Tuesday, July 29, 2008

Harryhausina marinus


This giant wyvern, the only living marine species known, was named in 1999 by Heathcote when she thought it looked like a beast from one of the famed special-effects guru's films. "Harryhausia marinus would not look out of place in some Greek adventure like Clash of the Titans," she wrote in the wyvern's initial description. And like Ray Harryhausen's creations, Harryhausia is a fearsome, destructive beast, greatly feared by the captains of smaller fishing vessels in the Pacific Ocean. Although principally found near Indonesia, Harryhausia has been sighted much farther south, in the waters west of Australia and between that continent and New Zealand. Although Heathcote's description was based largely on beached carcasses, authors since then (notably Garcia & Garcia, 2002) have published accounts of the wyvern's activities in the wild.
Harryhausia is a whopping sixty feet long, with a twenty-foot "wingspan." Its wings are short, and the patagium is thick and fairly inflexible. The forelimbs are quadradactyl, in an odd configuration. The thumb and index finger are free from the patagium, while the middle finger and ring fingers anchor the patagium to the arm, while bony spines erupt from the bottom of the wrist and elbow to broaden the wing surface. Draconologists are unsure exactly what purpose the vestigal wings serve, as Harryhausia's main method of propulsion is to undulate its body from side to side through the water, using its sizeable caudal fins to provide thrust. Heathcote suggested that perhaps the wings were used for threat displays, or aided in mating rituals, but to this day, their exact function remains mysterious.
The wyvern's body is fairly wide in the middle and tapers towards the head and tail. The body is green and smooth, though the belly is covered in wide, overlapping white scales. A series of cartiliginous spines runs down the back, anchoring a short dorsal sail. The spines are tallest above the arms and become more tightly packed toward the end of the tail. The sail is made of the same tough dermal material as the patagium and is resistant to bending.
Harryhausia marinus lacks any trace of hindlimbs. Were it to lose its wings, the monster would resemble an overweight sea snake more than a wyvern. The head is flat and roughly triangular in dorsal view. The dentition is extremely reduced, with only four large teeth in the upper jaw, and two in the lower jaw. The jaw tips are covered by a horny beak, and Harryhausia has a series of recurved palatal teeth. The wyvern also has two bulbous fleshy pads on its head, one over either eye, which are bioluminescent. Garcia & Garcia reported that Harryhausia will often dive to great depths, and that the pads may aid in prey capture or intraspecies signaling in darker waters. Despite its size, Harryhausia feeds mainly on prey much smaller than itself, mostly fish and young marine mammals like dolphins and pinnipeds.
Young marine wyverns are at risk from shark attacks, but juveniles will often swim together in groups of up to ten individuals (Cope, 2001) for their first few years, leaving the safety of the creche only when they approach thirty feet in length. Whether adults lay eggs or give bith to live young is unknown at this time, although Harryhausia is perfectly able to beach itself. Individuals are often seen sunning themselves on islands and beaches across the sea, although they do not venture farther than the beach on any landmass. Cope wrote that babies "must be hatched from eggs, as groups of juveniles are almost always the same age. Unless adults females were giving birth to up to ten, and possibly more, brothers and sisters at a time, one must conclude that these babies hatched at the same time and, from birth, swam together as a group." Munster (2002) dealt a blow to Cope's assumption, noting that many living animals, especially reptiles, give birth to multiple live young at once, and that the babies often stay together for a short time.
Harryhausia marinus is unique from a phylogenetic perspective in that it seems to have no living or extinct relatives. A swath of wyvern fossils are known from marine deposits, but most are from arboreal forms. Even the most fragmentary marine-buried wyvern fossils are no indication of a marine wyvern. In his brief review of wyvern systematics, Mantell lamented: "The fact that wyverns and dragons are primarily arboreal means that they, like seagulls, could die while over water, and thus fall into the sea and be buried and fossilized, only later to be unearthed by paleontologists who would be remiss in theorizing that they lived in a marine environment. As such, even fragmentary wyverns discovered in marine deposits cannot be readily shown to be relatives of Harryhausia marinus . . . without specific features linking it to the extent marine wyvern. As of this writing, there are no such specimens." This situation may change in the coming years. A team from Australia recovered a partial skull of what they consider a relative of Harryhausia in 2005, but alas, the specimen remains unpublished.
References:

Heathcote, J. (1999). A giant sea-serpent wyvern from the Indian Ocean. European Journal of Draconology 100(3): 450-461.

