Pterosaurs: What the hell ARE they?

Pterosaurs were, as far as anyone can tell, the first vertebrates to achieve powered flight. These little reptiles developed a unique method of flight via elongation of the fourth manual digit. This is unlike the case in bats, wherein digits II, III, IV, and V are elongated. The pterosaur wing was, by comparison, long and narrow. It must have worked out alright, though, because pterosaurs ruled the skies for the entirety of the Mesozoic. In fact, although the first unquestionably pterosaurian fossils are of Late Jurassic age, those unquestionable specimens are unquestionably advanced. There is no Archaeopteryx among pterosaurs. This means two things: First, pterosaurs were probably around for quite some time before they show up in the fossil record. Second, their ancestry is a matter of some debate. Traditionally, the Pterosauria has been seen as either an outgroup to either the Ornithodira or, in some cases, the Dinosaurmorpha. Other workers see them branching from the more basal archosaurs. Still others see the pterosaurs as closer to protorosaurs or even, dare I say it, the prolacertiforms.

Part of the problem, of course, is that the first pterosaur fossils known (Eudimorphodon, Dimorphodon) are already incredibly derived. Ironically, this quandry is the same as for bats, who just "appear" in their modern form. Molecular evidence points to a Canivora ancestry for bats, but there is no such evidence for pterosaurs. I suppose a good analogy would be whales: If you had to figure out where whales fit into the Mammalia, but the only whale you could look at was a modern baleen whale, you'd have some trouble. This is essentially the situation with pterosaurs, who, even at their earliest known appearance, are so derived and suited for a flying lifestyle that their ancestry is clouded by those very derivations.

One thing we can be sure of is that pterosaurs are reptiles. Better yet, they are diapsid reptiles. Of course, seeing as diapsid reptiles ruled the world for the better part of the Mesozoic, our search for a pterosaur ancestor still crosses a broad spectrum. Like I said before, the traditional model is that pterosaurs are, in some vague way, related to dinosaurs. But I'm hoping you'll see, after reading this post, that this hypothesis is in fact not very well supported.

Ornithodirans?

Behold, Marasuchus, the iconic dinosaurmorph. Fully digigrade and bipedal with a tri-radiate pelvis, shortened forearms, a long, flexible tail, armor scutes, and a unique ornithodiran ankle structure allowing that specialized horizontal posture. Surely, pterosaurs even as "primitive" as Dimorphodon could not have come from as specialized a creature as this. Marasuchus stood on the very threshold of being called a dinosaur. Indeed, Greg Paul has said that "lagosuchids" were early dinosaurs. We know that pterosaurs were not dinosaurs, so perhaps Marasuchus is a bad example. We need something a little more basal, but still among the ornithodirs.

This big-headed cutie is Scleromochlus, a primitive ornithodir discovered in Scotland, and it has been suggested by a few scientists as being a pterosaur ancestor. This seems to be due to its basal nature, as it's usually considered an outgroup of the Ornithodira. So, if we want pterosaurs to be ornithodirs, then maybe Scleromochlus is a kind of ornithodiran "Euparkeria," providing a nice basal form from which several more specialized animals can branch from. However, both Marasuchus and Scleromochlus do nothing more than emphasize the problem with placing the Pterosauria within the Ornithodira. Specifically, the structure of the pelvis is completely different in pterosaurs compared to ornithodirans (I'll get to specific aspects of pterosaur anatomy in a bit). Whereas ornithodiran pelves are built with strut-like elements that point forward and back, and connect in the middle, pterosaur pelvises are shield-like when viewed laterally with no elements connecting in the middle. Moreover, pterosaurs were plantigrade like humans and bears--we walk on the soles of our feet. One of the highlights of being an ornithodir is that you walk on your tip-toes, thus increasing the length of your stride. Finally, ornithodir arms are short while the legs are long. In pterosaurs, the opposite is true. And perhaps most frustratingly, pterosaurs are unquestionably sprawling in their gait (rhamphyrhychids moreso than pterodacyloids), while Marasuchus, Scleromochlus, and all of their cousins were fully bipedal with parasaggital stances. In his 1998 redescription of Scleromochlus, Michael Benton had this to say:

