I was in Philadelphia and New York last week, visiting colleagues on the East Coast and getting in some collaborative research. Much more to say about that in the future – even just the touristy stuff will fill several posts.

One highlight of the trip was visiting the Academy of Natural Sciences in Philadelphia last Friday. Ted Daeschler (of Tiktaalik fame) and Jason Poole (who illustrated this sweet book) were my generous hosts and I got to see a ton of cool stuff both out on exhibit and behind the scenes. Seriously, I could post for a month just on the Academy visit.

A personal highlight for me was seeing the cervical vertebrae of the sauropod dinosaur Suuwassea on exhibit. They are in a glass case and you can get around them pretty well to see a lot of anatomy. At first I was pumped to get nice color photos of all the vertebrae from up close and from multiple angles. Then I thought, “Huh, maybe I should just shoot a video.” So I did. Here you go, four minutes of hot sauropod vertebra action:

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Back in 2009, I posted on a big cervical series discovered in Big Bend National Park. Then in 2013 I posted again about how I was going to the Perot Museum in Dallas to see that cervical series, which by then was fully prepped and on display but awaiting a full description. Ron Tykoski and Tony Fiorillo (2016) published that description a couple of years ago, and after almost five years it’s probably time I posted an update.

I did visit the Perot Museum in 2013 and Ron and Tony kindly let me hop the fence and get up close and personal with their baby. I got a lot of nice photos and measurements of the big specimen. It’s an impressive thing. Compared to the other big sauropod cervicals I’ve gotten to play with, these vertebrae aren’t all that long – the two longest centra are about 80cm, compared to ~120cm for Sauroposeidon, Puertasaurus, and Patagotitan, and 137cm for Supersaurus (more details here) – but they are massive. According to the table of measurements (yay!) in Tykoski and Fiorillo (2016), which accord well with the measurements I took when I was there, the last vert is 117.5cm tall from the bottom of the cervical rib to the top of the neural spine, 98.4cm wide across the diapophyses, and has a cotyle measuring 29cm tall by 42cm wide. Here it is with me for scale:

I guarantee you, standing next to that thing and imagining it being inside the neck of a living animal is a breathtaking experience.

I failed in my mission in one way. In a comment on my 2013 post, I said, “I’ll try to get some good lateral views of the mount with as little perspective as possible.” But it can’t be done – the geometry of the room and the size of the skeleton don’t allow it, as Ron noted in the very next comment. There is one place in the exhibit hall where you can get the whole skeleton into the frame, and that’s a sort of right anterolateral oblique view. Here’s my best attempt:

So, this is an awesome specimen and you should go see it. As you can see from the photos, the vertebrae are right on the other side of the signage, with no glass between you and them, so you can see a lot. The rest of the exhibits are top notch as well. Definitely worth a visit if you find yourself within striking distance of Dallas.

Reference

Tykoski, R.S. and Fiorillo, A.R. 2016. An articulated cervical series of Alamosaurus sanjuanensis Gilmore, 1922 (Dinosauria, Sauropoda) from Texas: new perspective on the relationships of North America’s last giant sauropod. Journal of Systematic Palaeontology 15(5):339-364.

Back in the spring of 1998, Kent Sanders and I started CT scanning sauropod vertebrae. We started just to get a baseline for the Sauroposeidon project, but in time the data we collected formed the basis for my MS thesis, and for a good chunk of my dissertation as well. Mostly what we had available to scan was Morrison material. Between imperfect preservation, inexpert prep (by WPA guys back in the ’30s), and several moves over the decades, most of the verts from the Oklahoma Morrison have their neural spines and cervical ribs broken off. One of the first things I had to figure out was how to tell broken vertebrae of Camarasaurus from those of Apatosaurus (at the time; Brontosaurus is back in contention now). Here’s a thing I made up to help me sort out cervical centra of Camarasaurus and whatever the Oklahoma apatosaurine turns out to be. It’s a recent production, but it embodies stuff from my notebooks from 20 years ago. Should be useful for other times and places in the Morrison as well, given the broad spatiotemporal overlap of Camarasaurus and the various apatosaurines.

