I knew that Xenoposeidon is awesome. But I wasn’t prepared for the fact that the rest of the world seems to realise this, too. I got up at 4:45 this morning to get a train into London to do, as I thought, a brief bit of film for ITN about the new dinosaur. But I kept on — and on — getting calls from other media outlets wanting a piece of the hot Xenoposeidon action. As I write this, I am finally on the train home, having done:

  • Interview with ITN at the musuem, in front of (why not?) the Camarasaurus mount with the painfully disarticulated sacrum.
  • Phone interview with Wave FM, which I think is a South Coast commercial station. (I did this on a mobile while in the car in which those nice ITN people were giving me a lift to their building).
  • Channel 4 News, live at about 12:20.
  • Another live TV interview, this one on BBC News 24 at about 2pm.
  • Recorded radio interview to go out later on BBC Radio Five Live Drive. (I think that’s the correct name but I might have missed out a Dive or a Thrive or something. Clive. Shrive.)
  • Remote-in-the-studio interview with BBC Radio Solent, which those nice people at BBC Broadcasting House provided a studio for.

Then, after opportunistically getting my photo taken with a Dalek (it would have seemed churlish not to) …

dalek-500px.jpeg

… I finally left Broadcasting House to get back to the Natural History Musuem (for reasons that will become apparent later), and was just about to get onto the tube when I got a call from BBC Radio Scotland who also wanted to do an interview. So I got back into the BBC where some nice people set me up in the Unattended Studio (its real name) and I did:

  • Radio interview for BBC Scotland

But while that was being arranged, I got yet another call from yet another hunk of the geographically dispersed BBC, which thankfully I was able to get technical support for and go ahead with:

  • Live TV interview with BBC South, done over the wire with an interviewer down in Southampton and with me staring at a blank hunk of black glass trying to smile naturally as though it were an interviewer.

All the while these extra last-minute BBC interviews were going on, I kept phoning to repeatedly postpone the next hunk of filming I was scheduled to do at the musuem, but I finally got there at 4:30 and was able to do:

  • TV interview for Spanish television, apparently to go out across the southern states of the USA as well, with a company whose name I’m afraid eludes me for the moment.
  • Live phone interview with BBC Wales — which I did in the quietest public gallery I could find at the museum, since they weren’t able to find me a proper quiet room to do it in. And finally:
  • Long phone interview with a reporter for Spanish newspaper which, again, to my shame, I can’t remember at the moment.

Plus, I am pretty sure, a bunch more phone interviews, some for radio and some for print, the details of which are now lost to me.

While all this was going, a lot of the daily papers were running the story: I saw it in the Times, Sun, Mirror, Metro, and — the best of all by far — the Guardian. Ian Sample, who wrote the Guardian story, spent a solid 50 minutes on the phone with me yesterday, and did a superb job of putting the story together. We got basically the whole of page 3, which is better than I had dared hope. Isolated partial mid-to-posterior sauropod dorsals are sexy again! I tell you all this not to emphasize how awesome I am (people who know me will tell you that I’m not so hot) but as a tribute to the glory of Xenoposeidon, which the world seems to recognise as the wonder it is.

Throughout the whole experience, I’ve been really impressed by the media people I’ve met, all of whom seem to have been very careful not to misrepresent the story, and most of whom asked intelligent questions. A special shout goes to Catherine Hole of ITV Meridian, who filmed an interview in advance last week and who had clearly done her research in great depth; and also to the Channel 4 News presenter (whose name, you will not be at all surprised to hear, I don’t know) who asked aggressively confrontational questions that gave me the chance to talk about postcranial skeletal pneumaticity live on national television (take that, Wedel!)

While I’m in the thanking-people groove, and without wanting to sound too much like I’m accepting an Oscar, I’ve had superb support throughout from Kate Daniell of the University of Portsmouth Press Office. She’s fielded calls, scheduled interviews, kept me informed, made calls on my behalf when I couldn’t make them, and generally held the ship together while I went swanning off around London having fun. I’ve been jocularly referring to Kate as my agent, but the fact is that she really couldn’t have been more helpful even if that really had been her role in all this.

So hopefully this is a good day for sauropod vertebrae: I think it’s a while since one was so prominently in the national news, and hopefully it’ll open the way for more sauropods in the media down the line. I don’t think I said anything outstandingly dumb … although I might have inadvertently suggested on BBC News 24 that it would be a good idea to cut the head off an elephant. (Kids: don’t try this at home. Or, if you must, at least get a grown-up to help you with the scissors.)

