs, appendicular bits–were sculpted by the OMNH head preparator, Kyle Davies. Kyle is one of those frighteningly talented people who, if they don’t have what they need, will just freaking build it from scratch. Over the years he has helped me out a LOT with the OMNH sauropod material–including building a clamshell storage jacket for the referred scapula of Brontomerus so we could photograph it from the lateral side–so it’s about time I gave him some props.
Case in point: this sweet atlas-axis complex that Kyle sculpted for the juvenile Apatosaurus mount.
Most fish, amphibians, and other non-amniote tetrapods only have a single specialized vertebra for attaching to the skull. But amniotes have two: a ring- or doughnut-shaped first cervical vertebra (the atlas) that articulates with the occipital condyle(s) of the skull, and a second cervical vertebra (the axis) that articulates with the atlas and sometimes with the skull as well. Mammals have paired occipital condyles on the backs or bottoms of our skulls, so our skulls rock up and down on the atlas (nodding “yes” motion), and our skull+atlas rotates around a peg of bone on the axis called the odontoid process or dens epistrophei (shaking head “no” motion). As shown in the photos and diagrams below, the dens of the axis is actually part of the atlas that fuses to the second vertebra instead of the first. Also, reptiles, including dinosaurs and birds, tend to have a single ball-shaped occipital condyle that fits into the round socket formed by the atlas, so their “yes” and “no” motions are less segregated by location.
Anyway, the whole shebang is often referred to as the atlas-axis complex, and that’s the reconstructed setup for a baby Apatosaurus in the photo above. In addition to making a dull-colored one for the mount, Kyle made this festive version for the vert paleo teaching collection. Why so polychromatic?
Because in fact he built two: the fully assembled one two photos above, and a completely disassembled one, some of which is shown in this photo (I had to move the bigger bits out of the tray so they wouldn’t block the key card at the back). I originally composed this post as a tutorial. But frankly, since Kyle did all of the heavy lifting of (a) making the thing in the first place, (2) making a color-coded key to it, and (d) giving me permission to post these photos, it would be redundant to walk through every element. So think of this as a self-study rather than a tutorial.
Oh, all right, here’s a labeled version. Note that normally in an adult animal the single piece of bone called the atlas would consist of the paired atlas neural arches (na1) and single atlas intercentrum (ic1), and would probably have a pair of fused cervical ribs (r1). Everything else would be fused together to form the axis, including the atlas pleurocentrum (c1), which forms the odontoid process or dens epistrophei (etymologically the “tooth” of the axis).
Here’s the complete Romer (1956) figure from the key card, with a mammalian atlas-axis complex for comparison. Incidentally, the entire book this is drawn from, Osteology of the Reptiles, is freely available online.
And here’s the complete Gilmore (1936) figure. Sorry for the craptastic scan–amazingly, this one is NOT freely available online as far as I can tell, and Mike and I have been trying to get good scans of the plates for years. Getting back on topic, single-headed atlantal cervical ribs have been found in several sauropods, especially Camarasaurus where several examples are known, so they were probably a regular feature, even though they aren’t always preserved.
Also, as noted in this post, it is odd that in this specimen of Apatosaurus the cervical ribs had not fused to the first two vertebrae, even though they normally do, and despite the fact that the vertebrae had fused to each other, even though they normally don’t. Further demonstration, if any were needed, that sauropod skeletal fusions were wacky.
For comparison to the above images, here is the atlas-axis complex in the synapsid Varanops, from Campione and Reisz (2011: fig. 2C).
Those proatlas thingies are present in some sauropods, but that’s about all I know about them, so I’ll say no more for now.
There is a good overview of the atlas-axis complex with lots of photos of vertebrae of extant animals on this page.
Previous SV-POW! posts dealing with atlantes and axes (that’s right) include:
- A fused atlas and axis in Apatosaurus
- Yet more uninformed noodling on the future of scientific publishing and that kind of thing
- Another mystery: embossed laminae and “unfossae”
- Tutorial 15: the bones of the sauropod skeleton
- Campione, N.E. and Reisz, R.R. 2011. Morphology and evolutionary significance of the atlas−axis complex in varanopid synapsids. Acta Palaeontologica Polonica 56 (4): 739–748.
- Gilmore, C.W. 1936. Osteology of Apatosaurus with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11: 175-300.
- Romer, A.S. 1956. Osteology of the Reptiles. University of Chicago Press, Chicago. 772 pp.