Norwescon 41 Guests of Honor: Ken Liu, Galen Dara, and, er, me. Mike would like to remind you that you can get your own ‘Kylo Stabbed First’ t-shirt here.

The week before last I was fortunate to be the Science Guest of Honor at Norwescon 41 in Seattle (as threatened back when). I had a fantastic time. I got to give talks on binocular stargazing and the sizes of the largest sauropods and whales (ahem), participate on panels on alien biology and creature drawing, and meet a ton of cool people, including my fellow Guests of Honor, multiple-award-winning author Ken Liu and multiple-award-winning artist Galen Dara, both of whom turned out to be humble, easygoing, regular folks (if frighteningly talented).

I also had a lot of great conversations with folks who were attending the con, which is exactly what I wanted. One of the most interesting was a hallway conversation with a fellow DM named Shawn Connor. He had a great question for me, which I liked so much I wanted to answer it here on the blog. Here’s his question, copied with permission from a follow-up email:

I run tabletop RPGs, and in my current game one of the characters is a caveman type who naturally grew up hunting dinosaurs. As one does. His weapon is a dinosaur bone, customized and used as a club. I have attached the picture that he came up with [below]. Now understanding the picture is obviously not of a real dinosaur bone – it’s probably a chicken bone or a cow bone or something – let’s assume for the sake of this exercise that it is and that it is four feet long stem to stern. Given that, two questions: discounting the extra bling attached how heavy would such a bone be, and what kind of dinosaur could it have come from?

I’m going to answer those questions out of order. Advance warning: this will be a loooong post that will go down several rabbit holes that are likely of more intense interest to me, personally, than to anyone else on the planet. Read on at your own risk.

Whose femur is in the image?

First, Shawn is correct in noting that the femur in the image provided by his player is not a dinosaur femur. The prominent trochanters and spherical head offset on a narrow neck clearly make it a mammal femur, and if it’s four feet long, it could only have come from an elephant or an indricothere. Or a giant humanoid, I suppose, which is what the anatomy of the bone in the image most closely resembles. (It also appears to be foreshortened to make the distal end look bigger, or deliberately distorted to enhance the clubby-ness.)

Mounted elephant at the Museum of Osteology in Oklahoma City, with Tyler Hunt for scale.

But let’s play along and assume it’s from a non-human mammal. How big? Back in 2016 I was fortunate to get to measure most of the mounted large mammal skeletons at the Museum of Osteology in Oklahoma City, along with Tyler Hunt, then a University of Oklahoma undergrad and now finishing up his MS thesis under my mentor, Rich Cifelli.* The mounted elephant at the Museum of Osteology has a shoulder height of 254 cm (8 ft, 4 in) and a femur length of 102 cm (3 ft, 4 in). Assuming isometric scaling, a world record elephant with a shoulder height of 366 cm (12 ft) would have a femur length of 147 cm (4 ft, 10 in). So a four-foot (122 cm) femur would belong to an elephant roughly in the middle of that range, about ten feet (3 m) tall at the shoulder. That’s the size of the big bull elephant mounted at the Field Museum in Chicago.

The big mounted bull elephant at the Field Museum is 10 feet tall at the shoulder and weighed 6 tons in life. Note Mike for scale on the lower right. He and the elephant are about equidistant from the camera, so he should make a roughly accurate scale bar. Photo from our visit in 2005!

* Two further notes: first, I have roughly a zillion awesome photos from that 2016 visit to the Museum of Osteology, both of the specimens and of Tyler and me measuring them – not having posted them yet is one of the things I was whingeing about in the post that kicked off our return-to-weekly-posting thing this year. And second, I owe a belated and public thanks to the folks at the Museum of Osteology for accommodating Tyler and me. They helped us with ladders and so on and basically gave us free rein to play with collect data from their mounted skeletons, which was incredibly generous and helpful, and fortunately reflects the pro-research and pro-researcher attitude of most museums.

Which dinos had four-foot femora?

As for what kind of dinosaur a four-foot femur could have come from, we can rapidly narrow it down to a handful of clades: sauropods, ornithopods, theropods, and stegosaurs.

  • Sauropods. The longest complete femora of Patagotitan are 238 cm (7 ft, 10 in; Carballido et al. 2017), and an incomplete femur of Argentinosaurus has an estimated complete length of 250 cm (8 ft, 2 in; Mazzetta et al. 2004). So a four-foot femur would not be from a particularly large sauropod – something about elephant-sized, as you might expect from the elephant comparison above. Our old friend Haplocanthosaurus will fit the bill, as we’ll see in a bit.
  • Ornithopods. Femora of 172 cm (5 ft, 8 in) are known for the hadrosaurs Shantungosaurus (Hone et al. 2014) and Huaxiaosaurus (Zhao and Li 2009), and Zhao et al. (2007) reported a 170 cm (5 ft, 7 in) femur for Zhuchengosaurus (Huaxiaosaurus and Zhuchengosaurus may be junior synonyms of Shantungosaurus). But those are all monsters, well over 10 metric tons in estimated mass. So a four-foot femur would be from a large but not insanely large hadrosaur.

