Know Your Ankylosaurs: China Edition

I'm in Utah digging up dinosaurs! But also, one of the last big chunks of my PhD thesis has just been published online at the Journal ofSystematic Palaeontology. They are generously allowing free access to the paper through the end of August, so head on over and grab a copy while it's free! This time, I'm taking all of the knowledge gained from my previous taxonomic revisions, adding in some more taxa, and doing a revised phylogenetic analysis building on previous analyses to see how everyone shakes out and to learn a little bit more about ankylosaurid biogeography. I'll cover some of the taxonomic stuff over the next few posts, and finish off with the big picture of ankylosaurid evolution.

Pinacosaurus!

I've talked previously about the ankylosaurs of Mongolia, but I've also had the opportunity to study some of their friends from across the border in China. In particular, I got to see lots of specimens of Pinacosaurus, both from the Alag Teeg bonebed in Mongolia, and from Bayan Mandahu in China. Because Pinacosaurus specimens are relatively abundant and usually well preserved, there has already been lots of descriptive work on this taxon, including on the skull (and here, and here), hands and feet, and general postcrania. 

Baby Pinacosaurus are so teeny tiny! This one is from Bayan Mandahu and was collected during the Canada-China Dinosaur Project back in the 1980s.

I've discussed just a few new points about Pinacosaurus, especially about how we tell the two species of Pinacosaurus apart. Pinacosaurus grangeri is known from lots of specimens, almost all of which are juveniles; it has relatively short horns at the back of its skull, a constriction in the snout between its nose and its eyes, and a notch in the rough ornamentation above each nostril. Pinacosaurus mephistocephalus is known from just one specimen (also a juvenile), and it has long squamosal horns, no constriction in its snout, and no notch in the ornamentation above each nostril (it looks like it does on one side, but I think this is just damage given that it is not present on the other side). Both species are known from Bayan Mandahu, and so it is reasonable to ask whether or not these could represent the same taxon – given the differences in skull morphology, I suspect we're not looking at intraspecific variation here, although more specimens of P. mephistocephalus would be very helpful in this regard!

Crichtonsaurus becomes Crichtonpelta

Crichtonsaurus is another cool ankylosaur that has received surprisingly little attention given its Jurassic Park affinities. Two species have been named: Crichtonsaurus bohlini (the type species), and Crichtonsaurusbenxiensis. Crichtonsaurus bohlini is, unfortunately, a very incomplete jaw that does not bear any diagnostic features, and so we argue that Crichtonsaurus should be considered a nomen dubium. Crichtonsaurus benxiensis, on the other hand, is a great specimen with a really good skull and a fair bit of the postcrania, and the skull has some unique features that make it easy to distinguish from other taxa, most specifically the upturned quadratojugal horns. We've proposed the new name Crichtonpelta benxiensis for this material – Crichtonsaurus was a good name and we wanted to keep the replacement name similar, so now we have Crichton's shield instead of Crichton's lizard.

During the Flugsaurier symposium in 2010, while I was visiting Beijing and the IVPP, we took a field trip out to Liaoning and visited the Sihetun Fossil Site. It has a cool museum, including a mounted Crichtonpelta skeleton! I don't think this specimen has been described, but it does corroborate certain aspects of the holotype skull. Crichtonpelta seems to lack discrete caputegulae (tile-like ornamentation) on its skull, which gives it a similar appearance to Pinacosaurus. I don't think the osteoderms have been placed quite correctly on this skeletal mount – I think they've been tipped on their sides so that the keel forms part of the 'base', giving it a somewhat stegosaur-like appearance.

Liaoningosaurus and Chuanqilong

I'm going to talk more about Liaoningosaurus in a few months, but it is one cool little ankylosaur! At only about 30 cm long, the holotype is one of the smallest known ankylosaur specimens and probably represents a very young individual. There may be a few osteoderms in the cervical/scapular region, but that's about it. I've previously argued that the putative plastron in this specimen is more likely skin impressions, which is still pretty cool because we don't have a lot of belly skin for ankylosaurs. 

Liaoningosaurus! YAY!

I also wanted to give a shout out to here to Chuanqilong, a larger ankylosaur from Liaoning that was described last summer and which didn't make it into my thesis but which I did include in the revised phylogenetic analysis in the final paper.

