Nothing too serious here, just a fun shot I got while in the collections at BYU this past week. The Brachiosaurus element is metacarpal 1 (thumb column) from BYU 4744, the Potter Creek material. I highlighted my own metacarpal 3. There is a metacarpal 3 from this specimen, but I didn’t see it on the shelf. According to D’Emic and Carrano (2019), the MC3 is 60cm long, vs 57cm for this MC1. So this photo could have been 3cm more impressive!

Oh, ignore the tag on the left that says “radius”. You could be forgiven for thinking that the bone I have my hand on is a radius, but the radius from this individual is 1.34 meters long, or about two-and-a-third times the length of this metacarpal.

Reference

D’Emic, M.D. and Carrano, M.T., 2019. Redescription of Brachiosaurid Sauropod Dinosaur Material From the Upper Jurassic Morrison Formation, Colorado, USA. The Anatomical Record.

Left lateral view

Have we ever posted decent photos of the Brachiosaurus altithorax caudals? Has anyone? I can’t remember either thing ever happening. When I need images of brachiosaur bits, including caudals, I usually go to Taylor (2009).

Taylor (2009: fig. 3)

Which is silly, not because Mike’s diagrams compiling old illustrations aren’t good – they definitely are – but because I’m sitting on a war chest of decent photos of the actual material. I am home sick with a sore throat today, and I can’t be arsed to (1) follow up on the “Down in Flames” post, (2) add anything thoughtful to the vertebral orientation discussion, or (3) crop or color-adjust these photos. You’re getting them just as they came out of my camera, from my trip to the Field Museum in 2012.

Here are the rest of the orthogonal views:

Right lateral view

 

Anterior view

 

Posterior view

 

Dorsal view of caudal 1

 

Dorsal view of caudal 2

And here’s a virtual walkaround using a series of oblique shots. Making a set like this is part of my standard practice now for important specimens during museum visits.

 

 

 

 

 

 

 

Now, I said up top that I wasn’t going to add anything thoughtful to the vertebral orientation discussion. I have thoughts on that, but I’m tired and hopped up on cold medicine and now ain’t the time. In lieu of blather, here are a couple of relevant photos.

 

I wanted to capture for my future self the pronounced non-orthogonality of the neural canal and centrum, so I rolled up a piece of paper and stuck it through the neural canal. I haven’t run the numbers, but in terms of “angle of the articular faces away from the neural canal”, these verts look like they’re right up there with my beloved Snowmass Haplocanthosaurus.

More on that next time, I reckon. In the meantime, all these photos are yours now (CC-BY, like everything on this site [that someone else hasn’t asserted copyright over]). Go have fun.

Reference

We all know that apatosaurines have big honkin’ cervical ribs (well, most of us know that). But did they also have unusually large neural spines?

The question occurred to me the other day when I was driving home from work. I was thinking about C10 of CM 3018, the holotype of Apatosaurus louisae, and I thought, “Man, that is a lot of neural spine right there.”

Why was I thinking about C10, particularly? I traced and also stacked Gilmore’s (1936) drawing for my 2002 paper with Kent Sanders, and recycled the trace for my 2007 prosauropod paper, and recycled the stack-o-C10s for my 2013 PeerJ paper with Mike. So for better or worse C10 is my mental shorthand for A. louisae, the same way that their respective C8s seem to capture the essence of Giraffatitan and Sauroposeidon.

I decided that the quick-and-dirty solution was to compare the vertebrae of A. louisae with those of Diplodocus carnegii, the default reference diplodocid, and see how they stacked up. With the cotyles scaled to the same vertical diameters, this is what we get for C9 and C10 of CM 3018 (lighter gray, background, traced from Gilmore 1936) vs CM 84/94 (darker gray, foreground, traced from Hatcher 1901):

The A. louisae verts are a hair taller, proportionally, than those of D. carnegii, but not by much. The difference is trivial compared to the differences in centrum length and cervical rib size.

So where did I get this apparently erroneous impression that Apatosaurus had giant neural spines? Maybe it’s not that the neural spines of apatosaurines in particular are so large, but rather than diplodocids of all types have large neural spines compared to non-diplodocids. Here are the same vertebrae compared for D. carnegii (dark gray, background) and Camarasaurus supremus (black, foreground, traced from Osborn and Mook 1921):

I deliberately picked the longest C9 in the AMNH collection, and the least-distorted C10. The first surprise for me was how well this C. supremus C9 hangs with D. carnegii in terms of proportions. That is one looooong Cam vert. In any other sauropod, it would probably be beautiful. But because it’s Camarasaurus it attained its length in the most lumpen possible way, with the diapophysis way up front, the neural spine apex way at the back, and in the middle just…more vertebra. Like a stretch limo made from a Ford Pinto, or Mike’s horrifying BOBA-horse.

