November 26, 2009
Trying two new things this morning: grilling a turkey, and live-blogging on SV-POW!
I like to grill. Steak, chicken, kebabs, yams, pineapple, bananas–as long as it’s an edible solid, I’m up for it. But I’ve never grilled a turkey before. Neighbor, colleague, fellow paleontologist and grillmeister Brian Kraatz sent me his recipe, which is also posted on Facebook for the edification of the masses. See Brian’s excellent writeup for the whole process, I’m just going to hit the photogenic parts here. Oh, and usually I tweak any photos I post within an inch of their lives, but I don’t have time for that this morning, so you’re getting as close to a live, unedited feed as I can manage. Stay tuned for updates.
Enough of that. Let’s rock!
The process starts more than a day in advance, with the brine. Salt water, fruit, onions, garlic, spices, and some apple juice.
The turkey needs to be entirely immersed in the brine for at least 24 hours. Doing this in a solid container would require an extra big container and too much liquid to cover the bird. I follow Brian’s method of brining in a triple-layer of trash bags. You can see a turkey roaster peeking out underneath the trash bags. Helps with the carrying.
Put the turkey in the trash bags first, then pour in the brine. Unless you like huge messes.
The genius of the trash bag method on display. You can squeeze out all the air so that the volume of the bag is equal to just the turkey and the brine.
Into the fridge for a day.
First thing this morning: out come the giblets, and save the goodies from the brine. We’ll get back to the neck later.
The bird awaits.
Crucial step: putting in a drip pan. Keeps the coals off to the side for indirect heat, and catches the grease so you don’t burn down the neighborhood.
Putting in the herb butter. I used three short sticks of butter mixed with sage, lemon pepper, and Mrs. Dash. Working the skin away from the meat and then filling the space with butter was extremely nasty. This must be what diverticula feel like.
A chimney is helpful to get the coals going.
To eat is human; to grill is divine.
Smoke bombs: mesquite chips soaked in water, wrapped up in balls of tinfoil, with holes poked on top to let the smoke out.
Fruit and spices into the body cavity.
At this point, I was fairly certain that today would be the greatest day of my life. The turkey is centered over the drip pan, stuffed with goodness, subcutaneously loaded with herb butter, draped with bacon. You can see one of the smoke bombs sitting right on top of the coals.
Know what you’re getting into. This 15 lb bird just barely cleared the lid of my grill.
A little over an hour in. I installed foil heat shields to keep the wings and thighs from cooking too fast. It’s all about the indirect heat. Some of the bacon comes off now, as a mid-morning treat.
Okay, the bird is about halfway done, and I have to whip up some sustainer coals and another batch of smoke bombs. Further updates as and when. Happy Thanksgiving!
I was hoping to get some more pictures posted before we ate, but you know how it is in the kitchen on Thanksgiving Day (or, if you’re not an American, maybe you don’t know, so I’ll tell you: dogs and cats living together, we’re talking total chaos).
The turkey just before I pulled it off the grill. The heat shields turned out to be clutch, I would have completely destroyed the limbs without them. That’s going to be SOP from now on.
Ah yes, the bird, she turned out even more succulent than I hadda expected. Check out the pink shade of the meat just below the skin. I recognize that, from good barbeque, but I’ve never produced it before.
That’s it for the cooking part of today’s program. As for the ultimate fate of the bird…we ate a stupifying amount of it. I sent even more home with our guests. And the other half–yes, half–of this thunder beast is sitting in the fridge. Hello-o leftovers!
And hello-o science!
I was going to post some more pictures of the neck, but I didn’t get around to eating it, so…another time, perhaps. In lieu, here’s Mike’s turkey vertebra in left lateral view (see the original in all its supersized glory here). Note the pneumatic foramen in the lateral wall of the centrum, just behind the cervical rib loop. This is actually kind of a lucky catch; a lot of times with chickens and turkeys, the pneumatic foramina are so far up in the cervical rib loop that they can’t be seen in lateral view.
It used to freak me out a little bit that birds often don’t have their pneumatic foramina in the middle of the lateral wall of the centrum, like sauropods. But a possible explanation occurred to me just this morning as I was planning this post. I think that birds have their pneumatic foramina right where you’d expect them, based on sauropods. I’ll explain why.
