An important paper is out today: Carpenter (2018) names Maraapunisaurus, a new genus to contain the species Amphicoelias fragillimus, on the basis that it’s actually a rebbachisaurid rather than being closely related to the type species Amphicoelias altus.

Carpenter 2018: Figure 5. Comparison of the neural spine of Maraapunisaurus fragillimus restored as a rebbachisaurid (A), and the dorsal vertebrae of Rebbachisaurus garasbae (B), and Histriasaurus boscarollii (C). Increments on scale bars = 10 cm.

And it’s a compelling idea, as the illustration above shows. The specimen (AMNH FR 5777) has the distinctive dorsolaterally inclined lateral processes of a rebbachisaur, as implied by the inclined laminae meeting at the base of the SPOLs, and famously has the very excavated and highly laminar structure found in rebbachisaurs — hence the species name fragillimus.

Ken’s paper gives us more historical detail than we’ve ever had before on this enigmatic and controversial specimen, including extensive background to the excavations. The basics of that history will be familiar to long-time readers, but in a nutshell, E. D. Cope excavated the partial neural arch of single stupendous dorsal vertebra, very briefly described it and illustrated it (Cope 1878), and then … somehow lost it. No-one knows how or where it went missing, though Carpenter offers some informed speculation. Most likely, given the primitive stabilisation methods of the day, it simply crumbled to dust on the journey east.

Carpenter 2018: Frontispiece. E. D. Cope, the discoverer of AMNH FR 5777, drawn to scale with the specimen itself.

Cope himself referred the vertebra to his own existing sauropod genus Amphicoelias — basically because that was the only diplodocoid he’d named — and there it has stayed, more or less unchallenged ever since. Because everyone knows Amphicoelias (based on the type species A. altus) is sort of like Diplodocus(*), everyone who’s tried to reconstruct the size of the AMNH FR 5777 animal has done so by analogy with Diplodocus — including Carpenter himself in 2006, Woodruff and Foster (2014) and of course my own blog-post (Taylor 2010).

(*) Actually, it’s not; but that’s been conventional wisdom.

Ken argues, convincingly to my mind, that Woodruff and Foster (2014) were mistaken in attributing the great size of the specimen to a typo in Cope’s description, and that it really was as big as described. And he argues for a rebbachisaurid identity based on the fragility of the construction, the lamination of the neural spine, the extensive pneumaticity, the sheetlike SDL, the height of the postzygapophyses above the centrum, the dorsolateral orientation of the transverse processes, and other features of the laminae. Again, I find this persuasive (and said so in my peer-review of the manuscript).

Carpenter 2018: Figure 3. Drawing made by E.D. Cope of the holotype of Maraapunisaurus fragillimus (Cope, 1878f) with parts labeled. “Pneumatic chambers*” indicate the pneumatic cavities dorsolateral of the neural canal, a feature also seen in several rebbachisaurids. Terminology from Wilson (1999, 2011) and Wilson and others (2011).

If AMNH FR 5777 is indeed a rebbachisaur, then it can’t be a species of Amphicoelias, whose type species is not part of that clade. Accordingly, Ken gives it a new generic name in this paper, Maraapunisaurus, meaning “huge reptile” based on Maraapuni, the Southern Ute for “huge” — a name arrived at in consultation with the Southern Ute Cultural Department, Ignacio, Colorado.

How surprising is this?

On one level, not very: Amphicoelias is generally thought to be a basal diplodocoid, and Rebbachisauridae was the first major clade to diverge within Diplodocoidae. In fact, if Maraapunisaurus is basal within Rebbachisauridae, it may be only a few nodes away from where everyone previously assumed it sat.

On the other hand, a Morrison Formation rebbachisaurid would be a big deal for two reasons. First, because it would be the only known North American rebbachisaur — all the others we know are from South America, Africa and Europe. And second, because it would be, by some ten million years, the oldest known rebbachisaur — irritatingly, knocking out my own baby Xenoposeidon (Taylor 2018), but that can’t be helped.

Finally, what would this new identity mean for AMNH FR 5777’s size?

Carpenter 2018: Figure 7. Body comparisons of Maraapunisaurus as a 30.3-m-long rebbachisaurid (green) compared with previous version as a 58-m-long diplodocid (black). Lines within the silhouettes approximate the distal end of the diapophyses (i.e., top of the ribcage). Rebbachisaurid version based on Limaysaurus by Paul (2016), with outline of dorsal based on Rebbachisaurus; diplodocid version modified from Carpenter (2006).

