Back in 2012, when Matt and I were at the American Museum of Natural History to work on Apatosaurus” minimus, we also photographed some other sacra for comparative purposes. One of them you’ve already seen — that of the Camarasaurus supremus holotype AMNH 5761. Here is another:

diplodocus-sacrum-composite

(Click through for glorious 3983 x 4488 resolution.)

This is AMNH 3532, a diplodocid sacrum with the left ilium coalesced and the right ilium helpfully missing, so we can see the structure of the sacral ribs. Top row: dorsal view, with anterior to the left; middle row, left to right: anterior, left lateral and posterior views; bottom row: right lateral view.

As a matter of fact, we’ve seen this sacrum before, too, in a photo from Matt’s much earlier AMNH visit. But only from a left dorsolateral perspective.

When we first saw this, it didn’t even occur to us that it could be anything other than good old Diplodocus. And indeed it’s a pretty good match for the same area in the CM 84/94 cast in the Museum für Naturkunde Berlin (this image extracted from Heinrich Mallison’s beautiful giant composite):

img_4853-img_4886-v3-sm-sacrum

And the general narrowness of the AMNH sacrum says Diplodocus to me. But what is that expectation of narrowness based on? When I compared the AMNH specimen with Hatcher’s (1901) ventral-view illustration in his classic Diplodocus monograph, I had second thoughts:

Hatcher (1901: fig. 9). Inferior view of sacrum and ilia of Diplodocus carnegii (No. 94), one tenth natural size; bp, public peduncle; is, ischiadic peduncle; a, anterior end; p, posterior end.

Hatcher (1901: fig. 9). Inferior view of sacrum and ilia of Diplodocus carnegii (No. 94), one tenth natural size; pp, public peduncle; is, ischiadic peduncle; a, anterior end; p, posterior end.

That is a much wider sacrum than I’d expected from Diplodocus.

So what is going on here? Is Diplodocus a fatter-assed beast than I’d realised? I am guessing not, since my expectation of narrowness has been built up across years of looking at (if not necessarily paying much attention to) Diplodocus sacra.

So could it be that CM 94, the referred specimen that Hatcher used to make up some of the missing parts of the CM 84 mount, is not Diplodocus?

Well. That is certainly now how I expected to finish this post. Funny how blogging leads you down unexpected paths. It’s a big part of why I recommend blogging to pretty much everyone. It forces you to think down pathways that you wouldn’t otherwise wander.

References

  • Hatcher, Jonathan B. 1901. Diplodocus (Marsh): its osteology, taxonomy and probable habits, with a restoration of the skeleton. Memoirs of the Carnegie Museum 1:1-63 and plates I-XIII.

 

Look on my works, ye mighty, and despair!

DSCN0476

[Giraffatitan brancai paralectotype MB.R.2181 (formerly HMN S II), mounted skeleton in left anteroventrolateral view. Presacral vertebrae sculpted, skull scaled and 3d-printed from specimen T1. Round the decay of that colossal wreck, boundless and bare, the lone and level sands stretch far away.]

apatosaurus-maquette-whole-lateral cropped - angle 2

I made these for my own use in talks, and then thought, why be selfish? Like everything else on this blog, these images are now released to the world under the CC-BY license. Have fun with them.

apatosaurus-maquette-whole-lateral cropped

You can read my review of the Sideshow Apatosaurus here; the TL;DR is that it’s awesome. And if you’re bummed that you missed out on getting one last time around, they’re rereleasing it later this spring with a slightly different paint job – details here.

Arriving as an early Christmas present, and coming in just a week before the end of what would otherwise have been a barren 2014, my paper Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs is out! You can read it on PeerJ (or download the PDF).

Figure 4. Effect of adding cartilage to the neutral pose of the neck of Diplodocus carnegii CM 84. Images of vertebra from Hatcher (1901:plate III). At the bottom, the vertebrae are composed in a horizontal posture. Superimposed, the same vertebrae are shown inclined by the additional extension angles indicated in Table 2.