Here's Chuanqilong, from Han et al. (2014).

Dongyangopelta, Taohelong, and Sauroplites

Let's finish off this post today with a triad of interesting but enigmatic ankylosaurs. Dongyangopelta and Taohelong are relatively new entries to the world of ankylosaurs, with both taxa appearing in 2013. Neither are particularly complete, but they are interesting because both species possess chunks of fused osteoderms, which would have been found over the pelvis and which are most commonly encountered in nodosaurids and 'polacanthids/polacanthines', and are presently unknown in ankylosaurids – and indeed, Yang et al. described Taohelong as the first example of a polacanthine from Asia. Nodosaurids (including 'polacanthines' as basal taxa within this clade) have been tentatively identified from Asia previously (an interesting but fragmentary specimen from Japan may be a nodosaurid), but to find a Polacanthus-like animal in Asia is unexpected and very interesting. The two species can be differentiated based on the morphology of these pelvic shield pieces. Dongyangopelta comes from the Chaochuan Formation, and another ankylosaur, Zhejiangosaurus, had been named from that formation in 2007; it may eventually shake out that Dongyangopelta is a junior synonym of Zhejiangosaurus, but in the absence of overlapping diagnostic material we opted to keep these taxa separate for now.

Pelvic shield fragments - Dongyangopelta redrawn from Chen et al. (2013), Taohelong redrawn from Yang et al. (2013), and Sauroplites redrawn from Bohlin (1953).

Sauroplites, on the other hand, is a very old name that has been largely overlooked in recent assessments of ankylosaurs. The material was originally described by Bohlin in 1953, but sadly the whereabouts of the original material is unknown today (although there are casts at the American Museum of Natural History). I think Sauroplites was overlooked for a while because it's based off of osteoderms alone, and it's hard to assess diagnostic characters in osteoderms sometimes because they vary so much along the body. This is partly why I like cervical half rings and pelvic shields – in these structures, you can understand the positions of the osteoderms on the body and directly compare patterns and morphologies across different taxa. Supposedly, the osteoderms for Sauroplites were preserved in their original positions when the specimen was excavated, and if so, it's a bit surprising that more of the skeleton was not preserved. Bohlin correctly identified some of these pieces as elements of the sacral armour, and the morphology of these pieces can be used to differentiate Sauroplites from Taohelong and Dongyangopelta, and we consider Sauroplites to be a valid, but poorly known, taxon. It's good to revisit poorly figured and fragmentary taxa from time to time, because new discoveries might help put those pieces in context.

Next time: we head south! See you then!


Arbour VM, Currie PJ. In press. Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs. Journal of Systematic Palaeontology.

Why does Jurassic World hate dinosaurs?

I have some Thoughts and Feelings about Jurassic World! Spoiler alert, I'm going to talk about details and plot points and this post is really for people who have seen the film. Also, while I'm going to talk about the dinosaurs a bit, this isn't really a review of the science of the film, because that's already been done to death. Ok, onwards and upwards into something that wound up being way too long!

Does Jurassic World hate dinosaurs?

I think the answer to that question is yes. Jurassic World keeps making these little homages and throwbacks to the earlier films (there are lots of shots that echo iconic moments in the earlier films, and some of the plot points mirror the original film almost exactly), and yet I feel like we could consider the theme of Jurassic World to be about rejecting nostalgia and childhood. It's buried under an interesting discussion of the role of the military in funding scientific research, and why some kinds of research are prioritized over others, and it may actually be unintentional, but it's the theme I took away most immediately from this film.

There are two characters that I think are supposed to represent the audience, and neither are treated particularly well by the other characters. And by 'the audience', I'm going to be really self-centered and say that I mean the 30-somethings like myself who saw the original film when we were in that 8-12 year old bracket, or 'peak Jurassic Park' age, and who this film is clearly pandering to. Firstly, we have Gray Mitchell, a 10-ish year old who represents us when we first saw Jurassic Park: he's a dinosaur geek and is one of the only characters to show unrelenting enthusiasm for dinosaurs while visiting Jurassic World. Secondly, we have Lowery, the 30-something computer room dude, who wears an original Jurassic Park shirt and has dinosaur toys on his desk and is obviously super into the dinosaurs in the dinosaur theme park. He is us, now, grown up and nostalgic for the original film. Multiple times throughout the film, Gray's older brother tells him he needs to grow up, and points out that many of the things are for little kids. Claire makes fun of Lowery's shirt, and I think in general we're supposed to think he's kind of a weird man-child who hasn't really grown up.