Garcia, M. J. & Garcia, N. G. (2002). Notes on the behavior of Harryhausina marinus (Heathcote, 1999). Natura Historia 409: 677-689.

Cope, E. D. (2001). Incidental observations of Harryhausina marinus. Brevia (July): 56-61.

Mantell, G. (2001). A broad look at wyvern systematics. European Journal of Draconology 102(2): 305-311.

Monday, July 28, 2008

Witness the Power!


So my brother needed money to get his new car insured. His new car is pretty awesome, by the way--it's an '08 Ford Focus. Anyway, he offered me his PS3 + games and accessories for a mere $300. He knew that I'd been shopping around for a used system for months. But really, three hundred smackers is a whale of a deal. Why? Because the 40 gig'er is, by itself, $400.
So I got a deal. I traded Rainbow Six Vegas in immediately for Ratchet & Clank Future. People tell me that GTA4 is very fun, though I haven't tried it yet. Call of Duty 4 is beyond awesome, though. And now I can play Ratchet & Clank and MGS4 whenever I want. My network name is Sillysaur. Add me, and toss your network name in the comments and I'll add you! And now I can stop ignoring all the PS3 previews and reviews in GameInformer, like Bioshock, Silent Hill 5, and Tomb Raider: Underworld.

Thursday, July 24, 2008

Caprawyvern mencotti


As far as wyverns go, none of them are quite as strange as Caprawyvern mencotti (Dawson, 1976). Large and ferocious, the "goat wyvern" is also one of the most dangerous. Caprawyvern is a fairly rare wyvern that lives in the American southwest, feeding primarily on domestic cattle. The creature is not above stalking smaller vertebrates, however, and in fact young wyverns are fond of jackrabbits. At twenty-two feet long, with a wingspan of between fifty-six and sixty feet, Caprawyvern is a sight to behold. The wyvern's most obvious feature is its namesake--a pair of curved, ram-like horns emerging from the head, one behind each eye. The horns are used in intraspecific territorial and dominance disputes. Only males seem to have curved horns. Like mammalian rams, females have fairly small, back-swept horns. The large horns of the males are in stark contrast to the relatively small skull and narrow mouth.

From a taxonomic perspective, however, Caprawyvern's most striking feature is the structure of its wing, which is totally unlike any other known living wyvern. The arms are short but dominated by an elongate humerus. The radius has been lost--only a rod-like ulna remains. The radius' job is supplemented by a strong tendon which seems to help flex the tiny hand bones. Two fingers, most likely digits I and II, are free from the patagium and assist in prey capture and terrestrial movement. The other fingers have degenerated completely, replaced by a series of nine rigid cartiliginous structures. Three of these "spines" eminate from where one would normally find digits III-V, two laterally from the wrist, two more from the elbow, and two more from the middle of the humerus. In addition to these "main" spines, a smaller spine erupts from between each pair of "main" spines but does not reach the end of the patagium. Rather, Benton (1994) believes they serve simply to strengthen the patagium.

