The lack of a scanner frustrates me

I'd be posting more, like about how I've learned a lot from Mark Witton's pterosaur page (about drawing pterosaurs correctly) and Indohyus and Julia's Cetiosaurus and how everyone knows it's Butters (That's me!), but there's not a good scanner here in Topeka. I mean, a scanner exists, but it is sub-par. And that's a shame, because I've got some kick-ass pictures to show you all.

I've got a "series" post on my mind: Adventures in Flying Vertebrates. I'd like it to cover ten animals, in six parts. And it wouldn't just be pterosaurs, birds and bats. I'll throw Sharovipteryx in there, rib-gliding lizards, flying lemurs, and various other odds and ends. What would be really awesome is if I could get some guest writers, like Anne-Marie for bats and Mark Witton for pterosaurs. Definately something to think about.

Oh, and check the blogroll. I've managed to (finally) get Mark's pterosaur page up there. The man can draw!

Name Me!!!

This ceratopsian, nicknamed the "Last Chance Ceratopsian" when it was announced in 2006 (originally found in 2002) has yet to be named. I blogged about this critter back then on the original blog, including a hastily-drawn picture that's still better than what you see at the left, which was floating around the Interweb. All of the news stories (at the time) claimed that "octoceratops" (my name, not theirs) would get a formal name and description sometime in 2007.

That leaves...five days...for Kirkland and DeBlieux to put something in print. Jim Kirkland was actually good enough to send me a great picture of this new ceratopsian, but alas, it is in a format unrecognized by both eBlogger and most file converting sites. I also wouldn't want to distribute the picture without his permission. At any rate, it's an awesome ceratopsian. I'll email the picture to anyone who wants it.

Click here for the most in-depth information yet written about this taxon to date. It is a basal centrosaurine and probably sits right next to Albertaceratops, what with its long brow horns and very small nasal horn(s).

Postscript: I just realized that I can't send that picture to anybody because, alas, it was on my Gmail account, which was arbitrarily deleted by Google earlier this year. *sigh*

Post-postscript: To the describers of "octoceratops:" Please do not name it "Utahceratops."

This is Unacceptable

That's a pretty cool looking oviraptorosaur, right? That's Hagryphus giganteus, an animal first published in 2005 in JVP, and restored above, by the good Michael Skrepnick. That's the picture that accompanied a minor flood of news items at the time, anyway. It looks a bit like Citipati, with emphasis on the head, hands, and tail. In fact, I'd hazard to guess that really is Citipati. Sadly though, Hagryphus is a far different animal. How different? Well, aside from size, it's hard to say. Why?


Because this hand, and some scraps from the foot, are all that paleontologists have of Hagryphus. Now, by itself, Hagryphus is a very interesting beastie. It is from Utah, and it's 30-40% larger than the largest specimen of Chirostenotes. The range of oviraptorosaurs doubled in North America with Hagryphus' discovery. The bones of the hand are also proportionately thicker and larger, which isn't surprising given the probable larger size of Hagryphus.

Remember a few posts back when I was rambling about how I can't stand it when paleoartists restore animals known from scrappy remains (Masiakosaurus)? This incident may be the worst case I've ever seen. You cannot generalize an oviraptorosaur. Citipati is actually a fairly unique genus, and it may be what we used to call Oviraptor! Here are just a few reasons why Mr. Skrepnick's beautiful picture may not be attributable to Hagryphus:

1) Not all oviraptorosaurs had crests. In fact, only a few Asian taxa did.
2) There are significant proportional differences between Asian (Oviraptoridae) and North American (Caegnathidae) oviraptorosaurs. Citipati is a good representative of the former, but Caegnathus or Chirostenotes are more typical of the latter.
3) Based on their horrible record of preservation, caegnathids are difficult to restore with good confidence. Citipati is known from excellent remains (even embryos!). Chirostenotes...not so much.

So I truly question assigning Mr. Skrepnick's Citipati to Hagryphus, given its extemely fragmentary remains. I think it's a tough call whether to put a crest on Gigantoraptor or not (as the skull was not found). How should I illustrate an animal based solely on a hand and bits of the foot? I shouldn't, and here's why.

The public takes dinosaurs in visually, as do we all. You can spout out a bunch of words Joe Shmo won't understand as to why this new dinosaur is awesome, but you know what they say: a picture is worth a thousand words. That's why Sereno's Nigersaurus press release was accompanied by a beautiful picture. But Sereno has a complete skull and like 95% of the skeleton. For Nigersaurus, the lack of a good illustration would be idiotic. At least for me, if I cannot draw an animal, I don't know what it looks like. At least give me a skeletal restoration! That's what I'm going to base my drawings off of anyway! In this case, the worst offenders are Coria & Currie, who handily forgot to include kind of skeletal restoration in their 40-odd-page description of Mapusaurus roseae, even though virtually every bone was accounted for.