Mmmmmm…suffering. OM NOM NOM NOM!!

  • Theropods. Among the largest theropods, the holotype of Giganotosaurus has a femur length of 143 cm (4 ft, 8 in; Coria and Salgado 1995), and ‘Sue’ the T. rex (a.k.a. FMNH PR2081) has a right femur 132 cm long (4 ft, 4 in; Brochu 2003). So a four-foot femur from a theropod would definitely be from one of the monsters. The femur of Saurophaganax was 113.5 cm long (Chure 1995), just under four feet, which I only note as an excuse to use the above photo, which I adore.
  • Stegosaurs. I don’t know the longest femur that has been recovered from a stegosaur, but getting in the ballpark is easy. NHMUK PV R36730 has a femur 87 cm long, and the whole animal was approximately 6 m long (Maidment et al. 2015). Partial bits and bobs of the largest stegosaurs suggest animals about 9 m long, implying a femur length of about 130 cm (4 ft, 3 in), or just over the line.

I think that’s it. I don’t know of any ceratopsians or ankylosaurs with femora long enough to qualify – I assume someone will let me know in the comments if I’ve forgotten any.

How much would a four-foot femur weigh?

There are a couple of ways to get to the answer here. One is to use Graphic Double Integration, which is explained in this post.

Limb bones are not solid – in terrestrial tetrapods there is virtually always a marrow cavity of some sort, and in marine tetrapods the limb bones tend to be cancellous all the way through. Estimating the mass of a limb bone is a lot like estimating the mass of a pneumatic bone: figure out the cross-sectional areas of the cortex and marrow cavity (or air space if the bone is pneumatic), multiply by the length of the element to get volumes, and multiply those volumes by the density of the materials to get masses. I piled up all the relevant numbers and formulas in Tutorial 24, a move that has frequently made me grateful to my former self (instead of cussing his lazy ass, which is my more usual attitude toward Past Matt).

Currey and Alexander (1985: fig. 1)

Sauropod limb bones are pretty darned dense, with extremely thick cortices and smallish marrow spaces that are not actually hollow (tubular) but are instead filled with trabecular bone. My gut feeling is that even a four-foot sauropod femur would be almost too heavy to lift, let alone wield as a club, so in the coming calculations I will err in the direction of underestimating the mass, to give our hypothetical caveman the best possible chance of realizing his dream.

Some of the proportionally thinnest cortices I’ve seen in sauropod limb bones are those of the macronarian Haestasaurus becklesii NHMUK R1870, which Mike conveniently showed in cross-section in this post. I could look up the actual dimensions of the bones (in Upchurch et al 2015: table 1 – they passed the MYDD test, as expected), but for these calculations I don’t need them. All I need are relative areas, for which pixels are good enough.

First, I took Mike’s photo into GIMP and drew two diameters across each bone, one maximum diameter and a second at right angles. Then I drew tick marks about where I think the boundaries lie between the cortex and the trabecular marrow cavity. Next, I used those lines as guides to determine the outer diameters (D) and inner diameters (d) in pixels, as noted in the image.

For the radius, on the left, the mean diameters are D = 891 and d = 648. I could divide those by 2 to get radii and then plug them into the formula for the area of a circle, etc., but there’s an easier way still. For a tubular bone, the proportional area of the inner circle or ellipse is equal to k^2, where k = r/R. Or d/D. (See Wedel 2005 and Tutorial 24 for the derivation of that.) For the Haestasaurus radius (the bone, not the geometric dimension), d/D = 0.727, and that number squared is 0.529. So the marrow cavity occupies 53% of the cross-sectional area, and the cortex occupies the other 47%.

For the ulna, on the right, the mean diameters are D = 896 and d = 606, d/D = 0.676, and that number squared is 0.457. So in this element, the marrow cavity occupies 46% of the cross-sectional area, and the cortex occupies the other 54%.

(For this quick-and-dirty calculation, I am going to ignore the fact that limb bones are more complex than tubes and that their cross-sectional properties change along their lengths – what I am doing here is closer to Fermi estimation than to anything I would publish. And we’ll ground-truth it before the end anyway.)

Left: rat humerus, right: mole humerus. The mole humerus spits upon my simple geometric models, with extreme prejudice. From this post.