Because dorsal vertebrae in rebbachisaurids are proportionally taller than in diplodocids, the length reconstructed from a given dorsal height is much less for rebbachisaurs: so much so that Ken brings in the new version, based on the well-represented rebbachisaur Limaysaurus tessonei, at a mere 30.3 m, only a little over half of the 58 m he previously calculated for a diplodocine version. That’s disappointing for those of us who like our sauropods stupidly huge. But the good news is, it makes virtually no difference to the height of the animal, which remains prodigious — 8 m at the hips, twice the height of a giraffe’s raised head. So not wholly contemptible.

Exciting times!

References

 

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In my recent visit to the LACM herpetology collection, I was interested to note that almost every croc, lizard, and snake vertebra I saw had a pair of neurovascular foramina on either side of the centrum, in “pleurocoel” position. You can see these in the baby Tomistoma tail, above. Some vertebrae have a big foramen, some have a small foramen, and some have no visible foramen at all. Somehow I’d never noticed this before.

This is particularly interesting in light of the observation from birds that pneumatic diverticula tend to follow nerves and vessels as they spread through the body. Maybe we find pneumatic features where we do in dinosaurs and pterosaurs because that’s where the blood vessels were going in the babies. Also, these neurovascular foramina in extant reptiles are highly variable in size and often asymmetric – sound familiar?

It should. Caudal pneumaticity in the tail of Giraffatitan MB.R.5000. Dark blue vertebrae are pneumatic on both sides, light blue vertebrae only have fossae on the right side. Wedel and Taylor (2013b: Figure 4).

I am starting to wonder if some of the variability we associate with pneumaticity is just the variability of soft tissue, full stop. Or if pneumaticity is variable because it developmentally follows in the footsteps of the blood vessels, which are themselves inherently variable. That seems like a promising line of inquiry. And also something I should have though of a lot sooner.

A while back — near the start of the year, in fact — Szymon Górnicki interviewed me by email about palaeontology, alternative career paths, open access, palaeoart, PeerJ, scholarly infrastructure, the wonder of blogging, and how to get started learning about palaeo. He also illustrated it with this caricature of me, nicely illustrating our 2009 paper on neck posture.

For one reason and another, it’s taken a long while for me get around to linking to it — but here we are in October and I’ve finally arrived :-)

With apologies to Szymon for the delay: here is the interview!

By the way, Szymon’s also done interviews with other, more interesting people: Davide Bonadonna, Steve Brusatte, Tim Haines and Phil Currie. Check them out!

I did a fieldwork!

This is going to set new records for “almost too late to be worth posting”, but here goes.

First up, this Wednesday evening, Oct. 18, at 6:00 PM (in about 18 hours), while most of the paleontologists in the West are at SVP in Albuquerque, I will giving a public lecture at the Canyonlands Natural History Assocation’s Moab Information Center, at the corner of Main St. and Center in Moab (link). The talk is titled, “Lost worlds of the Jurassic: Diverse dinosaurs and plants in the lower Morrison Formation of south-central Utah”, and it is free to the public. It’s a report on the fieldwork I’ve been doing in the Morrison Formation of southern Utah for the past few summers with John Foster, Brian Engh, and Jessie Atterholt. I promise lots of pretty pictures and probably more yapping about sauropods than anyone really needs. Did I mention it’s free? I hope to see you there.

Second, I will be at SVP myself, for a bit. Basically Friday night and Saturday. Gotta catch up with collaborators and go see Brian Engh pick up his Lanzendorf Paleoart Prize Saturday night. Why do you care? Western University of Health Sciences has an open position for an anatomist, and a lot of paleo folks have anatomy training, so…if you are interested in this position specifically, or if you have general questions about what it’s like to be a paleontologist teaching gross anatomy at a med school (spoiler: mostly awesome), come find me sometime Friday evening or Saturday and chat me up. I’ll probably be roaming the hallways and talking with folks instead of attending talks (sorry, talk-givers–you all rock, I’m just too slammed this year). And if you are on the job market, have some anatomy experience, and aren’t allergic to sun, palm trees, and amazing colleagues, please consider applying for the position. We’re taking applications through October 26, so don’t tarry. Here’s that link again.