However, giving the public a picture of a complete animal that's known only from scraps is insulting, and it skews the public perception of the paleontology and science behind a discovery. I don't think that Hagryphus really deserved a press release, honestly, because aside from extending the known range of North American oviraptorosaurs, it's not that exciting. But in an age where press release = publicity = funding, I'm sorry to say that every minor find has to be treated like it's the next Microraptor gui.

I'd appreciate it if my readers chimed in on this issue. Do you think that even fragmentary finds warrent a complete illustration? Does doing so injure or help public perception of paleontology? Am I totally missing the boat on Hagryphus' significance? Let me know!

Clark, J. M., Norell, M. A. & Rowe, T. (2002). Cranial anatomy of Citipati osmolskae (Theropoda, Oviraptorosauria), and a reinterpretation of of the holotype of Oviraptor philoceratops. American Museum Novitates 3364.

Coria, R. A. & Currie, P. J. (2006). A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina. Geodiversitas 28(1): 71-118.

Zanno, L. E. & Sampson, S. D. (2005). A new oviraptorosaur (Theropoda, Maniraptora) from the Late Cretaceous (Campanian) of Utah. JVP 25(4): 897-904.

Pakicetus' Vegetarian Ancestry

Well, it turns out that pakicetids, known to you and I as the earliest known whale ancestors, had vegetarian ancestors of their own. This week's Nature has an article about Indohyus, a new deer-like terrestrial whale from India. The creature can be identified as a whale based on the structure of its middle ear. Surprisingly, it is herbivorous. Pakicetus, Ambulocetus, and all the other whales are carnivorous, so one would expect that whales came from a carnivorous ancestor. Such, it seems, is not the case.

More surprisingly, this is the first time in MY experience that an herbivorous animal has gone back to being carnivorous. The evolution of herbivory requires several changes in the body, including the gut, dentition, behavior, and metabolism. To go BACK to carnivory seems like a waste of all that effort. Indohyus supposedly fed on water-based vegetation. Why did whales so quickly turn to meat? Are there not enough plants underwater?

And then, of course, there's some exciting marsupial news: It turns out that kangaroos didn't always hop. Early versions galloped. Nambaroo gillespieae is a virtually complete early kangaroo that ran on all fours, may have had an arboreal streak, and had "fangs." Despite the fearsome dentition, Nambaroo was still a vegetarian at heart.

Indohyus is in this week's Nature, and Nambaroo is in the Journal of Paleontology. If any of you out there in Readerland have access to these journals, I would greatly appreciate the PDF.

Dracorex = Pachycephalosaurus? My Two Cents

Although I still haven't read the Science article about this, Brian was kind enough to give us a brief summary of a controversy surrounding pachycephalosaurs at this year's SVP conference. Jack Horner has proposed that Bob Bakker's recent flat-headed Dracorex is really a juvenile Pachycephalosaurus, and that yet another taxon, Stygimoloch, is a "teenage" thick-headed lizard. We all know that I'm not Horner's biggest fan, but this idea does have some merit. I am all for investigating ontogenic and gender differences between dinosaurs, because I think that it's just not done enough. Cope & Marsh were famous for giving every animal that came out of the ground a different name, and that mindset is not entirely different today. We are certainly more aware that sexual and ontogenic dimorphism occurred in extinct taxa, but it's not always obvious, and it's much easier (and, I assume, satisfying) to name a new species.

This happy little bonehead is Dracorex hogwartsi, a Late Cretaceous pachycephalosaur that is contemporaneous with Pachycephalosaurus, both locally and temporally. While the original fossil was crushed dorsoventrally, Bob Bakker provided a wonderful restoration in the description. Notice the two distinct "bands" of small horns on the snout, the decorated jugal, and the large horn rosettes erupting from the squamosals. Most importantly, though, check out those supratemporal fenestrae--they're unique among known pachycephalosaurs, which seem to have closed their supratemporals in favor of developing thickened bony domes.

This is the beautifully-preserved skull of an adult Pachycephalosaurus. It is a wonderful skull, and when it was discovered, it was the only other complete skull known from a pachycephalosaur, the other being Stegoceras (who still holds the record for "best known postcranial skeleton among boneheads"). Pachycephalosaurus also has a double-band of small horns on the snout (though they are compressed because of the large dome) and a decorated jugal. The large squamosal horns of Dracorex are not seen in Pachycephalosaurus, although the latter certainly has squamosal horns--they just aren't as prominant. Finally, of course, the supratemporal fenestrae have been completely closed off, and a huge 8-inch-thick dome has overtaken the top of the skull.