"Padian (1997) named the postulated clade containing Scleromochlus and Pterosauria the Pterosauromorpha. The characters proposed to link Scleromochlus with either pterosaurs or dinosaurs are not wholly convincing. Sereno (1991, pp. 36-37) listed the following as potential synapomophies of Sclermochlus and Pterosauria: (33) Skull more than 50 percent presacral column length; (34) Length of scapula is less than 75 percent of humeral length; (35) Fourth trochanter absent; (36) Metatarsal 1 length is at least 85 percent of metatarsal 3 length.
"The first three of these could relate simply to the small size of the animals. Character (33) is true also for phytosaurs and many crocodylomorphs (although because of snout elongation). Character (34) is probably spurious because it compares what is genuinely a relatively short scapula in Scleromochlus with the relatively elongated forelimbs of pterosaurs (Bennet 1996, p. 279). Character (36) is present also in some basal crocodylomorphs, so it can evidently arise convergently."

So what, pray tell, is keeping pterosaurs rooted so firmly in the Ornithodira in the first place? Quite simply, the structure of the ankles share features with ornithodirans and dinosaurs which no other diapsid group (heck, reptile group) shares. This could, of course, be due to convergence. And I'm tempted to think so. After all, when the number of features that would keep an organism out of a particular group so heavily outnumbers the quota for keeping that animal in, something's up.

Archosauriforms, perhaps?

If Scleromochlus does not provide a basal enough form, than why not just start climbing down the diapsid family tree until we get somebody who fits the bill? Pterosaurs are almost always thought of as archosaurs based mainly on a single, perhaps unambiguous character: the antorbital fenestrae, that big skull window in front of the eyes shared by all archosauriforms (and secondarily lost in many crurotarsians). However, practicality puts a dent in even this idea. If it were true that pterosaurs, those most lightweight and long-armed of organisms, would sit among fat, heavy, short-limbed crocodile-like critters. Also of note is that pterosaurs lack a mandibular fenestrae, a hole in the jaw that is also diagnostic of the Archosauriformes. If pterosaurs are archosauriforms, then that means that they, for whatever reason, secondarily lost the mandibular fenestrae. This makes no sense at all, given that pterosaurs excavated their skeletons like crazy in an effort to become more lightweight.

Sharovipteryx cousins?

There are few gliding vertebrates stranger than Sharovipteryx. Aside from its strange anatomy, Sharovipteryx is unique because it was found in the same area (Kyrgyzastan) in the same year (1965) by the same person (Alexander Sharov) as the infamous Longisquama, the animal that because Alan Feduccia's posterchild for a non-dinosaurian avian ancestor. At any rate, Sharovipteryx has often been suggested as a pterosaur ancestor, and it does have one big thing going for it: gliding membranes. This little prolacertiform, who is also related to Tanystropheus, was clearly arboreal. The physical remnants of Sharovipteryx, however, provide little more than trace evidence for the creature. It's clear that the legs were extremely long, as was the tail, and the spine and parts of the skull are preserved. Aside from some questionable humeri shapes, the arms are unknown. Sharovipteryx's fossil, however, does preserve impressions of a skin membrane stretching from the toes of the feet to the tail. Sadly, the state of preservation above the pelvis is terrible, so whether Sharovipteryx actually had gliding membranes above the waist is unknown.

However, several studies involving paper and computer models have suggested that, in order to control aerial stability and extend the gliding period, Sharovipteryx must have had a sort of canard membrane originating on the forelimbs. Whether this membrane stretched from the front of the arm and attached to the neck, or the back of the arm to the body, or both, is unknown. A 2006 study by Dyke, et al. suggested that Sharovipteryx had a forelimb membrane like the one above, making it the first "Delta-wing glider," like a Vulcan bomber.

Tempting though Sharovipteryx is as a pterosaur ancestor, there are several problems even with it. Despite its aerodynamic capabilities, Sharovipteryx has extremely long legs and ridiculously small forelimbs (from what's known). Its arms are also simply unknown, and although Sharov suggested in 1971 that the animal's fourth finger may have been elongated, but there is no evidence of the animal's hands. So, although the gliding membranes provide some indirect evidence for a pterosaurian relationship, Sharovipteryx is simply too poorly preserved to answer our question.

So what ARE they?