You can see from the photo (the Haestasaurus photo, not the mole photo) that neither bone has a completely hollow marrow cavity – both marrow cavities are filled with trabecular bone. By cutting out good-looking chunks in GIMP and thresholding them, I estimate that these trabecular areas are about 30% bone and 70% marrow (actual marrow space with no bone tissue) by cross-sectional area. According to Currey and Alexader (1985: 455), the specific gravities of fatty marrow and bone tissue are 0.93 and 2.1, respectively. The density of the trabecular area is then (0.3*2.1)+(0.7*0.93) =  1.28 kg/L, or about one quarter more dense than water.

But that’s just the trabecular area, which accounts for about one half of the cross-sectional area of each bone. The other half is cortex, which is probably close to 2.1 kg/L throughout. The estimated whole-element densities are then:

Radius: (0.53*1.28)+(0.47*2.1) = 1.67 kg/L

Ulna: (0.46*1.28)+(0.54*2.1) = 1.72 kg/L

Do those numbers pass the sniff test? Well, any skeletal elements that are composed of bone tissue (SG = 2.1) and marrow (SG = 0.93) are constrained to have densities somewhere between those extremes (some animals beat this by building parts of their skeletons out of [bone tissue + air] instead of [bone tissue + marrow]). We know that sauropod limb bones tend to have thick cortices and small marrow cavities, and that the marrow cavities are themselves a combination of trabecular bone and actual marrow space, so we’d expect the overall density to be closer to the 2.1 kg/L end of the scale than the 0.93 kg/L end. And our rough estimates of ~1.7 kg/L fall about where we’d expect.

Femur of Haplocanthosaurus priscus, CM 572, modified from Hatcher (1903: fig. 14).

To convert to masses, we need to know volumes. We can use Haplocanthosaurus here – the femur of the holotype of H. priscus, CM 572, is 1275 mm long (Hatcher 1903), which is just a hair over four feet (4 ft, 2.2 in to be exact). The midshaft width is 207 mm, and the proximal and distal max widths are 353 and 309 mm, respectively. I could do a for-real GDI, but I’m lazy and approximate numbers are good enough here. Just eyeballing it, the width of the femur is about the same over most of its length, so I’m guessing the average width is about 23 cm. The average width:length ratio for the femora of non-titanosaur sauropods is 3:2 (Wilson and Carrano 1999: table 1), which would give an anteroposterior diameter of about 15 cm and an average diameter over the whole length of 19 cm. The volume would then be the average cross-section area, 3.14*9.5*9.5, multiplied by the length, 128 cm, or 36,273 cm^3, or 36.3 L. Multiplied by the ~1.7 kg/L density we estimated above, that gives an estimated mass of 62 kg, or about 137 lbs. A femur that was exactly four feet long would be a little lighter – 86.6% as massive, to be exact, or 53.4 kg (118 lbs).

I know that the PCs in RPGs are supposed to be heroes, but that seems a little extreme.

But wait! Bones dry out and they lose mass as they do so. Lawes and Gilbert (1859) reported that the dry weight of bones of healthy sheep and cattle was only 74% of the wet mass. Cows and sheep have thinner bone cortices than sauropods or elephants, but it doesn’t seem unreasonable that a dry sauropod femur might only weigh 80% as much as a fresh one. That gets us down to 43 kg – about 95 lbs – which is still well beyond what anyone is probably going to be wielding, even if they’re Conan the Cimmerian.

Picture is unrelated.

I mentioned at the top of this section that there are a couple of ways to get here. The second way is to simply see what actual elephant femora weigh, and then scale up to dinosaur size. According to Tefera (2012: table 1), a 110-cm elephant femur has a mass of 21.5 kg (47 lbs). I reckon that’s a dry mass, since the femur in question had sat in a shed for 50 years before being weighed (Tefera 2012: p. 17). Assuming isometry, a four-foot (122 cm) elephant femur would have a dry mass of 29.4 kg (65 lbs). That’s a lot lighter than the estimated mass of the sauropod femur – can we explain the discrepancy?

 

Femora of a horse, a cow, and an elephant (from left to right in each set), from Tefera (2012: plate 1).

I think so. Elephant femora are more slender than Haplocanthosaurus femora. Tefera (2012) reported a circumference of 44 cm for a 110-cm elephant femur. Scaling up from 110 cm to 122 cm would increase that femur circumference to 49 cm, implying a mean diameter of 15.6 cm, compared to 19 cm for the Haplo femur. That might not seem like a big difference, but it means a cross-sectional area only 2/3 as great, and hence a volume about 2/3 that of a sauropod femur of the same length. And that lines up almost eerily well with our estimated masses of 29 and 43 kg (ratio 2:3) for the four-foot elephant and sauropod femora.

A Better Weapon?