The spines are rigid and inflexible. The groups of spines are so distinctly placed along the arm that they have each been given name. The "manual group" is the first group and erupts from from the distal end of digit II. Unlike the others, the manual group is composed of four spines--two long spines, a short spine, and a final long one. The "carpal group" originates from the wrist and is positioned perpendicular to the ulna. The "elbow group" originates, as the name would imply, from the elbow. Finally, the "humeral group" erupts towards the proximal end of the humerus. The longest spine in all the groups is CG-III, or "carpal group III," the second long spine in the carpal group. Benton hypothesized that the wing spines were a sort of hypertrophied version of pterosaur actinofibrils, though they obviously evolved independantly. Interestingly, Caprawyvern hatchlings only have a single spine per adult group (except the manual group, where hatchlings have two). Growth studies carried out by Delphi (1997) suggest that these single rods correspond to the "short" spines in adult growth stages, except for MG-I, which is the distalmost spine in both adults and hatchlings. The main spines grow out as the animal matures, eventually surpassing their predecessors.
As noted above, Caprawyvern is extremely hostile to territorial invaders. Five human deaths have been attributed to the goat wyvern, and there have been dozens of reported attacks. The wyvern apparently attacks from above with its talons, scratching and kicking while flapping its wings and screeching. Males are far more aggressive than females, though females are, themselves, surprisingly confrontational.
Without fossil forms, Caprawyvern would be impossible to place among other wyvern clades. The strange wing configuration alone makes classification difficult. Thankfully, a few extinct forms have shed light on the process by which Caprawyvern lost the more traditional wyvern wing. Zhouwyvern haduken (Ryu, 1995) is a small wyvern from China that only has four wing fingers, including a free thumb. What makes Zhouwyvern unique is that the humerus, like that of Caprawyvern, is unusually long while the radius/ulna is proportionatelly short. The structure of the wing fingers suggests that the wing was narrow. Ryu suggested that Zhouwyvern may have had a spine (or spines) erupting from the elbow, as such a structure would have deepened the wing surface. Another caprawyvernine, Protocaprawyvern tusconi (Elyard, 2003), only has three wing fingers, just one of which is connected to the wing surface. Its wing strongly resembles that of Harenadracos. Elyard theorized that, given the resemblence of the wrist and elbow joints to those of Caprawyvern, that Protocaprawyvern must have had cartiliginous spines from at least these two points.
As far as where Caprawyvern, Protocaprawyvern, and Zhouwyvern (the Ceratowyvernidae), we'll leave that to Mantell (2001), who suggested that, based on the unique curved horns and reduced number of wing fingers (four in Zhouwyvern), that the Ceratowyvernidae is a sister group to the Gigantowyvernidae.
References:
Dawson, G. M. (1976). The first comprehensive description of Caprawyvern mencotti, the well-known "goat wyvern" from the American southwest. American Journal of Zoology 23(4): 67-89.
Benton, C. S. (1994). On the unique wing structure of Caprawyvern. Draconium 35(1): 88-94.
Delphi, J. (1997). Ontogeny and Caprawyvern. Wellnhoferia 15(2): 105-111.
Ryu, K. (1995). A primitive fossil wyvern with similarities to Caprawyvern (Dawson 1976). European Journal of Draconology 86(3): 361-366.
Elyard, S. (2003). A new spine-winged wyvern from Arizona. Draconium 44(2): 235-241.
Mantell, G. (2001). A broad look at wyvern systematics. European Journal of Draconology 102(2): 305-311.
Coming Up: Harryhausina marinus, a marine wyvern named after the famed stop-motion animator!

Monday, July 21, 2008

Zhongornis haoae


Zhongornis haoae is an itty-bitty, teeny-weeny juvenile bird from the Early Cretaceous of China. At just over 10 centimeters long, the little guy is positively tiny. The drawing above is a measured one: every piece of the body was drawn according to its length as described in the description. Zhongornis is unique for a number of reasons. First and foremost, its tail is transitional between the long bony tails of Archaeopteryx and Jeholornis and the short lil' pygostyles of the...Pygostylia. Zhongornis has 13 short 'n' stumpy caudal vertebrae which anchored a lengthy tail fan. Additionally, Zhongornis' third manual digit is made up of only three phalanxes, making Zhongornis unique among known birds, both living and extinct.


