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I just read Mark Witton’s piece on the new new titanosaur Rukwatitan (as opposed to the old new titanosaur Dreadnoughtus). I was going to write something about it, but I realised that Mark has already said everything I would have, but better. So get yourselves over to his piece and enjoy the titanosaurianness of it all!

Podageddon low res Witton

Supersaurus vs Brachiosaurus - BYU 9024 and FMNH P25107

This was inspired by an email Mike sent a couple of days ago:

Remind yourself of the awesomeness of Giraffatitan:
http://svpow.files.wordpress.com/2008/11/mike-by-jango-elbow.jpeg

Now think of this. Its neck is 8.5m long. Knock of one measly meter — for example, by removing one vertebra from the middle of the neck — and you have 7.5 m.

Supersaurus’s neck was probably TWICE that long.

Holy poo.

I replied that I was indeed freaked out, and that it had given me an idea for a post, which you are now reading. I didn’t have a Giraffatitan that was sufficiently distortion-free, so I used my old trusty Brachiosaurus. The vertebra you see there next to Mike and next to the neck of Brachiosaurus is BYU 9024, the longest vertebra that has ever been found from anything, ever.

Regarding the neck length of Supersaurus, and how BYU 9024 came to be referred to Supersaurus, here’s the relevant chunk of my dissertation (Wedel 2007: pp. 208-209):

Supersaurus is without question the longest-necked animal with preserved cervical material. Jim Jensen recovered a single cervical vertebra of Supersaurus from Dry Mesa Quarry in western Colorado. The vertebra, BYU 9024, was originally referred to “Ultrasauros”. Later, both the cervical and the holotype dorsal of “Ultrasauros” were shown to belong to a diplodocid, and they were separately referred to Supersaurus by Jensen (1987) and Curtice et al. (1996), respectively.

BYU 9024 has a centrum length of 1378 mm, and a functional length of 1203 mm (Figure 4-3). At 1400 mm, the longest vertebra of Sauroposeidon is marginally longer in total length [see this post for a visual comparison]. However, that length includes the prezygapophyses, which overhang the condyle, and which are missing from BYU 9024. The centrum length of the largest Sauroposeidon vertebra is about 1250 mm, and the functional length is 1190 mm. BYU 9024 therefore has the largest centrum length and functional length of any vertebra that has ever been discovered for any animal. Furthermore, the Supersaurus vertebra is much larger than the Sauroposeidon vertebrae in diameter, and it is a much more massive element overall.

Neck length estimates for Supersaurus vary depending on the taxon chosen for comparison and the serial position assumed for BYU 9024. The vertebra shares many similarities with Barosaurus that are not found in other diplodocines, including a proportionally long centrum, dual posterior centrodiapophyseal laminae, a low neural spine, and ventrolateral flanges that connect to the parapophyses (and thus might be considered posterior centroparapophyseal laminae, similar to those of Sauroposeidon). The neural spine of BYU 9024 is very low and only very slightly bifurcated at its apex. In these characters, it is most similar to C9 of Barosaurus. However, theproportions of the centrum of BYU 9024 are more similar to those of C14 of Barosaurus, which is the longest vertebra of the neck in AMNH 6341. BYU 9024 is 1.6 times as long as C14 of AMNH 6341 and 1.9 times as long as C9. If it was built like that of Barosaurus, the neck of Supersaurus was at least 13.7 meters (44.8 feet) long, and may have been as long as 16.2 meters (53.2 feet).

Based on new material from Wyoming, Lovelace et al. (2005 [published as Lovelace et al. 2008]) noted potential synapomorphies shared by Supersaurus and Apatosaurus. BYU 9024 does not closely resemble any of the cervical vertebrae of Apatosaurus. Instead of trying to assign its serial position based on morphology, I conservatively assume that it is the longest vertebra in the series if it is from an Apatosaurus-like neck. At 2.7 times longer than C11 of CM 3018, BYU 9024 implies an Apatosaurus-like neck about 13.3 meters
(43.6 feet) long.