Inevitable and entirely justified Cam-bashing aside, it’s striking how much smaller the whole neural arch-and-spine complex is in C. supremus than in D. carnegii. And remember that D. carnegii is itself a bit smaller than Apatosaurus, spine-wise. Is this maybe a diplodocoid-vs-macronarian thing, at least in the Morrison? Here’s the C10 stack with Brachiosaurus included, represented by BYU 12867 (which I think is probably a C10 based on both centrum proportions and neural spine shape – see Wedel et al. 2000b for details), and with labels added because it’s getting a little nuts:

I like this; it shows a lot. Here are some things to note:

  • The diplodocids don’t just have taller neural spines, their pre- and postzygapophyses are also higher than in the macronarians. That’s gotta mean something, right? All else being equal, putting the zygs farther from the intervertebral joints would reduce the flexibility of the neck. Maybe diplodocoids could get away with it because they had more cervicals, or maybe their necks were stiffened for some reason.
  • The zygs being set forward of their respective centrum ends in the macronarians really comes through here.
  • The Brachiosaurus vert isn’t that different from a stretched (and de-uglified) Cam vert, with a slightly higher neural spine to help support the longer neck. (Maybe this is why Cam inspires such visceral revulsion: it reads as a failed brachiosaur.)
  • This emphasizes the outlier status of Apatosaurus in the cervical rib department. It bears repeating: the cervical ribs of Camarasaurus are certainly wide, but they’re not nearly as massive or ventrally expanded as in apatosaurines.

So far, pretty interesting. I’d like to add Barosaurus and Haplocanthosaurus to round out the “big six” Morrison sauropods. I known Haplo has big, tall, almost apatosaurine neural spines (as shown above, with arrows highlighting the epipophyses), but for Baro I’d have to actually do the comparison to see where it falls out.

The idea of bringing in Barosaurus also forces the question, previously glossed over, of how legit it is to compare C10s of all these animals when their cervical counts differed. C. supremus is thought to have had 12 vertebrae in its neck, Brachiosaurus 13 (based on Giraffatitan), A. louisae and D. carnegii 15, and Barosaurus probably 16. It would be more informative to graph neural spine height divided by cotyle diameter along the column for all of these critters, plus Kaatedocus and Galeamopus. But that’s a lot of actual work, and as much fun as it sounds (really, I’d rather be doing that), I have summer teaching to prep for and field gear to wrangle. So I’ll have to revisit this stuff another time.

References

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

 

Wedel 2005 Morrison sauropod cervicals 1 - Diplodocus

When I was back in Oklahoma in March, I met with Anne Weil to see some of the new Apatosaurus material she’s getting out of her Homestead Quarry. It’s nice material, but that’s a post for another day. Anne said something that really resonated with me, which was, “I love it when you guys post about vertebral morphology, because it helps me learn this stuff.” Okay, Anne, message received. This will begin to make things right.

Wedel 2005 Morrison sauropod cervicals 2 - Barosaurus and centra shapes

I spent a week at BYU back in 2005, collecting data for my dissertation. One of the first things I had to do was teach myself how to identify the vertebrae of different sauropods, because BYU has just about all of the common Morrison taxa. These are the notes I made back then.

Wedel 2005 Morrison sauropod cervicals 3 - Brachiosaurus and Apatosaurus

I always planned to do something with them – clean them up, get them into a more usable form. There are a lot of scribbly asides that are probably hard for others to read, and it would be more useful if I put the easily confused taxa next to each other – Barosaurus next to Brachiosaurus, for example. And I didn’t go into serial changes at all.

Wedel 2005 Morrison sauropod cervicals 4 - Camarasaurus and Haplocanthosaurus

Still, hopefully someone will find these useful. If there are things I missed or got wrong, the comment thread is open. And if you want all four spreads in one convenient package, here’s a PDF: Wedel 2005 notes on Morrison sauropod cervicals

Mike and I leave for the Sauropocalypse tomorrow. I’m hoping to post at least a few pretty pictures from the road, as I did for the Mid-Mesozoic Field Conference two years ago. Stand by…

A couple of months ago, Darren (the silent partner in the SV-POW! organisation) tweeted this photo …

felch-quarry-brachiosaur-skull

… describing it as “Skull of the Morrison Formation Brachiosaurus at Denver Museum of Nature & Science”.

Well.

As Darren knows well (but didn’t have have space to explain in the tweet), it’s not quite as simple as that. What follows is adapted from Taylor 2009:789.

In 1883, a large sauropod skull (81 cm in length) was found in Felch Quarry 1, Garden Park, Colorado. It was shipped to O. C. Marsh in Yale that year and an illustration of the skull was used in his second attempt at reconstructing the skeleton of Brontosaurus (Marsh, 1891: plate 16).

Marsh's second attempt at reconstructing the skeleton of Brontosaurus, based primary on the holotype YPM 1980, using a skull based on the Felch Quarry specimen. From Marsh (1891:plate XVI)

Marsh’s second attempt at reconstructing the skeleton of Brontosaurus, based primary on the holotype YPM 1980, using a skull based on the Felch Quarry specimen. From Marsh (1891:plate XVI)

And here’s that skull in close-up:

Marsh1891-plateXVI-Apatosaurus-skull-UNREVERSED

This is often described as a “Camarasaurus-type” skull, but it’s not, really. It’s too long and low, and not stupid and ugly enough, to be Camarasaurus.

