Apatosaurus is — still — Just Plain Wrong
November 30, 2018
We’ve posted a lot here about how crazy the cervical vertebrae of apatosaurines are (for example: 1, 2, 3), and especially the redonkulosity of their cervical ribs. But I think you will agree with me that this is still an arresting sight:
That’s MWC 1946, a mid-cervical from the Mygatt-Moore Quarry that was figured by Foster et al. (2018: fig. 18 A-B) and referred with the rest of the Mygatt-Moore apatosaur material to Apatosaurus cf. louisae (entirely correctly, in my view). This is a ventral view, with the condyle down by the scale bar.
Here’s the same thing cropped from the background to emphasize its unbelievableness:
and mirrored and restored a bit in GIMP to give a taste of its probable appearance in life (if you had an apatosaur, an x-ray machine, and a lot of confidence about not getting stepped on):
For obvious reasons, my nickname for this specimen is the Brontosmasher.
Keep in mind that the centrum was full of air in life, whereas the cervical ribs and the bony struts that support them are just huge slabs of bone. I strongly suspect that the volume of bone in the cervical ribs and their supporting struts is vastly more than in the centrum and neural arch. I will soon have the ability to test that hypothesis–I have this specimen on loan from Dinosaur Journey for CT scanning and 3D modeling. Watch this space.
Many thanks to Julia McHugh at Dinosaur Journey for access to the specimen and assistance during my frequent visits.
Reference
- Foster, J.R., Hunt-Foster, R.K., Gorman, M.A., II, Trujillo, K.C., Suarez, C.A., McHugh, J.B., Peterson, J.E., Warnock, J.P., and Schoenstein, H.E. 2018. Paleontology, taphonomy, and sedimentology of the Mygatt-Moore Quarry, a large dinosaur bonebed in the Morrison Formation, western Colorado—implications for Upper Jurassic dinosaur preservation modes: Geology of the Intermountain West 5: 23–93.
Academic-Led Publishing: an interview in which I am somehow represented as an expert
November 26, 2018
Scholastica is a publishing platform that offers support for super-low-cost open-access journals such as Discrete Analysis, led by Tim Gowers. They’re putting together the first Academic-Led Publishing Day on 7 February next year, and as part of the build-up, they kindly invited me to do an interview for them, kicking off their Academic-Led Publishing From the Experts series.
I did tell them that I wasn’t qualified — “I am about as far from an expert as I could possibly be in the field of Academic-led publishing. I’ve never even been an academic editor for a journal, far less started one or run one. All I’ve ever done, really (beyond writing and peer-reviewing articles) is have opinions and write about them.” But they wanted to push ahead anyway, so I was happy to go along with it.
Here’s the interview: enjoy!
Pelican cervico-dorsal transition, backlit
November 24, 2018
What it says on the tin. This is a specimen from the UCMP comparative collection.
I was just going to post this photo with zero commentary, but I can’t help myself. Note that on the two vertebrae in the middle, the crista transverso-obliqua (what in non-avian dinos would be the spinopostzygapophyseal lamina or SPOL) rises higher than either the neural spine apex or the epipophyses. That’s crazy. And it demonstrates something we also see in sauropods, which is that laminae are not merely the plates of bone left behind after pneumatization has scooped all of the unnecessary material out of a normal vertebra–sometimes they are additive structures, too.
If all of that sounded like gibberish, I can sympathize. I spent my first few months as a sauropodologist just learning the lingo (another thing I should blog about sometimes). Here’s a labeled version:
As long as I’m yapping, note the light shining through the honeycombed internal structure of these highly pneumatic vertebrae. For more on the ridiculous pneumaticity of pelican bones, see this post and this one. For more on the homology of bird and sauropod vertebrae, see Wedel and Sanders (2002), and for more on laminae as additive versus reductive structures, see the discussion on pages 210-212 of Wedel (2007).
References
- Wedel, M.J. 2007a. What pneumaticity tells us about ‘prosauropods’, and vice versa. Special Papers in Palaeontology 77:207-222.
- Wedel, M.J., and Sanders, R.K. 2002. Osteological correlates of cervical musculature in Aves and Sauropoda (Dinosauria: Saurischia), with comments on the cervical ribs of Apatosaurus. PaleoBios 22(3):1-6.