Supersaurus vs Diplodocus BYU 9024 and USNM 10865 - Gilmore 1932 pl 6

Bonus comparo: BYU 9024 vs USNM 10865, the mounted Diplodocus longus at the Smithsonian, modified from Gilmore 1932 (plate 6). For this I scaled BYU 9024 against the 1.6-meter femur of this specimen.

If you’d like to gaze upon BYU 9024 without distraction, or put it into a composite of your own, here you go:

Supersaurus cervical BYU 9024

References

 

Get your red/cyan anaglyph glasses on, and feast your eyes:

xenoposeidon--nhm-r2095--left-lateral--anaglyph

Click through for stupidly high resolution.

Those of you who are still too cheap to have sprung 99¢ for a pair of glasses, you can make do with this grossly inferior wigglegram:

xenoposeidon--nhm-r2095--left-lateral--wigglegram

Last time we looked at the humeri in the Field Museum’s mounted Brachiosaurus skeleton — especially the right humerus, which is a cast from the holotype, while the left is a sculpture. But Matt’s and my photos of that mount are all pretty much useless scientifically — partly because we were terrible photographers back then, but also partly because the very light background of sky tended to put the skeleton into silhouette and lose a lot of detail.

But fortunately there’s another Brachiosaurus in Chicago!

dscn1156

(We’ve featured this mount once before.)

This in fact the original Brachiosaurus mount that was erected in the Field Museum’s main hall in 1993. When a certain vulgar, over-studied theropod was installed in that hall in 2000, the surprising decision was made to remove the Brachiosaurus to “make room” for it (even though it’s objectively tiny). The mount was not built to be exposed to the elements, so it couldn’t just be moved outdoors. Instead, a new one was made from more suitable materials for the picnic area, and the original mount was moved to O’Hare Airport.

[Aside: what the heck were the museum thinking when they booted Brachiosaurus out of the main hall? However much you love T. rex, and I admit I do, Sue makes a feeble centrepiece compared with a brachiosaur. I can only assume there was some subtle political motivation for reducing their main hall's Awesome Quotient so dramatically. The poor thing was only there seven years.]

Anyway, the original mount is now at Terminal 1 at O’Hare Airport, where it can be photographed less inadequately than outdoors. Here are those contrasting humeri again: the real cast on the right side of the animal (left side of photo) and the sculpture on the left (right side of photo):

dscn1158

And a zoom into the relevant section:

dscn1158-closeup

As it happens, I flew into a different terminal at O’Hare. But I knew that this mount was in Terminal 1, so before I get the transit to my hotel, I dragged my luggage across to Terminal 1 and begged the ticket clerk to let me through into the departure area so I could look at it. I don’t now remember exactly what the sequence of events was, but I do recall that phone-calls were made and supervisors were consulted. In the end, someone on staff gave me a platform ticket, and I was able to go and spend a quality hour with this glorious object.

It also meant I got to watch nearly every single traveller amble straight past Brachiosaurus giving it literally not even a single glance — see the first photo for an example. Truly depressing.

Anyway, I was able to get some slightly better photos of this cast humerus than I subsequently got of the outdoor mount. Though not very many, because — stop me if you’ve heard this — I was young and stupid then.

Anyway, here is the humerus in anterior view. Or as close to anterior as I could manage. By holding the camera above my head, I could get it nearly level with the distal margin of the mounted bone, so what we have here is really more like anterodistal:

dscn1161-brightened

And here is that some bone in lateral view (again, really laterodistal). From this angle, you can really see how shapeless parts of the lateral border of the cast are — which is off, because there are sharp lips on the actual fossil.

dscn1163

In terms of general appreciation of the bone, this next one, in anterolaterodistal view,  is probably best — the light caught it in an informative way. Unfortunately, I cut off the distal margin. Sorry.

dscn1164

As you can see, the level of detail in the cast is mostly pretty good. For example, you can clearly make out the broken-off base of the deltopectoral crest (the tall light-coloured oval about a quarter of the way down and a third of the way across the bone). That makes the lumpenness of the distal part of the lateral aspect all the more mysterious.

Finally, here are both humeri, more or less from the left, so that the real cast is in something approaching medial view.

dscn1165

From this angle, you can see that the humerus is noticeably less anteroposteriorly deep than its transverse width. We’ll see this theme cropping up again with brachiosaur limb bones — stay tuned for future posts!