Could our hypothetical caveman do better by choosing a different dinosaur’s femur? Doubtful – the femora of ‘Sue’ are roughly the same length as the Haplo femur mentioned above, and have similar cross-sectional dimensions. Hadrosaur and stegosaur femora don’t look any better. Even if the theropod femur was somewhat lighter because of thinner cortices, how are you going to effectively grip and wield something 15-19 cm in diameter?

I note that the largest axes and sledgehammers sold by Forestry Suppliers, Inc., are about 3 feet long. Could we get our large-animal-femur-based-clubs into the realm of believability by shrinking them to 3 feet instead of 4? Possibly – 0.75 to the third power is 0.42. That brings the elephant femur club down to 12.3 kg (27 lbs) and the sauropod femur club down to 18 kg (40 lbs), only 2-3 times the mass of the largest commonly-available sledgehammers. I sure as heck wouldn’t want to lug such a thing around, much less swing it, but I can just about imagine a mighty hero doing so.

Yes, there were longer historical weapons. Among swing-able weapons (as opposed to spears, etc.), Scottish claymores could be more than four feet long, but crucially they were quite light compared to the clubs we’ve been discussing, maxing out under 3 kg, at least according to Wikipedia.

T. rex FMNH PR2081 right fibula in lateral (top) and medial (bottom) views. Scale is 30 cm. From Brochu (2003: fig. 97).

If one is looking for a good dinosaur bone to wield as a club, may I suggest the fibula of a large theropod? The right (non-pathologic) fibula of ‘Sue’ is 103 cm long (3 ft, 4.5 in), has a max shaft diameter just under 3 inches – so it could plausibly be held by (large) human hands, and it probably massed something like 8-9 kg (17-20 lbs) in life, based on some quick-and-dirty calculations like those I did above. The proximal end is even expanded like the head of a war club. The length and mass are both in the realm of possibility for large, fit, non-supernaturally-boosted humans. Half-orc barbarians will love them.

And that’s my ‘expert’ recommendation as a dice-slinging paleontologist. Thanks for reading – you have Conan-level stamina if you got this far – and thanks to Shawn for letting me use his question to freewheel on some of my favorite geeky topics.

References

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With our baby’s appearance in National Geographic this week, she’s now been in four mainstream magazines:

That’s National Geographic at top left, Macleans  next to it; The Scientist at bottom left, and National Geographic Kids next to that.  (The articles in the first three of these are available online here, here and here, but I can’t find anything on the NG Kids web-site.)

There is a point to this post, beyond gloating celebrating Brontomerus: it’s that diligent preparation improves a study’s chance of getting good coverage.  A few people have asked us to write a bit about what we did, so at the risk of sounding self-congratulatory, here it is.

Most of Brontomerus‘s visibility is due to the hard work of the UCL Publicity team, and especially the excellent and widely-reproduced video that they made in the Grant Museum.  But we made it easy for UCL to take an interest by preparing a bunch of materials ahead of time, before they even knew that there was a paper coming out.  We called it the Brontomerus press pack, and made sure it contained everything anyone could need for writing and illustrating stories about our animal:

In short, we tried to give journalists, and radio and TV researchers, everything they needed to put together a story aimed at their own audience.  More than that — we tried to make it easy for them.  They have plenty going on, after all: Brontomerus came out on the day that the Libyan protests really took off, so it’s not as though news editors were short of material to fill their slots.  I suspect that if we’d not got all the ducks in such a neat row, Brontomerus would have disappeared from the news schedule in double-quick time.

Another important thing you can do to make news editors’ jobs easier: make sure that the images you provide are in high resolution, so they don’t pixellate when they’re blown up to fill a screen; and be explicit about image/video credit, copyright and permissions.  Let them know what they can use and under what conditions.  If you make them hunt for that information, or even chase you for it, they’ll probably lose interest and do a different piece instead.  And we really wanted the artist who’d done the Brontomerus work to be credited: Paco Gasco did a fantastic job, and deserved to be known for it.

Equally important, by getting as much material as possible ready before even contacting the university publicity people, we made their job easier.  Once they were on board, we were able to extend the page with extras like an official press release and the video, but the framework was all in place ahead of time.

In short, there is a whole load that you can do to prepare a study for media coverage.  Not much of it is rocket-science.  It’s basically just about getting the work done.  And it is work, plenty of it.

Still.  It’s worth it.

And another thing …

You should all get across to Heinrich Mallison’s new blog and check it out.  Lots of excellent palaeo-photography, even if today’s post is about a stinkin’ mammal.

Addendum (from Matt)

First, some credit where it’s due. We didn’t figure all of this out on our own. For Brontomerus in particular, we took a lot of cues from  the fact sheet that Irmis et al. put together for their 2007 “rise of dinosaurs” paper that made the cover of Science.