Lydekker’s (1893) illustration of Xenoposeidon
November 19, 2018
Matt’s drawn my attention to a bizarre fact: despite 17 separate posts about Xenoposeidon on this blog (linked from here and here), we’ve never shown a decent scan of Lydekker’s (1893) original illustration of NHMUK PV R2095, the partial mid-to-posterior dorsal vertebra that since Taylor and Naish (2007) has been the holotype specimen of Xenoposeidon proneneukos — and since Taylor (2018) has been known to represent a rebbachisaurid.
Well, here it is at last!
That’s Xeno on the left, of course. On the right, we have one of the various Wealden titanosauriform dorsal vertebrae that were constantly getting referred back and forth between taxa in the late 1800s. I think it might be one of the NPMUK PR R90 vertebrae, perhaps the one that, for disambiguation purposes, I’ve informally named R90a.
Lydekker — or, more likely, an uncredited illustrator — did rather a good job on this, as we can see by juxtaposing the illustration with the now well-known left-lateral photo that’s launched a thousand blog-posts:
The main differences here seem to pertain to how Lydekker and I perceived “lateral”. I think he has the vertebra rotated slightly away from us, so that it’s leaning into the page, and that’s why the centrum appears slightly taller and the arch slightly less tall than in my photo. He seems to have a bit more matrix stuck on the front of the centrum — perhaps because slightly more prep has been done since 1893 — but, worryingly, slightly less bone around the cotyle. I think that can only be illustration error, since that bone is definitely there.
References
- Lydekker, R. 1893. On a sauropodous dinosaurian vertebra from the Wealden of Hastings. Quarterly Journal of the Geological Society, London 49:276-280.
- Taylor, Michael P. 2018. Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur. PeerJ 6:e5212. doi: 10.7717/peerj.5212
- Taylor, Michael P., and Darren Naish. 2007. An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England. Palaeontology 50(6):1547-1564. doi: 10.1111/j.1475-4983.2007.00728.x
My new dinosaur book for kids is out
November 16, 2018
Late last year I got tapped by the good folks at Capstone Press to write a dinosaur book for their Mind Benders series for intermediate readers. Now it’s out. (In fact, it’s been out for a couple of months now, I’ve just been too busy with other things to get this post up.) Covers all the major groups and some of the minor ones, includes a timeline and evolutionary tree, 112 pages, $6.95 in paperback. Despite the short, punchy, 2-3 facts per critter format, I tried to pack in as many new findings and as much weird trivia as possible, so hopefully it won’t all be old news (facts chosen for the cover notwithstanding). Suggested age range is grades 1-6 but who knows what that means; one of the best reviews that Mark Hallett and I got for our big semi-technical sauropod tome was written by a 6-year-old. Many thanks to my editors at Capstone, Shelly Lyons and Marissa Bolte, for helping me get it over the finish line and wrangling about a trillion details of art and science along the way.
If you need a gateway drug or stocking stuffer for a curious kid, give it a look. Here’s the Amazon link (and for teachers, librarians, and my future reference, the publisher’s link).
Please welcome Mirarce eatoni
November 13, 2018
Skeletal reconstruction of Mirarce by Scott Hartman (Atterholt et al. 2018: fig. 19). Recovered bones in white, missing bones in gray. The humerus is 95.9mm long.
Today sees the publication of the monster enantiornithine Mirarce eatoni (“Eaton’s wonderful winged messenger”) from the Kaiparowits Formation of Utah, by Jessie Atterholt, Howard Hutchinson, and Jingmai O’Connor. Not my critter, not my story, but it is SV-POW!-adjacent. (Just here for the paper? Here’s the link.)
Xiphoid process of sternum of Mirarce (Atterholt et al. 2018: fig. 5). Scale bar = 1cm.
As of this past summer, I knew that Jessie had a prehistoric monster coming out soon, and I knew that Brian Engh liked bringing prehistoric monsters to life, and I suspected that if the two reagents were combined, the rest of us might get something cool out of it.
Jessie and Brian talking about Mirarce, Utah for scale. July 13, 2018.