This is Stygimoloch, a genus known only from extremely fragmentary remains. All of the named specimens are pieces of dome with some squamosal thrown in. The genus is diagnosed by its three or four large squamosal horns, which resemble those of Dracorex. Despite its rarity, however, Stygimoloch most certainly had a dome. In his 2006 treatment of the Pachycephalosauridae, Robert Sullivan suggest that, based on squamosal morphology, Dracorex, Sygimoloch, and Pachyrhinosaurus form a natural group (the Pachycephalosaurini).

Now, the question is this: Can all three taxa be folded into Pachycephalosaurus based on ontogeny? That's a difficult question, especially given the extremely fragmentary remains of Stygimoloch. Ignoring that thorny devil for now, though, let's focus on the dragon king and the thick-headed lizard.

If Pachycephalosaurus is an adult Dracorex, then we must account for the differing squamosal morphology. In Dracorex, the squamosal horns are large, pointy, and obvious. In Pachycephalosaurus, they are large, rounded, and short. Sullivan does not believe that the "nodes" of Pachycephalosaurus have been "worn down," a contention that I agree with. How would Pachycephalosaurus have been using its squamosal spikes that would result in wearing them down? We must also account for the domelessness in Dracorex. The lack of unquestionable juvenile remains of pachycephalosaurs is troubling, here. Sullivan suggests that the flat-headed condition of some Asian taxa (i.e. Homocephale) is a derived feature, and that the dome is basal for Pachycephalosauridae. This is not to say that the dome was not present right out of the egg, but rather the dome is a defining ancestral feature of the family. Pachycephalosaurs did not diverge along two lines from a domeless form, nor did domeless forms predate the domed animals. Rather, the first pachycephalosaur had a dome, and domeless adult species secondarily lost it.

This has important implications for Dracorex. First, if we consider Dracorex to be a member of the Pachycephalosaurini (which I believe it is), its domelessness must be considered either a juvenile trait or a derived feature that runs counter to the other members of its immediate clade and instead converges on a few Asian taxa. This would be like Citipati regrowing a long tail while its sister taxa (Nomengia and Oviraptor) retain a pseudo-pygostyle. A reduced tail is a primitive trait for the Oviraptoridae. That's not very parsimonious, and I don't think it flies. If Dracorex is of the Pachycephalosaurini, I believe it is a juvenile.

Did juvenile pachycephalosaur lack a dome? For that answer, we must turn to the Pachycephalosauridae's sister group, the Ceratopsia. Peter Dodson has repeatedly shown that all of species-specific features of the horned dinosaurs are related, primarily, to sexual maturity. Centrosaurus and Pachyrhinosaurus looked essentially the same as juveniles and teenagers (Brachyceratops and Monoclonius are now considered juvenile and teenage ceratopsians of general affinity, respectively). It was only when those pubescent hormones started kicking in that ceratopsians began to grow their specific horns and frills. Notice that Monoclonius has a large nasal horn. Well, that horn was reabsored and reworked into a roughened bony boss in Achuelosaurus. The small orbital horns of Monoclonius were reabsorbed in Styracosaurus. In Triceratops, it's possible that the solid frill so characteristic of that taxon were simply closed off in adults, while juveniles still had frill "windows."

The point here is that all of the visual aides produced by the Ceratopsia seem to be linked with sexual maturity. The same could very well be true of Pachycephalosauridae. This would mean that the characteristic dome of Pachycephalosaurus, Stegoceras, Prenocephale, Tylocephale, etc. would all be secondary sexual characteristics that "arose" (HA!) after sexual maturity. This would also mean that dome-less adults, like Homocephale, are paedomorphic features, retained into adulthood (there is a ceratopsian analogue here--Avaceratops may be a hornless adult, although that verdict is far from certain).

So, we can establish with some certainty that Dracorex may be a juvenile pachycephalosaurine. It is certainly not immediately related to the Asian flat-headed pachycephalosaurs, so it is not an Asian export living alongside North American boneheads. But how do you explain the complex spikes and scutes of Dracorex's head? Are the spike bands, decorated jugals, and large squamosal horns not sexual characters? If those features are purely for protection (and they certainly would provide it), I would expect to see them in juveniles. And it's entirely possible that the impressive squamosal horns of Dracorex were reabsorbed as it grew, so that they appear to be blunt in Pachycephalosaurus. As it stands, the jury is out on this one.