Here’s D10 and the sacrum of Diplodocus AMNH 516 in left lateral and ventral view, from Osborn (1904: fig. 3). Note how the big lateral pneumatic foramina, here labeled ‘pleurocoelia’, start out up at the top of the centrum in D10 and kind of pinch out up there, seemingly entirely absent by S3 (although there is a suspicious-looking shadowed spot above and behind the sacral rib stump labeled ‘r3’). Then on S4 and S5 the big foramina are back, but now they’re low on the centrum, ventral to the sacral ribs. In ventral view, the foramina on D10, S1, and S2 aren’t visible–they’re both over the curve of the centrum, and in the case of S1 and S2, obscured by the sacral ribs. But in S4 and S5, the big lateral foramina are visible in ventral view.

I’ve been interested in a while in this seeming hand-off in centrum pneumatization from dorsolateral, which prevails in the dorsal vertebrae, to ventrolateral, which prevails in the posterior sacral and caudal vertebrae. Almost all sauropod dorsals have the pneumatic foramina quite high on the centrum, sometimes even encroaching on the neural arch. But if sauropod caudals have pneumatic fossae or foramina on the centrum, they’re usually quite low, and almost always below the caudal rib or transverse process (there may also be pneumatic fossae on the neural arch and spine)–for evidence, see Wedel and Taylor (2013b). To me this implies two different sets of diverticula.

I think that in part because sometimes you get both sets of diverticula acting on a single vert. Here’s the centrum of sacral 4 of Haplocanthosaurus CM 879 in right dorsolateral view; anterior is to the right.

Here’s the same thing annotated (yeah, it does look a little like an Ent who is alarmed because his left eye has been overgrown by a huge nasal tumor). This vert has two sets of pneumatic features on the centrum: a big lateral fossa below the sacral rib articulation, presumably homologous with the same feature in S4 of the Diplodocus above; and a smaller dorsolateral fossa above and behind sacral rib articulation.

Unfortunately, CM 879 doesn’t tell us much about how these two sets of diverticula might have changed along the column. The centra of S1-S3 were not found, S5 lacks both sets of fossae, the first caudal has fossae both on the centrum, below the caudal rib, and low on the arch, and the second and subsequent caudals lack both sets of fossae. (I wrote a LOT more about pneumaticity in this individual in my 2009 air sacs paper, which is linked below.)

Working out how these diverticula change serially is a tractable problem. Someone just needs to sit down with a reasonably complete, well-preserved series that includes posterior dorsals, all the sacrals, and the proximal caudals–or ideally several such series–and trace out all of the pneumatic features. As far as I know, that’s never been done, but feel free to correct me if I’ve missed something. I’m neck deep in other stuff, so if someone wants that project, have at it. (If you happen to look into this, I’d be grateful for a heads up, so we don’t run over each other if I do get a yen to investigate further myself.)

References

The afternoon of Day 1 at TetZooCon 2018 was split into two parallel streams: downstairs, some talks that I would have loved to see; and upstairs, a palaeoart workshop that I was even keener not to miss out on.

There were talks by Luis Rey (on how palaeoart has had to be dragged kicking and screaming into accepting feathers and bright colours) and by Mark Witton (on the future of palaeoart — sadly, bereft of slides). Both fascinating.

But better still was the wide-ranging informal discussion between Luis, Mark, John Conway, Bob Nicholls and others on what palaeoart is actually all about. For Luis, it’s basically fun; for Mark, it’s primarily science communication; for John, it’s art first, and palaeontology only because that’s what he happens to be depicting; and for Bob, as well as all those things, it’s crucially important as a job of work, satisfying the requirements of those who commission that work. Obviously that’s a huge over-simplification: all of them have all these aspects going on in varying proportions. But that’s how I read it.

At the same time that all this was going on, we — maybe 60 or 70 of us? — were encouraged to create our own art, either attempting styles that are different to what we usually do, are using materials we’re not so familiar with. For the many excellent artists in the group, this challenge must have been interestingly novel. For non-artists like myself, it was just a chance to play.

I took the opportunity to try my hand with charcoal, in the hope of getting some suggestive or even impressionistic textures. Here’s my first work — an indeterminate brachiosaur with an inexplicably big head.

Aside from the head — I can’t do heads! — I’m reasonably happy with that. I got a decent sense of bulk in the torso, anyway.

Encouraged, I made a start on a second piece: a BRONTOSMASH!ing apatosaur that didn’t come out so well.