So I’m shattered. But at least I got to eat a lot of sushi on UoP’s dime. Tomorrow I attempt to return to civilian life, the task ahead of me right now being to do enough day-job work this month to pay the mortgage. Hey, it’s not easy being an international media superstar.

Finally: I’m sorry this post has been short on sauropod vertebrae. But normal service will be resumed tomorrow, with Darren’s post on how we interpreted the vertebra.

P.S. The article in The Times translated the name Xenoposeidon proneneukos as “Forward-sloping alien earthquake god”. I kind of like that. It would make a good end-of-level boss in a video game.

Advertisements

Today is an exciting day here at SV-POW! Towers, with the publication of the new dinosaur Xenoposeidon proneneukos, based on — you guessed it — a sauropod vertebra. The reference is:

Taylor, Michael P. and Darren Naish. 2007. An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England. Palaeontology 50 (6): 1547-1564. doi: 10.1111/j.1475-4983.2007.00728.x

And what a vertebra it is! Let’s take a look:

Xenoposeidon holotype vertebra BMNH R2095 in left and right lateral views

Here we see the vertebra from both sides: on the left side, we see it in left lateral aspect, and on the right, in right lateral. The images at the top are photographs, and those at the bottom are the interpretive drawing, so you should be able to find all the parts.

Those of you who are long-time sauropod-vertebra lovers will immediately spot two things: first, this thing is weird. And second, the left and right sides are significantly different. We’ll show you the anterior and posterior views later this week: we have a lot to say about the vertebra, and we don’t want to dump it all on you at once. There is a lot to say about this bone, and I’ll talk in detail about the autapomorphies and asymmetry later today. (By the way, Autapomorphies and Asymmetry would have been a good a name for Jane Austen novel). I’d love to do it now, but as I write (5:07am) I have eight minutes before a taxi arrives to whisk me away to Gloucester station, whence a train will take me to London for a day of filming news stories about this awesome bone. I have to say in all honesty that I am surprised at the level of media interest: pleasantly surprised, but surprised. For example, there are articles in Nature News, The Guardian (where it’s on the front page of the online edition), The Times, The Mail, The Sun (though happily thire photograph shows me fully clothed), The Scotsman, Metro (a free daily paper that people pick up on the tube in London) and no doubt many others that I’ve not yet seen.

For those of you who can’t wait, the paper describing this specimen formally can be downloaded. But stay tuned: we can say things here on the blog that we couldn’t say in the paper.

Sorry to rush: the taxi waits; and so do ITN, Sky News and Channel 4. Plus I need to photograph some bird skeletons while I’m at the museum (hey, they’re saurischians, right?)

The sacral and the profane

November 10, 2007

I see now that Mike has beaten me to the punch in providing your at-least-weekly dose of sauroponderous vertebrawesome. And a nice job it is. Still, I feel funny about you not getting a new picture (ahem), so I’m posting my late entry anyway. For some reason, despite–or perhaps because of–my ardent devotion to cervicals, I have taken it on myself to push the anatomical boundaries of SV-POW! again.

amnh-diplodocus-500.jpg

Here’s a partial pelvis of Diplodocus in the American Museum of Natural History, in left lateral view. The big, vertically-oriented slab is the ilium. The semicircular concavity on the bottom of the ilium is the top half of the acetabulum, or hip socket. The bottom half of the acetabulum was formed by the other two pelvic bones, the pubis, which pointed down and forward, and the ischium, which pointed down and back. Behind the ilium you can see five sacral vertebrae, and the sacral ribs that connect the ilium to the vertebral column. The neural spines of the middle three vertebrae are fused together. The first and fifth have free neural spines, but all five are fused together at the centra.

The number of sacral vertebrae increased several times in the evolution of sauropodomorphs (sauropods and “prosauropods”). Almost all “prosauropods” have three sacrals, basal sauropods have four, most neosauropods have five, most titanosaurs and some elderly individuals of Camarasaurus have six, and Neuquensaurus is reported to have seven. It is a little weird that sacral count increases so regularly and straightforwardly up the tree. The sacrum is the only bony connection between limbs and the vertebral column (recall that the shoulder girdle “floats” in a sling of muscles and ligaments), so it’s pretty important mechanically. You might expect that bigger sauropods would have more sacral vertebrae and smaller sauropods would have fewer, but that’s not the case. Monsters like Apatosaurus and Brachiosaurus only have five, and little ole titanosaurs like Malawisaurus and Saltasaurus have six (“little” in this case means up to the size of an elephant–big for an animal, kinda pathetic for a sauropod). Now, granted, there were much bigger titanosaurs, like Argentinosaurus, Puertasaurus, and Paralititan, but the sixth sacral shows up early in titanosaurian history, in the little guys. So there does not seem to be much of a connection between sacral count and body size. Which raises the question: what was driving the increase?