There's a moment in the film where Gray and his brother Zach stumble upon the old Jurassic Park visitor center building. The T. rex cast skeleton lies on the ground covered in vegetation, and a little piece of the "When Dinosaurs Ruled the Earth" banner is visible. Zach uses it to make a torch so they can investigate the rest of the suspiciously-well-lit ruins. Visiting the old building felt like some gratuitous fan-service to me, but then burning the banner felt like a purposeful statement about rejecting the nostalgia of the original film.

Jurassic World is constantly setting up little nostalgic moments and then seemingly stomping all over them. It's like the filmmakers wanted to pay tribute to Jurassic Park but then were embarassed to show that they liked it – or maybe they didn't really like that movie at all, but wanted to make lots of money (success!). I don't know, but I find it thematically problematic and a bit sad, since the excitement over DINOSAURS! in the first movie is one of the defining aspects of that film, and that sense of wonder and grandeur has rarely been replicated. Jurassic World feels jaded, and like it's too cool for dinosaurs.

Can we talk about ladies in this movie for a moment?

Did we really need to introduce our main female character with the camera sweeping up her legs to her face? Was that absolutely necessary? Also, could we just not use the 'frigid, uptight workaholic woman needs to learn to loosen up and become sexually free with a man, and also needs to remember that all women will have children eventually' stereotype? COULD WE JUST NOT?

It's an intriguing throwback to the original Jurassic Park movie, which I feel successfully used the kids as a character development point for Alan Grant. But Sam Neill managed to portray Grant's discomfort with kids in a more organic way, and the movie gave that plotline a bit of breathing room to develop during some of its quieter moments AND its action sequences (see: sitting in the tree feeding Brachiosaurus; escaping the falling car in the tree; the fence). It's less believable with Claire Dearing, because she doesn't even spend any time with the kids in peril until almost the very end of the movie, at which point she basically worried herself into liking kids? Or something?

Look, not every movie is going to have (or should have) a Strong Female Character(TM), because there are lots of ways to be a lady just like there are lots of ways to be a dude. But the first two Jurassic Park movies had some cool female characters: Ellie Sattler, a palaeobotanist, who was brave and curious and smart! Lex Murphy, who knew those UNIX systems! Sarah Harding, who was a bit foolish but was also brave and curious! Kelly Curtis Malcolm, who gymnastic-ed a Velociraptor to death! In Jurassic World, we get a woman who has great power and authority (she runs a theme park full of dinosaurs!) being told she should be different at almost every opportunity, and we get a distracted babysitter who is killed in the most gratuitous, drawn-out sequence of all. Thanks, movie.

Ok, now let's actually talk about dinosaurs (and other prehistoric creatures) in Jurassic World.

Other palaeontologists have already beaten me to much of this, but I still had a few thoughts I wanted to share. Ultimately I don't have a big problem with the 'retro' dinosaurs of 1993 appearing in this film, because I'm willing to go with the flow in terms of continuity. But there were some pretty dumb things in this film:

· The pterosaur sequence was pretty godawful and brought the action to a screeching halt. I can't suspend disbelief that the pterosaurs would immediately rampage and murder a bunch of people, and I can't suspend disbelief over the physics of that sequence. Refrigerating that babysitter lady was also pretty awful. Sweet jeepers, Jurassic World, you're going to make me say something horrible: this sequence was better in Jurassic Park III. THERE. I hope you're happy.

·  I never really bought Indominus rex as anything more than a really big Allosaurus or Saurophaganax. (Sorry, theropod people! Allosaurus is cool, but not, like, THAT cool.) I did, however, like the incorporation of the camouflage idea from the Carnotaurus in the Lost World book, something that I had missed from the film adaptation. Overall, I'm frustrated that Indominus exists mostly so they had a dinosaur they could trademark. Because that's totally what that is, and everything else is secondary to that, including its incorporation into the plot.

· That mosasaur is just so gigantic. I'm on board, but that was starting to stretch credulity as well.

·  Why doesn't Rexy eat Blue after the fight? The mind boggles.