I did some heavy eavesdropping while the three of us were stomping around southern Utah looking for dinosaurs, so I got to hear Jessie and Brian batting ideas back and forth. By the end of our Utah trip Brian had sketches, and not long after, finished art (his post on Mirarce, including process sketches, is here). If you’ve seen one of my talks in the last month or so, you’ve gotten a teaser (with Jessie’s and Brian’s permission), and I know the piece got shown around a bit at SVP, too. You’ve waited long enough, here you go:
Not that the art is the whole story! Mirarce is a legitimately awesome find and Jessie and her coauthors poured a ton of work into the description. I’d tell you all about it, but much more capable and bird-fluent folks are on that already, and I have spinal cord and brainstem lectures to polish. So I’m gonna leave you with some links, which I’ll try to keep updated as different outlets get the story out:
- Berkeley News
- National Geographic
- Independent
- Gizmodo
- PeerJ Blog – a guest post in which Jessie herself explains what’s cool about the find
Reference
Atterholt, J., Hutchinson, J.H.., and O’Connor, J.K. 2018. The most complete enantiornithine from North America and a phylogenetic analysis of the Avisauridae. PeerJ 6:e5910 https://doi.org/10.7717/peerj.5910
We may never know how flexible sauropod necks were
November 8, 2018
The more I look at the problem of how flexible sauropod necks were, the more I think we’re going to struggle to ever know their range of motion It’s just too dependent on soft tissue that doesn’t fossilise. Consider for example the difference between horse necks (above) and camel necks (below).
The skeletons of both consist of vertebrae that are pronouncedly opisthocoelous (convex in front and concave behind), so you might think their necks would be similarly flexible.
But the balls of horse cevicals are deeply embedded in their corresponding sockets, while those of camels have so much cartilage around and between them that the tip of the ball doesn’t even reach the rim of the socket. As a result of this (and maybe other factors), camel necks are far more flexible than those of horses.
Which do sauropod necks resemble? We don’t currently know, and we may never know. It will help if someone gets a good handle on osteological correlates of intervertebral cartilage.
[This post is recycled and expanded from a comment that I left on a Tetrapod Zoology post, but since Tet Zoo ate that comment it’s just as well I kept a copy.]
T. rex mount at New Mexico Museum of Natural History and Science
November 7, 2018
The Sunday after SVP, Brian Engh and I visited the museum in Albuquerque. I was quite taken with the mounted T. rex. It’s waaaay more interesting and dynamic than any other T. rex mount I’ve seen. It even beats the “Rockette rex” in Denver (which I really like and need to blog about), by virtue of putting the body and head down at eye level where you can study them up close.
The only thing I don’t like about this mount is that it has the dumb teeth-hanging-out-too-far thing going on. Why the heck people don’t fix that, I have no idea. Like, even if that’s the way the jaws are molded, cut off the excess and glue the crowns back up where they belong. Or fix the friggin’ mold. It’s not like the problem hasn’t been obvious for decades.
On the upside, pretty much everything else about this mount is awesome. Brian and I spent a fair amount of time working through the muscle attachments and thinking about how bulky the animal would have been in life. The answer is “very”.
Pretty cool to think that a fleshier, more aggro version of this was the last thing that many animals ever saw. And by ‘cool’ I mean ‘terrifying’.
Diverticulum, diverticula
November 4, 2018
This is not ‘Nam. This is Latin. There are rules.
The term for a small growth off an organ or body is diverticulum, singular, or diverticula, plural. There are no diverticulae or God forbid diverticuli, no matter what you might read in some papers. Diverticuli is a word – it’s the genitive form of diverticulum. But I’ve never seen it used that way in an anatomy or paleo paper. Diverticuli and diverticulae as alt-plurals for diverticulum are abominations that must be stomped out with extreme prejudice. If you want to get cute with alternative spellings, Wiktionary says you can use deverticulum. Wiktionary does not warn you that you will be mocked for doing so, but it is true nonetheless.
Stop jacking up straightforward anatomical terms, authors who should know better.
Here’s a swan. Unlike diverticuli and diverticulae, this unlikely morphology is real.
Sauropod Vertebra Picture of the Week 