The first part of the explanation is that instead of wearing their pneumatic cavities on the outside, like this Giraffatitan cervical, bird vertebrae tend to be inflated from within, with just a few tiny foramina outside. The second part is that birds have HUGE cervical rib loops compared to sauropods. If the sauropod vert shown above had its rib on, the resulting loop would be fairly dainty, the osteological equivalent of a bracelet. The cervical rib loops of birds are more like tubes, they’re so antero-posteriorly elongated.
So take the brachiosaur cervical shown above and shrink all of the external pneumatic spaces by several inches. The cavities on the arch and spine would close up entirely, and the complex of fossae and foramina on the lateral side of the centrum would be reduced to a small hole right behind the cervical rib. Then stretch out the cervical rib loop in the fore-aft direction and voila, you’d have something like a turkey cervical, with a little tiny pneumatic foramen tucked up inside the cervical rib loop.
This doesn’t explain why bird verts are inflated from within instead of being eroded from without, or why sauropods had such dinky cervical rib loops (mechanical what, now?), or why pneumatic diverticula tend to make the biggest holes in the front half of the centrum, adjacent to the cervical ribs. I just think that maybe bird and sauropod pneumaticity are not as different as they appear at first glance. Your thoughts are welcome.
November 24, 2009
I drew a couple of these a while back, and I’m posting them now both to fire discussion and because I’m too lazy to write anything new.
Here’s the neck of Apatosaurus, my own reconstruction based on Gilmore (1936), showing the possible paths and dimensions of continuous airways (diverticula) outside the vertebrae.
Here’s figure 4 from Lovelace et al. (2007), which first got me thinking about pneumatic traces on the ventral surfaces of the centra and what they might imply. You can see pneumatic spaces between the parapophyses in Supersaurus (A) and Apatosaurus (C) but not in Barosaurus (B).
This is another of my moldy oldies, again based on one of Gilmore’s pretty pictures, showing how I think the soft tissues were probably arranged. The muscles are basically the technicolor version of Wedel and Sanders (2002). Two points:
- How bulky you make the neck depends mainly on how much muscle you think was present (which of course depends on how heavy you think the neck was…). Here I was just trying to get the relationships right without worrying about bulk, but it’s worth considering.
- The volume of air inside the vertebra was dinky compared to the probable volume of air outside. In Apatosaurus, either of the canals formed by the transverse foramina has almost twice the cross-sectional area of the centrum.
A fair amount of this has been superseded with better data and prettier pictures by Schwarz et al. (2007), so don’t neglect that work in any ensuing discussion (it’s free, fer cryin’ out loud). And have a happy Thanksgiving!
- Gilmore, C.W. 1936. Osteology of Apatosaurus with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11: 175-300.
- Lovelace, D.M., Hartman, S.A., and Wahl, W.R. 2007. Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional, Rio de Janeiro 65(4):527-544.
- Schwarz, D., Frey, E., and Meyer, C.A. 2007. Pneumaticity and soft−tissue reconstructions in the neck of diplodocid and dicraeosaurid sauropods. Acta Palaeontologica Polonica 52 (1): 167–188.
- Wedel, M.J., and Sanders, R.K. 2002. Osteological correlates of cervical musculature in Aves and Sauropoda (Dinosauria: Saurischia), with comments on the cervical ribs of Apatosaurus. PaleoBios 22(3):1-6.
Mike asked me to add the labeled version of Nima’s brachiosaur parade, so here you go. Click to embiggen.
November 18, 2009
Last week, for the first time ever, I spent the entire working week on palaeo. I took a week away from my job, and spent it staying in London, working on the Archbishop at the Natural History Museum. (For those of you who have not been paying attention, the Archbishop is the informal name of the specimen NHM R5937, a brachiosaurid sauropod from the same Tendaguru area that produced Giraffatitan brancai, and which has been generally assumed to represent that species.)
My main goal was to take final publication-quality photographs that I can use in the description (which I have committed to try really, really hard to get submitted by the end of 2009). There’s quite a bit of material (more than for Xenoposeidon, anyway!) — six cervicals in various states of preservation/preparation, cervical ribs, two complete dorsals, two more dorsal centra and a dorsal spine, some scap scraps, a partial ?pubis, a long-bone fragment and “Lump Z“, whatever that is. What you see above is my best lateral-view photograph of what I’ve designated “Cervical U”. One of these days, I’m going to do a post on how to photograph large fossils — something it’s taken me five years to get the hang of — but for today, I want to tell you about an exciting adventure with Cervical U. [Update: I wrote the How To post a few months later.]