What makes pterosaurs so hard to place, like I said before, is their level of derivation. And whether certain features are actually primitive or derived is hard to say. For example, pterosaurs were plantigrade--they walked on the soles of their feet like humans, bears, lizards, and crurotarsians. Pterosaur trackways and a well-preserved 3D fossil of a Dimorphodon foot have secured pterosaurs as plantigrade. However, is the plantigrade posture retained from an ancestor or was that ancestor digigrade, only to switch over to plantigrade due to the physical constraints of the connecting wing membrane? In discussing Dimorphodon weintraubi's plantigrade posture to the competing bipedal pterosaur model, Clark et al had this to say:

"Other features of digits I-IV of the D. weintraubi foot indicate a capacity for grasping that is consistent with an ability to climb but is unexpected in an obligate cursor. The claws are moderately curved (nearly as strongly as the claws of the manus); all phalanges except the most proximal have well developed flexor tubercles for the insertion of digital flexors (Fig. 2); and all of the IP joints allow for extensive flexion of the digits (as exhibited by digit IV; Fig. 2). Furthermore, the phalangeal proportions of the digits of Dimorphodon and other basal pterosaurs are similar to those of birds with grasping feet (that is, perching, climbing, and raptorial species) and unlike those of primarily ground-living birds, bipedal dinosaurs and the primitive dinosauromorphs Lagerpeton and Marasuchus."

Pterosaurs, or at least rhamphorhychoids, were scansorial and probably rarely ventured to the ground. In fact, according to David Unwin, no confirmed rhamphorhychoid trackways have ever been found. Perhaps, given the extremely limiting connections of the rhamphorhychoid wing membranes, being grounded meant getting eaten.

Pterosaurs pelves are also a bit of a mystery. Again, the old bipedal model depends on the structure and orientation of the femur socket, and a bipedal posture was proposed by Padian and Bennett at different times (Padian preferring a horizontal posture while Bennett suggested a rather comical human-like construction). For a dinosaurian bipedal posture to work, however, the legs would have to be able to be held underneath the body. This picture, as well as the next one, are from Wellnhofer's excellent study of an Anhanguera pelvis from Brazil. While this particular pterosaur is fairly large pterodactyloid, it is comparable to rhamphorhychoid pelves and so serves as a great model for pterosaurs in general. The first thing I notice upon looking at this is that the acetabula is completely closed. In ornithodirans, the acetabula is at least partially open, and in early dinosaurs it is mostly open if not completely so. The construction of the iliac blades are also wildly divergent from a supposed ornithodiran (or even archosaurian) ancestor in that they are thin, not flat. The pubis is wide, as is the ischium. In rhamphyrhynchoids, the pubis and ischium actually fuse to form a sort of D-shaped bone. Pterosaurs also developed "prepubes." A prepube looks a bit like a traditional theropod pubis, but chopped off right above the boot. The prepubes attach to the front of the pubis and connect to the belly ribs. They essentially anchor the pelvis to the sternum, making the body even more immobile than birds. Prepubes are "new" bones which, in addition to the pteroid wrist bones, are entirely unique to pterosaurs.

As you can see from a front view of Anhanguera's pelvis, the pubis and ischium do not connect in the middle. Rather, each side forms a sort of "pelvic shield" which widens and strengthens the body. In addition, the position of the acetabula prohibit a parasaggital posture. Notice that the femur sockets actually point out and up. Wellnhofer reflects on the diagram above:

"Putting the femur in its proper place and allowing some space for cartilage in the acetabulum, the most comfortable setting for the head would result in a horizontal position of the shaft (Figure 6, left). Then, the axis of the collum femoris coincides with the axis of the plane of the acetabular rim directed 35 degrees upward. A higher lifting of the femur was certainly possible. In the opposite direction, the femur could not be adducted too much (Figure 6, right). A maximal angle of the shaft 150 degrees downward would have been achieved at best, because the ventral rim of the acetabulum formed by the pubis was a natural stop. On the other hand, the head could no longer find support in the hip socket without being in danger of luxation. Therefore, the orientation of the femora during terrestrial locomotion was probably less extreme than shown here."

In other words, pterosaurs who tried a parasagittal posture would have dislocated their hips. More to the point this time, Wellnhofer continues:

"In any case, a parasagittal swing of the hind legs was absolutely impossible. The femora of pterosaurs were splayed out, their stance and gait was semi-erect. Consequently they could not have been bipedal animals. Furthermore, the morphology of the foot skeleton suggests that they were not digigrade."

That last comment makes me chuckle, because Wellnhofer realized that pterosaurs were plantigrade in 1988, ten years before the foot of Dimorphodon weintraubi was described.