Tutorial 4: Laminae!

November 10, 2007

For the first time in SV-POW! history, a full week has passed between successive posts — well, at least we didn’t actually fail with the “of the week” part, even if it was a close thing. It’s been a busy week, for reasons that will soon be apparent; and for the same reasons, the posting frequency will ramp right up in another week or so.

We usually don’t like to follow one tutorial directly with another, preferring to sweeten the deal by putting out a sheer-beauty-of-sauropod-vertebrae post in between tutorials. But this time, we need to push the tutorial out straight away, because it’s about laminae; and we’re going to be talking a lot about laminae in the next fortnight.

So with that disclaimer, please brace yourself for what even I have to admit is by no means a particularly beautiful picture:

HMN SII C8 yet again, a mid-cervical from the Brachiosaurus brancai type specimen, with laminae highlighted and labelled

You’ll recognise this picture from Tutorial 2: Basic vertebral anatomy; but this time I’ve highlighted and labelled the laminae in red.

Now let me admit right off the bat that this looks horrible and complicated. When you see the names of the laminae written out in full — the PRDL, for example, is the prezygadipophyseal lamina — it doesn’t help much, either. But this complexity is an illusion: in truth, laminae are not complex structures — they’re just sheets of bone — and the nomenclature that we use for them is not so much complicated as explicit.

One of the nice things about laminae is that they are just about the only anatomical feature that has a single key paper that you can read to learn pretty much everything you need to know. That paper is Jeff Wilson’s 1999 offering A nomenclature for vertebral laminae in sauropods and other saurischian dinosaurs (JVP 19:639-653). Like all Jeff’s publications, it can be freely downloaded from his publications page, [NOTE in 2013: not any more!] so a hat-tip there for open-access publication. (One of these days, an SV-POW! post is going to be an extended rant about the absurd current publication/copyright/access situations … but not today.) Anyway, if you want more details on laminae after reading this post, Wilson 1999 is definitely the place to go — use of his nomenclature is near-universal these days.

So here’s how it works. In tutorial 2, we learned about the “landmarks” on a sauropod vertebra — most of which are shared by the vertebrae of other tetrapods: the centrum, neural arch and neural spine, pre- and postzygapophyses, diapophyses and parapophyses. Laminae are sheets of bone connecting one landmark to another. And each lamina is simply named after the two landmarks that it connects. So suppose you have a lamina connecting the spine to the postzygapophysis: that would be a spinopostzygapophyseal lamina. A lamina connecting the anterior aspect of the parapophysis with the centrum is an anterior centroparaphophyseal lamina.

Wilson’s paper did three important things: it enumerated nineteen of the most common laminae; it standardised what order the landmarks are named in (so it’s a spinopostzygapophyseal lamina, not a postzygapospinal lamina or similar); and it specified standard four-letter abbreviations for each lamina, as in SPOL for the spinopostzygapophyseal lamina and ACPL for anterior centroparapophyseal lamina. You can look these up in Wilson 1999; but if you know what the landmarks are, it’s usually obvious what the four letters stand for. (Actually, Wilson’s abbreviations are composed of lower-case letters, like “spol”; but Matt, Darren and I find it more convenient to use capitals so that it’s easy to form plurals like “SPOLs”.)

As I said, Wilson listed 19 laminae.  There are a few others that occur less often and didn’t get a mention in that paper, such as a ?unique spinoparapophyseal laminae on the 7th dorsal vertebra of the ubiquitous B. brancai type specimen HMN SII. But the picture above only shows nine. That’s because of serial variation. Wilson’s paper figures eight different vertebrae (four cervicals and four dorsals) and it’s apparent as you look at them that different lamina come in and drop out at different points along the sequence. For example, some dorsal vertebrae have a paradiapophyseal lamina that connects the parapophysis with the diapophyis, but you don’t get that in cervicals.

One of the ways we can determine which taxon a sauropod vertebra belongs to is by looking at its laminae.

That’s all for now, I have to go and watch a Harry Potter film with the boys.

UPDATE, September 25, 2011

Wilson (1999) is no longer freely available, and this tutorial is quite a bit less useful without it as a universally available reference, so here are all 19 of the commonly named laminae and their abbreviations.