I’m happy with the forelimbs here, but something is dreadfully wrong with the torso and I can’t put a finger on what it is. If I’d had more time, I’d have put in the second hindlimb, which might have helped me figure out what was going wrong. The other thing I fluffed here was that I should have made the neck even fatter and more robust. Oh, and of course the head. I might return to this and see if I can sort out, if I can find some charcoal.

Anyway, it was a fascinating experience. And it’s left me with a new favourite art medium.

 

Last night, Fiona and I got back from an exhausting but very satisfying weekend spent at TetZooCon 2018, the conference of the famous Tetrapod Zoology blog run by Darren Naish — the sleeping third partner here at SV-POW!.

What made this particularly special is that Fiona was one of the speakers this time. She’s not a tetrapod zoologist, but a composer with a special interest in wildlife documentaries. She had half an hour on Music for Wildlife Documentaries – A Composer’s Perspective, with examples of her own work. I thought it was superb, but then I would — I’m biased. I’ll hand over to Twitter for a more objective overview:


Darren Naish: Now at #TetZooCon: Fiona Taylor on music in wildlife documentaries. Fiona is a professional composer.

Ellie Mowforth: Next up, it’s “Music for Wildlife Documentaries”. I am SHOCKED to hear that not everyone shares my love for the waddling penguin comedy trombone. #TetZooCon

Nathan Redland: Nature documentaries are entertainment, not just education: and the composer’s budget comes from the studio, not an academic institution #TetZooCon

“If these shows were just a string of facts about animals, most of us wouldn’t watch. That’s why they carve out stories in editing, why they use intense music, and why they recreate the sound effects — because story-telling is what engages us.”
— Simon Cade.

Will Goring: Very effective demonstration; same image, 5 different scores = 5 different interpretations. #TetZooCon

… and here is the relevant segment of video, together with the script that Fiona used:

Picture of wolf

We’re going to play “What kind of wolf is this?” or perhaps a better question is: “what is the music telling us to feel about this wolf?” I written 5 brief musical clips in 5 very different styles I’m hoping will showhow very differently we can be led into feeling about one image.

  1. This wolf is bad, suspense, about to kill something cute.
  2. Preparing to spring into action, attack.
  3. This wolf is sad, it has just lost its pups, if it doesn’t eat soon, it will starve.
  4. This wolf is cute, and cuddly and very playful. You just want to stroke him.
  5. This wolf is noble, kingly, will survive because his race has always survived, with dignity.

Alberta Claw: #TetZooCon Taylor: Provides detailed analysis of musical accompaniment in several documentary clips. Only a few seconds long each, but incredible amount of nuance and thought goes into these decisions.

Dr Caitlin R Kight: I responded exactly as she predicted and would have even without the explanation, but it was more interesting to know why I was feeling what I was, when I was!

Samhain Barnett: At 25 frames a second, a drumbeat has to occur within 2 frames of a nut being cracked, for our brains to accept it as in sync. Computers have made composers lives a lot easier here. #TetZooCon

(I’d like to show the video clip that that last tweet pertains to, but complicated rightsholder issues make that impractical. Sorry.)

Alberta Claw: #TetZooCon Taylor: Given the power of music to influence emotions, documentary composers have responsibility to think about the effects of music. Peer-reviewed research has shown that musical accompaniment can impact motivation of viewers to contribute to shark conservation.

Here are two sketches from Sara Otterstätter, who did this for every talk:

First one: About music in Nature documentaries. Useful or manipulative? #TetZooCon #sketch #sketchbook

Second one: Show documentaries always reality? #TetZooCon #Sketching #sketch

And two final comments …

Filipe Martinho: Quite often the most interesting talks are completely outside my area. Fiona Taylor gave an amazing eye and ear opener on the role of music in nature documentaries and #scicomm. #TetZooCon

Flo: Thanks to Fiona Taylor I will from now on listen more carefully to the music accompanying wildlife docs. #TetZooCon #musicforwildlifedocumentaries


We both had a great time at TetZooCon. As I said in an email to Darren after I got home, “It made me wonder what they heck I’d been thinking, missing the last few”. I don’t plan to repeat that mistake.

Hearing the talks through the ears of someone without much background was an interesting experience. Some of the speakers did a fantastic job of providing just enough background to make their work comprehensible to an intelligent layman: for example, Jennifer Jackson on whales, Robyn Womack on bird circadian rhythms and Albert Chen on crown-bird evolution. There’s a tough line to walk in figuring out what kind of audience to expect at an
event like this, and I take my hat off to those who did it so well.