The skull is badly crushed, so whether the little bird had teeth or not is unknown. I decided to give it a short little beak instead--maybe its teeth grew in later. Gao, et al. (the describers) suggest that Zhongornis' reduced third finger is also in line with the transition from outgroup birds to modern forms, but that can't be true. If Zhongornis is intermediate between long-tailed birds and Pygostylia, one would expect to see confuciusornid birds with just three phalanxes in their third manual digit, but in fact they retain all four. So Zhongornis developed that particular mutation by itself. If anybody would like a copy of the paper, I have it in PDF form, so let me know and I'll send it your way.
Reference:
Gao, C., Chiappe, L. M., MEng, Q., O'Connor, J. K., Wang, X., Cheng, X. & Liu, J. (2008). A new basal lineage of Early Cretaceous birds from China and its implications on the evolution of the avian tail. Palaeontology 51(4): 775-791.

Zhongornis is coming...


I've got a life restoration brewing. Life-size, if you're lucky! Look for it in the coming days.

Wednesday, July 16, 2008

I Need a Mnemonic

Okay, I already know a mnemonic device for figuring out Linnean taxonomy: Kings Play Chess On Fine Green Squares (Kingdom, Phylum, Class, Order, Family, Genus, Speces). I also know a funny one for the major time periods of the Cenozoic: Purple Elephants On My Purple Pajamas (Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene).

Now I need another one. I'm trying to learn the names of the shorter time periods which make up the Mesozoic. I know Triassic, Jurassic, Cretaceous, of course. But there are other, briefer, periods which further divides that time period into more accessable segments. Do any of you out there in Readerland know a helpful mnemonic device for them?

For the curious:

Early Triassic: Induan, Olenekian
Middle Triassic: Anisian, Ladinian
Late Triassic: Carnian, Norian, Rhaetian
Early Jurassic: Hattangian, Sinemurian, Pliensbachian, Toarcian
Middle Jurassic: Aalenian, Bajocian, Bathonian, Callovian
Late Jurassic: Oxfordian, Kimmeridgian, Tithonian
Early Cretaceous: Berriasian, Valanginian, Hauterivian, Barremian, Aptian, Albian
Late Cretaceous: Cenomanian, Turonian, Coniacian, Santonian, Campanian, Maastrichtian

I think I'm screwed.

Tuesday, July 15, 2008

In case you were wondering about E3...

The Electronic Entertainment Expo is this week. Sony, Microsoft, and Nintendo have already given their press conferences, so all the cats are out of their respective bags. It's a ho-hum year, honestly. More of the same from all three companies. Microsoft is implementing a Mii rip-off (sorry, they're "avatars") and touting Gears of War 2 and Fable 2 as the best things ever.

Nintendo continues to roll out the casual bandwagon with a sequel to Wii Sports called Wii Sports Resort. It will probably come with a new attachment for the Wii Remote called Wii Remote Plus, which further refines the motion sensitivity of the Wii Remote. Yipee. Also in the pipe is Wii Music, which utilizes the Balance Board and the Wii Remote plus your monkey-like motions to make music. The game simulates over 50 different instruments. Again, yipee. Nothing about any new Mario, Zelda, or Metroid games. The closest we'll get to classic Nintendo is a new Animal Crossing (Wii) and a remake of the old SNES classic Kirby: Super Star for the DS. Weaksauce, Nintendo. Most surprisingly, however, an original Grand Theft Auto game is coming to the DS, and Call of Duty: World at War is hitting the Wii.

Sony showed off Resistance 2 and gave us a little teaser for God of War 3 (as expected). Downloadable movies and content were the big topic, though, and PS3 owners will be able to rent and buy movies for their systems tonight. There will also be a downloadable "sequel" to Ratchet & Clank Future that will cost $15. The PSP is getting a bunch of useless new bundle packs and its own Resistance game.

What am I most excited about? They announced a PSP sequel to Patapon!

Lackluster E3, for the most part. No big shockers, and I'm disappointed overall.

My Name is LUCA

As written by Howard Landman, and originally posted at Catalogue of Organisms, I give you the most awesome science song ever:

Sung to the tune of "My Name is Luca."

