I'm teaching an online course on anatomy

So it turns out I haven't vanished (and actually have a lot of new content to share) but I've been swamped working on several projects of late. One of them I'd like to share, for those of you who really like dinosaurs but actually have different job aspirations:

I'll be teaching a course for Visualarium, one of the leading educational resources for visual effects artists (and artists in training) that use Pixologic ZBrush. The class is Advanced Creature Anatomy, and rather than being on dinosaurs (although you'll see some of them!) it centers on learning enough comparative anatomy from living and extinct animals to develop your own mental toolkit of concepts you can apply when to design more plausible speculative anatomy for fictional creature design.

I'll do my best to keep it fun, so if ZBrush and 3D art is your thing, I invite you to check it out; we'll be conducting a free webinar this Thursday so people can get a taste of what the course will be like.

Yup, the OK Apatosaurus is freakin' huge!

How big did Apatosaurus get? Well, that gray silhouette that is being dwarfed in terms of bulk there is Supersaurus vivianae. So yeah, that's one big honk'in sauropod...

The genesis of this post comes courtesy of a Matt Wedel post over at the excellent SV-POW! blog, where he was taking a look at the size of the partial Apatosaurus specimen preserved in Oklahoma, specimen OMNH 1670. Matt took a measuring tape to the OMNH specimen himself, and it measures up at a whopping 135 cm (for those of you who don't know the metric system, 135 centimeters is equal to one really big vertebra...).

But Matt really caught my attention when he stated:

...so the big Oklahoma Apatosaurus was probably in Supersaurus territory, mass-wise, and may have rivaled some of the big titanosaurs.

A younger me carving a pedal ungal. Look at that hair - what a hippy!

Supersaurus is an animal near and dear to my heart - it's an animal I've literally shed blood over. Yes really. In addition to working with my coauthors on a description of the second specimen of Supersaurusj and a reassessment of diplodocid phylogeny, we also had to produce a full mount of the animal under exceedingly tight time constraints. As with many small museums this meant we all had to pitch in, and that included learning how to sculpt missing bones. Near the very end of the project, while getting by on little more than 2 hours of sleep and coffee doses that would kill a small horse, I had a very small boo-boo with a carving knife (see photographic evidence at right). No stitches were necessary, and thankfully no sauropods where injured in the process.

The end result of our work was a mount that received top billing in a temporary exhibit in Japan in summer 2006. While the estimated length of 34 meters and mass estimate of 36-40 tonnes is smaller than some of the more sensational numbers that have been floated in popular books (and of course the internet), we suggested in our paper that many of those estimates were, shall we say... extravagant. Supersaurus appears to be close to the longest animal whose length can be reliably estimated (read: not counting Amphiceolias fragilimus), though it was lighter than the giant titanosaurs.

Given my personal stake here I wasn't about to take Matt's vicious maligning of Supersaurus  on faith. But - and this is the darndest thing about science - the facts are on his side. After scaling the fourth dorsal of Apatosaurus louisae up to the appropriate size, it turns out that the thing definitely is bulkier than Supersaurus.

 And if you try it with the other species of Apatosaurus (to whit: A. ajax and A. excelsus), it turns out just as bad - or worse in the case of A. ajax, who seems to have a proportionately shorter D4, which in turn leads to a larger animal when it's scaled to 135 cm.

Of course Supersaurus still looks to be longer by a fair amount, in large part due to the highly elongate neck. But when it comes to moving the dial on a scale, it's clear that Apatosaurus is just more sauropod than Supersaurus. Oh well Jimbo, we'll always have Japan...

Fishing at Dawn

Unenlagia comahuensis looking for fish at dawn.

What can I say, it's been over a year since I tried my hand at something more artistic than a muscle or skeletal reconstruction. I did the sketch over a year ago, and had it ready to go (it's a digital painting in Photoshop), so I decided to give it a crack and it fell into place a lot faster than I'd expected (most of the time was spent painting water detail).

I've reconstructed Unenlagia as somewhat less ecologically specialized than it's relatives Buitreraptor and Austroraptor, but fishing nonetheless. I don't really have a lot more to say about it - we'll get back to more hard core skeletal stuff soon, I promise! If you have any questions about the process I used I'll do my best to answer in the comments section.