For a related thing in the same vein, see Tutorial 30: how to identify Morrison sauropod cervicals.

More elephant seals soon, I promise.

UPDATE 20 Feb 2018

Ken Carpenter sent this by email, with a request that I post it as a comment. Since it includes an image, I’m appending to the post, because it makes an important point that I neglected to mention.

Camar post cerv

Ken: Sorry, Matt. Not so easy. The last cervical of Camarasaurus from the Cleveland Lloyd Quarry is more apatosaurine-like than Camarasaurus-like based on your posting. Note the position of both zygapohyses with both ends of the centrum.

My response: Yes, good catch. I meant to say in the post that my distinguishing characters break down at the cervico-dorsal transition. Even so, in this Cleveland Lloyd vert the postzyg is still forward of a line drawn directly up from the cotyle. I’ve never seen that in an apatosaurine–going into the dorsal series, the postzygs tend to be centered over a line projected up from the rim of the cotyle. (If anyone knows of counterexamples, speak up!)

For distinguishing cervico-dorsals, apatosaurines tend to have much taller neural spines than Camarasaurus, and this carries on through the rest of the dorsal series. In apatosaurine dorsals, the height of the spine above the transverse processes always equals or exceeds the height of the arch below the transverse processes. In Camarasaurus, the height of the dorsal neural spines is always less than or equal to the height of the arch. The shapes of the spines are fairly different, too. Maybe that will be the subject of a future post.

 

As part of a major spring cleaning operation that we started the first week of January, this week I opened the last two boxes left over from when we moved into our current house. One of them had a bundle of framed art. I knew most of what was in there before I opened the box, but I had somehow completely forgotten about this. I must have gotten it framed in late 90s, and it hung on the walls of our apartments in Norman and Santa Cruz. At some point it went into a box, and I forgot it even existed.

This is the first technical drawing I ever attempted of OMNH 53062, which would later become the holotype of Sauroposeidon. I drew it for my poster at the 1997 SVP meeting in Chicago, and it went on to become Figure 5 in my undergraduate thesis (which is preserved for posterity here). I’d do other, better drawings of the specimen in later years, but this one came first.

I know I’m biased, but that second vertebra in the preserved series, which I interpreted as C6 back when, will probably always be the most gorgeous natural object on the planet in my book. I don’t expect anyone else to feel the same. I worked on that specimen for three years – some of it seeped into my soul, and vice versa. Then again, I don’t care how jaded you are about long vertebrae, that one is still a pretty arresting sight.

For a much more recent take on the appearance of the Sauroposeidon vertebrae, see this post.

There’s a new paper out, describing the Argentinian titanosaur Mendozasaurus in detail (Gonzalez Riga et al. 2018): 46 pages of multi-view photos, tables of measurement, and careful, detailed description and discussion. But here’s what leapt out at me when I skimmed the paper:

Gonzalez Riga et al. (2018: figure 6). Mendozasaurus neguyelap cervical vertebra (IANIGLA-PV 076/1) in (A) anterior, (B) left lateral, (C) posterior, (D) right lateral, (E) ventral and (F) dorsal views. Scale bar = 150 mm. Sorry it’s monochrome, but that’s how it appears in the paper.

Just look at that thing. It’s ridiculous. In our 2013 PeerJ paper “Why Giraffes have Short Necks” (Taylor and Wedel 2013), we included a “freak gallery” as figure 7: five very different sauropod cervicals:

Taylor and Wedel (2013: figure 7). Disparity of sauropod cervical vertebrae. 1, Apatosaurus “laticollis” Marsh, 1879b holotype YPM 1861, cervical ?13, now referred to Apatosaurus ajax (see McIntosh, 1995), in posterior and left lateral views, after Ostrom & McIntosh (1966, plate 15); the portion reconstructed in plaster (Barbour, 1890, figure 1) is grayed out in posterior view; lateral view reconstructed after Apatosaurus louisae (Gilmore, 1936, plate XXIV). 2, “Brontosaurus excelsus” Marsh, 1879a holotype YPM 1980, cervical 8, now referred to Apatosaurus excelsus (see Riggs, 1903), in anterior and left lateral views, after Ostrom & McIntosh (1966, plate 12); lateral view reconstructed after Apatosaurus louisae (Gilmore, 1936, plate XXIV). 3, “Titanosaurus” colberti Jain & Bandyopadhyay, 1997 holotype ISIR 335/2, mid-cervical vertebra, now referred to Isisaurus (See Wilson & Upchurch, 2003), in posterior and left lateral views, after Jain & Bandyopadhyay (1997, figure 4). 4, “Brachiosaurus” brancai paralectotype MB.R.2181, cervical 8, now referred to Giraffatitan (see Taylor, 2009), in posterior and left lateral views, modified from Janensch (1950, figures 43–46). 5, Erketu ellisoni holotype IGM 100/1803, cervical 4 in anterior and left lateral views, modified from Ksepka & Norell (2006, figures 5a–d).

But this Mendozasaurus vertebra is crazier than any of them, with its tiny centrum, its huge, broad but anteroposteriorly flattened neural spine, and its pronounced lSPRLs.

I just don’t know what to make of this, and neither does Matt. And part of the reason for this may be that neither of us has had that much to do with titanosaurs. As Matt said in email, “Those weird ballooned-up neural spines in titanosaurs kind of freak me out.” And I could not agree more.

And of course as sauropodologists, we really should familiarise ourselves with titanosaurs. There are a lot of them, and they account for a lot of sauropod evolution. Someone recently made the point, either in an SV-POW! comment or on Facebook, that titanosaurs may be to sauropods what monkeys and apes are to primates: a subclade that is way more diverse than the rest of the clade put together.

It’s starting to look like an extreme historical accident that Camarasaurus, diplodocines and brachiosaurids — all temporally and/or geographically restricted groups — were the first well-known sauropods, and for decades defined our notion of what sauropods were like. Meanwhile, the much more widespread and long-surviving rebbachisaurs and titanosaurs were poorly understood until really the last 25 years or so. For the first century of sauropodology, our ideas about sauropods were driven by weird, comparatively short-lived outliers.

That our appreciation of titanosaur diversity has come so late says something about how our discovery of the natural world is more to do with geopolitics and the quirks of exploration than what’s actually out there. Sauropods were defined by diplodocids for so long because that’s what happened to be in the ground in the exposed rocks of North America, and that’s where the well-funded museums and expeditions were.

We at SV-POW! towards have often wondered how different our idea of what dinosaurs even were would be if the Liaoning deposits had been available to Buckland, Mantell, and Owen. It seems like that unavoidable that, if they’d first become familiar with feathered but osteologically aberrant (by modern standards) birds, one of two things would have happened. Either they would either have never coined the term “Dinosauria” at all, recognizing that Megalosaurus (and later Allosaurus and Tyrannosaurus) were just big versions of their little feathered ur-birds. Or they would have included Dinosauria as a primitive subclass of Aves.

References

  • González Riga, Bernardo J., Philip D. Mannion, Stephen F. Poropat, Leonardo D. Ortiz David and Juan Pedro Coria. 2018. Osteology of the Late Cretaceous Argentinean sauropod dinosaur Mendozasaurus neguyelap: implications for basal titanosaur relationships. Zoological Journal of the Linnean Society, 46 pages, 28 figures. doi:10.1093/zoolinnean/zlx103
  • Taylor, Michael P., and Mathew J. Wedel. 2013. Why sauropods had long necks; and why giraffes have short necks. PeerJ 1:e36. 41 pages, 11 figures, 3 tables. doi:10.7717/peerj.36

 


Note. This post contains material from all three of us (Darren included), harvested from an email conversation.

 

Here’s BYU 12866, a mid-cervical of a neosauropod from Dry Mesa Quarry. It’s cataloged as Brachiosaurus, an identification I’ve never found any compelling reason to doubt. It’s definitely brachiosaurid, and for now Brachiosaurus is the only game in town for the Late Jurassic of North America. I expect that will change when more and better material comes to light, based on the different coracoid shapes of the Brachiosaurus holotype and the “Ultrasauros” scapulocoracoid.