My name is LUCA,
I lived on the ocean floor
near some hydrothermal vent
or maybe in a tidepool by the shore.
And everything that's now alive
is my descendant that survived.
All the others went away (x3)

I'm not the first life, no,
That was way before my time.
Things were so much simpler then,
the start of evolution's climb.
Born in a world of RNA,
or some say protein, some say clay.
No one knows just what it was (x3)

Now if you feel inclined
to explore your family tree,
you're gonna have a real hard time
tracing your way back down to me
'cause horizontal gene transfer
has left the path a tangled blur.
Still, it wouldn't hurt to try (x3)

(repeat first verse)

Must...learn...guitar!

Monday, July 14, 2008

The Trouble with Scavenging

Blogging on Peer-Reviewed Research
Here's the thing about Jack Horner's much-talked-about T.rex scavenging hypothesis: It's not so much an actual theory as a Creationist-like argument about why T.rex could not have been a predator. The king has puny arms, tiny eyes, a big nose, couldn't run very fast, and was "ugly," which apparently means that Tyrannosaurus rex was just plain incapable of killing its own dinner, and was thusly forced to walk the Earth a lowly scavenger, picking across any food it stumbled over. Horner's theory is more personal preference than anything else. Just because he can't see it any other way must mean that he's right. Well, I was so happy to see a paper in my new T.rex book by Thomas Holtz, Jr. that sets the record straight. And by "sets the record straight" I mean "mowed down the obligate scavenger hypothesis."

The claims bombarded by Dr. Holtz's silly "evidence" are as follows: T.rex has small eyes relative to skull size; the tibia and femur are about the same length; the forelimbs are really short; the teeth are wide and not bladelike. These passive-aggressive questions really mean the following: T.rex couldn't see very well; T.rex couldn't run very fast; T.rex had puny little worthless arms; T.rex's teeth were not very strong and would have shattered if they hit bone. I've called bullshit on those claims for years. It's good to see somebody actually throw some hard evidence at the problem, and maybe this will finally shut Horner up.

T.rex had "beady little eyes."
I wish I'd made that up, but it comes right out of Horner's mouth. T.rex's eyes are unlike those of, say, Velociraptor, which has large eyes. The first question here is "so what?" But also, how do T.rex's eyes compare to other theropods? It turns out that as theropod dinosaurs get larger, their eyes get smaller. And the eyes don't actually shrink--the skull just grows faster than the eyes as skull size increases. In fact, there are other theropods with smaller-than-average eyes including Giganotosaurus and Dilophosaurus. They must have been scavengers! T.rex was just about average given its size. Besides, in terms of absolute size, T.rex had really big eyes! The largest measured specimen's orbit diameter is 120 mm. That's pretty big. And keep in mind that unlike allosauroids, T.rex had pretty respectable binocular vision. If you're scavenging all day, why do you need binocular vision?

T.rex couldn't run very fast.
That's true, but it ultimately doesn't matter as long as T.rex could run faster than its prey, Einstein. When you plot the measurements, it turns out that T.rex's hind limbs were quite fast, and one step taken by a T.rex was longer than that of an allosauroid or ceratosaur of the same femur length. This means that--gasp--the tibia and metatarsals were elongated relative to the femur. Thus, tyrannosaurs were faster than other similarly-sized theropods. And you're never going to believe this, but bear with me here: tyrannosaurs were faster than contemporary herbivorous dinosaurs! SHOCK AND AWE! Better yet, tyrannosaurs developed arcometatarsus, or a "pinched" metatarsus which suggests that T.rex could turn faster on its narrow feet than non-arcometatarsus theropods. And wouldn't you know it? Duckbills, ceratopsids, and ankylosaurs lack the arcometatarsal condition. So T.rex could run faster and turn quicker than his prey. Go figure.

T.rex had useless little forelimbs that were totally useless. Useless.
Several papers in this book deal with T.rex's pectoral girdle and arms specifically. Muscular reconstructions, pathologies of the arms and furcula (Rothschild & Molnar), and range of motion of the arms have shown that--guess what--T.rex actively used its arms. The king probably got its forelimb workout by clinging to struggling prey (Lipkin & Carpenter) and/or helping right itself while getting up from a sitting position (Stevens, Wills, Larson & Anderson). Even besides that, there are plenty of modern (and extinct) carnivores that hunt prey without the help of their arms, including orcas, modern raptors, terror birds, Diatryma, and crocodilians.