I.O.Yutyrannus

Hey, it's not every day that a completely fuzzy, nearly 30-foot long meat-eating dinosaur is described, now is it? I'm afraid my current schedule won't allow for a full skeletal of this critter for several more weeks, so consider the skull a down payment.

First, I should say that I'm not going to retread much of the excellent writing that has already been done onYutyrannus. If you'd like more in depth coverage, I highly recommend David Hone's excellent write-up on his blog Archosaur Musings. For more coverage and some reasons to question whetherYutyrannus is a actually a tyrannosauroid, check out Darren Naish's coverage on his Scientific American TetZoo blog. I'd also be remiss to not mention Brian Switek's article over at the Smithsonian website.

Photograph by Roberto Appiani 

What I will cover are some of the difficulties I've already observed in restoring Yutyrannus. The reconstruction above is based on one of the beautifully preserved skulls (there are 3!); like everything else found in the Yixian Formation, the specimens have been squashed flat. Relatively robust bones like a femur hold up fairly well, but skulls really don't. They tend to be highly three-dimensional in shape, and are made out of relatively thin elements. In particular, on theropod skulls the top and rear of the skull tend to fold upward as the head undergoes the pancake treatment of diagenesis

.Small dinosaurs with larger eyes and brains (like the juvenile Scipionyx above seen at right) exaggerate the problem even more, and unsuspecting artists can restore the skulls as having huge domes over the eyes if they don't know better. In Yutyrannus I suspect we are seeing something similar, which probably exaggerates the apparent size of the nasals (especially as you move closer to the eyes), as well as the top of the skull at the back.

If you check out the beautiful photograph of the head of juvenile specimen ELDM V1001 in David Hone's blog (the same one I've restored above), you can probably see what I'm getting at.

The skull restoration at the beginning of this article takes those things into account, attempting to return a 3-dimensional shape to the steam-rolled remains of the skull (by the way, the mandible is largely a place holder for now, the surangular is actually a fairly different shape). Below I've included a comparison of the the skull with and without those "corrections". Because there are three skulls, and because they have likely been subject to distortion from somewhat different angles, I should be able to double check this with greater precision once I get around to doing the full skeletal.

For those of you investing the time to study the comparison image, the top one is the restored version, while the bottom one treats the outline more literally. In both cases I've re-articulated the lacrimal (the bone in front of the eye) with the jugal (the bone underneath the orbit). In both cases the lower jaw is (as mentioned above) just a generic placeholder that is the correct size, but doesn't take the information from other specimens into account.

That's all the time I have to put into a new skeletal on my own whim for the moment. Until I get a chance to do the whole thing enjoy this Yutyrannus I.O.U.

When journalists attack!

As recently reported on several apparently legitimate news sources, a new interpretation of dinosaur biology has been proposed that is "so revolutionary it stands the whole world of palaeontology on its head." What is this landmark new idea that has set paleontologists agog? It's being termed the "Aquatic Dinosaur" hypothesis, and as the name implies it suggests that the Charles Knight painting you see above isn't out of date, it was just ahead of its time. And not just for sauropods, but all large dinosaurs.

If something smells fishy to you, it's not just the swamp water; something is very wrong here. First, to be clear, there is no such controversy, or even an idea that you need to take seriously. To be sure, some guy wrote an article in Laboratory News, so I've listed the evidence below in a handy tabulated format:

Literally, no data was provided in the article. The author makes references to "calculations" that were run, but they never make it into print. The article is mostly long-winded hyperbole, filled with such gems as "Dinosaurs look more convincing in water, and the physics stands up more soundly."

So the author's main point appears to be "See??! They look better in the water, so it must be true! Also, I have some secret calculations I won't bother to share with you support my aesthetic preference!"  The fact that it was in the April edition might give us pause to wonder if this isn't a big joke, but alas there are reasons to suspect otherwise (see below).

 Two general claims seem to permeate the article, that dinosaurs were just really big so water would help, and that dinosaur footprints aren't as deep as you'd expect from such big animals. Of course how deep a footprint sinks is only partially related to the mass of an animal. The surface area of the foot must be taken into account, as smaller feet concentrate the weight while large feet spread it out. That's why a woman in high heels can dent substrates that elephants won't. And of course the substrate itself matters - no animals leave tracks on concrete, while people easily get bogged down in viscous mud.