Again, however, we can't be sure whether the strangely-directed acetabulum is a primitive or derived characteristic among pterosaurs. Perhaps the hip socket was directed upwards as a necessity for a smooth wing surface. When a pterosaur flew, it moved its legs into a full lateral position, which straightened the patagium but also moved the foot into a position perpendicular to the wing surface. According to Unwin, the toes of pterosaurs were webbed, not to aid in aquatic habits, but to control yaw during flight. Had the acetabula of pterosaurs been directed fully to the side, it is doubtful that the legs could have been of much use during flight. Thus, it is entirely possible that the seemingly primitive sprawling condition of the hind legs is a derivational necessity of the flight aparatus.

I cannot pretend to advance my own theory of pterosaur origins here, but I often find myself questioning the traditional viewpoints regarding their branching-off points. It seems obvious to me that pterosaur cannot be ornithodirs, and perhaps just as unlikely that they are archosaurs proper. A more basal archosauriform is more likely, in my opinion. Certainly the possibility of a relationship with Sharovipteryx and the greater Prolacertiformes cannot be ruled out. Like I find myself saying at the end of almost every paleo-related post, we need more specimens! And better ones! It would be fantastic to find the arms of Sharovipteryx, for example, or better yet, a pterosaur who could only glide instead of fly. That would make my day. Pterosaurs are my favorite flying vertebrates by far, and I hope you've enjoyed reading about their murky origins as much as I've enjoyed writing about them.

P.S. Much as I'd love to keep writing about how pterosaurs are incredibly unique--for example, I didn't even go into their bizarre forelimb anatomy--I've got to force myself to stop at some point, because otherwise, I'll write a book. And nobody wants that.

References:

Unwin, D. M. (2006). The Pterosaurs from Deep Time. Pi Press, New York, NY.

Wellnhofer, P. (1996). The Illustrated Encyclopedia of Prehistoric Flying Reptiles. Barnes & Noble Books, London, UK

Wellnhofer, P. (1988). Terrestrial locomotion in pterosaurs. Historical Biology(1): 3-16.

Clark, J. M. et al (1998). Foot posture in a primitive pterosaur. Nature(391): 886-889.

Benton, M. J. (1999). Scleromochlus taylori and the origin of dinosaurs and pterosaurs. Phil. Trans. R. Soc. Lond. B(354): 1423-1446.

Dyke, G. J. et al (2006). Flight of Sharovipteryx mirabilis: the world's first delta-winged glider. Journal of Evolutionary Biology (published online).

Lions and tigers and memes, oh my!

Stolen from Laelaps and Julia, here is my meme survey:

Three things in my fridge that define life right now:
1) Moutain Dew, the drink of the gods. I became "addicted" to this greenish substance during my lifeguarding days, and I haven't looked back since.
2) Milk. I drink more milk in a week than a family of five. Seriously, I go through three gallons in a six or seven day period. This is, of course, because I have cystic fibrosis (I should really blog about that sometime) and milk has lots of fat and calories. And it's not that weak 2% crap. I'm downing several glasses of whole milk a day. Oh yeah, 4%, baby.
3) Tobi and Pulmozime. Also related to CF, these are the inhalents I do on a daily basis. Well, I do the pulmozime once a day every day of my life. Tobi is a strong antibiotic that suppresses bacterial growth in my lungs. However, because one can quickly become immune to its effects, I do Tobi twice a day for thirty days in a row, then take a thirty-day break. I don't like Tobi, because it takes between twenty and thirty minutes to complete, and it tastes like metal. :-(

Three recent acquisitions:
1) Resident Evil 4: Wii Edition. I didn't think they could improve on the GameCube original, but the motion control and 1:1 aiming kind of blow the first edition out of the water. This is my favorite game right now, and in my top 5 of all time. Just bought the Chicago Typewriter on Normal mode. I am determined to earn the Handcannon this time, even though it will take perhaps weeks.
2) A whole bunch of Neo4 Pokemon cards that I don't have. I used to play the Pokemon card game in my youth, and a few years ago I decided to save one of every card I still had. That's a lot of cards and a lot of holos. I check local comic shops once and awhile to see if they have any that I don't already have. My friend John from the GameInformer forums was good enough to send me a whole bunch of holos, including several triple-rare Shining Pokemon.
3) Road Trip and Deep Blue Sea. The former is one of my favorite comedies, and the latter is one of my favorite popcorn movies. And they were only $6 each!

Three classics I reach for every day:
1) My video games. They're how I unwind.
2) My drawing pad. Got to get some sketching in on a daily basis.
3) My iPod, just like Julia. Love my tunes.

