September 8, 2012
August 15, 2012
You haven’t heard from me much lately because I’ve been busy teaching anatomy. Still, I get to help people dissect for a living, so I can’t complain.
Further bulletins as events warrant.
July 18, 2012
This is the sacrum of Camarasaurus supremus AMNH 5761. Top row: dorsal view, with anterior to left. Middle row, from left to right: anterior, left lateral and posterior views. Bottom row: ventral view, with anterior to left. Modified from Ostrom and Mook (1921:figs. 43-44).
It’s instructive to compare with the “Apatosaurus” minimus sacrum. Direct comparison is somewhat hindered for two reasons: first, the ilia are fused to that sacrum but not to this; and second, different views are available, so I put the composites together differently. We can’t do anything about the ilia. But to facilitate comparison, here is a reworked version of the “Apatosaurus” minimus illustration with the right-lateral view discarded, a ventral-view silhouette added, and the composition mirroring that of Osborn and Mook’s Camarasaurus:
One thing is for sure: whatever else “Apatosaurus“ minimus might be, it ain’t Camarasaurus.
July 14, 2012
More goodness from Osborn and Mook’s (1921) gargantuan Camarasaurus monograph, again prepared largely for comparison with “Apatosaurus” minimus. Last time, I showed you one of O&M’s pubis illustrations. Now an ischium:
This shows the left ischium AMNH 576o’/Is.4. Left column: proximal aspect. Middle column, from top to bottom: medial, lateral, posterior (no dorsal view was provided). Right column: distal. Heavily modified from Osborn and Mook (1921: fig. 101) — cleaned up, lettering and lines removed, recomposed in a more informative layout, views rescaled to better match each other, and tweaked for colour.
As usual, click through for full resolution (only 989 x 978 this time).
It’s interesting to compare this with the similarly composed illustration of the “Apatosaurus” minimus ischium from last week.
July 13, 2012
(First of all, for anyone who’s not familiar with the plural of “pubis”, it’s spelled “pubes” but pronounced “pyoo-bees”. Stop sniggering at the back.)
As Matt and I struggle to figure out the partial pubis that is one of the elements of the “Apatosaurus” minimus specimen AMNH 675, one of the most helpful references is Osborn and Mook’s (1921) epic monograph on Camarasaurus. It’s not that 675 particularly resembles Cam — it doesn’t. It’s just that Osborn and Mook is very lavishly illustrated, so that it is (as far as I know) the only published paper in the history of sauropod studies to have shown a sauropod pubis in more than one aspect.
Here is one of the two pubes that they illustrated in the six cardinal aspects:
This shows the left pubis AMNH 5761/Pb.2. Top row: proximal aspect, with anterior to left. Middle row, from left to right: anterior, lateral, posterior, medial. Bottom row: distal, with anterior to left. Heavily modified from Osborn and Mook (1921: fig. 102) — cleaned up, lettering and lines removed, recomposed in a more informative layout, views rescaled to better match each other, and tweaked for colour.
As usual, click through for full resolution (only 1159 x 940 this time).
As you can see, the pubis is a very strangely shaped bone, twisted and with odd rugosities everywhere. If you’re very lucky, we’ll discuss these in more detail later. For now, the take-home message is that sauropod pubes are very weird and confusing, and the simple lateral view that’s typically all you ever see is terribly misleading.
June 27, 2012
From the collections of the American Museum of Natural History, I give you the sacrum and fused ilia of “Apatosaurus” minimus AMNH 675, as correctly identified by Steve P in a comment to the previous post:
As Steve P rightly pointed out, AMNH 675 was designated as Brontosaurus sp. by Osborn (1904), and made the type of Apatosaurus minimus by Mook (1917).
It’s been known for some time that whatever this is, it’s not Apatosaurus — see for example McIntosh (1990a:398), McIntosh (1990b:59) and Upchurch et al. (2004:298). But what actually is it? Well, at the moment, no-one knows. Matt and I now have a manuscript in prep that we hope will somewhat elucidate this question. More to come on this specimen, most likely.
McIntosh, John S. 1990a. Sauropoda. In The Dinosauria, pp. 345–401. Berkeley and Los Angeles: University of California Press.
McIntosh, John S. 1990b. Species Determination in Sauropod Dinosaurs with Tentative Suggestions for the Their Classification. In Dinosaur Systematics: Approaches and Perspectives, pp. 53–69. Cambridge: Cambridge University Press.