Also of interest: the very nice sculpted humerus on the left side has a complete deltopectoral crest — modelled, I imagine, after those of the various Giraffatitan humeri. It also has a finished distal end which is much broader than that of the cast humerus. In this, it’s probably right, as the real bone suffered from some decay.

And that, I am afraid, is all: stupidly, I neglected to photograph the humerus in posterior aspect, or any of the diagonals other than anterolateral.

Next time: exciting news about the relative breadth of humerus and femur in brachiosaurs!

As we noted yesterday, the humerus of the Brachiosaurus altithorax holotype FMNH P25107 is inconveniently embedded in a plaster jacket — but it wasn’t always. That’s very strange. I have an idea about that which I’ll come to later.

Anyway, although the humerus is now half in a jacket and fully inside a cabinet, we can see it from all angles thanks to the cast that’s part of the mounted skeleton outside the Field Museum. (I can definitively state that this is the greatest picnic area in the universe).

dscn9650

As noted in the previous post, Matt and I were idiots back when we visited Chicago, so our photos are mostly useless. We have lots that show the mounted skeleton as art, but very few that are scientifically useful. But what you can make out from the photo above (especially if you click through) is that the textures of the two humeri are very different.

You can see it more clearly from in front:

dscn9672

(There I am, microscopic and easily overlooked, on the left.)

Here’s a close-up of the humeri from that photo, sharpened and contrast/brightness-balanced so you can more easily see what’s going on:

dscn9672-close-up

Contrast the scarred, pitted surface of the right humerus (on the left of the picture) with the much cleaner and bone-like texture of the left one (on the right of the picture). What’s going on here is that the right humerus of the mounted skeleton is a cast of the original element (bad preservation and all) whereas the left humerus is a sculpture. (Or possibly a cast of one of the Giraffatitan humeri, but I doubt that — it’s a bit too clean and seems more robust than those bones.) The real humerus is very distinctive, especially in the progressive flaking away on the lateral side of the distal end.

Of course you can walk all around the cast humerus and photograph it from every angle — both the posterior that is apparent in the jacket, and the anterior that’s face down and inaccessible.

You can walk all around the cast humerus and photograph it from every angle. But we didn’t. Because, as noted here and yesterday (and previously, come to think of it) we used to be idiots back then. As Matt has pithily observed:

“About every three or four months I realize that I’ve spent my entire life up until now being a dumbass; the problem is that ‘now’ keeps moving and every time I think I’ve finally got everything figured out, I later determine that I was/am still a moron.  I distinctly remember having this feeling for the first time in third grade, age of eight, and I keep hoping it will eventually go away, but that hope seems increasingly unfounded.”

That is a hauntingly familiar feeling.

It seems that this cast-right, sculped-left humerus combo is common in Brachiosaurus mounts — I guess because they’re all cloned from the Field Museum’s original. Here, for example (from this post) is the mount at BYU the North American Museum of Ancient Life:

Utah 2008 07 Matt in lift

Once you’ve seen that humerus mismatch, you can’t miss it.

Finally, then — what about this historical oddity that the humerus was once out of its jacket but is now back in? That doesn’t make a lot of sense to me. I can’t really imagine why you’d do that.

So maybe that never happened? We’ve been taking it for granted that the humerus in the old Field-Museum photo is real, but maybe it’s not. Maybe it was a cast, and that cast is still somewhere in the museum (or indeed incorporated into the mount). Maybe when the fossil humerus was brought back from the field, the jacket was removed from the anterior face and that was cast; then this face was rejacketed, the bone was flipped, the posterior face was exposed (as it still is today) and that was cast. Then the two casts were joined together to make an apparently whole humerus.

If that speculation is right, then it should be possible to detect a join running down the lateral and medial faces of the cast humerus that’s in the mount (and apparently in all other mounts). That’s something I’ll look closely for the next time I’m lucky enough to be in Chicago.