Second, we did figure some of it out on our own, but not all at once. If you look at Mike’s unofficial online press packs for Xenoposeidon (2007), our neck posture paper (2009), and Brontomerus (2011), you’ll see that each one is better than the one before.

Finally, you may be saying to yourself, “Okay, I understand that I’m supposed to make things easy for journalists and have a bunch of stuff queued up for them. But where do I put it?”

Well, online, obviously. If you don’t already have a blog, WordPress and Blogger and probably a zillion other services give them out for free, and you can make an ad hoc, one-shot blog for every press-release-worthy paper, as Mark Witton and Darren did for their azhdarchid paleobiology paper in PLoS ONE.

But let me wax preachy for a minute. If you’re a young researcher and you’re trying to make an impact, why aren’t you blogging? It’s not an intolerable commitment. Sure, regular posting brings more readers, but irregular posting brings more readers than not having a blog at all.

We started SV-POW! as a joke, and continued it during the actually-posting-weekly-about-sauropod-vertebrae phase (which lasted for 2.5 years) because it was fun and challenging, and maintain it now because it’s fun, we enjoy the wacky discussions that get going from time to time in the comments, and, frankly, we’re addicted to having a soapbox where we can say pretty much whatever we want. We didn’t explicitly plan it as a way to funnel readers to our scientific work, but that has been one of its great exaptive benefits. I’d be shocked if the same isn’t true for other researchers who blog.

So, moral of the story: if you’re a researcher and you’re not blogging, you’re missing out. Your work is reaching fewer people than it might. Come out and play. Join the conversation. Interact. Your future self will thank you.

Brontomerus by Mauricio Antόn, copyright National Geographic

The October 2011 issue of National Geographic is out, and in the ‘Now’ section near the front there is a one-page feature on Brontomerus (in the US version anyway).  The whole thing is can be viewed online here.  It’s page 30 in the hardcopy, but NG seems pretty cavalier about printing page numbers.

The art is by Mauricio Antόn and we’re super happy with it; as before we had the opportunity to go back and forth a lot and arrive at a finished piece that shows essentially everything we wanted. The author of the piece, Catherine Zuckerman, was also very patient in distilling down the reams of information Mike and I sent her about the story. Many thanks to both Mauricio and Catherine for their interest and hard work!

Just noticed this over on ScienceBlogs:

Tetrapod Zoology conquers the world!

SV-POW!sketeer Darren’s Naish’s other blog Tetrapod Zoology has — rightly — often featured strongly in the Readers’ Picks sidebar; but this is the first time I’ve seen it, or indeed any blog, completely monopolise the list.

ScienceBlogs has other blogs that get more hits and more comments than Tet Zoo — mostly because they consist of flamebait — but when you want solid chunks of meaty, scientific nourishment, Tet Zoo now seems to be pretty well established as king of the hill.  On the slight chance that any SV-POW! readers aren’t already regulars at Tet Zoo, let me recommend it in the strongest terms: I know of no other blog that does such a good job of presenting hardcore science in a readable, approachable manner.

So congratulations to Darren, and long may it continue!

 

Here’s one of those text-light photo posts that we always aspire to but almost never achieve. In the spring of 2008 I flew to Utah to do some filming for the History Channel series “Evolve”, in particular the episode on size, which aired later that year. I always intended to post some pix from that trip once the show was done and out, and I’m just now getting around to it…a bit belatedly.

Utah 2008 01 mountains from museum door

Here’s the view out the back door of the BYU Earth Sciences Museum in Provo, Utah. Not bad–the mountains actually made me drag my eyes away from sauropod vertebrae for a few seconds here and there.

Utah 2008 02 Brooks driving forklift

Here’s the view in other direction, with Brooks  Britt using a forklift to retrieve the big Supersaurus cervical.

Utah 2008 03 Supes and giraffe

And here is said cervical, with a mid-cervical of a giraffe for scale. You may remember the big cervical from this post (and if you click that link, notice how much nicer the new collections area is than the off-site barn where I first encountered the Cervical of Doom). Sauropods FTW!

Utah 2008 04 taping down Diplo vert

While the film crew were shooting Brooks and picking up some establishing shots, I was ransacking the collections for pretty vertebrae. We took our treasures up to the University of Utah med center in Salt Lake for CT scanning. Here Kent Sanders is helping me tape down a Diplodocus cervical.

Utah 2008 05 Kent in reading room

And here’s Kent in the CT reading room playing with the data. Like old times–I spent most of my Saturdays in 1998 and 1999 scanning verts with Kent when he was at the University of Oklahoma Health Sciences Center.