The "they're just so big" meme is also painfully wrong; there's an entire literature of biomechanics that shows that dinosaur limbs are strong enough to support terrestrial locomotion. And of course dinosaurs lack the aquatic features seen in animals such as hippos or crocodiles, which actually spend most of their time in water. Running your mouth off (err, running your text editor off?) without even bothering to read the literature is one of those "the stupid, it hurts!" sorts of moments.

From xkcd

Ok, enough ragging on "professor" Ford; he's either a crank or a practical joker (perhaps those aren't mutually exclusive?), but he's not the first person to have a loony idea and not support it with any evidence. Heck, the internet is littered with such people.

The real problem here is that his personal speculation somehow got reported as news by the mainstream press. First, if this isn't an April Fools prank, it calls the editorial judgement of Laboratory News into serious question (and if it IS somehow a prank, why was it allowed to be spread pre- and post-April 1st to other media outlets?). Amusingly, on page 17 of the same issue of Laboratory News there is an article lamenting the state of science reporting in the news (seriously, I couldn't make this stuff up if I tried).

If you or your lab has a subscriptions to Lab News, I'd seriously consider making inquiries, or simply dropping it. If they allow this sort of thing to happen, how can you trust the rest of their articles?

More importantly, why on Earth was this story picked up and repeated by serious news outlets? Does BBC Radio 4 do any sort of review at all before they put someone on the air? Have journalistic standards sunk that low at the British Broadcasting Company? A quick listen to the audio shows the show starting out as mildly skeptical, but concluding by comparing Ford to Galileo freakin' Galilei!

W. T. F.?!!

Galileo, you may recall, did actual science and was being silenced by non-scientists due to the (presumed) theological implications of his findings. Mr. Ford (who the BBC charitably refers to as a "cell biologist" despite being more of a media gadfly and author of popular books and articles, not a publishing scientist) is not doing science - he in fact seems intent on ignoring science at all costs - and was simply being refuted by an actual, you know, paleontologist. Yet they whipped out the Galileo reference!

Which honestly begs the question of whether anyone should bother listening to BBC Radio 4. To be fair, actual paleontology has been covered on Radio 4 and it seems to otherwise have solid programming, but the BBC should move swiftly to clear this up if they don't want a permanent stain on their credibility.

Most of the web and print articles are based on the BBC interview, but that doesn't exonerate them; not a single one of them bothered to inquire as to whether there was any real science here, and when they did contact paleontologists, they presented it as another "side" in a debate, rather than the debunking of junk Science.

Regular readers have already seen that sources like Scientific American can get even basic anatomical facts wrong, but this goes well beyond an incorrect fact in an otherwise solid story; it's misleading through and through. In a follow up article the Telegraph directly compares the aquatic dinosaur nonsense with actual research, in the process repeatedly mutilating the concept of a scientific theory.

This stuff really matters. We live in a world where huge swaths of people don't understand basic scientific concepts, and this sort of nonsense just makes it harder to teach. Worse, listeners that were sympathetic to the reporting will become disillusioned when they find out the reality of the situation, possibly making them view all science more cynically (or simply avoiding science altogether).

We deserve better science reporting than this. The BBC and everyone else who carried this story should be ashamed. Perhaps the best way to sum this up is in grand internet fashion:

Carnotaurus - delving into self-parody?

This is Carnotaurus sastrei, a theropod that seems to be little more than a mouth with a set of legs to carry it around. Carnotaurus belongs to an aberrant group of theropods called abelisaurs, which dominated much of the southern hemisphere during the Cretaceous. While all abelisaurs appear odd to our tetanuran-biased eyes, it seems like Carnotaurus is striving for weirdness as a means to its own end; as if it were making some sort of meta-commentary on abelisaur diversity.

I should take a moment to make a public service announcement: I apologize for my absence from blogging and other social media that last several weeks - I've been producing more than a few new skeletals (on a schedule), so time has become a scarce resource. On the upshot, several of the new skeletals address blog-worthy topics, so I'm going to produce some shorter posts that examine them.

One of the questions raised in the comments of a previous post involved the hyoid bones - the bones that support several muscles, including in dinosaurs the tongue musculature. Being long, slender bones that don't directly articulate to other bones, hyoids are often not found (and other times are probably not collected or m-identified). Even when they are found, their lack of a direct connection to other bones makes restoring them problematic. In Carnotaurus this wasn't a problem, as they were found in direct association with the underside of the mandible, apparently in their life position. The fact that extensive skin impressions were found with Carnotaurus reinforces the likelihood that the soft tissue holding the hyoid in place had not been disturbed.

