Sauroposeidon in 3D

April 18, 2014

Sauroposeidon meet Sauroposeidon

I was in Oklahoma and Texas last week, seeing Sauroposeidon, Paluxysaurus, Astrophocaudia, and Alamosaurus, at the Sam Noble Oklahoma Museum of Natural History, the Fort Worth Museum of Science and History, the Shuler Museum of Paleontology at SMU, and the Perot Museum of Nature and Science, respectively. I have a ton of interesting things from that trip that I could blog about, but unfortunately I have no time. Ten days from now, I’m off to Colorado and Utah for the Mid-Mesozoic conference and field trip, and between now and then I need to finish up my bits on three collaborative papers, get my summer anatomy lectures posted for internal peer review here at WesternU, and–oh yeah–actually write my conference talk. Fun times.

BUT after being subjected to the horror of the Yale Brontosaurus skull, I figured you all deserved a little awesome.

Photographing Sauroposeidon 2014-04-07

So here’s me getting one of 351 photos of the most posterior and largest of the Sauroposeidon jackets (this is not the awesome, BTW, just a stop along the way). This jacket holds what I once inferred to be the back half of C7 and all of C8. Now that Sauroposeidon may be a somphospondyl rather than a brachiosaur, who knows what verts these are–basal somphospondyls have up to 17 cervicals to brachiosaurids’ probable 13 (for a hypothetical view of an even-longer-necked Sauroposeidon, see this probably-prophetic post by Mike). The vertically-mounted skeleton in the background is Cotylorhynchus. Cotylorhynchus got a lot bigger than that–up to maybe 6 meters long and 2 or 3 tons–and was probably the largest land animal that had ever existed back in the Early Permian. Photo by OU grad student Andrew Thomas, whom you’ll be hearing about more here in the future.

I couldn’t crank the model myself on the road, thanks to the pathetic lack of processing power in my 6-year-old laptop (which will be replaced RSN). Andy Farke volunteered to do the photogrammetricizing with Agisoft Photoscan, if only I’d DropBox him the pictures. Here’s a screenshot from MeshLab showing the result:

Sauroposeidon lateral PLY 10 - 6 and 9 blended

And my best taken-from-overhead quasi-lateral photograph:

Sauroposeidon C8 jacket lateral photo 2014-04-07

If you’re curious, the meter stick at the top is actually one meter long, it just has the English measurement side showing. The giant caliper at the bottom is also marked off in inches, and it is open to 36.0 inches (it didn’t go to 1 meter, or I would have used that). You can tell that there is some perspective distortion involved here since 36 inches on the caliper is 1380 pixels, whereas the 39.4-inch meter stick is only 1341 pixels. Man, I hate scale bars. But they make good calibration targets.

Incidentally, after playing around with the model in orthographic mode in MeshLab, the distortions in the photos of the vertebrae themselves just scream at me. Finally, finally, I can escape the tyranny of perspective. Compare the ends of the big wooden beam at the top of the jacket to get a feel for how much the two views differ.

Working on Sauroposeidon again after all this time made me seriously nostalgic. I love that beast. I don’t think I’m exaggerating when I say that those vertebrae are the most gorgeous physical objects in the universe. Also, an appropriately huge thank-you to preparator Kyle Davies (of apatosaur-sculpting fame), collections manager Jen Larsen, and Andrew Thomas again for help with wrassling those verts around, and for sharing their thoughts and advice. Thanks also to curators Rich Cifelli and Nick Czaplewski for their hospitality and for the go-ahead to undertake this work, and to Andy Farke for generating the model.

I’ll have a lot more to say about this stuff in the future. I didn’t go to all this work just for giggles. For a long time I’ve had a hankering to do a paper on the detailed anatomy of Sauroposeidon, based on all of the things that I’ve noticed in the last decade that didn’t make it into any of the early papers. And now there’s the proposed synonymy of Paluxysaurus with Sauroposeidon. And “Angloposeidon” needs some attention–Darren and I have been thinking about writing “Angloposeidon II” for years now. And…well, plenty more.

So, loads more to come, but not for the next few weeks. Eventually I’ll be publishing all of this–the photos, the 3D models, the whole works. Stay tuned.

How can it be?

IMG_0517

All credit to the Yale Peabody Museum for having the courage to display this historically important object in their public gallery instead of hiding it in a basement. It’s the skull from the original mount of the Brontosaurus (= Apatosaurus) excelsus holotype YPM 1980.

Needless to say, it bears no resemblance at all to the actual skull of Apatosaurus, and the one they now have on the mount is much, much better:

IMG_0500-skull

But how did the YPM people ever arrive at this double-plus-ugly skull above? We see a similar skull in Marsh’s (1891) second attempt at restoring the skeleton of Brontosaurus:

Marsh1891-plateXVI-Apatosaurus-skull

But even this is not as ugly and Just Plain Wrong as the physical model they made. (Marsh’s first restoration of the Brontosaurus skeleton, in 1893, had a much less clear skull.)

So how did the YPM come to make such a monstrosity? What was it based on? Tune in next time for the surprising details!