Ok, things I liked!

·  The Ankylosaurus gives Indominus the old what-for and doesn't immediately die like everything else! Indominus needs to really work at murdering that poor fellow. The design of the Ankylosaurus themselves is pretty terrible (wrong osteoderms, tail too curly, nostrils in the wrong spot, head generally a bit off), although I think it's meant to be consistent with Jurassic Park III.

Here's what Ankylosaurus REALLY looks like!

Now that I can show my work for #Dinohunt, here's a look at Ankylosaurus magniventris for @VictoriaArbour 's b-day! pic.twitter.com/oivQbyOe5z

— Danielle Dufault (@MesozoicMuse) December 16, 2014

·  Dinosaur petting zoo! It should be for all ages!

· The big kaiju battle between Indominus and Tyrannosaurus was pretty well matched. I liked the little kick to JPIII when the Tyrannosaurus busts through the Spinosaurus skeleton on the way to the fight.

·  "Are they safe?" "Oh no, under no circumstances, not even a little."

Some final Thoughts and Feelings

I haven't decided yet if I liked Jurassic World. I can't help but think back to the original Jurassic Park with its iconic visual moments and charming, if hokey, dialogue. While it was fun to see an operational Jurassic Park with rides and attractions, I don't feel like Jurassic World had much visual flair. It's really hard to beat dramatic, symbolic visuals like this:

Interesting camera angles like this:

Or quiet moments of terror like this:

And I miss the yellow and green and red colour palette of the original park, replaced here with chrome and blue and silver like every other washed out movie in theatres lately. It is also interesting that all of the big sweeping themes from the original soundtrack are used not for the dinosaurs, but for the manmade structures of the park itself. It really does feel like Jurassic World doesn't care about dinosaurs.

Spared no expense.

Well, this weekend marked a major milestone for me: I saw Jurassic Park on the big screen for the very first time! Although I have watched it countless times, first on VHS and then on DVD, Victoria in 1993 was only 9 years old, squeamish, and easily scared by, well, scary stuff, and thus too small to see Jurassic Park during its initial theatrical release. 

The film was being shown as part of Alberta Innovates - Health Solutions film series called Science in the Cinema. They feature films with a biomedical slant, and ask health science and biomedical researchers to do a Q & A after the film. In Edmonton, the movies are shown at a cool old theatre called the Garneau Theatre, and admission is free (with free popcorn, too!).

For Jurassic Park, they also asked if some students from my lab could come out to talk about dinosaurs, and so Scott and I brought along some fossils to show off before and after the movie. We are lucky to have casts of many of the dinosaurs featured in Jurassic Park, so we brought along casts of Gallimimus, Tyrannosaurus, and of course, Velociraptor. We also brought along some sturdy, real, touchable Edmontosaurus fossils from a bonebed in Edmonton, which were also a big hit.

There were a lot of good questions about both the genetics and palaeontology sides of Jurassic Park, and apparently there were about 450 people in the audience. It was fun to see good ol' Jurassic Park with an enthusiastic crowd of people who obviously knew the film well, and lots of younger kids who were seeing it for the first time. It has held up surprisingly well, and I maintain that the computer animation in Jurassic Park, which was the first time that realistic living creatures were created using that technique, is still some of the best computer animation ever. Yes, there are some inaccuracies, and yes, the theropods should be feathered, but overall for a film that is now 19 years old, it's not too shabby. ("Cool, it's an interactive CD-ROM!" and "It's a UNIX system! I KNOW this!" both got some pretty big laughs.)

Junk in the Trunk Redux

Today I've got another interview from Scott Persons! Scott's going to tell us all about his new paper on the tail of Carnotaurus, which follows his paper on the tail of Tyrannosaurus published last year. Enjoy!


[Persons WS, Currie PJ. 2011. Dinosaur speed demon: the caudal musculature of Carnotaurus sastrei and implications for the evolution of South American abelisaurids. PLoS ONE 6(10): e25763.]

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1. What inspired you to conduct this study?