T.rex had stout, deeply-rooted teeth that would have shattered on impact with bone. Wait...seriously?
For me, this is the dumbest argument. It's been demonstrated multiple times that Tyrannosaurus rex and its immediate relatives had ridiculous, astronomical bite forces and that their teeth and jaws were specialized for crushing bone. I imagine that their teeth were modified to allow such an activity. There are at least three instances in the fossil record of a tyrannosaur tearing through bone in the pusuit of food: an Edmontosaurus tail with several neural spines lobbed off, a Triceratops pelvis with several deep scraping tooth marks in it, and a Triceratops skull with a bitten-off horn core (Happ, this book). While the Triceratops pelvis may have been so marred by scavenging activity, the Edmontosaurus lived another day, and the bones healed. Thus, it escaped its pursuer. And one can only imagine that T.rex did not pick its teeth with the orbital horn cores of dead ceratopsians, so that particular exchange probably took place during either an attack by the tyrannosaur or an attack by the Triceratops, perhaps defending its brood from the marauding predator.

So, while it's difficult to prove that Tyrannosaurus rex was a predatory animal, it turns out that all of Horner's claims which would force the king into a purely scavenging role are wrong. It's silly to say that Tyrannosaurus never scavenged--like any other wild carnivore alive today, it probably would've happily feasted on a fresh corpse if it found one. However, it's clear that Tyrannosaurus rex was perfectly capable of finding and taking down its own meals. And circumstantial evidence (the Edmontosaurus tail in particular) suggests that it did. It's also worth mentioning that not a single modern animal that scavenges exclusively. Hyenas actually kill a lot of their meat, and turkey vultures are not above eating hares, lizards, and other small vertebrates.

There is another classic Horner claim that I would like to address, though it is not addressed by Dr. Holtz. The fact that Tyrannosaurus rex had a great sense of smell is apparently indicative of a scavenging lifestyle. Like the tiny arms, I don't see the connection. Dinosaurs in general had above-average olfactory senses (except the more avian ones). Ankylosaurs had large, complex sinus passages. Does that mean they scavenged carcasses? No! Modern animals with great senses of smell, like dogs, do not use their noses exclusively to find dead meat. Often, they use their noses to find live meat, or marks left by other dogs, or other dogs. Perhaps dinosaurs had a complex marking system. Maybe they just had a good sense of smell! If Tyrannosaurus rex lived in a family unit, a good sense of smell would be advantageous to finding your chicks, your mate, and rival families. Great sense of smell does not equal obligate scavenger.

In fact, in every Horner claim made above, the man makes a very basic logical error: the fallacy of equivocation. Although his claims are patently false, even if they were true, that doesn't mean that Tyrannosaurus rex was an obligate scavenger. He fails to make any real connection between, say, short arms and scavenging. Allosaurus didn't have arms as long as Velociraptor either. Does that mean it was a scavenger? In fact, Allosaurus had fairly short arms, very little binocular vision, a shorter femur/tibia ratio than Velociraptor (or T.rex), and blade-like teeth that certainly couldn't damage bone. According to Dr. Horner, it must have scavenged, too! In fact, virtually all large carnivorous dinosaurs must have been scavengers! Those big sauropods in Gondwanaland had nothing to worry about.

I'm so thankful that Dr. Holtz shot the obligate scavenger hypothesis down. I have never liked it, and I'm glad somebody finally threw some facts at it. Also, if you have any interest in the Tyrant Lizard King, this book is really awesome.

Update

I got my awesome T.rex book on Friday, and it kicks ass. My favorite paper is one in which Thomas Holtz, Jr. tears apart the "obligate scavenger" hypothesis, which I'll be blogging about shortly. The book comes with a cool CD-ROM which includes supplementary material including an awesome animated T.rex skeleton (investigating how T.rex sat down and got back up), a visual atlas of the big theropod's skull bones, and some other interesting nuggets. All in all, it's a great book. I'm still waiting on the fossil dog book, though. That book was delayed, which is odd, because there are two copies in the physical store.