ACDL – anterior centrodiapophyseal lamina

PCDL – posterior centrodiapophyseal lamina

PRDL – prezygodiapophyseal lamina

SPDL – spinodiapophyseal lamina

PODL – postzygodiapophyseal lamina

PPDL – paradiapophyseal lamina

CPRL – centroprezygapophyseal lamina

SPRL – spinoprezygapophyseal lamina

TPRL – intraprezygapophyseal lamina

CPOL – centropostzygapophyseal lamina

SPOL – spinopostzygapophyseal lamina

Med. SPOL – medial spinopostzygapophyseal lamina

Lat. SPOL – lateral spinopotzygapophyseal lamina

TPOL – interpostzygapophyseal lamina

ACPL – anterior centroparapophyseal lamina

PCPL – posterior centroparapophyseal lamina

PRPL – prezgyoparapophyseal lamina

PRSL – prespinal lamina

POSL – postspinal lamina

Tutorial 3: Pneumaticity

November 3, 2007

It’s come up here a few times already–it’s hard to talk about sauropod vertebrae without bringing it up–but now it’s time to get it out in the open. In almost all sauropods, and certainly in all the ones you learned about as a kid, at least some of the vertebrae were pneumatic (air-filled). Now, this is a very strange thing. Most bones are filled with marrow, so if we find a bone that is filled with air, somebody’s got some ‘splainin’ to do.

 

pneumatic-diversity-small.jpg

Figure 1. Pneumatic bones of various animals. Compare the air spaces in the skull of a cow (A) and a hornbill (B) with those in the vertebrae of a turkey (C) and Apatosaurus (D). The front of the turkey vertebra was worn off with sandpaper. Erosion did the same thing for Apatosaurus. The vertebra, OMNH 1312, has a preserved height of 53 cm, but the neural spine is missing.

 

How does the air get into the bone?

You probably know more about pneumatic bones than you think, because you’ve carrying some around your whole life. Some of the bones of your skull are pneumatic, and we call the air-filled spaces sinuses. Your sinuses are connected to your nasal passages or the air-filled spaces in your middle ear—but connected by what? These connections are made and maintained by diverticula, which are pouches of epithelium (tissue that lines your internal surfaces) that grow out into the surrounding bones. For example, when you were a baby, pouches of epithelial tissue in your nose pushed up into the bones of your forehead. The spaces enlarged as you grew up, and today they form your frontal sinuses. But those sinuses are still lined with epithelium that is much like the inner lining of your nose, and the sinuses are still connected to your nasal passages, as you may discover when you have a cold. The air-filled pouches of epithelium that fill your sinuses are called pneumatic diverticula. The growth of the diverticula into the bones produces the pneumatic cavities, or holes in the bone, that house the diverticula.

In mammals, pneumatic bones are normally only found in the skull (there are very rare cases of diverticula getting loose and invading the first cervical vertebra). But in birds almost any bone in the body can be pneumatized, by diverticula of the lungs and air sacs. The lungs of birds are very different from our lungs–in fact, they are unique in the animal kingdom. The lungs themselves are small and not very flexible, but they are attached to a system of large air sacs in the thorax and abdomen. These air sacs are empty—in other words, they contain no tissue except a thin lining of epithelium. Like us, birds breathe by movements of muscles and bones, but instead of expanding and compressing the lungs as we do, the breathing movements of birds expand and compress the air sacs, and the air sacs blow air through the lungs. The air sacs are connected in such a way that birds get fresh air blown through their lungs when they inhale, and then again when they exhale (fresh air is stored in some of the air sacs between inhalation and exhalation). This constant flow of fresh air through the lungs (which are arranged into tubes rather than small sacs, like ours) means that birds have the ability to pull much more oxygen out of the air than mammals can.

In addition to providing large amounts of oxygen, the air sacs give rise to a network of pneumatic diverticula. These diverticula spread throughout the body: in between the internal organs, between the bodies of the muscles, and even under the skin. If one of these diverticula comes into contact with a bone, it may press into the bone in the same way that the diverticula of your nasal cavities pressed into the bones of your forehead when you were young. Because the diverticula go just about everywhere, they can pneumatize almost all of the bones in the body. In some birds, such as pelicans, almost the entire skeleton is pneumatic, but in most birds only the vertebrae, sternum, hip and shoulder bones, and humeri and femora (upper arm and leg bones) are pneumatic.