Because my other big goal on this trip was to get it CT-scanned. Thanks to the generosity of John Hutchinson of the Royal Veterinary College, and to the help of the NHM people in arranging a loan, everything was set up for my host Vince Bickers and me to ferry the specimen up to the RVC, scan it and return it.
But first it had to be packed:
Lorna and Sandra spent a long time looking for a crate big enough to pack the bone in, but came up empty — there was one that was long enough but not wide enough, one that was tall enough but not long enough, and so on. In the end we sat the bone, on its very solid plaster base, on a plastic pallet, and wrapped it in pillows, bubble-wrap and that blue stuff whose name I don’t know.
As it happened, the scan had to be delayed for a day due to lack of personnel at RVC, but Vince and I took the vertebra up on the Thursday anyway; he had to return to work on the Friday, but I took public transport to RVC for the big day. Before we went into the scanning room, John showed me his freezer room:
I found it amusing that they have enough Segments Of Awesome that they have to label the various elephant-part freezers differently. And further down the aisle:
Then it was off to the scanning facility, where we found that we had to unpack the vertebra: it was small enough to go through the machine, but there was no way the pallet was going through. Once we’d unpacked it and removed it, it fit pretty nicely:
Because the scanner spits out X-rays in all directions, it’s controlled from a separate room, behind lead-impregnated glass:
We ran three scans before we got the settings right — we needed more voltage to get through the bone and matrix than we’d first realised, and a filter was causing unhelpful moire patterns. The third scan was definitely the best, and the one I expect to be working with.
[Boring technical side-note: I plan to use 3D Slicer for visualisation thanks to Andy Farke’s series of tutorials. But, frustratingly, I wasn’t able to load the DICOM files from the scan into that program: it crashes when trying to load them (segmentation fault) even though it works fine on the ankylosaur skull that Andy walked us through in the tutorials. I fixed this by gluing the 300-odd files together into a single stack file that 3D Slicer was able to read. For the benefit of anyone else who needs to do this, the command (on a Ubuntu Linux box) was: medcon -f *.dcm -c dicom -stack3d -n -qc]
Here is an example slice, showing part of the condyle in posterior view:
The grey blobs at the bottom of the image are the plaster jacket that supports the vertebra; the white is bone, and the light grey inside it is matrix that fills the pneumatic spaces. I’m showing the condyle here because its cavities are clearly visible: further back in the vertebra, they are harder to pick out, perhaps in part because of the iron bars scattering the X-rays. It’s notable that this vertebra is less pneumatic than would be expected for a brachiosaurid — by eye, it looks like like the condyle is only 20-30% air, and this slice is not unrepresentative. Most neosauropods would be at least twice this pneumatic, so we may have an Archbishop autapomorphy here.
I’ve not yet persuaded 3D Slicer to build a 3D model for me, but I’m pleased to say that before I left RVC, John mocked up a quick-and-dirty render of the bone using only density threshholding, and I can at least show you that.
Here we see the bone from the left side, previously obscured by solid plaster. From a single static image, it’s not easy to make out details, but we can at least see that there is a solid ventral floor to the centrum … and that those two crossed iron bars obscure much that we would like to see. You will get more of an idea from the rotating video that this is screencapped from.
Looking at this and comparing it with the right-lateral photo at the top of the post, it’s apparent that the density threshhold was set too high when making this model: all the bone along the lower right margin of the middle part of the centrum is good, but it’s been omitted from the model. In other words, the vertebra is more complete than this proof-of-concept model suggests. Hopefully I will shortly be able to show you a better model.
November 12, 2009
Get on over to Art Evolved and scope out the sauroponderous Sauropod Gallery. It’s brobdingnaginormous. I don’t want to seem biased, but there’s a lot of hot brachiosaurian action on display. I’m happy to say that the other clades are not ignored–diplodocids, dicraeosaurids, titanosaurs, mamenchisaurids, basal eusauropods, and even a basal sauropodomorph are all in the mix.
Normally my brachiosaurcentricity would lead me to steal one of the numerous brachiosaur images–perhaps the awesome parade of brachiosaurs that includes both Sauroposeidon and the Archbishop (!!)–BUT my laziness led me to choose another piece by the same artist, Nima Sassani. That would be the Puertasaurus reconstruction shown at top, which includes vertebrae and thus fulfills our titular mandate. That means I can stop writing now and get back to gawking. Go do likewise.