I also found a way to make my own DS/GBA game cases. The problem first arose when I bought Guitar Hero: On Tour for the DS, and found that the game came in a big cardboard box without a proper game case. The solution was quite simple: find an empty DS case and create my own insert label. One of my NWR colleagues turned me on to The Cover Project, a site dedicated to creating custom game case insert labels (including On Tour). It didn't take me long to realize that I could do the same for GBA games, as DS cases include a space for GBA games. So I ordered a set of 10 empty DS boxes from Nintendo of America's website, and printed a bunch of awesome high-res insert labels. I am very excited.

Friday, July 11, 2008

Michael Trcic Awesomeness

Must save pennies, must save pennies, must save pennies...that site actually has a TON of awesome stuff, including awesome dinosaur skulls and skeletons from Dinostoreus and various other cool knick-knacks. Maybe I'll put this whopper on my birthday wish list. It's $200, but it's also 18.5 inches long! Trcic's sculptures are beautiful--the Dilophosaurus vs. Yunnanosaurus is also on my "must have" list. And how does one pronounce "Trcic?"

Tuesday, July 08, 2008

Glyptodon crivapes


I was browsing through the Tetrapod Zoology archives when I rediscovered this brilliant photo of Glyptodon crivapes' skull. Glyptodonts are big armadillo-like xenarthans, although how closely related they are to modern armadillos is a bit hazy. Personally, I think the skull looks a bit more like the skull of, say, Megatherium (giant ground sloth) than a nine-banded armadillo, but of course I know very little about mammalian taxonomy.

Anyway, look at how beautiful that skull is! It looks like it died a few months ago, not millions of years ago! The preservation is astounding. I'd love to see a real "live" glypodont skeleton in a museum.

One more thing, dear readers. Given their bizarrre skulls (look at that jugal flange!), it's incredibly difficult for me to envision their muscular anatomy. Are there any papers, books, etc. which investigates xenarthan cranial musculature? In the meantime, check out this post at Tet Zoo for more information on the Cenozoic's take on ankylosaurs!

Monday, July 07, 2008

I Can READ?!

I'm just as shocked as you are, but there were two books at Barnes & Nobel that I couldn't say no to. The first is Dogs: Their Fossil Relatives and Evolutionary History. I'm not a fan of canids per say, but I love Mauricio Anton's art. He illustrated Evolving Eden and Mammoths, Sabertooths and Hominids, and his mammalian reconstructions are unmatched in paleoart circles. In my opinion, anyway. The book is authored by Wang & Tedford and seems to be a exhaustive history of doggies. After leafing through the book in the physical store, I was incredibly happy to see an entire chapter dedicated to reconstructing dogs, from the fur to the muscles to the skeleton. This will be ridiculously helpful not just for drawing dogs, but mammals in general. As I've mentioned before, mammals' anatomy is deeply divergent from reptiles and I find them much more difficult to draw.


I'm far MORE excited about Tyrannosaurus Rex, the Tyrant King, a symposium-type book edited by Larson & Carpenter, all about everyone's favorite giant carnivorous theropod. Like Scott Elyard, I think T.rex is a little...overdone, but I also think that the animal is loaded down by a bunch of dogmatic baggage, and it'll be interesting to see what modern studies say about the beast. Some of the essays look pretty intruiging: Thomas Holtz, Jr. tests Horner's obligate scavenging hypothesis, Ralph Molnar discusses tyrannosaur jaw musculature, Larson talks about sexual dimorphism, and a bunch of authors discuss the king's puny forearms...among many other interesting papers!
From what I understand, a new technical volume on ceratopsids is set to come out this year, too. Does anybody have any information on that book? And please tell me it's going to be better than that lackluster Horns & Beaks.

OMGS!