My kids right now, in three words or less:
Nonexistent, Thank God.

My sweetie right now, in three words or less:
Pretty and patient.

What's on my to-do list:
Digitally color those pictures I posted a few days ago; pay John for those Pokecards; buy Metroid Prime 3 on Tuesday; find a new job.

What I'm listening to right now:
My wife, who continually finds chores for me to do (it's quite amazing, really).

What I'm worried about right now:
Finding a replacement job come mid-September, the condo association finding fault with our renters, which because of other idiot tenants cannot help those faults (long story).

Which news stories I'm following right now:
Not a lot, actually. Unless it's related to biology or paleontology, that is.

What I'm reading right now:
Wading through The Dinosaura, 2nd Edition (it's a beast).

What I'm looking forward to right now:
Metal Gear Solid 4, sitting down with a person who might hire me on Wednesday or Thursday.

A thought I keep returning to right now:
I really don't want to walk the damn dog tonight.

One small thing that's making me happy right now:
Watching "The Sopranos" a little later. I like that show a lot.

Hosting the Boneyard

Well, friends, I have the honor and pleasure of hosting The Boneyard on September 1st. If you have any awesome paleo-related stories or posts you'd like me to link to, feel free to post them in the comments section of this post (you'll need an eBlogger account), or email me (zman1902@hotmail.com). I'll turn the spam filter down so that your emails actually reach my Inbox instead of my Junk folder.

Now, you may say, "Why not just get a Gmail account, Zach?" I once had a Gmail account, in fact, but Gmail screwed me by one day, without warning, canceling said account. That was after only a few months with Gmail. So screw you, Gmail. Hotmail is where it's at. For now. So send those submissions, folks--you've got until August 31st to write up something awesome.

Prehistoric Wierdness

In preparation for the upcoming Boneyard, I've compiled some original art. The general theme is "prehistoric wierdness," although a few of the critters are just incredible examples of convergence (which is wierd). So prepare to be amazed!

Carnotaurus sastrei (Bonaparte, 1985)
This is by far and away my favorite dinosaur. Abelisaurs, as a group, are my favorite theropods (as readers of the original When Pigs Fly surely know), and Carnotaurus seems to have been the pinnicle of these Gondawanna carnivores. The Abelisauridae is characterized by many odd features including a blunt yet tall skull, arms that make Tyrannosaurus look like a gibbon, and incredible head ornamentations. Carnotaurus is no exception, featuring large bull-like horns atop the skull, horny projections along the nasals, and skin impressions showing rows upon rows of tough scales and largish pointy scutes. The beastie was featured in the Disney movie Dinosaur and was, perhaps, the only dinosaur that was portrayed with any level of accuracy (aside from making it too big). The only other member of Carnotaurus' tribe, the Carnotaurini, Aucasaurus, oddly enough lacks the big brow horns of its sister species.

Effigia okeeffaea (Nesbitt & Norell, 2006)
This picture could probably be more detailed, but I honestly couldn't decide whether to give it dinosaur-like integument or crocodilian integument. One might think that this decision would be easy enough. Effigia is a dinosaur, right? Well, that's the amazing part--it's a crurotarian. That means Effigia is a whole lot closer to modern crocodilians than any dinosaur. Even stranger is the fact that Effigia turns up in the same place and time as Coelophysis, a Late Triassic theropod dinosaur. Looks like crocodilians figured out the bipedality thing a little too late, as theropods by then already had their foot through the door.
Still, Effigia is my favorite example of convergent evolution. Why its close relative, Shuvosaurus, was discovered, it was thought to be an incredibly primitive ostrich dinosaur. But an ostrich dinosaur in the Triassic? No way, right? Well, Effigia proved to be a sister taxon to Shuvosaurus, finally illuminating the latter's true position on the archosaur family tree. What's so fascinating is that Effigia has converged not just with theropods but also tetanurine theropods and the Ornithomimosauridae. It has a toothless beak, booted pubis, tridacyl pes, and various other dinosaurian features. Were it not for Effigia's crocodilian ankle joint (which makes me wonder how it's able to walk upright), paleontologists might still think that it, and Shuvosaurus, are early ornithomimosaurs!