This was a case where no inspiration was required, just thoroughness . . . and a pinch of luck. My work on Carnotaurus was part of my Master’s thesis, which looked at the tail morphology of a wide range of carnivorous dinosaurs. Carnotaurus, a member of the unusual abelisaurid group, was on my list of potential dinosaurs to examine. The first Carnotaurus material that I saw was a cast at the Natural History Museum of Los Angeles County. Examining the L.A. Carnotaurus cast fit in nicely with my schedule, but I was in California primarily to measure the tail of a Dilophosaurus skeleton at Berkley.

Fortunately, it only takes one look at a Carnotaurus tail vertebra to realize that something dramatically weird is going on with the animal’s tail.  On a “normal” theropod tail vertebra (or, for that matter, a “normal” anything-else tail vertebra), boney projections, called the caudal ribs, stick out horizontally and have a simple rod-like shape. In Carnotaurus, the caudal ribs of the basal tail vertebrae project more vertically than horizontally, and their shape is complex – with tips that are thin and shaped like half-crescents. After examining the specimen in California, I realized how interesting a Carnotaurus tail study would be, and it became a major focus of my research (which meant Dilophosaurus and several other theropods had to take a backseat).

The 6^th tail vertebra of Carnotaurus, as seen from the side (upper left), the front (upper right), and from above (lower center).

2. Why “speed demon”?

The title of the Carnotaurus tail paper (published in the online scientific journal PLoS ONE) is "Dinosaur Speed Demon". It is an unusual title. Supernatural fiends (fast or otherwise) and peer-reviewed natural history literature don't usually mix. But the explanation is straightforward:

Carnotaurus is famous for its ugly mug and two large conical horns that stick out from its forehead in an indisputably devilish style (hence “Demon”).  As for “Speed”, the conclusion that I and Dr. Phil Currie came to was that the vertically oriented caudal ribs and their bizarre half-crescent-shaped tips (which interlocked with those adjacent in the vertebral series) provided an expanded and ridged framework for one super-sized tail muscle: the caudofemoralis. The caudofemoralis is a locomotive muscle that attaches to the femur and lends considerable force to the power strokes of the legs. Except for some birds, all dinosaurs had caudofemoral muscles (that’s a major reason why dinosaurs have big tails), but I estimate that, relative to its body-size, Carnotaurus had the biggest.

A new Carnotaurus illustration created for the paper by artists Lida Xing and Yi Liu.

Big locomotive muscles mean more locomotive power, which means Carnotaurus was adapted for speed.  Some puns are too good to pass up.


3. So...could Carnotaurus outrun the Jeep in Jurassic Park?

Estimating the maximum running speed of a dinosaur or any other extinct animal is hard. (So hard that in the published paper, I stick to offering a qualitative rather than a quantitative assessment of Carnotaurus running performance.) There are lots of important variables besides absolute muscle mass that determine how fast an animal can run.

As I said in my previous blog post, just keeping pace with the JP Jeep would require a speed of 30-40 mph (48-64 kph) (remember, the black-leather-clad rump of a certain chaotician was preventing the driver from switching into high gear).  So, achieving Jeep-catching speed would mean a charging Carnotaurus was roughly 30% faster than a charging black rhinoceros – a scary thought, but not an implausible one. If I had to guess, I would say: Yes, Carnotaurus was fast enough to outrun the Jeep. Just the same, I don’t think Carnotaurus would have caught it. Here’s why:

The tree branch doesn’t move, and the T. rex doesn’t appear to see it.

Jurassic Park fans will recall that in the chase scene, just as the T. rex is getting close enough for Jeff Goldbloom to feel its hot breath, the Jeep drives under a low tree branch. Being the colossus that it is, the Tyrannosaurus just smashes through the branch and stays on course. At roughly one third T. rex’s size, Carnotaurus probably couldn’t do that. Instead, the abelisaurid would have had to avoid the collision. While my study indicates that Carnotaurus was evolutionarily engineered for speed, it also indicates that this speed came at the cost of turning performance.

The rigid framework provided by the interlocking caudal ribs would have limited sinuous motions, which would have disadvantageously increased the animal’s effective rotational inertia. When turning, Carnotaurus would have been forced to awkwardly swing its hips and the front half of its tail all at once, like a single stiff board. The set of a tropical Hawaiian forest just isn’t the ideal hunting ground for Carnotaurus, and I think having to swerve around the foliage would have slowed Carnotaurus down considerably.


4. Does this tell us anything about the evolution of abelisaurids?

Yes, but exactly what it tells us is a matter of debate.