In the skeletal above you can see part of the hyoid sticking out from under the bottom-rear part of the jaw. Part of the hyoid is obscured, but there's not much I can do about that. Having the hyoid is actually pretty useful - the trachea and esophagus have to pass through it (or above it), so having a properly positioned hyoid constrains the throat tissue. 

Carnotaurus is also striking due to its advanced arm reduction - in side view the arms almost disappear, as they don't even extend past the stomach. What on Earth could such arms be used for? Hold on to that thought, as I'm not ready to go public with my thoughts on that just yet. But it sure reinforces the "legs carrying a head" image.

Finally, for those of you paleo-artists out there considering Carnotaurus as your next paleo-subject, I wanted to point out something not obvious in side view: Carnotaurus is really flat on top. The transverse processes on the tail actually stick up in a V-shape that reaches just about to the level of the neural spine. Persons & Currie recently described how this impacts the tail muscles (TL;DR version is the tail is very wide at the base, and quite flat on top).

From Person's & Currie

The back and neck also have osteological structures that raise up to, or above the level of the neural spine. So most of the animal should be restored as having a remarkably flat top. Given how narrow the head is, this must have produced a really strange life appearance. 

A final note on the skeletal itself: while Carnotaurus is a wonderfully complete specimen, the lower legs and much of the tail is missing, so those elements were restored after its close cousin Aucasaurus.

The evolution of (my) Acrocanthosaurus

WithSpinosaurus temporarily out of the way, we're going to take a closer look at Acrocanthosaurus. This series is going to include a post on what we know and don't know about Acrocanthosaurus, how to restore the skeletal in multiple views, and how to restore the muscles. At the end of that series I'll also comment on some areas of soft-tissue variation that artists should keep in mind when they envision "their" Acrocanthosaurus.

First though, I wanted to take a moment to look at how my own reconstruction of Acrocanthosaurus has changed over the last decade. With any luck some of my earlier errors in methodology might help others who want to do skeletals. Also I hope to provide some insight to how I update skeletals over time, and the importance of revising your work as new data is published.

Although Acrocanthosaurus is hardly the best known theropod, it provides more than its share of challenges when attempting to reconstruct it. In my case, I attempted the original skeletals during what I'd call a methodological nexus - it was one of the first skeletals I attempted within an entirely digital environment, and to some degree the initial reconstruction suffered as a result. I had developed many techniques when I executed skeletals in pen and ink, and most of those translated fairly well during the years (roughly 2000-2004) when I used a hybrid method of digital and ink work. Alas, attempting to work entirely inside a computer forced me to rediscover how to accomplish the same things inside of Photoshop, and as a result the first couple of attempts were actually a step backward in some ways. Luckily I stuck with it, and the results are now far better then anything I accomplished in the "analog" world.

In the beginning...

Acrocanthosaurus itself is not a new dinosaur. It was described in 1950, and it was noted at the time that the specimen was a carnosaur with enlarged neural spines on the back. What really brought Acrocanthosaurus to my attention, however, was the reconstruction of NCSM 14345, the "Fran" specimen, which was prepared, molded, and mounted by Black Hills in the 1990s. One of those specimens became part of a travelling display that I contributed to, and I was inspired by the fully restored mount, as well as my ability to take lots of photographs of the mount.

Alas, that was in the "olden days" when cameras captured light on sheets impregnated with silver nitrate rather than CCDs, and I never did scan in those photos. I still had them in 2003, but they appear to be one of many casualties of moving around frequently.

I was also attending the University of Wyoming, and their Geology library had supplied valuable gifts: descriptions of Acrocanthosaurus specimens by Jerry Harris (1998), and Currie & Carpenter (2000). Armed with proto-pdfs (read: xeroxed copies), lots of photos, and an abundance of enthusiasm I sat down to create my first all-digital skeletal reconstruction.

The tomb of the unknown skeletal...

