October 31, 2013
First, there’s a nice write-up of one of our papers (Wedel and Taylor 2013b on pneumaticity in sauropod tails) in the Huffington Post today. It’s the work of PLOS blogger Brad Balukjian, a former student of Matt’s from Berkeley days. The introduction added by the PLOS blogs manager is one of those where you keep wanting to interrupt, “Well, actually it’s not quite like that …” but the post itself, once it kicks in, is good. Go read it.
Brad also has a guest-post on Discover magazine’s Crux blog: How Brachiosaurus (and Brethren) Became So Gigantic. He gives an overview of the sauropod gigantism collection as a whole. Well worth a read to get your bearings on the issue of sauropod gigantism in general, and the new collection in particular.
PLOS’s own community blog EveryONE also has its own brief introduction to the collection.
And PLOS and PeerJ editor Andy Farke, recently in these pages because of his sensational juvenile Parasaurolophus paper, contributes his own overview of the collection, How Big? How Tall? And…How Did It Happen?
Finally, if you’re at SVP, go and pick up your free copy of the collection. Matt was somehow under the impression that the PLOS USB drives with the sauropod gigantism collection would be distributed with the conference packet when people registered. In fact, people have to go by the PLOS table in the exhibitor area (booth 4 in the San Diego ballroom) to pick them up. There are plenty of them, but apparently a lot of people don’t know that they can get them.
- Wedel, Mathew J., and Michael P. Taylor. 2013. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus. PLOS ONE 8(10):e78213. 14 pages. doi:10.1371/journal.pone.0078213 [PDF]
October 30, 2013
This is an exciting day: the new PLOS Collection on sauropod gigantism is published to coincide with the start of this year’s SVP meeting! Like all PLOS papers, the contents are free to the world: free to read and to re-use. (What is a Collection? It’s like an edited volume, but free online instead of printed on paper.)
There are fourteen papers in the new Collection, encompassing neck posture (yay!), nutrition (finally putting to bed the Nourishing Vomit Of Eucamerotus hypothesis), locomotion, physiology and evolutionary ecology. Lots every sauropod-lover to enjoy.
Matt and I are particularly excited that we have two papers in this collection: Taylor and Wedel (2013c) on intervertebral cartilage in necks, and Wedel and Taylor (2013b) on pneumaticity in the tails of (particularly) Giraffatitan and Apatosaurus. So we have both ends of the animal covered. It also represents a long-overdue notch on our bed-post: for all our pro-PLOS rhetoric, this is the first time either of has had a paper published in a PLOS journal.
It’s a bit of a statistical anomaly that after a decade of collaboration in which there was never a Taylor & Wedel or Wedel & Taylor paper, suddenly we have five of them out in a single year (including the Barosaurus preprint, which we expect to eventually wind up as Taylor and Wedel 2014). Sorry about the alphabet soup.
Since Matt is away at SVP this week, I’ll be blogging mostly about the Taylor and Wedel paper this week. When Matt returns to civilian life, the stage should be clear for him to blog about pneumatic caudals.
- Taylor, Michael P., and Matthew J. Wedel. 2013c. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs. PLOS ONE 8(10): e78214. 17 pages. doi:10.1371/journal.pone.0078214 [PDF]
- Wedel, Mathew J., and Michael P. Taylor. 2013. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus. PLOS ONE 8(10):e78213. 14 pages. doi:10.1371/journal.pone.0078213 [PDF]
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.
I was recently bemoaning the lack of published diplodocid cervical illustrations in dorsal view. Subsequently I mentioned that Upchurch et al. (2005) had illustrated five cervicals of an Apatosaurus specimen.
I was overlooking one other paper that contains such an illustration. Which is a bit embarrassing, as it’s one of ours. In fact, it’s our most recent paper, Wedel and Taylor (2013) on sauropod neural spine bifurcation. The very first figure in that paper (the first of 25!) is relevant to my interests. So here it is:
Click through for glorious high-resolution goodness!
Upchurch, Paul, Yukimitsu Tomida, and Paul M. Barrett. 2005. A new specimen of Apatosaurus ajax (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA. National Science Museum Monographs No. 26. Tokyo. ISSN 1342-9574.
Wedel, M.J., and Taylor, M.P. 2013. Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications. Palarch’s Journal of Vertebrate Palaeontology 10(1): 1-34. ISSN 1567-2158.
September 1, 2013
Last time, I asked if anyone has dorsal-view photos of the cervical vertebrae of Diplodocus. No responses yet, and I do urge you to chip in if you have any ideas. But here’s something to keep us positive: Apatosaurus cervicals!
This is Plate 1 from Upchurch et al.’s (2005) excellent descriptive monograph of a specimen of Apatosaurus ajax, NSMT-PV 20375. It shows cervicals 3, 6, 7, 12 and 14, each in left lateral, dorsal and right lateral view; and C14 in ventral view. Click through for the glorious full-resolution version (5183 × 2876).