Abelisaurids are known from Africa, India, Madagascar, and South America. Carnotaurus is from South America. If you look at the tails of older South American abelisaurids, you will see what I think is a clear evolutionary sequence of adaptations in the vertebrae that leads to the advanced form of Carnotaurus. I would argue this shows that, over time, South American abelisaurids were getting faster. I would also argue this strongly suggests that Carnotaurus is more closely related to other abelisaurids from South America than it is to abelisaurids from Africa, India, or Madagascar (all of which lack special tail-vertebrae adaptations). The argument is important, and a matter of contention, because it has been previously asserted (by paleontologists much more experienced than myself) that Carnotaurus is most closely related to abelisaurids from outside South America.

The evolution of South American abelisaurid tail vertebrae through time (each vertebra is depicted in frontal and top-down views, numbers are millions of years from now).

 

5. Carnotaurus may not be as famous as Tyrannosaurus, but it has popped up occasionally in film and TV. What are your favorite portrayals of Carnotaurus?

Yeah, Carnotaurus has had its chance in the spotlight, probably because its striking facial profile makes it a natural fill for villainous roles. Picking my favorite portrayals is hard . . . because most have been so terrible.

In Michael Crichton’s second Jurassic Park novel, a Carnotaurus pack poses a threat to the inexplicably resurrected character of Ian Malcolm. The book gives Carnotaurus cuttlefish-like powers of camouflage, but the dinosaurs ultimately prove no match for the tactic of annoyingly waving flashlights (really, that’s what Crichton wrote).

A pair of marauding Carnotaurus played the bad guys in Disney’s Dinosaur. But these red menaces had to suffer an anatomical redesign and wound up looking more like tyrannosaurs with horns.

By giving some of the Iguanodon a nose horn, the Mickey Mouse organization set paleontology back to the days of Gideon Mantell. The big red Carnotaurus, or “Carnotaur”, wasn’t much better.

A Carnotaurus had the starring dinosaur role in the 2008 animated movie Turok: Son of Stone. This was a film that managed to be offensive at an artistic, intellectual, and social level (kind of like Transformers 2 [Victoria's note: don't get me started on Transformers 2...]), but the Carnotaurus does get some good (though ridiculously over-the-top) action scenes.

Turok and his trusty steed prepare to go all Stone Age on a gang of Neanderthal sumo wrestlers.

Most recently, Fox TV’s Terra Nova series showed us a new CGI Carnotaurus. Terra Nova’s Carnotaurus has its flaws (though, perhaps no more so than any of its other cast members), but I enjoyed seeing it in action.

 

Outside the Terra Nova compound, a Carnotaurus squares off against what I thought was a beige version of the new Batmobile.

I would have to say my favorite media portrayal of Carnotaurus is in the absurd Japanese cartoon series Dinosaur King. In the show, a Carnotaurus named Ace is the loyal companion of a young boy and helps him fight evil.

Ace and Rex take the bus (the pet dinosaur is named “Ace” and the boy is named “Rex”).

The Dinosaur King’s CGI cartoon Carnotaurus actually suffers from fewer anatomical inaccuracies than ether Disney’s or Terra Nova’s, and it’s nice to see a theropod get to play the hero for a change. From what I’ve seen, Dinosaur King is a something of a Pokemon rip-off, and all the dinosaurs get special super powers -- some of the dinos breathe fire, others cause earthquakes, etc. And what is Ace’s special power? Super speed!

Valiantly defending us from alien invaders, mad scientist, and temporal paradoxes, Ace (seen here in his grownup form) is a two-horned, purple, people protector.

Ankylosaurus through the Ages

I saw a post up at Love in the Time of Chasmosaurs today – did you know Ankylosaurus could fly? The original Sinclair World’s Fair Ankylosaurus was being lifted by crane from the Houston Museum of Natural History as the museum undergoes expansion and renovations.

This got me thinking about a talk I gave for the Alberta Palaeontological Society annual meeting last March: “My ankylosaur is a big dumb tank! Ankylosaur reconstructions in the scientific literature and popular media.” I talked about why ankylosaurs are reconstructed in certain ways, both accurate and inaccurate. Darren Naish at Tetrapod Zoology has been talking about memes in palaeontological illustration, and how certain wacky reconstructions and poses pop up again and again. I think this is perhaps especially well illustrated by several ankylosaur taxa and today I’d like to talk about Ankylosaurus.