I reckon it’s probably a C5 or so, based on its proportions and comparisons with Giraffatitan (for example).

As you can see, it’s a bit distorted, sheared over with the dorsal side to the right and the ventral side to the left.

I don’t think there’s any major anterior/posterior shearing – the zygs are set forward of their respective centrum ends by about the same amount in this specimen as in Giraffatitan.

Kent Sanders and I CT scanned this vert back in the day and those scans made it into several papers, including Wedel et al. (2000b) on Sauroposeidon and Wedel (2005) on sauropod pneumaticity and mass estimates.

I have the original, uncropped, full-res photos, and I’ll probably get them posted at some point (faster if people bug me to do so, so speak up in the comments if you want them). But for now I’m sticking to getting stuff posted quickly, easily, and regularly, and I found these as-is on my hard drive, so here we are.

References

 

Out today: a new Turiasaurian sauropod, Mierasaurus bobyoungi, from the Early Cretaceous Cedar Mountain formation in Utah. This comes to us courtesy of a nice paper by Royo Torres et al. (2017),

Royo-Torres et al. 2017, fig. 3. The postcranial skeleton (UMNH.VP.26004) of Mierasaurus bobyoungi gen. nov, sp. nov. with the following elements: (a) middle cervical vertebra (DBGI 69 h) in right lateral view; (b) middle cervical vertebra (DBGI 69G1) in right lateral view; (c) anterior cervical vertebra (DBGI 165) in right lateral view; (d) anterior cervical vertebra (DBGI 69G2) in right lateral view; (e) atlas (DBGI 5I) in anterior view; (f) atlas (DBGI 5I) in right lateral view; (g) posterior cervical vertebra (DBGI 95) in right lateral view; (h) posterior cervical vertebra (DBGI 19 A) in right lateral view; (i) posterior cervical vertebra (DBGI 19 A) in ventral view; (j) middle cervical vertebra (DBGI 38) in right lateral view; (k) middle cervical vertebra (DBGI 38) in dorsal view; (l) middle cervical vertebra in posterior view; (m) middle cervical vertebra (DBGI 38) in left lateral view; (n) right anterior cervical rib (DBGI 5D) in medial view; (o) right anterior cervical rib (DBGI 28 A) in medial view; (p) right anterior-middle cervical rib (DBGI 95 C) in medial view; (q) right middle cervical rib (DBGI 45 F) in dorsal view; (r) right middle cervical rib (DBGI 95 A) in dorsal view; (s) left anterior cervical rib (DBGI 95B) in lateral view; (t) left middle cervical rib (DBGI 95 H) in lateral view; (u) left middle cervical rib (DBGI 95D) in dorsal view; (v) right posterior cervical rib (DBGI 10) in dorsal view. A plus sign (+) indicates a diagnostic character for Mierasaurus bobyoungi gen. et sp. nov. An asterisk (*) indicates an autapomorphy of Mierasaurus bobyoungi gen. et sp. nov. (© Fundación Conjunto Paleontológico de Teruel-Dinópolis) in Adobe Illustrator CS5 (www.adobe.com/es/products/illustrator.html).

[Because this paper is in Nature’s Scientific Reports, it inexplicably has a big chunk of manuscript chopped out of the middle, supplied separately, not formatted properly, and for all we know not peer-reviewed. This includes such minor details as the specimen numbers of the elements that make up the holotype, and the measurements. Note to self: rant about how objectively inferior Scientific Reports is to PeerJ and PLOS ONE some time.]

Anyway, this is a nice specimen represented by lots of decent material, including plenty of presacral vertebrae, which is great.

But here’s where it gets weird. Until now, Turiasauria has been an exclusively European clade. Just like Diplodocidae used to be an exclusively North American clade until Tornieria turned up, and Dicraeosauridae used to be an exclusively Gondwanan clade until Suuwassea turned out to be a dicraeosaur, and so on.

I mentioned this in an email to Matt. His initial take was:

There is a semi-tongue-in-cheek biogeography “law” that states “Everything is everywhere, and the environment selects”.