…oh, and don’t forget to stop by Dracovenator and congratulate Adam Yates on his new critter, Aardonyx. You’ll be hearing more about Aardonyx here at SV-POW! in the hopefully not-too-distant future. I can say no more for now…
November 6, 2009
I’m following up immediately on my last post because I am having so much fun with my wallaby carcass. As you’ll recall, I was lucky enough to score a subadult male wallaby from a local farm park. Today, we’re going to look at its feet.
Wallabies are macropods; together with their close relatives the kangaroos and Wallaroos, they make up the genus Macropus, literally “bigfoot”. So wallabies got there long before cryptic North American anthropoids. And indeed their feet are big. Here are those feet, in dorsal view, from before I started doing unspeakable things to my specimen:
From here they look pretty weird, but it’s only when we go round the back that we really see how odd they are. Same feet in ventral view:
There are (at least) three things to notice here: first just that the feet are very long; second, the thick, scaly pad that runs all the way up to the heel; and third, the bizarre arrangement of toes. At first glance, it seems that there is one main toe and a smaller one each side, but if you look more closely you’ll see that the medial “toe” is really two tiny toes closely appressed, so that they function as a single toe. This condition is known as syndactyly, Darren tells me. Also from Darren: it’s digit I that is missing in macropods, so the tiny-toe pair are digits II and III, the main toe is IV and the lateral one is V.
(By the way, seeing my patio in these photos reminds me of something I forgot to mention in the previous post: it’s surprisingly difficult to wash wallaby blood off paving slabs. Remember that, kids, it’ll be on the test.)
Regular readers will remember from last time that I planned to prepare the skull and left fore- and hindlimbs by simmering and dissection, and let nature deal with the rest of the elements. You’ve already seen the skull, so here goes with that foot.
After an initial simmer, I was able to skin the left pes, so here it is at that stage, in medial view:
From this angle, you can clearly see the absurdly thin second metatarsal (MT II) that supports the innermost of those two tiny digits. MT III is just as long and thin, but is fused proximally to the much larger MT IV, as we shall see below. The simmering has resulted in the more distal phalanges breaking away from their more proximal brethren, and being pulled downwards and beneath them. This is most apparent with the tiny digits, whose supporting phalanges are clearly visible poking out above the claws. So the large lump of what looks like cartilage at top right is actually phalanx IV-I, with IV-II and IV-III (the ungual) beneath it. Also note the significant amount of resilient tissue below the metatarsals. I’ve cut most of it away, but you can get a good idea from the bits that are still attached distally.
Here is the metatarsus in ventral view after I had removed the phalanges:
Here you can clearly see the syndactyly (in those two closely appressed thin metatarsals II and III at the top of the picture) and the very sculpted distal ends of the larger metatarsals IV and V.
Now let’s skip straight to to the completed stripped-down pes, now in dorsal view:
It’s interesting that the phalangeal formula is so uniform: 0-3-3-3-3. That is, all four digits have two normal phalanges and an ungual. But the differences in proportions between them are quite something.
This is our first look at the tarsals — those seven bones on the left of the picture, before we get to the metatarsals. The three big ones fit together very nicely. At the back you see the calcaneum, where the achilles tendon attaches; next is the astragalus, which sits on top of the calcaneum and where the distal end of the tibia articulates. Next up is a bone whose name I don’t know, being pretty darned ignorant of ankles — might it be the cuboid? Anyway, even after cleaning and cartilage-removal , this articulates very nicely indeed with both the calcaneum and MT IV.
Medial to these (i.e. below them in the picture) are four much smaller tarsal bones whose identity I can’t even guess at. It’s not clear to me how they articulate with the big tarsals — they were all pretty solidly embedded in cartilage and gloop and I fear that they’re not going to fit neatly whatever I do. Hints will be welcome.
One big surprise was the small bones between the metatarsals and their corresponding phalanges: one each at the ends of MT II and MT III, and two each at the ends of MT IV and MT V. Because the proximal phalanges articulate so nicely with their metatarsals, it’s clear that these small bones were not positioned between them in life, but rather floated above them — rather as your kneecap, or patella, floats above your femur-tibia joint. They are sesamoids. Does anyone know whether this sesamoid formula of 0-1-1-2-2 is common? Seems a bit weird to me.
Finally, I leave you with the entire left hindlimb: foot as in the previous picture, surmounted by the tibia and fibula, then by the femur, all in anterior view. Just to the left of the femur-tibia joint is a small bone which I assume is the patella.