Brown 1908. The Ankylosauridae, a new family of armored dinosaurs from the upper Cretaceous. AMNH Bulletin 24:187-201.

Oh, Ankylosaurus. The namesake of the Ankylosauria and Ankylosauridae. One of the most popular ankylosaurs. And yet Ankylosaurus is not particularly well known in terms of skeletal material – some skulls, a tail club, and miscellaneous postcranial bits. Barnum Brown’s 1908 description included the pictured reconstruction of the armour. At the time Brown did not know that Ankylosaurus had a tail club, so he reconstructed it with a more Stegosaurus-like tail. The armour is shown as pretty uniform across the body, mostly because Brown didn’t have a lot to work with and little to compare Ankylosaurus to.

Enter the World’s Fair dinosaurs by Sinclair, including Ankylosaurus. We have a replica (cast? Model? Does anyone know?) at the Royal Alberta Museum in Edmonton (along with a Sinclair Corythosaurus), which I think is pretty rad. Note the strange, pustulated tail club back there, dragging on the ground. Boo. There’s really no reason for the tail club to be portrayed as a lumpy, gross thing – the only known tail club of Ankylosaurus actually has a very smooth texture! The World’s Fair Ankylosaurus (along with the Zallinger mural at the Peabody Museum) would define how Ankylosaurus is drawn and modeled for a very long time – I have a pink Ankylosaurus eraser from an elementary school book fair that is clearly modeled on this fellow, for example.

Walking with Dinosaurs included an Ankylosaurus in the final episode, Death of a Dyanasty, back in 1999. There’s that lumpy tail club again! Again, we see the influences of Brown and the Sinclair World’s Fair Ankylosaurus. A couple of Ankylosaurus make an appearance in Jurassic Park 3 (briefly, as they float down the river after escaping the Pteranodon aviary), and holy smokes are they ever strange.

(From the delightfully thorough Dinosaur Toy Blog.)

In 2004, Ken Carpenter published a wonderful, long, detailed revision of Ankylosaurus in the Canadian Journal of Earth Sciences, and offered a new armour reconstruction. If you’ve got the Carnegie series Ankylosaurus toy, you’ll be familiar with this new interpretation – they clearly drew much of their inspiration and information from Carpenter’s new reconstruction. There are a few minor points I could quibble about, but overall it’s a good reconstruction of the armour, and a big change from the uniform spiky Ankylosaurus. And the tail club isn’t horrible!

The most recent TV Ankylosaurus I know of was in Clash of the Dinosaurs. Say what you will about the show, but I thought the ankylosaur segment was pretty good. I had the opportunity to do a bit of advising for that segment, and it was a lot of fun to work with the producers to try to get Ankylosaurus just right. They did a great job on the head, and the body is almost like a little bit of a mix between the Brown/World’s Fair Ankylosaurus and the Carpenter Ankylosaurus. And the tail club was not gross! Hooray and success!

It is a less well-known fact that Ankylosaurus looked quite dapper in a hat.

5 Questions for Scott Persons

A few weeks ago my friend and colleague Scott Persons published his first ever paper, detailing the results of the first phase of his Masters research at the University of Alberta. The paper received a fair amount of media and blog attention, but I demand attention as well, so here is a mini-interview with Scott  about the paper.

(But before we get started, you should check out Scott on Daily Planet, a very popular science variety show on Discovery Canada that I was shocked to learn is not carried by the American Discovery Channel. Tragedy!)

  

(Sadly, the frozen dissected lizard did not make the final cut for the segment.) 

1. What inspired you to conduct this study?

The inspiration to do a project on theropod tails came the summer before I began grad school in Edmonton. I was working at the Paleon Museum in Glenrock, Wyoming, and helping to put together a display case on the predatory dinosaurs of the Morrison Formation. Included in the display were two tail vertebrae. One from an Allosaurus and one from a Torvosaurus . . . and they looked really different! (For those of you interested, one major difference is the angle of the caudal ribs. In Torvosaurus the caudal ribs are strongly angled backwards, while the caudal ribs of Allosaurus are nearly perpendicular to the neural spines.) I asked the curator, Shawn Smith, about the differences, and he told me that no one really understood the functional significances. So, that got me thinking about tails, and this study was only the first part of a much larger project investigating theropod tail morphology and function.