It is kinda blowing my mind that so many taxa were shared between North America, Europe, and Africa in the Late Jurassic and yet we don’t see any turiasaurs in North America until the Cretaceous. I wonder if they are there in the Morrison and just not recognized — either some of the undescribed or undiscovered northern-Morrison weirdness, or currently lumped in with Camarasaurus.

I responded “That’s one read. Another is that we’re seeing convergence on similar eco-niches within widely different clades, and our analyses are not figuring this out.”

What I mean is this: what if our “Brachiosauridae” clade is really just a collection of not-closely-related taxa in the tall-shouldered very-high-browser ecological niche? And what if our “Dicraeosauridae” clade is just a collection of short-necked grazers, with independent evolutionary origins, but all converging on morphology that suits the same lifestyle?

And that is the thought that is currently freaking me out.

Royo-Torres et al. 2107, fig. 4. The postcranial skeleton (UMNH.VP.26004) of Mierasaurus bobyoungi gen. nov, sp. nov. with the following elements: (a) anterior dorsal vertebra (DBGI 54 A) in posterior view; (b) anterior dorsal vertebra (DBGI 54 A) in anteroventral view; (c) neural arch of a middle dorsal vertebra (DBGI 37) in right anterolateral view; (d) posterior neural arch of a dorsal vertebra (DBGI 19 A) in posterior view; (e) anterior dorsal vertebra (DBGI 16) in right lateral view; (f) anterior dorsal vertebra (DBGI 16) in posterior view; (g) posterior dorsal vertebra (DBGI 16) in anterior view; (h,i) posterior dorsal vertebra (DBGI 100NA 1) in anterior view; (j,k) posterior dorsal vertebra (DBGI 100NA 1) in posterior view; (l) posterior dorsal vertebra (DBGI 100NA 1) in left lateral view; (m) middle dorsal vertebra (DBGI 11) in anterior view; (n) centrum of a posterior dorsal vertebra (DBGI 24B) in ventral view; (o) centrum of a posterior dorsal vertebra (DBGI 24B) in anterior view; (p) centrum of a posterior dorsal vertebra (DBGI 192) in ventral view; (q) anterior-middle caudal vertebra (DBGI 23B) in anterior view; (r) anterior-middle caudal vertebra (DBGI 23B) in right lateral view; (s) posterior neural arch of a posterior caudal vertebra (DBGI 48) in left lateral view; (t) posterior caudal vertebra (DBGI 21) in anterior view; (u) posterior caudal vertebra (DBGI 21) in right lateral view; (v) distal caudal vertebra (DBI 37-34-529) in right lateral view; (W) anterior caudal vertebra (DBGI 192) in posterior view. For abbreviations see supplementary information. (i), (k) and (l) were drafted by R.R.T. (© Fundación Conjunto Paleontológico de Teruel-Dinópolis) in Adobe Illustrator CS5 (www.adobe.com/es/products/illustrator.html).

When I mentioned this possibility to Matt, he shared my existential terror:

What haunts me is this: we know from mammals and extant reptiles that morphological analyses suck. Laurasian moles, African moles, and Australian moles all look the same, despite evolving from very different ancestors. Ditto wolves and thylacines, horses and litopterns, etc.

Matt reminded of a paper we’ve talked about before (Losos et al. 1998), showing that this is exactly what happens with Caribbean anole lizards. Each island has forms that live on the ground, on the trunks of trees, and on branches. Phylogenetic analyses based on morphology put all the ground-livers together, ditto for trunk-climbers, ditto for branch-climbers. But molecular analyses show that each island was colonized once and the ground, trunk, and branch forms evolved separately for each island.

What if “turiasaur”, “brachiosaur”, and “titanosaur” are the sauropod equivalents? For “Caribbean island” read “continent”; for “lizard species”, read “sauropod clade”.

Will we ever know?

Matt is hopeful that we will. He’s confident that in time, we’ll get molecular analyses of dinosaur relationships — that it’s just a matter of time and cleverness. When that happens, things could be upended bigtime.

References