Here is a close-up of C12 in dorsal view.
April 19, 2013
Up top there is a commercially obtained
cast sculpture of a thumb claw of Megaraptor. Down below is an unpainted urethane cast of one of my favorite inanimate objects in the universe: OMNH 780, a thumb claw of Saurophaganax. I dunno how much of the Megaraptor claw is real [none, it turns out, but it's based on a true story]; certainly the cast is faithful enough to record some tool-marks in the rugose part near the base. But I know how much of OMNH 780 is legit, and that is all of it. I would have put in a photo of the actual specimen but irritatingly I forgot to take any during my recent visit, and I didn’t have the Megaraptor claw back then anyway. Hopefully I’ll get back to the OMNH this summer, and then it is ON.
The kaiju-loving fanboys of CarnivoraForum undoubtedly want to know how these two compare. Well, much to my disappointment, the Megaraptor claw is a shade longer (28.7 cm max straight-line distance) than the Saurophaganax claw (26.3 cm). But the Saurophaganax claw is about twice as thick and way more robust, and the flexor tubercle which anchored the tendon that powered the claw’s movement is friggin’ immense. It’s like pitting an NBA forward against an NFL linebacker: one is a little taller, but the other one will pound you like a tent stake.
If anyone’s wondering, these claws are both waaay shorter than those of Therizinosaurus (half a meter and up), which still holds the longest-claws-of-anything-ever title. The problem for fans of excessive violence is that Therizinosaurus probably wasn’t doing terribly exciting things with its claws–grooming its feathers, making veggie kabobs, and scratching its ample behind, most likely.
The same was not true for Saurophaganax, which the unbelievers call Allosaurus maximus, a red-blooded all-American murder machine with a triple PhD in kicking your ass. When it wasn’t drinking camptosaur blood straight from the jugular, it was eating mud-mired diplodocids butt first while they were still alive. And what about those rumors that Saurophaganax was completely feathered in $100 bills, or that it was the direct linear ancestor of Charles Bronson and Steven McQueen? It’s probably too soon to say, since I just made them up, but I’ll bet your mind is blown nonetheless.
How dangerous was Saurophaganax? Let me put it this way: it’s still dangerous. Thanks to the high concentration of heavy elements in Morrison dinosaur bones, you’re supposed to air out the specimen cabinets before you start working so the radon can escape. Otherwise you might breathe in freakin’ radioactive gas and get cancer (in contrast to some “facts” in the previous paragraph, this is actually true). That’s right, Saurophaganax can kill you, just by lying around in a drawer. After 145 million years, it’s still reaping souls for Hades. By god, that’s giving them what for!
In short, the thumb claw of Saurophaganax is the most impressive instrument of dinosaurian destruction I’ve yet laid eyes on. If you want to see it in context, check out the mounted skeleton at the Oklahoma Museum of Natural History in Norman.
March 26, 2013
Another raw photo from the road.
The Morrison fossils from the Oklahoma panhandle were dug up and prepped out by WPA workers in the 1930s, and their preparation toolkit consisted of hammers, chisels, pen-knives, and sandpaper. (Feel free to take a minute if you need to get your nausea under control.) And whereas most Morrison fossils are much darker than the surrounding matrix, in the Oklahoma panhandle the bone and matrix are about the same color. Sometimes the prep guys didn’t know they’d gone too deep until they sanded into the trabecular bone. Or in this case, into the air spaces in the condyle of this anterior dorsal of Apatosaurus.
Still, we have lots of anterior dorsals of Apatosaurus, and very few we can see inside, and they’re too darned big to scan, so this gives us useful information that a more perfect specimen would not. So I salute you, underemployed dude from eighty-odd years ago. Thanks for showing me something cool.
March 24, 2013
Here’s an update from the road–get ready for some crappy raw images, because that’s all I have the time or energy to post (with one exception).
Here’s OMNH 1331. It’s just the slightly convex articular end off a big vertebra, collected near Kenton, Oklahoma, in 1930s by one of J. Willis Stovall’s field crews. I measured the preserved width at 45 cm using a tape measure, and at 44.5 in GIMP using the scale bar in the photo, which is up on a piece of styrofoam so it’s about the same distance from the camera as the rim of the vertebra (i.e, about 8 feet–as high as I could get and still shoot straight down). So whether your distrust runs to tape measures or scale bars in photos, I am prepared to argue that this sucker is roughly 45 cm wide.
There’s admittedly not a ton of morphology here, but the size and the fact that the other side is hollow and has a midline bony septum show that it is a pneumatic vertebra from a sauropod, and given that the quarry it’s from was chock-full of Apatosaurus, and liberally salted with gigantic Apatosaurus, I feel pretty good about calling it Apatosaurus.
To figure out how wide the articular face was when it was intact, I duplicated the image and reversed it left-to-right in GIMP, which yields an intact max width of about 49 cm. That is friggin’ immense.