 

apatosaurus-and-swan-small.jpg

Figure 2. CT slices through cervical vertebrae of Apatosaurus (left) and a swan (right). Although the two animals are very different in size, the construction of their vertebrae is very similar. The Apatosaurus vertebra, OMNH 1094, is 51 cm long. The swan vert is 2.5 cm long (1/20 as large).

 

What does this have to do with sauropods?

If a bone is pneumatic, the air has to get into the bone through a diverticulum, and the diverticulum has to get into the bone through a hole. So almost all pneumatic bones have one or more large holes on the outside, which are the pneumatic foramina. Human medical histories and experiments on birds have shown that these pneumatic foramina must remain open for a pneumatic bone to develop properly and be maintained. If the foramen is closed—for example, by a disease or injury—the air space inside the bone will eventually be replaced by new bone growth.

In addition, pneumatic bones tend to have relatively large, smooth-walled chambers inside, compared to non-pneumatic bones that are filled with marrow. These chambers have a distinct appearance and they are not easily confused with anything else. So if we find a bone with a good-sized foramen leading to big internal chambers, we can infer that the bone was pneumatized. No other anatomical system makes the same traces on the skeleton.

A lot of sauropod vertebrae are crazy pneumatic. In fact, the only non-pneumatic vertebrae we’ve shown so far are these, and you can see big obvious pneumatic foramina in the vertebrae shown here and here and here and here.

 

respiratory-system-small.jpg

Figure 3. Reconstruction of the respiratory system of a diplodocid sauropod. The left forelimb, shoulder, and ribs have been removed for clarity. The cervical vertebra is AMNH 7535, and the caudal vertebra is OMNH 2055.

 

Air, air, what is it good faer?

(Sorry, that’s my Scottish brogue coming out.) Pneumatic vertebrae tell us some important things about sauropods as living animals. First, sauropods clearly had some kind of air sac system like that of birds. I’ve spilled a lot of ink on that already, and you can find those papers here. Second, we can use the distribution of pneumatic vertebrae to plot the extent of the pneumatic diverticula. Recall that if a bone is to stay pneumatic it has to remain connected to an outside air source. So if we find pneumatic vertebrae from the front of the neck to the middle of the tail, which is the case in most diplodocids, then we know that pneumatic diverticula spanned that whole distance as well.

Finally, it is surely no coincidence that the largest and longest-necked terrestrial animals had mastered ultralight construction. How light is ultralight? Well, the vertebrae of most sauropods were 60% air by volume, and in brachiosaurids like Sauroposeidon that number could be up to 89%. That’s a handy thing to have if you want to hang a long neck off your front end. Every major sauropod clade–Mamenchisauridae, Diplodocoidea, Brachiosauridae, and Titanosauria–had at least one member with a 9-meter neck, and the first three had members with 12-meter necks.

On a personal level, pneumaticity is also a great intellectual playground. There are so many things we don’t know about how it works, even in living birds. How do these spaces form, and what are the physiological controls? Why all the variation among clades, in birds and non-avian dinosaurs alike? Why are some bones 50% air and others 75% and still others 90%? Why do birds pneumatize the bones of their skeletons in the same order as their dinosaurian ancestors? How do body size and pneumaticity influence each other, in development and in evolution?

Morpheus told Neo that the Matrix is a system, with rules, and some rules can be bent and others broken. I want to be Pneo. I want to understand the rules. I want to see the code.

I want to play, too!

Groovy! Pneumaticity is wicked cool, and you don’t have to have a zillion dollars and an ion reflux pronabulator to get a good look at it. The holidays are coming up, and bringing with them the annual spike in the availability of turkey bones (you can get ’em from the neighbors if you aren’t having turkey yourself). Boil the vertebrae or humeri (the “drumsticks” of the wings) for half and hour or so to get all the soft tissue off, then soak them overnight in ordinary drugstore hydrogen peroxide to degrease them. Then you can use a small hacksaw or a Dremel to cut them open and see the air spaces inside, or you sand off the ends of the bones with sandpaper. The spaces you’ll see are identical to the air spaces in sauropod vertebrae, just a little smaller.

If you’re really ambitious, figure out what the bone-to-air ratio is in turkey vertebrae, and compare that to what you find for the humeri. There are a handful of papers on bone-to-air ratios in bird limb bones, but there is almost zero published data on the same ratios in vertebrae, or on how the bone-to-air ratio compares in vertebrae and limb bones of the same animal. There is a nice opportunity here for someone with little or no formal training to make a real (and publishable) contribution. Gimme a holler if you’d like to know more.