I was going to write a bit more about my recent paper The Concrete Diplodocus of Vernal (seriously, go and read it, you’ll like it, it’s fun). But then something more urgent came up. And here it is!

This is the work of our old friend Mark Witton, so we’ll let him explain it:

More new at for ! Tyrannosaurus takes on a giant Alamosaurus. Alamosaurus laughs. Sauropods really do win this time.

Full resolution version available at:
patreon.com/posts/79152256

Darren, the silent partner at SV-POW!, pointed me to this tweet by Duc de Vinney, displaying a tableau of “A bunch of Boners (people who study bones) Not just paleontologists, some naturalists and cryptozoologists too”, apparently commissioned by @EDGEinthewild:

As you can see, Darren, Matt and I (as well as long-time Friend Of SV-POW! Mark Witton) somehow all made it into the cartoon, ahead of numerous far more deserving people. Whatever the criterion was, and whatever reason Edge In The Wild had for wanting this, I am delighted to be included alongside the likes of Owen, Osborn, Cope, Marsh, and Bob Bakker. Even if the caricatures are not especially flattering.

Here is an edit showing only the three of us, which I am sure I will find many fruitful uses for:

My thanks to Duc de Vinney for creating this!

 

I’ve been in contact recently with Matt Lamanna, Associate Curator in the Section of Vertebrate Paleontology at the Carnegie Museum of Natural History — which is obviously the best job in the world. Among a batch of photos that he sent me recently, I seized on this gem:

Tyrannosaurus rex, Diplodocus carnegii, Apatosaurus louisae and multiple mostly juvenile individuals of Homo sapiens. Photograph taken between 1941 and 1965. Courtesy of Carnegie Museum of Natural History.

There’s so much to appreciate in this picture: the hunchbacked, tail-dragging Tyrannosaurus; the camarasaur-style skull on the Apatosaurus; the hard-to-pin-down archaic air of Diplodocus.

But the thing I love about it is the 1950s kids. (Or, to be fair, maybe the 1940s kids or early 1960s kids, but you get the point.) They way they’ve all been asked to look up at the tyrannosaur skull, and are obediently doing it. How earnest they all appear. How they’re all dressed as tiny adults. How self-consciously some of them have posed themselves — the thoughtful kid one in from the left, his foot up on the plinth and his chin resting on his hand; the cool kid to his right, arms crossed, interested but careful not to seem too impressed.

Where are these kids now? Assuming it was taken in 1953, the midpoint of the possible range, and assuming they’re about 12 years old in this photo, they were born around 1941, which would make them 81 now. Statistically, somewhere around half of them are still alive. I wonder how many of them remember this day, and the strange blend of awe, fascination, and self-consciousness.

This is a time-capsule, friends. Enjoy it.

We’ve shown you the Apatosaurus louisae holotype mounted skeleton CM 3018 several times: shot from the hip, posing with another massive vertebrate, photographed from above, and more. Today we bring you a world first: Apatosaurus from below. Scroll and enjoy!

Obviously there’s a lot of perspective distortion here. You have to imagine yourself lying underneath the skeleton and looking up — as I was, when I took the short video that was converted into this image.

Many thanks to special-effects wizard Jarrod Davis for stitching the video into the glorious image you see here.

The most obvious effect of the perspective distortion is that the neck and tail both look tiny: we are effectively looking along them, the neck in posteroventral view and the tail in anteroventral. The ribs are also flared in this perspective, making Apato look even broader than it is in real life. Which is pretty broad. One odd effect of this is that this makes the scapulae look as though they are sitting on top of the ribcage rather than appressed to its sides.

 

Gilmore (1936:243) says of the mounted skeleton of Apatosaurus louisae CM 3018 in the Carnegie Museum that “with the skull in position the specimen has a total length between perpendiculars of about 71 feet and six inches. If the missing eighteen terminal caudal vertebrae were added to the tip of the tail, in order to make it conform to known evidence, the skeleton will reach an estimated length of 76 feet, 6 inches.” That’s 23.3 meters.

But what if it was 800 meters long instead? That would be 34.3 times as big in linear dimension (and so would mass 34.3^3 = 40387 time as much, perhaps a million tonnes — but that’s not my point).

What would a cervical vertebra of an 800m sauropod look like?

Gilmore (1936:196) gives the centrum length of CM 3018’s C10 as 530 mm. In our 34.3 times as long Apatosaurus, it would be 18.17 meters long. So here is what that would look like compared with two London Routemaster buses (each 8.38 meters long).