Although I've been done with the game for awhile now, I only recently posted a review of Metal Gear Solid 4: Guns of the Patriots. It can be found here, at Nintendo World Report.

Saturday, July 05, 2008

Dino Diagnosis of the Day

Time for another edition of Dino Diagnosis of the Day! Remember, these diagnoses are taken directly from the original publication, and any pertinant names have been removed. This is an old dinosaur, so you might not know it right off the bat! And awaaay we go!

"A bipedal saurischian of small size, with strong hind limbs and small forelimbs. The bones are hollow, but with rather thick walls. The lower jaws are long, about equal to the length of the femur, indicating a skull quite large in relation to the size of the body. The theeth are thecodont. There were probably about 23 to 25 presacral vertebrae (the anterior ones are missing), three sacrals and a long tail with perhaps 40 or more vertebrae. The centra of the vertebrae are platycoelous and constricted in their mid-portions. The vertebrae have strong diapophyses, with buttresses beneath them, and rather short, heavy neural spines. The ilium is deep and short, its iliac crest being abbreviated, and produced posteriorly. The acetabulum is deep within the ilium and its upper margin forms a shelf to take the thrust of the femur against it. The pubis is long, about two-thirds as long as the femur, broad and platelike, and the two pubes are joined along their midlines by a long symphysis. The ischium is broad proximally, but narrows to a rodlike bone in its more distal portions. The bones of the pelvis seemingly do not unite firmly, but rather are joined by restricted facets, so that the central portion of the acetabulum is open. The femur is a curved, heavy bone, the head strongly set off from the shaft, with no lesser trochanter, but with a strong fourth trochanter. The tibia is strong and the tibia and fibula are elongated, being slightly longer than the femur. The astragalus and calcaneum are obviously separate, but evidently in life were closely appressed to the limb bones."

It just keeps going on like this. The paper has no short "diagnosis" section, thus I've left off the rest of the paper. But this should be enough to get you started.

Friday, July 04, 2008

Happy Birthday, Lady Liberty

Shoot--somebody find me a lapel pin! My patriotism is in doubt! It's the only thing that matters!

Wednesday, July 02, 2008

The Ultimate Introvert

As you readers may have heard me lament before, chameleons are shy and antisocial. Both of my Jackson chameleons (Darwin moreso than Eldridge) would simply lean away from my hand, avoiding human contact unless actively picked up, at which point they would both sit on my outstretched fingers and pout. Eldridge would get over it and start exploring, but Darwin would just stare at me with a certain death gaze, utterly refusing to have fun.



Well, as bad as those two were, neither can even compete with the introversion of the Labord's Chameleon. According to a new paper in PNAS, these little buggers would rather spend most of their lives within the confines of an egg than be forced to explore the outside world. In fact, Labord's Chameleons spend 8 or 9 months in the egg and only 4 or 5 months outside of it. The animals reach sexual maturity within two months, breed, and proceed to die. When the dry season hits, all of the adults are dead, and the population consists only of embryos in eggs. The babies hatch 8 or 9 months later at the start of the rainy season, grow quickly, get lucky, lay their eggs, and drop from their perches. And so the bizarre, morbid cycle continues.

Most animals would opt to evolve a mechanism for getting through the dry season while still alive, but it would seem that Furcifer labordi has put all of its eggs in one basket, as it were.

Hat-tip to Zooillogix for reporting the story!

Tuesday, July 01, 2008

April O'Neil coming soon!


Remember those awesome NECA Ninja Turtles figures I posted awhile back? Well, I bought 'em (I should really take a picture), and was very happy to learn today that NECA plans on releasing an April O'Neil figure later this year or early next year. Her look is sort of taken from the original comics, although her hair isn't right (much frizzier in the comics) and her face seems too long. What really makes me happy, though, is her blue jumpsuit and the Mousers at her feet! Those are some kickass Mouser sculpts. The fact that April connects to a base makes me suspect that NECA has more TMNT toys on the drawing board. I'd love to see their interpretations of the Shredder, Dr. Honeycutt, and the Triceratons!