It's a shame we can't say too much about Stygimoloch, but a few things are clear. First, Stygimoloch is probably of the Pachycephalosaurini, based solely on its squamosal morphology. Second, because Stygimoloch has a dome, the holotype is probably an adult. Third, because the adult seems to have large pointy squamosal spikes, it seems clear that you can have both impressive squamosal spikes AND a dome.

So what does THAT mean for Dracorex? It probably means that Dracorex is a juvenile Stygimoloch, although more complete remains of the latter would undoubtedly clear up the situation. As for Pachycephalosaurus, I think that it is a unique taxon. I would expect to see similar squamosal horn morphology in a juvenile animal, given that Dracorex has horned squamosals. Pachycephalosaurus is also a larger animal than either Dracorex or Stygimoloch, and why would an animal grow significantly larger after attaining sexual maturity?

So my conclusions are as follows:

1) Dracorex is of the Pachycephalosaurini, and it represents a juvenile animal.
2) Juvenile pachycephalosaurs were most likely domeless.
3) Domes in pachycephalosaurs are related to sexual maturity.
4) Domeless adult pachycephalosaurs (Homocephale) have secondarily lost their domes through paedomophosis.
5) Stygimoloch is of the Pachycephalosaurini.
6) Stygimoloch retains the large squamosal horns of Dracorex, but also has a dome.
7) Dracorex is a juvenile Stygimoloch, and Stygimoloch is a sister taxon to Pachycephalosaurus.
8) In the future, I predict that if any juvenile Pachycephalosaurus are found, it will have no dome, but also rounded squamosal spines.

Jurassic Park 4: Dinosaurmaggedon

As some of you may well be aware, Jurassic Park IV: Dinosaurmaggedon is fast approaching. From what I've read on the interweb, the film is, at the very least, in pre-production. I've read at least three "insider"treatments of the screenplay, most of which involve the dinosaurs getting off the island(s). Raptors in central park? Pterosaurs torturing little-leaguers? The possibilities are endless. I'm sure my readers are well aware of this, but the Jurassic Park series just gets a little worse with each passing sequel. The first film blew my mind like no other had. The second film was...well...it was there. The third film made me laugh.* But now that the rumor mill has started back up for Jurassic Park 4, I fear that When Raptors Attack may not be that far off. What would I like to see in JP4? And more importantly, what would I be adverse to?

1) Don't hire Jack Horner as your consultant. There are many strikes against using Mr. Duckbill, including the awful JP3 DVD interview in which he lies to us by making mention of reasonably complete Spinosaurus remains (which he calls a "superpredator"), and then remarking how he basically stood by and did nothing while the animators showed him a clip of the bulky giant running faster than it probably could in real life. Also, did anyone see those chiropterosaurs?** I was mortified, but maybe flying reptiles aren't Horner's field...

2) Jurassic Park was good partially because, at the time, it successfully blended current scientific knowledge with monster movie fare. Yeah, Deinonychus might not have hunted in packs, but if you strip the feathers off (and snarling lips), that's basically what it looked like. The Lost World used basically the same dinosaurs, but added an interesting hunting method for the dromaeosaurs and parenting techniques for the tyrannosaurs. I do not object to any of this. In fact, The Lost World may be the best attempt at scientific accuracy in the series. But by the time JP3 comes along, it's clear that the effects team was shooting from the hip, making the dinosaurs more movie monster than living, breathing animal. Let's get back to the basics. Dinosaurs were living animals, and they were awesome. In fact, they were awesome without any Hollywood flair. Keep that in mind, movie-people.

3) A larger focus on herbivorous dinosaurs would be appreciated. Again, The Lost World leads the way here, showing what happens when you mess with a cow Stegosaurus. I dispute the idea of parental care by a thyreophoran (no evidence for it), but the scene in question demonstrates that it isn't just the theropods that were dangerous. There was a scene in the second book where a dude is stuck in a jeep that's surrounded by pachycephalosaurs. I would like to see that scene. I'd also like to see a large ornithopod get attacked by a single large carnivore or a group of small ones. That would utterly kick ass.

4) Please, please, please give us some new dinosaurs. If you have to keep the raptors, at least give them feathers. The technology must be there by now. While it's true that feathers are much more difficult to render and animate than mammalian hair, I'm sure you've got the money. Anyway, oviraptoroids might have been mean buggers, troodontids too. Or what about a roving gang of Coelophysis? Those guys fight dirty.