As we described in a previous post, this skull was also apparently the inspiration for the horrible, horrible sculpted skull that was originally used on the mounted Brontosaurus. (And let me reiterate my praise of the Yale museum for displaying this important historic object in their gallery instead of hiding it away.)

Anyway, the Felch Quarry skull was subsequently transferred to the National Museum of Natural History, where it was accessioned as USNM 5730. McIntosh and Berman (1975:195-198) recognized that whatever the skull was, it wasn’t Brontosaurus, but chickened out a bit by describing it as being “of the general Camarasaurus type” (p. 196). But McIntosh subsequently identified the skull tentatively as Brachiosaurus (Carpenter and Tidwell, 1998:70) and it was later described by Carpenter and Tidwell (1998), who considered it intermediate between the skulls of Camarasaurus and Giraffatitan, and referred it to Brachiosaurus sp.

The skull may be that of Brachiosaurus altithorax, but this is currently impossible to test due to the lack of comparable parts. Near this skull was a 99 cm cervical vertebra, probably of Brachiosaurus, but this was destroyed during attempts to collect it (McIntosh and Berman, 1975:196). Shame there are no photos.

References

  • Carpenter, Kenneth, and Virginia Tidwell. 1998. Preliminary description of a Brachiosaurus skull from Felch Quarry 1, Garden Park, Colorado. Modern Geology 23:69-84.
  • Marsh, Othniel Charles. 1891. Restoration of Triceratops. American Journal of Science, Series 3, 41:339-342.
  • McIntosh, John S., and David S. Berman. 1975. Description of the palate and lower jaw of the sauropod dinosaur Diplodocus (Reptilia: Saurischia) with remarks on the nature of the skull of Apatosaurus. Journal of Paleontology 49:187-199.
  • Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806.

I’ve been taking a long-overdue look at some of the recently-described giant sauropods from China, trying to sort out just how big they were. Not a new pursuit for me, just one I hadn’t been back to in a while. Also, I’m not trying to debunk anything about this animal – as far as I know, there was no bunk to begin with – I’m just trying to get a handle on how big it might have been, for my own obscure purposes.

‘Huanghetitan’ ruyangensis was named by Lu et al. (2007) on the basis of a sacrum, the first 10 caudal vertebrae, some dorsal ribs and haemal arches, and a partial ischium. The holotype is 41HIII-0001 in the Henan Geological Museum. Lu et al. (2007) referred the new animal to the genus Huanghetitan, which was already known from the type species H. liujiaxiaensis (You et al., 2006). However, Mannion et al. (2013) found that the two species are not sister taxa and therefore ‘H.’ ruyangensis probably belongs to another genus, which has yet to be erected. Hence my use of scare quotes around the genus name.

Huanghetitan ruyangensis sacrum comparison

Here’s the sacrum of ‘H.’ ruyangensis from Lu et al. (2007: fig. 2). The original small scale bar is supposed to be 10cm. You know how I feel about scale bars (or maybe you don’t, in which case read this and this), but in this case the scale seems pretty legit based on limited measurements that are also given in the paper. I comped in the sacrum of Brachiosaurus altithorax FMNH P25107 from this post (many thanks to Phil Mannion for the photos!), and scaled it according to the max width across the second pair of sacral ribs, which Riggs (1904: p. 236) gives as 105 cm. The sacrum of ‘H.’ ruyangensis is a little bigger, but not vastly bigger. ‘H.’ ruyangensis had six sacrals to Brachiosaurus‘s five, so extra length is mostly illusory, whereas the extra width is mostly legit.

According to Lu et al. (2007), the anterior face of the first caudal vertebra in ‘H.’ ruyangensis measures 26.9 cm tall by 32 cm wide, and the centrum is 18.2 cm long. The same measurements in Brachiosaurus are 28 x 33 cm for the anterior face and 16 cm for the centrum length. It’s basically a tie.

What about the big rib? Lu et al. (2007) show a complete dorsal rib of ‘H.’ ruyangensis that is 293 cm long. That’s nothing to sniff at – the longest rib of Brachiosaurus, and the cause for the specific name altithorax (‘tall-bodied’), measures 274.5 cm, so the ‘H.’ ruyangensis rib is about 7% longer. But it’s not the longest rib known for any sauropod. As far as I know, that honor goes to a Supersaurus dorsal rib measuring 305 cm (Lovelace et al., 2008). The biggest Supersaurus caudal also blows away the caudals of both ‘H.’ ruyangensis and Brachiosaurus, with a anterior face 39 cm tall by 46 cm wide. But then diplodocids were all about that bass, so there’s not much point in comparing tail size with a titanosauriform if you’re trying to get a handle on overall body size. Still, the 35-40 ton Supersaurus shows that you can have 3-meter ribs without being anywhere near Argentinosaurus territory, mass-wise.

So what’s the verdict? ‘H.’ ruyangensis was a little bigger than the holotype of Brachiosaurus altithorax, but only by a few percent. It might have been about the same size as the XV2 specimen of Giraffatitan brancai. Or, who knows, it could have had completely different proportions and massed considerably more (or less). But on the current evidence, it doesn’t seem to have been one of the biggest sauropods of all time. I hope we get some more of it one of these days.

References