Cervical vertebra 10 of a hypothetical 800 meter long Apatosaurus louisae, with London Routemaster buses for scale. Vertebra image from Gilmore 1936:plate XXIV; bus image by Graham Todman, from Illustrations for t-shirts.

What is the research significance of this? None at all, of course. Still I think further study is warranted. Some look at sauropods that once were, and ask “why?”; but I go further; I look at sauropods that never were, and ask “why not?”

 

These are nice. Click through to empiggen.

I ripped them from Parker (1874), which appears to be a free download from JSTOR, here, and tweaked the colors just a bit.

If you are here for serious science, these guides to the abbreviations used in the plates will come in handy. I hacked the second one, below, to include the descriptions of the plates above, which are the last in the series, not the first.

EDIT: Nick Gardner pointed out that the copy of Parker (1874) at the Biodiversity Heritage Library is a slightly sharper scan, so if you’d prefer that version, it’s here.

Reference

Parker, W.K. 1874. On the structure and development of the skull in the pig (Sus scrofa). Philosophical Transactions of the Royal Society of London 164: 289-336.

 

This beautiful image is bird 52659 from Florida Museum, a green heron Butorides virescens, CT scanned and published on Twitter.

(The scan is apparently from MorphoSource, but I can’t find it there.)

There is lots to love here: for example, you can see that the long bones of the arm are pneumatic, because the margins of the bones show up more strongly than the cores. But you won’t be surprised that I am interested mostly in the neck.

As you can see, while the vertebrae of the neck are pulled back into a strong curve, the trachea doesn’t bother, and just sort of hangs there from the base of the head to the top of the lungs, cheerfully crossing over (i.e. passing to the side of) the vertebral sequence. So the trachea here is not much more than half the length of the vertebral sequence.

Now this is the opposite of what we see in some birds. Here, for example, is a trumpet manucode Phonygammus keraudrenii (a bird-of-paradise) as illustrated in Katrina van Grouw’s book The Unfeathered Bird:

Yes, all those coils visible in the torso are the trachea, which is many times longer than it needs to be to connect the head to the lungs. Birds-of-paradise do this sort of thing a lot (Clench 1978).

And they are not alone: cranes and others also have elongated and contorted tracheal trajectories. So it’s odd that herons seem to do the opposite.

But the heron is even odder than that. As we have noted before, herons can stretch their necks out to the point where you would scarcely believe the unstretched and stretched animals are the same thing. But they are:

The CT-scanned heron at the top of this post is in a pose intermediate between the two shown here. But since it can adopt the long-necked pose on the right, it’s apparent that the trachea can become long enough to connect the head and lungs in that pose. Which means it must be able to stretch to nearly twice the length we see in the CT scan.

Don’t try this at home, kids!

References

  • Clench, Mary H. 1978. Tracheal elongation in birds-of-paradise. The Condor 80(4):423–430. doi:10.2307/1367193

Accidental anaglyphs

October 16, 2020

Everyone knows that the very first thing you should do to improve your specimen photography is to use a tripod: it eliminates hand-shake and gives you much crisper photos. In most respects, my photographs have got much, much better since I’ve been habitually using a tripod.

But it has meant I’ve not been able to benefit from happy accidents like the one that gave me this 3D anaglyph of the Archbishop‘s Cervical S in dorsal view:

(Do you have red-cyan glasses? Yes? Good! You will be able to appreciate all the delicious morphological information in this photo. No? Go and order some right now — they cost literally a dollar.)

The reason I was able to make this very useful image is because back in the old pre-tripod days I would sometimes accidentally move a little bit between taking two more-or-less identical photographs. Here are the two images that I was able to composite into the anaglyph above:

Each of them is pretty uninformative alone: who can tell one nondescript area of brown bone from another? But when combined, they are extraordinarily more informative. If you don’t have 3D glasses then (A) get some! and (B) you can get some idea of how helpful the 3D information is from the crude wigglegram below, which simply switches back and forth between the two images.

And I can’t overstate how enormously helpful I have found these accidentally sourced anaglyphs as I write the descriptive part of the Archbishop manuscript. Even at this level of crudity, they have shown me several important points of morphology that I would certainly have missed if I’d been working only from my orthogonal-view photos, and saved me from more than one misinterpretation.