5) It doesn't have to be a humans vs. dinosaurs story. I've always thought it would be cool to make a movie about humans documenting life on the islands, Planet Earth-style. The humans could have adventures in getting the awesome shots or whatever. All people are seeing the JP films for are the dinosaurs, not the intricate plotline or Oscar-winning script!

6) My brain is not tricked by CGI. I know it's not real. However, I can easily discern when something is a model, and I appreciate the effort required by modelwork a lot more than I appreciate a polygonal image. The original Jurassic Park used mostly modelwork, to wonderful effect. The new Star Wars trilogy made me gag from GCI overexposure. I'd like to see some more modelwork, and less CGI.

7) The original cast does not have to be involved. No, really, Sam Neil and Jeff Goldblume can have the day off for this one--new characters are desperately needed to move the franchise forward.

8) Dennis Nedry's shaving cream can had a 36-hour expiration date. Here's the proof. The DNA is not viable anymore. Do not retrieve the can.

9) No hybrid dinosaurs or genetically engineered raptors. Dinosaurs would make awful military weapons, as they are made of flesh and bone. Please do not turn Jurassic Park into Aliens.

10) I swear to Bokonan, if I see one pterosaur flying like a bat and picking people up off the ground, I will firebomb Universal Studios.

How about you, readers? What would you like to see, or not see, in the next Jurassic Park movie?

*So, remember the scene in JP3 when Alan and...that guy...are looking at the spinosaur tracks, and Alan asks what kind of dinosaur it is? And the guy says Suchomimus, but Alan says "think bigger." And his idiot grad student says Baryonyx, a spinosaur that's actually smaller. I laughed so hard in the theater, but I was the only person laughing. My friends gave me a wierd look, and then again when I explained it afterwards. And now that Suchomimus is probably synonymous with Baryonyx, a whole new level of hilarity is added to that exchange.

**The Pteranodons in JP3 must have been reproducing with bats, because the Pteranodon in the final scene in The Lost World is great and completely accurate (although landing on a branch seems like a stretch). Anyway, JP3 gave us inherently evil pterosaurs...with teeth. Ironically, Pteranodon means "winged and toothless," so that's ONE strike against the film's portrayal. They also weren't flying like bats or carrying kids that were likely just as heavy, if not heavier, than they are off to their nests. And how was this Pteranodon flock living before those moronic humans stumbled into their enclosure? They're caged in, for pete's sake, so where is their food coming from? Also, the Pteranodon sequence has the film's stupidest scene: After an adult pterosaur is seen trying to carry off Grant's grad student, a pterosaur in the foreground turns its head and looks straight at the camera (and the remaining people) as if to say "You're next." Awful, awful film.

LEGO Albertaceratops

This LEGO scupture is a real hoot. I wonder how long it took to build, and how much time it took to plan!

Carcharodontosaurus iguidensis

Today's Journal of Vertebrate Paleontology (another journal I don't have access to) has a description of a new species of Carcharodontosaurus. This one is from Niger, and is apparently "significantly" different from the previously known species, C. saharicus. There's not a lot more than a press release right now, but I imagine we'll see more in the coming week.

Tag! I'm It!

Amanda has tagged me for an internet meme. It's "Seven Things About Me." But because I'm feeling lazy today, I'm not going to follow the meme to a T. I'm leaving out the lineage part (feels too much like a chain letter). If you want to see my lineage, look at Amanda's. Otherwise, here goes!

1) I have Cystic Fibrosis, and making it to 25 without getting diabetes has been a relief. My new idiot-run mail order pharmacy (came with the job) has been royally f*cking up my medications, so there were a few weeks there where I just wasn't taking my antibiotic or one of my inhalents. That can't be good, and I can definately tell that my lung functions suffered as a result. Things are back on track now, though. It's a Tobi month, so I'm waking up earlier. I can't stand Tobi, because it tastes like metal and takes a half hour to complete. But it's the only medication I don't care for. The rest are (mainly) just pills. I haven't had an IV in like five years, though, so I must be doing something right! :-)

2) The CF isn't even what bugs me the most. Rather, it's my freaking back. Several years ago, one of my intervertebral disks collapsed (L5/S1). That caused me some pain, which comes back even today from time to time. Over the years, thanks to stupid decisions on my part, my back has "gone out" a few times. The last time it did, I ran out of Percocet, so I called my back doctor and asked what I should do. Seeing as it had been like four years since I saw him, he ordered an MRI and arranged an appointment. The prognosis? Two more disks had collapsed since the first one. So now I have to be a lot more careful of what I lift or how I twist. Back pain sucks, kiddies!