Bizarrely, we’ve never really featured the  YPM 1980 mount here on SV-POW! — we’ve often shown individual bones, but the mounted skeleton appears only in the background of the much less impressive Morosaurus (= Camarasaurus) lentus mount. We’ll fix that real soon.

 

Five days ago, I released a program for drawing comparative figures of vertebral columns, such as this one from our neural-spine bifurcation paper. With my idiot computer-scientist hat on, I gave that program the startlingly unmemorable name vcd2svg — the reasoning being that it takes Vertebral Column Descriptions and translates them into Scalable Vector Graphics.

In a comment on that post, Vertebrat rightly noted:

The name is a bit opaque. It sounds like a tool for people who have VCD files and want to convert them to SVG. Maybe this means extracting frames from Video CD files as SVG (a rather inappropriate format)? :)

Your target users don’t have VCD files, don’t want to convert anything, and have little or no preference for SVG. They want to make diagrams of vertebrae.

A fair point. Accordingly, I have renamed the program VertFigure — a name chosen in part because Google doesn’t know of anything else with the same name. The canonical GitHub page is now http://github.com/MikeTaylor/VertFigure but the old address still works, and git checkouts made from the old name will also continue to work. The command-line program that does the conversion is now also named VertFigure.

 

Visiting relatives in Texas, just like last spring. Very distant relatives. And this happened:

Photobombing fawn

Here’s the culprit, with his sidekicks Monorail Badger, Trashbag Tortoise, and Kas-Tor, Last Beaver of Krypton. A disreputable bunch.

Dude I am so stuffed

The victim. Some call him the Winter Cervical. He was fast, strong–and he had a metal arm…ature.

Paluxysaurus vert

Meanwhile, in the back:

DinoMorph horse

I think it’s fair to say that this “bifurcation heat-map”, from Wedel and Taylor (2013a: figure 9), has been one of the best-received illustrations that we’ve prepared:

Wedel and Taylor 2013 bifurcation Figure 9 - bifurcatogram

(See comments from Jaime and from Mark Robinson.)

Back when the paper came out, Matt rashly said “Stand by for a post by Mike explaining how it came it be” — a post which has not materialised. Until now!

This illustration was (apart from some minor tweaking) produced by a program that I wrote for that purpose, snappily named “vcd2svg“. That name is because it converts a vertebral column description (VCD) into a scalable vector graphics (SVG) file, which you can look at with a web-browser or load into an image editor for further processing.

The vertebral column description is in a format designed for this purpose, and I think it’s fairly intuitive. Here, for example, is the fragment describing the first three lines of the figure above:

Taxon: Apatosaurus louisae
Specimen: CM 3018
Data: —–YVVVVVVVVV|VVVuuunnn-

Taxon: Apatosaurus parvus
Specimen: UWGM 155556/CM 563
Data: –nnn-VVV—V-V|VVVu——

Taxon: Apatosaurus ajax
Specimen: NMST-PV 20375
Data: –n–VVVVVVVVVV|VVVVYunnnn

Basically, you draw little ASCII pictures of the vertebral column. Other directives in the file explain how to draw the various glyphs represented by (in this case) “Y”, “V”, “u”, and “n”.

It’s pretty flexible. We used the same program to generate the right-hand side (though not the phylogenetic tree) of Wedel and Taylor (2013b: figure 2):

Wedel and Taylor (2013b: Figure 2).

Wedel and Taylor (2013b: Figure 2).

The reason I mention this is because I released the software today under the GNU General Public Licence v3.0, which is kind of like CC By-SA. It’s free for anyone to download, use, modify and redistribute either verbatim or in modified form, subject only to attribution and the requirement that the same licence be used for modified versions.

vcd2svg is written in Perl, and implemented in part by the SVG::VCD module, which is included in the package. It’s available as a CPAN module and on GitHub. There’s documentation of the command-line vcd2svg program, and of the VCD file format. Also included in the distribution are two documented examples: the bifurcation heat-map and the caudal pneumaticity diagram.

Folks, please use it! And feel free to contribute, too: as the change-log notes, there’s work still to be done, and I’ll be happy to take pull requests from those of you who are programmers. And whether you’re a programmer or not, if you find a bug, or want a new feature, feel free to file an issue.

A final thought: in academia, you don’t really get credit for writing software. So to convert the work that went into this release into some kind of coin, I’ll probably have to write a short paper describing it, and let that stand as a proxy for the actual program. Hopefully people will cite that paper when they generate a figure using the software, the way we all reflexively cite Swofford every time we use PAUP*.

Update (12 April 2014)

On Vertebrat’s suggestion, I have renamed the program VertFigure.

References

Illustration talk slide 61

Illustration talk slide 62

Illustration talk slide 63

Illustration talk slide 64

Illustration talk slide 65

Illustration talk slide 66

The rest of the series is here. As promised, here are the files for the talk, in PPT and PDF formats.

Wedel 2014 Photography and illustration lecture (PPT, ~53 Mb)

Wedel 2014 Photography and illustration lecture (PDF, ~21 Mb)

References

Illustration talk slide 58

Illustration talk slide 59

Illustration talk slide 60

The rest of the series.

References

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