Utah 2008 06 NAMAL main drag

The next morning we went to the North American Museum of Ancient Life in Lehi. Here’s a view down the main drag, with the mounted Supersaurus on the left, mounted Brachiosaurus in the center, and original Supersaurus sacrum (on loan from BYU) in the case on the right.

Utah 2008 07 Matt in lift

The highlight of my day trip year.

I was back at BYU just a few months ago shooting another documentary, but that story will have to wait for the dramatically appropriate moment. Stay tuned!

So I finally got to see the Discovery Channel’s new series, Clash of the Dinosaurs. The show follows the common Discovery Channel MO of cutting between CGI critters and talking heads. I’m one of the talking heads, and I get a lot of air time, and I suppose I should be happy about that. But I’m not, for reasons I’ll explain.

I need to preface what follows by saying that I thought the other talking heads did a great job. My experience suggests that the scientific problems with the series didn’t originate with the scientists, infrasound weapons excepted. Tom Holtz–another of the talking heads, and a good one–nailed it on the DML:

For those going to watch the show, a warning:
The documentarians often take anything that any of the talking heads speculated about, and transformed these into declarative statements of fact. In some cases this is particularly egregious, because I strongly disagree with some of these statements and believe the facts are against some of these (say, about tyrannosaurid cranial kinesis…) and they present these as facts rather than suppositions.

Dangerous

In the fall of 2008 the folks  at Dangerous Ltd, a London-based film production company, asked me if I’d be interested in being part of a new documentary project, which had the working title “Dino Body” (this isn’t a trade secret or anything, that title was on the Dangerous webpage for months). The grand idea was to show how much we’ve learned about how dinosaurs actually lived.

Now, this is something I care about a lot. In the past couple of decades we’ve learned about the physiology, diets, nesting habits, growth rates, and social lives of dinosaurs, in unprecedented detail. Things no one predicted and that I would have bet heavily against, like burrowing dinosaurs, four-winged raptors, and comparative studies of dinosaur and pterosaur genomes, are backed by solid evidence. We are in a golden age of dinosaur paleobiology, and new discoveries, even new kinds of discoveries, are stacking up faster than I can really keep up. So it would be a great time to bring all this new evidence to the public.

In the late 2008 and early 2009 I spent a LOT of time with the people at Dangerous Pictures, going over all kinds of questions about dinosaur biology. I sent them papers, links to blog posts, diagrams, you name it. They seemed really keen to get the science right, and I was hopeful that we’d get a dinosaur documentary that wasn’t overly speculative sensationalized BS.

Sadly, that hope was to be mercilessly crushed.

Deja vu

The series has some obvious faults. It is incredibly repetitive, to the point that I found it hard to watch for any length of time without my attention wandering. Not just the CGI clips, but the narration as well. You’ll learn in 30 seconds why females tend to be choosier about mates than males (eggs are more expensive than sperm), and spend the next 15 minutes having that slowly beaten in your brain using as much empty verbiage as possible. Ditto every other fact on the show.

More galling are the places where animation is cleverly cut with talking head bits so that we end up describing things that were never in the script. I explained on camera about the unavoidably high mortality among juvenile sauropods, and how groups of Deinonychus could probably pick off the baby sauropods like popcorn. I had been speaking of hatchlings, but my words are cut together with a scene–which you’ll see about 15,000 times–of three Deinonychus taking down an elephant-sized subadult Sauroposeidon. In the real world, it would have pulped them. In the dramatically-lit world of Clash of the Dinosaurs, the three raptors inflict a handful of very shallow flesh wounds with their laughably tiny claws and the Sauroposeidon expires theatrically for no visible reason.

(If they really wanted to impress the audience with the implacability of Mesozoic death, they would have shown the three raptors mowing down a field of newly-hatched babies like so much wheat…)

I spent a long time explaining the evidence that sauropods buried their eggs, and at their request I mocked up diagrams showing the possible proportions of a hatchling Sauroposeidon. So naturally the program shows a mother abandoning her eggs in an exposed nest, and then a few minutes later, hatchlings that are perfect miniatures of the adults struggling up out of the ground. I guess they cut the scene in which the Sand Fairy buried the eggs, and lacked the budget to perform the simple morph of the digital model that would have made the babies look like babies, instead of ponderous adults emerging from the Sarlacc pit.

Some may complain that I am picking nits. But what the heck is the point of bringing on scientific advisors if you’re then going to ignore the stuff they tell you? Why not just make the crap up out of the whole cloth? In fact, there is far too much of that in the show. There is no evidence that Quetzalcoatlus could see dinosaur pee with its ultraviolet vision, or that a herd of hadrosaurs could knock over a predator with their concentrated infrasound blasts. Sorry, paleontologists, you’ll be fielding questions about these newly invented “facts” for the next decade at least.