3) This is where I got married:

This is Rabbit Lake, which you hike to from the southern end of Anchorage. It's a ten-mile round-trip hike. The lake (which is of glacial origin) sits below Suicide Peaks. That ridge connecting the two mountains is, at one point, about as wide as a balance beam. My wife's folks (and brother) flew up to hike out with my family and a few friends. My dad married us right on that rocky outcropping at the bottom of the picture. Happily, it wasn't real windy, which is unusual for Rabbit Lake. Gina and I try to hike out there every year, but last summer it didn't happen on account of the new house and all the work we had to put into it.

4) I don't drink because I see no good reason to. My friends do drink (a lot) and as far as I can tell, no good comes of it. I do "let myself go" once a year, on my birthday, and get a strawberry daqueri. And let me tell you, the gloves? They come off.* Likewise, I don't do any drugs, and for the same reason. Also, I'm on way too many as it is!

5) I'm thinking about getting my lower secondary incisors taken out. They're oversized and crowding my mouth, forcing my lower front teeth back. I'm worried that there will be a big gap between my canines and front teeth, but I'm sure my gums would balance everything out eventually. Maybe I should just floss more often...

6) My two vices? Mountain Dew and video games. Well, maybe just Mt. Dew. See, the video games help me unwind, and they also give me an enormous sense of accomplishment, as though I'm actually getting something done. Of course, time spent tracking down all the Power Stars in Super Mario Galaxy could be spent writing a book, but...I mean...Galaxy is so much fun. Mt. Dew, I'm sure, rots my teeth, and as Gina will tell you, it makes my breath smell awful. I don't want to use the word addiction, but there are days where I drink two or three cans of the stuff.

7) The enormous anatomical and muscular differences between mammals and reptiles bothers me to no end as a paleoartist. Mammalian musculature is not "obvious" in the way that a reptile's is. Lizards, crocs, and dinosaurs don't have all the fat stores and "droop" that, say, a dog does. And then there's the hair, which conceals so much! If you're looking at a crocodile skeleton, it's fairly easy to draw the living animal. The same cannot be said of a lion skeleton. If I apply dinosaurian restoration techniques to a lion skeleton, the end result will not be a lion. Mammal anatomy is something I really need to study, because I find them extremely tough to "get right."

I tag Marcus, Matt, Will, Scott (although he won't do it), Manabu, aaaaand Neil.

The Less Popular Deinonychosaurs

Dromaeosaurs are awesome. If you don't believe me, go watch Jurassic Park, and then check out the enormously wide range of dinosaur model toys available at nature and science stores. Aside from Tyrannosaurus, you're sure to find Velociraptor. Ever since that 1993 blockbuster, the Dromaeosauridae has been a crowd-pleaser. And, in keeping up with the family's popularity, the number of known "speedy lizards" has more than doubled since the film's release. Back when Jurassic Park was in theaters, only three raptors were known from good material: Dromaeosaurus, Deinonychus, and Velociraptor. There were other fragmentary, questionable raptor dinosaurs (like Adasaurus). Now, however, there are so many more: Sinornithosaurus, Microraptor, Unenlagia, Beuitreraptor, Utahraptor, Shanag, Luanchuanraptor, Graciliraptor, Mahakala*, Tsaagan, Rahonavis, Bambiraptor...the list goes on and on.

At any rate, clearly, Dromaeosauridae was quite successful. But the dromaeosaurs constitute but one branch of a larger Deinonychosauria. Their sister group, the Troodontidae, is not only far less popular, but also poorly represented.

In general, troodontids seem to be derived from a Mahakala-like ancestor, and earliest members of both the Troodontidae and Dromaeosauridae differ only in subtle ways. Troodontids seem to represent a lither, more gracile type of dromaeosaur. Troodonts also evolved in a slightly different direction from their more famous cousins. While dromaeosaurs kept their recurved, serrated teeth and hypertrophied raptorial claw, troodontids reduced their tooth size, changed the serration pattern, and reduced the size (and changed the shape) of the raptorial claw. Clearly, they two families were doing different things.


This first picture shows the raven-sized, exquisitely preserved Mei long, a basal troodontid from (where else?) China, that was described in 2004. It died in a sleeping posture similar to modern birds, with its head tucked under one arm. The only real difference is that Mei long's lengthy tail is wrapped neatly around its body. The flexibility of the tail is another differentiating factor from dromaeosaurs--Velociraptor and its cousins would not have been able to wrap their tails in such a way given their unique tails, in which the caudal vertebrae were all joined together by long prezygapophyses, a feature that troodontids seem to lack.