2. What are some of your favourite Tyrannosaurus reconstructions?

That’s hard. T. rex is the most commonly depicted dinosaur, and a lot of paleo artists, from Charles Knight to James Gurney, have given us their renditions. Two of my favorites are John Gurche’s illustration of Sue and Michael Skrepnick’s “The ‘King’ prepares to defend his meal” (I’m not sure that’s the proper title). Not only do these depictions get the anatomy right (for the most part), but they succeed in conveying a visceral sense of power and menace. Recently, my favorite is Scott Hartman’s depiction of Stan, because it was created in collaboration with my study and really shows off the beefiness of the tail.

(Scott Hartman's excellent drawing can also be seen in Persons and Currie 2010 --Victoria)

3. Could Tyrannosaurus outrun the Jeep in Jurassic Park?

Well, that depends on how fast you think the Jeep was going. John Hutchinson and Stephen Gatesy have watched this cinematic sequence closely, and they concluded that the Jeep was traveling at over 40 mph (64 kph). No, I don’t think T. rex could go that fast.

But Jurassic Park was actually pretty specific about the T. rex’s intended top speed. Early in the film Richard Attenborough says to Sam Neill “Well, we’ve clocked the T. rex at 32 miles per hour.” Could a Tyrannosaurus do 32 mph (51.5 kph)? That would be about twice as fast as a modern elephant, but not much faster than a black rhinoceros (although maximum rhino speeds are hotly debated). I think it’s important to emphasize that my study only provides one of the many pieces of evidence needed to answer this question, and I think a lot of those pieces are still missing.

However, if we want to force the issue, and if I had to place a bet at the Dino Derby, I’d bet on “yes”. But (just to hedge my bet) the T. rex that I’d enter in the race would be a sub-adult. Young tyrannosaurs were lighter and had proportionately longer shins, so they were probably significantly faster than the bulkier adults.

4. How does this relate to the idea that Tyrannosaurus rex was a scavenger rather than a predator? This is an important and timely debate.

Your sarcasm is well founded. The scavenger vs. predator debate has largely been perpetuated by paleontologist Jack Horner, who is a vocal advocate for the scavenger hypothesis. But, in his book The Complete T. rex, Horner wrote “I’m not convinced T.rex was only scavenger, though I will say so sometimes just to be contrary and to get my colleagues arguing.” – p. 218. Add to this the recent discovery of hadrosaur tail vertebrae with healed tyrannosaur bite wounds, and it’s safe to say the debate over whether T. rex was purely a scavenger is basically over (if, indeed, it ever really existed).

But, if we let ourselves be provoked by this contrarian notion, the tail study’s results are relevant. If Tyrannosaurus was a scavenger, then the big theropod wouldn’t need a large M. caudofemoralis, because it doesn’t take much athleticism to catch a rotting corpse, and a slowpoke T. rex would have been poorly adapted to chase after live prey. So, if Tyrannosaurus had a small M. caudofemoralis and was incapable of rapid locomotion, this would support the scavenger hypothesis. As it turns out, T. rex had what it took to chase and catch dinosaurs like ceratopsians (the horned dinosaurs) and hadrosaurs (the duckbilled dinosaurs) while they were still alive.

[Note from Victoria: I myself have no problem with speculating on the feeding strategies of Tyrannosaurus. However, I knew that this would be what many media sources would jump on with regards to Scott's paper, even though it is not the most interesting aspect of the study, and was correct. So there.]

5. Will it blend?

As demonstrated by Dickson et al. (2007), everything blends . . . except Chuck Norris.

Lastly, Victoria, in case your readers aren’t aware, I’d like to point out how helpful and important your work on ankylosaur tails was to this study. The theropod tail project has built directly on the caudal muscle classification scheme outlined in your 2009 paper in PLoS One.

Well Scott, with that you can occupy the same office as me for the next few weeks at least, I'd say.

You can find Scott's paper online here (PDF not available just yet though, I'm afraid). Scott also did a great guest post over at Dave Hone's Archosaur Musings which is well worth a read.

And finally, Pete would like me to point out the amusing list of results if you google 'scott persons tyrannosaur'.