Mook, Charles C. 1917. Criteria for the determination of species in the Sauropoda, with description of a new species of Apatosaurus. Bulletin of the American Museum of Natural History 38:355-360.
Osborn, Henry F. 1904. Manus, sacrum, and caudals of Sauropoda. Bulletin of the American Museum of Natural History 20:181-190.
June 25, 2012
A couple of posts back, when Matt was talking about turtle laminae, he included a photo of me in front of the skeleton of the giant turtle Archelon. Also in that photo is the tripod I was using — if you want to call it that — a tripod of altogether startling inadequacy. Here it is again, this time in the collections of the AMNH:
(Bonus SV-POW! points for anyone who can tell me what taxon or specimen I am working on. Sorry, Heinrich, you’re disqualified, since you already know.)
Why did we use such a poor tripod? Matt was planning to bring a proper one, but at the last minute decided to downsize his luggage by taking one small enough to fit into a smaller bag — in fact, it’s the tripod that came free with a telescope he recently bought. Not a good move: it was too short for many of the shots we wanted to take, too flimsy to properly stabilise the camera in many situations, and didn’t have enough degrees of freedom to let us get every shot we wanted from the best position.
Still, it was better than nothing, and we did contrive to get all the specimen photos we needed.
At the end of the week, when we finished up in collections and went to catch our taxi to the airport, Matt left the tripod behind. I emailed our AMNH host Carl Mehling to explain:
Matt deliberately left behind his tripod — it’s on the desk where we had the pelvic elements. He has much better tripods at home, and regrets the false economy of bringing that lighter and less stable one. But we figured it would be better than nothing for the use of anyone who turns up in collections with no tripod at all, so please feel free to make it available to visitors. Matt asks only that it be known as “The Mathew J. Wedel Memorial Tripod”.
Thanks so much for the tripod – I KNOW it will come in handy!
Ah, sorry about this but my client insists that it must be known by its full title The Mathew J. Wedel Memorial Tripod at all times. If necessary, you may abbreviate it to TMJWMT on second and subsequent mentions.
I can engrave it in the Lab and apply a B72/India Ink/B72 sandwich acronym/monogram on it. I will also construct an archival museum mount for it and put a security chip in its brain.
That’s when Matt himself weighed in:
Oh, and be sure that when the tripod is not in use it is stored in an airtight positive pressure chamber full of an inert gas. It should also be polished twice daily with the down of a hatchling bald eagle (fresh down each time, naturally). Finally, the tripod itself should be listed as an author on any publications that include photos taken with it. Please send a runner to my office in California to confirm that these instructions will be carried out to the letter.
The runner hasn’t arrived yet (to my knowledge) but I think we can take it as read that Carl will comply with these very reasonable conditions.
So, folks! If ever you’re working in the AMNH big-bone room, and you find you’ve forgotten your tripod … you might just be lucky enough to be allowed use of the Mathew J. Wedel Memorial Tripod!
June 24, 2012
Sometimes you just can’t make this stuff up.
You may recall a story from the Onion Our Dumb Century book, allegedly from 1904, about the skeleton of Satan being discovered in Wyoming. Mike used his occult powers to put together this scan from freely available online sources:
If you scrutinize the above image carefully, you’ll see that ‘Satan’ is an Allosaurus (I’m no theropod booster, but I always thought that was a little harsh on T. rex).
Why am I telling you this? Because last week Mike and I were toiling in the big bone room in the basement of the AMNH when we came across AMNH 666.
It’s an ilium. (Of course it would have to be an appendicular element. Vertebrae are from on high [or dorsal, if you prefer].)
The stomach-churning color here could be a manifestation of diabolical power, or just what happens when you try to photograph a pink specimen label on a yellow-orange forklift.
After this harrowing encounter, we cleansed our bodies, minds, and souls with street-vendor hot dogs and The Avengers.* That particular mode of exorcism may not be the most effective–I felt distinctly dodgy that evening. But the next day we received illumination at the Altar of Sauropod Awesomeness and were soon back to what we jokingly refer to as normal.
* The best way to see The Avengers is by going up to the observation deck of the Empire State Building shortly beforehand, so big swathes of the Manhattan skyline will still be in your mental RAM during the big final battle. I understand it’s not an option for everyone.