Special bonus wallaby limb: over there on the right is the left forelimb. As you can see, I’ve done the easy part (scapula, humerus, ulna and radius) but I still have to dissect out the bones from the wrist and hand — a picky, tedious job that to be frank I am not looking forward to. The feet are much more exciting than the hands.
That’s all for today. On Sunday evening I am off to London to spend a whole week in the company of the Archbishop. The plan is to spend Monday to Wednesday taking final publication-quality photos (I finally have a proper tripod) and digging out field photos and suchlike from the museum archives, then take Cervical U to be CT-scanned at the Royal Veterinary College, courtesy of theropod hindlimb mechanics guru John Hutchinson. Friday is emergency backup in case something crops up to delay the scanning, and also gives me a chance to retake any photos that didn’t come out as required. The plan is that this visit should give me everything I need (pictures, measurements, observations, historical documents) to finish up the long-overdue Archbishop description. Fingers crossed.
I leave you with a puzzle. This is the jacket that I have designated “Lump Z”:
Can anyone offer a guess as to what this is, and which way up it should be? It’s a jacket that was opened years ago — before I was involved with the specimen — but never fully prepared. Matt and I have discussed it a little, but I don’t want to prejudice anyone with our guesswork, so I leave the floor open. What is it?
SV-POW! Dollars are at stake!
November 3, 2009
Today, we’re going to be taking a wallaby apart. Specifically, a Bennett’s wallaby, the larger of the two subspecies of the red-necked wallaby Macropus rufogriseus. I was delighted (though of course also saddened) to get a call on Saturday afternoon from the very same mini-zoo that had given me Charlie the monitor — Dick Whittington Farm Park in Longhope, Gloucestershire. They have a small group of seven wallabies sharing a paddock with goats, and one had died — most likely from being butted by one of the goats, although there were no external signs of injury.
This is going to be the largest animal I’ve prepared the skeleton out of — I measured it at 123 cm from snout to tail and 10.5 kg total weight, which compares with 75 cm and 12 kg for the badger, 100 cm and 5.2 kg for the fox and 111 cm and 3.4 kg for the monitor. Yes, the badger was heavier, but the awkward shape of the wallaby makes it all-round “bigger” and harder to deal with. Both the badger and the fox would, just, fit into large plastic toy-boxes which I buried and will exhume after a suitable time has passed, but that wasn’t going to work for the wallaby. I needed to take that baby apart:
I was pleasantly surprised at what good condition the guts were in (compared with the horrible state of Charlie innards) — nice and fresh. If I’d had time, I’d have attempted to learn something from a proper dissection, but as I was pushed for time (trying to get this done in my lunch break) I had to push on. I discarded the guts and started to carve up the remainder.
The knife is a Norwegian fisherman’s knife — very sharp, and short enough to be easy to wield. It’s perfect for dismembering a carcass this size, even though previously I’ve only used it for slicing sushi rolls. It was a Christmas present from my employer, Index Data, a few years ago.
My plan was to carefully divide the animal into seven portions (head, torso, tail and four legs), remove as much skin and muscle as I could without risking damage to the bone, and to process the parts separately.
After some thought, I decided to prepare the skull and the left fore- and hind-limb by boiling, and to bury the rest in the box. Here are the relevant divisions:
Then I put the pot through an hour’s simmering, peeled the skin off the skull and feet, and removed what meat I could; then I simmered a second time and removed more meat. By this stage, I was able to remove the three most anterior cervicals, which had been attached to the back of the skull — but they are still so covered with attached flesh that they’re not much use yet. Here’s how the simmered material is looking:
And here is the skull as it looks now, after a little more flesh-picking (but not nearly enough):
I think that it (and the other boiled bones pictures above) would benefit from a third simmer-and-pick session before I put them out somewhere for invertebrates to deal with. While that’s going on, I’ll prep out the foot and the forelimb, which have also been boiled twice but phalanges are a right nasty piece of work.
And then I have to decide what to do with my big yellow box that has the rest of the bits in. Plan A is still burying, but it is kind of tempting to simmer these parts, too, and get the whole thing completed much more quickly.
On the other hand, now is not a good time for such an effort: I will be away from home all week on a mission of utmost importance, and of great relevance to this blog. Details to follow!
Finally, I leave you with your weekly sauropod-vertebra goodness!