As a troodontid, Mei displays unusual dentition, in that the teeth are small and tightly packed. Their curvature is not as extreme as that seen in dromaeosaurs, and the serrations are finer.

Surprisingly, more information on the anatomy of early troodontids can be gleaned from a more fragmentary skeleton. Sinovenator changiae was named in 2002. This chicken-sized troodontid actually helped re-establish the Troodontidae as a sister group to the Dromaeosauridae. Before its discovery, the only troodontid skeletal material was from derived members of the family like Troodon and Saurornithoides, and they displayed a non-retrovated pubis. For a long time, the troodontids were considered non-maniraptoran dromaeosaur mimics, and their true affinities were thought to lie closer to the Ornithomimosauridae (Holtz, Jr. placed troodontids, ornithomimids, and tyrannosaurs in a tri-radiate clade called "Bullatosauria," which has since been abandoned).

Sinovenator displayed clearly troodontid dentition, but had a dromaeosaurid retrovated pubis. Other features in the skull and axial skeleton link Sinovenator with primitive dromaeosaurs Microraptor and Sinornithosaurus, so trooodontids were clearly a sister group to their more famous cousins.

In 2005, yet another new primitive troodontid was discovered, although it wouldn't be recognized as such until earlier this year. Jinfengopteryx is known from a nearly complete skeleton, wonderfully preserved, including lots and lots of pennaceous feathers on the arms and tail. Unfortunately, its describers thought it was an archaeopterygian, despite its obvious troodontid features. Moreso than its basal characters, Jinfengopteryx is significant for demonstrating that troodontids had dromaeosaur-type feathers. This was, of course, predicted by troodontid phylogeny, but it's nice to have fossil confirmation.


The closely-packed, rostrally-placed teeth, long legs, short arms, and general shape of the pelvis were all quite clearly of troodontid origins, but Ji, et al. seemed unphased in their assignment of Jinfengopteryx to the Archaeopterygidae, even going so far as to publish a paper comparing the two "birds," in which they note, with some puzzlement, that the arms seem too short for flight, and that the teeth are wildly different from those of the urvogal. The pelvis, too, seemed divergent. Despite these glaring differences, it wasn't until Mahakala was described earlier this year that Turner, et al. finally placed Jinfengopteryx in the Troodontidae officially.

With all the primitive troodontids, known from virtually complete material, being dug out of the ground, you'd think the more derived members would be just as well known. Such is not the case, sadly, and derived troodontids are extremely rare and their remains tend to be fragmentary. The list of confirmed genera is extremely short: Sinornithoides, Byronosaurus, Troodon, and Saurornithoides (which may be a synonym of Troodon) make up the Late Cretaceous Troodontidae, the first half from Asia, and the second half from North America. There is also a problematic taxon named Borogovia that seems to have lost its sickle-claw altogether. These were not, though, diverse animals. And yet, they displayed some unique specializations which imply that troodontids were specialist hunters.

As Darren Naish so well describes, troodontids have asymmetrical ears, like owls. In addition, troodontids famously have the largest brains (compared to body size) of all dinosaurs. They compare to the ratios of ratite birds. In addition, troodontid eyes are unusually large, and their field of binocular vision was quite impressive. Taken together, these features suggest that troodontids were at least partially nocturnal, and that they hunted small prey. In 1998, Holtz et al. suggested that plants may have been at least part of Troodon's diet based on the denticle morphology of its teeth, but this idea is hard to test.

It's a shame that troodontids are so poorly known, because they are clearly specialized toward a particular lifestyle. With such incomplete material and the the rarity of troodontids in the fossil record, we may never know exactly what they were doing. Still, Troodontidae is a significant and fascinating group of deinonychosaurs that really should get more attention. I mean, Velociraptor is cool and all, but Troodon was an owl-like omnivore!

* Mahakala's diagnosis as a basal Dromaeosauridae is tenuous as best. It may simply be a basal Paravian.

Hat-tip to Neil, who has been bugging me for awhile to write a post about troodontids.

Moloch 'n' Phrynosoma: Freaky spiny lizards!

When I think of prehistoric animals, I'm always fascinated by how much more "exotic" they look in comparison to modern fauna. Dinosaurs look infinately cooler than mammals, for instance, what with their horns, spikes, frills, plates, and armor. Birds, I'll admit, look much more baddass today than they did in the Mesozoic, although some Cenozoic birds were pretty awesome--Teratornis, Diatryma, and South American terror birds? I'll take those any day over albatrosses and emus. But there are two modern lizards who look absolutely prehistoric, and I love them both. I doubt they'd make good pets, but dammit if I wouldn't try if given the chance. Moloch horridus, from Australia, and the various species of Phrynosoma, from the American southwest, are among my very favorite modern animals.