Rodhocetus balochistanensis (Gingerich et al. 2001)
Just ten years ago, the ancestry of whales was a total mystery of paleontology. They were mammals, sure, but from what branch of the Mammalia family tree did they originate? Whales give birth to fully-developed young (unlike marsupials), so they are surely placentals. The earliest well-known whale was the unfortunately named Eocene giant, Basilosaurus. However, that taxon is clearly far removed from its ancestor and gave few clues about its ancestry. Paleontologists did, however, notice similarities between the teeth and overall cranial builds of Basilosaurus (and its close relative, Dorudon) and mesonychids, a group of generalized hooved carnivorous mammals that were the Paleocene equivalent of wolves.Things changed, however, in 2001, when nearly complete skeletons of an early aquatic whale, Rodhocetus, were discovered. Although previous finds, including terrestrial Pakicetus and Ichthyolestes, as well as semi-aquatic Ambulocetus had shown the transition from land to water, Rodhocetus preserved ankle bones which showed a direct connection with the artiodactyl ungulates, far from the mesonychids and closer to modern deer, goats, hippes, giraffes, and pigs.
Rodhocetus itself is unique in that it must have swam somewhat like an otter, but had much longer feet with which to propel itself forward. Its arms and hands were fairly short. This is the reverse from normal whales, in which the legs actually disappear completely in many taxa. Rodhocetus would have walked on the sides of its feet on land while it stood digigrade on its strong 2nd, 3rd, and 4th fingers. While Rodhocetus may have been bulkier than I interpret it above (fat stores and all), I drew it this way in order to show off the musculature and overall structure of the creature.

Henodus chelyops (von Huene, 1936)
I can hear you now--what's so special about a turtle? Well, friend, for one thing, this "turtle" has a ridiculously wide carpace that, as far as anyone can tell, is unique in that it's made of interconnected bony scutes instead of ribs. Also, it's got a pretty long tail for a turtle. It also has a long, but flat-faced skull in which the eyes and nostrils face straight forward. The animal's beak is complimented by a small row of balleen-like structures on either side of the jaw, making Henodus' diet a bit of a puzzle. Finally, and this is the wierdest thing--it's not a turtle.
It's not clear whether Henodus is a turtle mimic or it's the other way around, but this bizarre animal is a member of the Placodontia, one of the less famous groups of marine reptiles. Placodonts were fat, heavy little diapsids who had tweezer-like incizors followed by big, flat molars and palate teeth which they used to grab and crush molluscs and brachiopods.
Well, most placodonts did that. Henodus is a bit of a mystery, because its incizors were replaced by a large beak and it seems to have grown balleen along the sides of its mouth. Henodus is usually thought of as a kind of reptilian ray, living on the bottom of the seabed and filtering prey out of the silt and sand. Whether it really did this or not can probably never be known. But isn't it wierd? Also, this drawing took forever. Kudos to Darren Naish for sending me his placodont paper and better pictures of the bugger's skull and shell. I had to simplify the latter for my own piece of mind.

Arizonasaurus babbitti (Welles, 1947)
I'm extremely proud of this picture. I drew and inked it (see below), then handed that picture over to fellow paleoartist Scott Elyard of Coherent Lighthouse fame to use his all-powerful knowledge of Photoshop to paint this lovely digital mural. Arizonasaurus is actually very close to Effigia--they're both from the same major crurotarsian group, the Poposauridae. Arizonasaurus was fairly unknown until just a few years ago, when a nearly complete skeleton was unearthed in Arizona,* and revealed that the creature has a spectacular dorsal sail not unlike those of Dimetrodon, Edaphosaurus, Platyhystrix, Ouranosaurus, and Spinosaurus. Unlike all of those sail-backed critters, however, Arizonasaurus' sail begins caudally to the scapula. In most sail-backed animals, the neural spines begin growing taller at the cervical/dorsal contact, if not before. Thus, Arizonasaurus had a tall, yet oddly abbreviated sail. It also appeared to be plantigrade. Thanks again to Scott for painting this wonderful picture.

*I cannot abide the naming of fossil animals after the place they're discovered. I find it lazy and insulting to the animal itself--Arizonasaurus didn't call its home "Arizona." Surely, Welles could have come up with a more imaginative name. Perhaps, due to the original specimen's fragmentation, a more descriptive name could not be found. However, that doesn't excuse animals like Albertasaurus, Albertaceratops, Utahraptor, Utahdactylus, Edmontonia, Edmontosaurus, Alaskacephalus (if that's even a valid genus), etc. I mean, seriously, Albertaceratops is a centrosaurine with long brow horns and two small nasal horns. According to Wikipedia, the name Medusaceratops was being batted around for awhile. That's so much better! Hell, you could call it Eocentrosaurus and I'd be happier! Or maybe Dirhinoceratops, or SOMETHING that reflected its uniqueness in the greater Ceratopsidae. But no, we get Alberaceratops. *grumble grumble*

And that's the tour, folks, through the Hall of Prehistoric Wierdness. I might start doing this on a regular basis, although perhaps not quite so many drawings all at once in future outings.