It’s like I had this great working relationship with the researchers, and they were really curious and careful, and we went to great lengths to do the best work we could, and then somewhere in between my filming back in February and the airing of the completed show, all of our diligent work was flushed right down the crapper, and a fresh script was written by a hyperactive child whose only prior preparation was reading Giant-Size X-Men and getting hit on the head a few times.

Do I sound too harsh? I’m just getting started. Let me tell you about the sacral expansion in sauropods.

Back in the Back in the Day

In many sauropods and stegosaurs and a few other archosaurs, the neural canal (the bony tube that houses the spinal cord) is massively enlarged in the sacral vertebrae. This is the origin of the goofy idea that big dinosaurs had a “second brain” back there to control their hind end, because the real brain up front was (supposedly) just too darn tiny and remote. The researchers at Dangerous asked me about this sacral enlargement, and this is what I told them (quoted from an e-mail I sent November 25, 2008):

The sacro-lumbar expansion is possibly the most misunderstood thing in sauropod biology. First, there are two separate things that have been referred to as sacro-lumbar expansions. The first is the slight swelling of the spinal cord in that region in almost all vertebrates, including humans, to accomodate the neurons that help run the hind limbs (you also have a swelling in the spinal cord at the base of your neck to help run your arms). Contrary to popular belief, a lot of your stereotyped actions require little direct involvement from the brain and are instead controlled by the spinal cord. When you walk, for example, most of the motor control is handled by the spinal cord, and your brain only steps in when you have to actually worry about where to place your feet–when you step over a puddle, for example. So there would be nothing remarkable about sauropods using their spinal cords to drive many of their limb movements, this is something that pretty much all vertebrates do, it’s just not widely known to the public. [Aside: this is true. Also, I have heard it claimed that sauropods could not have reared because their brains were too small to coordinate such an action. This was claimed by a non-biologist who evidently doesn’t know how the nervous system works.]

The other sacro-lumbar expansion really is an expansion, but it’s not unique to sauropods and it has nothing to do with running the hind limbs. Most birds have a very large expansion of the spinal cord in the sacro-lumbar region called the glycogen body. As the name implies, it stores energy-rich glycogen, but the function of the glycogen body is very poorly understood. It has been hypothesized to be an accessory organ of balance, or a reservoir of compounds to support the growth and maintenance of the nervous system. Since we don’t even know what it does in birds, we’re straight out of luck when it comes to figuring out what it did in sauropods. Here’s a brief overview:
http://www.innerbird.com/other_special_features/hips/other_features_hips.html

Here’s an explanatory diagram I sent with the message:

This business about the glycogen body caused some consternation and dithering in the production process. They wanted to bring up the second brain because it’s so entrenched in the popular consciousness (i.e., bad dinosaur books), but they were unhappy that the real explanation turned out to be so unsatisfying (“We don’t know what it does, but not that!”). In the end, we did discuss it briefly on camera. I said something like, “There was this old idea that the sacral expansion functioned as a second brain to control the hindlimbs and tail. But in fact, it almost certainly contained a glycogen body, like the sacral expansions of birds. Trouble is, nobody knows exactly what the glycogen bodies of birds do.”

Somebody in the editing room neatly sidestepped the mystery of the glycogen body by cutting that bit down, so what I am shown saying in the program is this, “The sacral expansion functioned as a second brain to control the hindlimbs and tail.” I’m paraphrasing because I don’t have a DVR, but that’s basically it. (Update: my memory was pretty good. Here’s the interview transcript.)

Do you see, do you understand, what they did there? I was explaining why an old idea was WRONG and they cut away the frame and left me presenting the discredited idea like it’s hot new science. How freaking unethical is that?

So. I don’t know if the decision to turn my words around 180 degrees was a mistake made by an individual editor, or if it was approved from someplace higher up the line. I aim to find out. Until I do, I’m boycotting Dangerous Ltd, and I encourage you to do likewise.

The Final Insult

Oh, and they spelled my name wrong, throughout. And also mispelled Sauroposeidon in one of the quiz bits at commercial time. “What does Sauroposeiden mean?” It means you don’t know the Greek pantheon, sauropods, or basic spellchecking, dumbasses.

Science journalism FAIL.

UPDATE, January 27, 2010

This is so perfect that it hurts. For “Science Channel” feel free to substitute any of the ignotainment feeds operated by Discovery Communications.

Broadly speaking, pneumatic sauropod vertebrae come in two flavors. In more primitive, camerate vertebrae, modeled here by Haplocanthosaurus, the centrum is a round-ended I-beam and the neural arch is composed of intersecting flat plates of bone called laminae (lam above; fos = fossa, nc = neural canal, ncs = neurocentral suture; Ye Olde Tyme vert pic from Hatcher 1903).