Figure 4: Effect of adding cartilage to the neutral pose of the neck of Diplodocus carnegii CM 84. Images of vertebra from Hatcher (1901:plate III). At the bottom, the vertebrae are composed in a horizontal posture. Superimposed, the same vertebrae are shown inclined by the additional extension angles indicated in Table 2.

Yes, that posture is ludicrous — but the best data we currently have says that something like this would have been neutral for Diplodocus once cartilage is taken into account. (Remember of course that animals do not hold their necks in neutral posture.)

The great news here is that PeerJ moved quickly. In fact here’s how the time breaks down since I submitted the manuscript (and made it available as a preprint) on 4 November:

28 days from submission to first decision
3 days to revise and resubmit
3 days to accept
15 days to publication

TOTAL 49 days

Which of course is how it ought to be! Great work here from handling editor Chris Noto and all three reviewers: Matt Bonnan, Heinrich Mallison and Eric Snively. They all elected not to be anonymous, and all gave really useful feedback — as you can see for yourself in the published peer-review history. When editors and reviewers do a job this good, they deserve credit, and it’s great that PeerJ’s (optional) open review lets the world see what they contributed. Note that you can cite, or link to, individual reviews. The reviews themselves are now first-class objects, as they should be.

At the time of writing, my paper is top of the PeerJ home-page — presumably just because it’s the most recent published paper, but it’s a nice feeling anyway!

Screenshot from 2014-12-23 10:39:34

 

A little further down the front-page there’s some great stuff about limb function in ratites — a whole slew of papers.

Well, I’m off to relax over Christmas. Have a good one, y’all!

A friend’s daughter owned a pet corn snake, and a hamster. About a month ago, the former got into the latter’s cage — and in a reversal of the usual course of such events, sustained some nasty injuries. As snakes often do, it struggled to recover, and the wound seems to have necrotised.

This morning I got an email from the friend saying that the snake had died, and asking whether I would like it. I managed to restrain my enthusiasm for long enough to express condolences to the daughter; and an hour later, the snake was delivered!

IMG_1861-cleaned

Here it is — as with all these images, click through for the full resolution. I’ve learned that it’s difficult to measure the length of a snake — they don’t lay out straight in the way that you’d like, even when they’re dead — but as best I can make out, it’s 120 cm long. It weighs 225 g, but don’t tell Fiona I used the kitchen scales.

The hamster wound is very apparent, just behind the neck, on the left hand side. Here’s the head and neck in close-up:

IMG_1847-cleaned

Ouch — very nasty. It can’t have been pleasant watching a pet linger on with a wound like that.

He (or she? How do you sex a snake?) was a handsome beast, too. Here’s the head. You can easily make out the individual large scales covering it, and make out some of the shape of the skull.

IMG_1852-cleaned

The skulls of snakes are beyond weird. Here is one from an unspecified non-venomous snake at Skulls Unlimited (i.e. probably not a corn snake):

variants_large_3861

Hopefully at some point I’ll be able to show you my own snake’s skull. In the mean time, this guy says he has a corn-snake skull, but the photography’s not very good.

Finally, here is my snake, mouth open, showing the pterygoid teeth on the roof of the mouth:

IMG_1857-cleaned

What next? It seems clear that bugging is the only realistic way to free up the skeleton, and this may be the specimen that persuades me to invest in a proper colony of dermestids rather than just relying on whatever inverts happen to wander past.

It might be worth trying to skin and gut the snake first. Gutting will be easy; skinning might be very difficult. I think that removing the skin from the skull without damaging the very delicate bones might be impossible. Can dermestids cope with snake skin?

I’m taking advice!

 



art

 




salamander

 








platyhystrix

 




another-temnospondyl

 




feathered-diplodocus


tyrannosaur


ankylosaur

 




braincase




 




diadectes

 




salamander

 




salamander-silhouette

 




gar

 




fish


shark



stamp-trex

 





lampreyhagfish

 




tsintaosaurus

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

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