TMNT is on DVD today

My most anticipated movie of the spring/summer, TMNT, which had a strong theatrical run in March, hits DVD/Blu-Ray/HD-DVD today. Unfortunately, there does not appear to be a Special Edition, although I have yet to read the box myself. Readers of this blog undoubtedly know me as a huge TMNT fan--since the tender age of something like ten I had idolized the Turtles. They are my favorite "superhero" group, and through the years of reading the original Mirage comics, the Archie Adventure Series (with its overt environmentalist tones), the Image series, and losing faith in the comics after a few issues of the terrible "new" Mirage series (at least they killed Splinter--'bout freakin' time). And then, of course, the "live-action" film trilogy. The first one is probably the best, the second one slightly worse, and the third one is just forgettable.

And then the cartoons. The old FOX Kids show was hokey but fun. Then the series moved to CBS and became an even more blatant advertisement for the action figures that before. Finally, a good-in-theory, horrible-in-execution live-action series ("The Next Mutation") hit Fox again, but lasted like six episodes before being cancelled. Surely the inclusion of a new female turtle was a sore spot for Turtle fans, as it was for me. The costumes were actually kind of cool, but I'm not sure why a female mutant reptile would have...*gulp*...mammary glands underneith her plastron. Go figure.

Through all this, I've developed a somewhat immobile view of what the Turtles should be about, molded mostly from the original series, the Image series, and the Archie Adventure series. I think the most compelling part of the franchise is that the Turtles are four brothers, each with very different personalities, living in a world that they can't really be a part of. In my "alternate Turtle universe," Casey Jones would be a rogue vigilante with no real affiliation with the Turtles, through friendship or otherwise. I'd probably kill Splinter, because so often I see him as a real crutch toward any personal development for any of the brothers. There was feeling for his loss in the "future" issues of the Archie series, and the boys had branched out because of it. I also don't see them all living together. The eventual gulf between Raphael and Leonardo would take its toll, and Raphael would become a vigilante. The other three brothers, led by Leonardo, would take on New York dangers as a group. Rarely would the three sects (Turtles, Raphael, Casey Jones) ever intersect. April O'Neil? Don't see her in the story at all, in fact.

As for villains, Shredder was killed (two or three times) in the original series, and I wouldn't bring him back. I also wouldn't force the storyline into the realm of science fiction or the supernatural, as so often happened back in the original series. I'm not sure who the villains would be, but I see the Turtles living in modern New York, with all the pitfalls and real-life problems that city produces. New villains would have to be thought up.

Now, the reason I loved the new TMNT movie is that many of my own views seem realized for the first time. Raphael is, in fact, a rogue agent. The boys all have their own hobbies. Shredder is dead, and Karai has taken his place (in a sort of fitting way). The Foot are still in New York, but they're not central to the plot. The story is fairly supernatural, but the four brothers face conflict among themselves just as much as the ancient monsters they're supposed to be fighting. Splinter is, sadly, still alive, and April is kind of a Lara Croft-type archaeologist/ninja (which I don't understand). I don't really like Casey's role at all, either. Also, and this was odd to me, the story focused so much on the conflict between Raphael and Leonardo that it forgets that Donatello and Michaelangelo are still there. Those two brothers are kind of left behind...

But the story is progressing nicely. Hopefully future iterations of the CGI series become a little grimmer and less science fiction-y.

The Boneyard

My blog buddy Brian Switek, a.k.a. Laelaps, has been compiling paleo-related blog stories from around the Interweb for some time now. In celebration of the 2nd Edition of the Boneyard, Julia Heathcote has conjured up a wonderful signpost pointing in the Boneyard's direction. Check out the fancy picture link below the main links!

Thanks to Julia, for teaching me how to post the thing in HTML, of which I know absolutely nothing about, and for creating such a wonderful little signpost!

And thanks to Brian, for creating the Boneyard in the first place. At the very least, it makes me work extra hard every two weeks to write something awesome about paleontology! :-)