I wish it was possible to know this kind of thing. I’d love it if every time a museum mounted a skeleton they published an account of how it was done, as Janensch (1950b) did for the original Giraffatitan mount in Berlin, and Remes (2011) did for the recent remount. Unfortunately I’ve never heard of such a paper regarding the Chicago mount, and I don’t even know how long ago it was done (or if anyone who was involved is still alive). The Wikipedia page says the mount went up in 1993, but gives no reference for that and doesn’t say who did it. Does anyone know?

Update (11:38pm)

Thanks to Ben (no surname given), whose comment below points to a useful 1993 Chicago Tribune article, “Brach To The Future“. This confirms the date of the mount as 1993, unveiled on Saturday 3rd July. The mount is the work of PAST (Prehistoric Animal Structures, Inc.), who bizarrely don’t seem to have a web-site. PAST president Gilles Danis was involved in the process, so he’d be the person to contact about how it was done.

Oh, and here’s another relevant Tribune article: “Out Of The Past“. Steven Godfrey is the key player in this account, so he’s someone else to track down.

References

  • Janensch, Werner. 1950b. Die Skelettrekonstruktion von Brachiosaurus brancai. Palaeontographica (Supplement 7) 3:97-103, and plates VI-VIII.
  • Remes, Kristian, David. M. Unwin, Nicole. Klein, Wolf-Dieter Heinrich, and Oliver Hampe. 2011. Skeletal reconstruction of Brachiosaurus brancai in the Museum für Naturkunde, Berlin: summarizing 70 years of sauropod research. pp. 305-316 in: Nicole Klein, Kristian Remes, Carole T. Gee, and P. Martin Sander (eds.), Biology of the Sauropod Dinosaurs: Understanding the Life of Giants. Indiana University Press, Bloomington and Indianapolis.

In the comments on Matt’s post about the giant new Argentine titanosaur specimens, Ian Corfe wondered why Benson et al. (2014) estimated the circumference of the humerus of Brachiosaurus altithorax instead of just measuring it. (Aside: I can’t find that data in their paper. Where is it?)

I replied:

Yes, the humerus is half-encased in a jacket, face down (we should post photos some time), which would make the circumference impossible to measure directly. But the mounted Brachiosaurus skeleton right outside the Field Museum (and the identical one at O’Hare Airport) have casts of that humerus, so measuring the circumference shouldn’t require any equipment more exotic than a stepladder. Maybe the anterior aspect was sculpted — but I doubt it, as there certainly was a time when the humerus was out of its jacket and mounted vertically.

Here is the evidence that the humerus wasn’t always in that jacket (from Getty Images):

Femur of Apatosaurus and right humerus Brachiosaurus altithorax holotype on wooden pedestal (exhibit) with labels and 6 foot ruler for scale, Geology specimen, Field Columbian Museum, 1905. (Photo by Charles Carpenter/Field Museum Library/Getty Images)

Femur of Apatosaurus and right humerus Brachiosaurus altithorax holotype on wooden pedestal (exhibit) with labels and 6 foot ruler for scale, Geology specimen, Field Columbian Museum, 1905. (Photo by Charles Carpenter/Field Museum Library/Getty Images)

I have no idea why it was put back in a plaster jacket: does anyone?

Back in 2005, when Matt and I visited the Field Museum, the staff were amazingly, almost embarrassingly, helpful. They mounted a whole elaborate project to remove the humerus jacket from the cabinet that held it, so we could get a better look:

dscn1375

Unfortunately, Matt and I were doofuses back in the day: terrible photographers who knew embarrassingly little about appendicular material. So nearly all of our photos are worthless. Here is a rare nice one, showing the humerus in posterodistal aspect. You can see how layers have flaked away towards this end:

dscn1382

Here is the humerus in proximal view — something that’s relevant to my interests, as at tells us about the area of articular cartilage where it connected to the shoulder:

dscn1385

And finally — because it would be rude not to — here is Matt, going the Full Jensen with the humerus:

dscn1395

Next time: what we can learn about the humerus from the mounted skeleton outside the museum!

References

Benson Roger B. J., Nicolás E. Campione, Matthew T. Carrano, Philip D. Mannion, Corwin Sullivan, Paul Upchurch, and David C. Evans. (2014) Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage. PLoS Biology 12(5):e1001853. doi:10.1371/journal.pbio.1001853

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