In more derived, camellate vertebrae, the centrum and neural arch are both honeycombed with many small air spaces. This inflated-looking morphology is very similar to that seen in birds, like the turkey we recently discussed. The fossae and foramina on the outside tend to be smaller and more numerous than in camerate vertebrae, as shown here in a titanosauriform axis from India (Figure 3 from Wilson and Mohabey 2006). The green arrows show that the fossae visible on the external surface are excavations or depressions into the honeycombed internal structure of the bone.

External fossae on bones can house many different soft tissues, including muscles, pads of fat or cartilage, and pneumatic diverticula (O’Connor 2006). Pneumatic fossae are often strongly lipped and internally subdivided and may contain pneumatic foramina, which makes them easier to diagnose (but they may also be simple, smooth, and “blind”, which makes them harder to diagnose as pneumatic). But in all of these cases we are usually talking about the same thing: a visible excavation into a corpus of bony tissue, which may have marrow spaces inside if it is apneumatic, or air spaces inside if it is pneumatic (the corpus of bone, not the dent). That’s probably how most of us think about fossae, and it would hardly need to be explained…except that sometimes, something much weirder happens.

Consider this cervical of Brachiosaurus (this is BYU 12866, from Dry Mesa, Colorado). Brachiosaurus and Giraffatitan have an in-between form of vertebral architecture that my colleagues and I have called semicamellate (Wedel et al. 2000); the centrum does have large simple chambers (camerae), but smaller, thin-walled camellae are also variably present, especially along the midline of the vertebra and in the ends of the centrum. As in Haplocanthosaurus, the neural arch is composed of intersecting plates of bone; unlike Haplocanthosaurus, these laminae are not flat or smooth but are instead highly sculpted with lots of small fossae. Janensch (1950) called these “Aussenkaverne”, or accessory outside cavities, because and they are smaller and more variable than the large fossae and foramina that invade the centrum.

And that’s the weird thing. As the red arrows in the above image show, the “Aussenkaverne” are not excavations or depressions into anything, except the space on the other side of the lamina (which in life would have been occupied by another diverticulum). The neural arches of Brachiosaurus and Giraffatitan are not excavated by fossae, they’re embossed, like corporate business cards and fancy napkins.

What’s up with that!? We tend to think of pneumaticity as reducing the mass of the affected elements, but the shortest distance between two vertebral landmarks is a smooth lamina. These embossed laminae actually require slightly more bony material than smooth ones would.

As you can see above, the outer edges of the laminae are thick but the bone everywhere else is very thin. Maybe, like the median septa in pneumatic sauropod vertebrae, the thin bone everywhere except the edges of the laminae was just not loaded very much or very often, and was therefore free to get pushed around by the diverticula on either side, in the sense of being continually and quasi-randomly remodeled into shapes that don’t strike us as being very mechanically efficient. But also like the median septa, the thin parts of the laminae are only rarely perforated (but it does happen), for possible (read: arm-wavy) reasons discussed in the recent FEA post. And maybe the amount of extra bone involved in making embossed laminae versus smooth ones was negligible even by the very light standards of sauropod vertebrae.

Another question: since these thin sheets of bone were sandwiched in between two sets of diverticula, why are the “unfossae” always embossed into them, in the medial or inferior direction? Why don’t any of them pop out laterally or dorsally, looking like domes or bubbles instead of holes, like Mount Fist-of-God from Larry Niven’s Ringworld? Did the developmental program get accustomed to making fossae that went down and into a corpus of bone, and just kept on with business as usual even when there was no corpus of bone to excavate into? I’m only half joking.

I don’t have good answers for any of these questions. I scanned this vert a decade ago and I only noticed how weird the “unfossae” were a few months ago. I’m putting all this here because “Hey, look at this weird thing that I can only wave my arms about” is not a great basis for a peer-reviewed paper, and because I’d like your thoughts on what might be going on.

In Other News

The Discovery Channel’s Clash of the Dinosaurs premiered last night. I would have given you a heads up, except that I didn’t get one myself. I only discovered it was on because of a Facebook posting (thanks, folks!).

COTD is intended to be the replacement, a decade on, for Walking With Dinosaurs. I’m happy to report that one of the featured critters is Sauroposeidon. I grabbed a couple of frames from the clips posted here.

I haven’t seen the series yet, because I don’t have cable. But I’m hoping to catch it at a friend’s place next Sunday night, Dec. 13, when the entire series will be shown again. With any luck, I’ll have more news next week.

Finally, I got to do an interview at Paw-Talk, a forum for all things animal. I’m very happy with how it turned out, so thanks to Ava for making it happen. While you’re over there, have a look around, there’s plenty of good stuff. Brian Switek, whom you hopefully know from this and this, is a contributor; check out his latest here.

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