You lookin' at me, punk?

Phrynosoma is better known as the horny toad. Aside from being the reptilian equivalent of a porcupine, Phrynosoma is famous for its ability to burst its own capilaries and shoot an impressive stream of blood from the corners of its eyes. This is not only a shocking display, but the blood apparently tastes quite bad to mammalian predators. Birds don't seem to mind the red stuff, though, and when attacked by one of its larger dinosaurian cousins, the horny toad will thrash its head around, attempting to injure its attacker with its impressive cranial horns. Thankfully, horny toads are quite small, and will often fit comfortably in the palm of one's hand. Given their ridiculously fat bodies and short little legs, horny toads are not terribly difficult to capture, although its body spines (which are merely modified scales) can be quite prickly, especially in older individuals.

Look at me! I'm scary!

Moloch horridus is, perhaps, the most decorated lizard on the planet, or at the very least, in Australia. Despite its fearsome appearance, Moloch is actually quite small, slow-moving, and docile. When confronted with predators, M. horridus is more often than not tuck its head down and prey that its attacker bites off the enlarged "false head" spine that erupts from the back of its neck. Moloch runs with a jerky, robotic gait, and will often stop mid-stride, with one or two feet off the ground. The "thorny devil" is a specialized ant eater, and will eat several thousand in one sitting. As eating ants nonestop requires a lot of time, the devil has special hydroscopic grooves in its skin and between its spines which guide water directly to its mouth. The lizards "gulp air" to move the water toward the gaping maw. Despite its namesake, though, Moloch horridus does not have a thorny skeleton. It's spines are entirely external.

Phrynosoma (top) vs. Moloch (bottom)

The CAT-scan image above, taken from here, illustrates this oddity. Moloch has some textured bone where its giant cranial spines originate, but there is no underlying bony structure to its horns. In stark contrast, Phrynosoma's cranial horns all have bony cores. In fact, its skull is just as spikey as a pachycephalosaur! I was surprised to see a lack of bony horn cores on Moloch, and there are implications here for paleoart. If large, impressive spines and growths don't always have bony cores, then just imagine how wrong we could be about some prehistoric animals. Paleontologists are always musing on how duckbill dinosaurs protected themselves from predators. Odor? Herding? Tail whacking? What if they had huge external, epidermal spines? That would disuade predation! Even Phrynosoma, whose head is the only part of the body with bony horn cores, has largish epidermal spines all over its body. The function of these structures is obviously for protection (there is no marked sexual dimorphism between males and females of these lizards).

It's also interesting that Phrynosoma is, like Moloch, an ant-eater. It does not have the complex hydroscopic system that Moloch has, but one wonders whether ant-eating lends itself to a spikey body type, at least among lizards.

I bring these animals up today to prepare you readers for a bizarre creature I'll be restoring for Will at The Dragons Tales on Saturday. It's a creature you're probably at least aware of, but restored in a way that's not necessarily "normal." Also, Phrynosoma and Moloch are awesome!

New Duckbill Mummy

National Geographic News has a story about a new duckbill mummy fossil. It's been nicknamed "Dakota," and it reminds me of "Leonardo," a similarly-preserved Brachylophosaurus from a few years back. Leonardo has since been given a description in the book Horns and Beaks, a symposium about ornithischian dinosaurs. Sadly, Dakota has been given neither a genus nor species title. As usual for the Associated Press, the scientific virtues of the story are vague and questionable. I really doubt that a 35-foot long duckbill dinosaur weighed 35 tons, for example. The fossil paints a better picture of what hadrosaurs looked like, though. Apparently they had a lot more muscle on their back halves than previously thought, and changes in scale size could indicate differences in color across the animal.

That's not a great indicator, though. I have a frog-eyed gecko (Teratoscincus scincus), and while he's certainly multi-colored, scale size has nothing to do with color boarders. Rather, scale size has everything to do with practicality. His legs, belly, and throat have tiny scales that interconnect. His back, tail, and thighs and upper arms have large overlapping scales, probably for protection (although, honestly, he's very soft). The situation is similar in crocodilians--smaller scales on mobile parts, larger armor scales on exposed areas.

At any rate, I have my doubts that scale size can be used to determine color placement on any reptile. I look forward to any publications on this mystery duckbill.

Also, I've recently memorized the HTML tags for links, hence my recent obsession with linking to things. I will use this power only for good, and I will cite my fellow bloggers and news sites (and free PDF's!) in the post body rather than creating a separate "citations" section, whenever possible.