The moral is twofold:

  1. When taking specimen photographs, use a tripod — but deliberately get some pairs of shots where the camera is moved to the side by about 7 cm (the distance between the pupils in an average human).
  2. If you don’t have any red-cyan glasses, get some!

This just in from John Conway:

John doesn’t say much about it in the tweet where he unveiled this piece: just “A new #painting, of a Saltapotamus”. His website is just a little more forthcoming:

Saltapotamus

Saltasaurus was a small (for a sauropod) sauropod from the Late Cretaceous of Argentina. It had a some armour, and a lot of girth.

This reminds me very strongly of Obesethocoelicaudia, a fat restoration of Opisthocoelicaudia that John kindly did for Matt and me to use in our 2014 SVPCA talk, “Slender Giants”:

(Saltasaurus and Opisthocoelicaudia are both derived titanosaurs, and in most phylogenies they come out as pretty closely related.)

Is this kind of restoration credible? After all, it’s a long way from how we’ve been used to seeing Saltasaurus. Here, for example, is how E. Guanuco restored a group of four Saltasaurus individuals in Powell (2003: plate 78):

In this illustration they are tubby in a Normanpedia kind of way, but nothing very different from how (say) Apatosaurus was being restored not too long before then.

But the truth is that lots of animals have flesh envelopes very different from what you might predict based on the skeleton alone. Exhibit A, the inspiration for John’s new piece: the humble hippopotamus. Skeleton:

And life appearance:

It seems more than reasonable that across a clade as diverse, disparate and long-lived as the sauropods, there would have been some that were similarly heavy with flesh. In fact, I think it would be special pleading to argue that there were not.

Which specific sauropods were obese? That is much harder to tell. Hippos can be very heavy with little penalty as they spend much of their time in the water. Perhaps the same was true of some sauropods. If that’s so, then our quest must be for sauropods whose skeletons show adaptations for a semi-aquatic lifestyle, and on that basis Opisthocoelicaudia may have at least two feature supporting this interpretation: very robust limb bones and (if the interpretation of Borsuk-Bialynicka 1977: figure 5 is to be trusted) a transversely broad torso.

References

  • Powell, Jaime E. 2003. Revision of South American Titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum 111:1-94.

 

Dodo monograph cover - Claessens et al 2016

Here’s an awesome thing that just landed in my mailbox: the new monograph on the Thirioux dodos by Leon Claessens and his collaborators. They’ve done a better job describing what’s cool about these specimens than I could, so for the rest of this post I’m just borrowing their text from the Aves3D site, where you can view 3D models of whole dodo skeletons and many individual elements (not to mention zillions of elements from lesser, non-dodo birds):

The dodo (Raphus cucullatus) skeleton on exhibit at the Durban Natural Science Museum is one of two unique skeletons discovered and assembled more than a century ago by the amateur naturalist Etienne Thirioux. Thirioux’s two dodos are unique, not just because they are the most complete skeletons in existence, but also because they are the only two skeletons comprised of the bones of either a single individual bird (the Port Louis dodo), or the bones of (only) a few different birds (the Durban dodo). In contrast, all other known dodo skeletons are incomplete and are typically put together from separate fossil bones uncovered at a marsh called the Mare aux Songes.

Port Louis dodo skull - Claessens et al 2016 figure 6

Port Louis dodo skull – Claessens et al 2016 figure 6

The Thirioux specimens contribute greatly to our understanding of the anatomy of the extinct dodo and are the subject of a new, major monographic treatise:

Anatomy of the dodo (Raphus cucullatus L., 1758): An Osteological Study of the Thirioux specimens.
Leon P. A. M. Claessens, Hanneke J. M. Meijer, Julian P. Hume, and Kenneth F. Rijsdijk (Editors).
Society of Vertebrate Paleontology Memoir 15, Journal of Vertebrate Paleontology Vol. 35, Supplement to No. 6.

We are pleased to make the Thirioux dodo skeletons available to the public for viewing on Aves 3D and Sketchfab. Please enjoy these wonderful scans of the skeleton of a fascinating bird, and check back on the site frequently, as we continue to upload more new dodo bone scans each week.

Sincerely,
Leon Claessens
for the Dodo Research Programme and the Aves 3D team

Congratulations, Leon and team, on a landmark publication. And thanks for all the free dodo visualizations!

For previous dödö-related musings, please see this pöst.

Port Louis dodo skeleton - Claessens et al 2016 plate 1

Port Louis dodo skeleton – Claessens et al 2016 plate 1