If we make the maximally conservative assumption that this is the largest centrum in the whole skeleton of a big Apatosaurus, then it has to be part of a dorsal vertebra. Here are the max diameters of the largest dorsal centra in some big mounted apatosaurs, taken from Gilmore (1936). The number in parentheses is how many percent bigger OMNH 1331 is.
- A. louisae CM 3018 – 36.5 cm (34%)
- A. parvus UWGM 15556 – 36.5 cm (34%)
- A. sp. FMNH P25112 – 41 cm (20%)
However, this might not be part of a dorsal vertebra. For one thing, it’s pretty convex, and Apatosaurus dorsals sometimes have a little bump but they’re pretty close to amphiplatyan, at least in the posterior half of the series. For another, I think that smooth lower margin on the right in the photo above is part of the rim of a big pneumatic foramen, but it’s waaay up high and pretty medial on the centrum, opening more dorsally than laterally, which I have seen a lot in anterior caudal vertebrae. Finally, Jack McIntosh went through the OMNH collections years ago and his identifications formed the basis for a lot of the catalogue IDs, and this thing is catalogued as the condyle off the back end of a proximal caudal.
Here are the max diameters of the largest caudal centra in those same mounted apatosaurs, again taken from Gilmore (1936). Once again, the number in parentheses is how many percent bigger OMNH 1331 is.
- A. louisae CM 3018 – 30 cm (63%)
- A. parvus UWGM 15556 – 32.5 cm (51%)
- A. sp. FMNH P25112 – 39 cm (26%)
(Aside: check out the skinny rear end on A. louisae. ‘Sup with that?)
So whatever vert it’s part of, OMNH 1331 is damn big bone from a damn big Apatosaurus. There are lots of other big Apatosaurus vertebrae in the OMNH collections, like OMNH 1670, but OMNH 1331 is the largest centrum that I know of in this museum. Which is why you’re getting a post about most of one end of a centrum in the wee hours of the morning–it’s most of one end of an awesome centrum. And it pains me when people do comparison figures of big sauropod vertebrae, or lists of the “Top 10 Largest Sauropods”, and put in stuff like Argentinosaurus and Puertasaurus and Supersaurus, but leave out Apatosaurus. It was legitimately huge, and it’s time the world realized that.
For more on the giant Oklahoma Apatosaurus, see:
Gilmore, C.W. 1936. Osteology of Apatosaurus with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11:175-300.
February 27, 2013
Well, this is rad. And adorable. Brian Switek, whom we adore, commissioned a fuzzy juvenile sauropod from Niroot, whom we adore, for his (Brian’s) upcoming book, My Beloved Brontosaurus, which I am gearing up to adore. And here is the result, which I adore, borrowed with permission from Love in the Time of Chasmosaurs.
There is much to like here. Here’s my rundown:
- Small forefeet that are the correct shape: good. Maybe too small, given that young animals often have big feet. But better too small than too big, given how often people screw this up.
- Pronounced forelimb-hindlimb disparity: win.
- Fat neck: pretty good.
In fact, let me interrupt the flow of praise here to put in Brant Bassam’s dorsal view of his mounted Phil Platt model Apatosaurus skeleton. I’ve been meaning to post about this for a while now and haven’t gotten to it, so now’s a good time: just look at how friggin’ FAT that neck is, and how it blends in with the body, and how the tail gets a lot skinnier a lot quicker (and, yeah, caudofemoralis, but not that much). Now, go look at a bunch of life restorations of Apatosaurus–drawings, paintings, sculptures, toys, whatever–and see how many people get this wrong, by giving Apatosaurus a too-skinny neck. The answer is, damn near everyone.
Okay, back to Niroot’s baby:
- Proportionally shorter neck and tail because it’s a juvenile: win.
- Neck wrinkles possibly corresponding to vertebrae: okay, just this once.
- Greenish fuzz possibly functioning as camouflage: We-ell…
Yes, it’s true that all of the known sauropod skin impressions show scales, not fuzz. But. We don’t have anything like full-body coverage. And I suspect that there is a collection bias against fuzzy skin impressions. Scaly skin impressions are probably easier to recognize than 3D feathery skin impressions (as opposed to feathers preserved flat as at Liaoning and Solnhofen) because the latter probably just look like wavy patterns on rock, and who is looking for feather impressions when swinging a pickaxe at a sauropod’s back end? And how many sauropods get buried in circumstances delicate enough to preserve dinofuzz anyway? Also, some kind of fuzz is probably primitive for Ornithodira, and scales do not necessarily indicate that feathers were absent because owl legs. So is this speculative? Yes. Is it out of the question? I think not. In the spirit of Mythbusters, I’m calling it ‘plausible’.
Oh, one more thing: Niroot posted this in honor of Brian Switek’s birthday. Happy birthday, Brian! (You owe me a book!)