Directly above, what you don't see is my first Acrocanthosaurus skeletal. I'm not being shy, I just didn't back up the original very carefully, and eventually the hard drive it was on suffered a systemic failure. Cloud storage was a pie-in-the-sky dream at the time, so I've lost several "original" skeletal files during the course of computer failures over the years. Luckily I've been anal retentive enough to keep current versions of skeletal files on multiple hard drives, so I haven't totally lost a reconstruction (at least, not a digital one).

What I can say is that in many ways my first attempt was an unmitigated failure. For starters, I didn't actually have the papers I mentioned above in their entirety. I'd read them in Laramie, but at the end of the semester I only photocopied the parts I thought I'd need (hey, it took time and money to copy texts in those days!). And of course the photocopies didn't always do justice to the original figures.

Instead I had to rely strongly on the photographs I had taken of the Fran mount. Even that was fraught with uncertainty, as I hadn't been able to take orthographic photos of the mount. Also, there were errors in the fully restored mount, but without all of the text from Currie & Carpenter I didn't always recall what was restored and what was cast from original bone. The results were predictably poor.

You don't  have to take my word for it though. I posted that first attempt to the Dinosaur Mailing List in early July of 2003. Jaimie Headden and Waylon Rowley made quick and (deservedly) pointed replies. I had missed several characteristic parts of the tail and neck vertebrae, and a bunch of other minor details had simply been missed.

What happened? For one thing I really didn't have enough data on hand. But more importantly, I was distracted by having to solve the technical problems of a new medium. Digital skeletal reconstructions have many advantages, but at the time they were lost on me as I struggled to figure out how to simply do the things I'd taken for granted in the "analog world".

The Acro strikes back

With a bit of work, I quickly produced the skeletal above, which addressed some of the basics. It wasn't a horrible attempt - it accurately captures almost all of the proportions, and many of the changes since have been either due to newer research getting published, or on changing interpretations in soft tissue reconstruction.

One thing mistake in this earlier version is that the neural spines were too tall - I had based their height on the mount of the Fran specimen, but it turned out that neural spines were not complete in that specimen (at least not the ones in the back, sacrum, or the front part of the tail). A review of other specimens ruled out such a grandiose neural spine height, and that also has implications for paleoartists wondering how to illustrate the back.

Two important papers were published on Acrocanthosaurus after that early skeletal. One was on the forearm, which showed that the arm couldn't actually reach as far forward as I'd illustrated it (and also clarified details of the size and shape of all the elements). Another paper was published in the last year that updated our understanding of the skull of Acrocanthosaurus. When I was asked if I could supply the skeletal to an upcoming book, it was clear that I had to revamp the skeletal before sending it along...

Back to the future

Which brings us back to my current skeletal. In addition to the new skull and arm data, the newfangled Acrocanthosaur naturally sports my new skeletal pose. So how crazy different is it? In some ways it's pretty similar - the overall dimensions really didn't change, and that's a good thing. A bunch of more subtle soft-tissue changes took place (at least some of which will get to star in their own post in the future), but a couple of obvious ones involve the tail and the neck.

The tail in the newer one has a heavier base, reflecting the research by Persons and Currie on tyrannosaur tails that I wrote about last year. The tail also is a bit less bouncy. The current skeletal is moving at a more sedate pace, and its tail is no longer bouncing along like a dropped garden hose. The neural spines on the tail have also been updated, with the spines on the front of the tail (near the hips) shorter to reflect other specimens, and the ones in the middle a bit taller, again based on other specimens.

Looking at the neck, the silhouette is no longer shrink-wrapped as tightly to the skeleton. I will probably address the "why" part of that in a later post, but suffice it to say that the newer Acro would have an easier time wolfing down large pieces of meat it tore off a carcass.

A final set of changes were made in the pectoral girdle (the shoulder region). I added a furcula which, while not found in Acrocanthosaurus, now appear to be a primitive feature found in all theropods. Additionally, I used to illustrate a large cartilaginous presternum that split the coracoids apart (you can see it poking out the bottom and front of the chest area on the older skeletal).

Reflecting the articulated chest regions of other non-maniraptoran theropods, I changed it to a smaller presternum, that would have ended sooner and allowed the coracoids to almost contact one another along the midline. This slightly changes the outline in side view, but in front or top view has the effect of narrowing the front of the torso across the shoulders.  Now if only someone would produce multiple-angle skeletals of Acrocanthosaurus to show this off...