Posts Tagged ‘serpentes’

Show Me Your Pits

13 June 2010

Totally over frogs.  Now we’re all about snakes.  Also, lizards.

See it? I'll give you a hint, it's a Teiid

What’s next?  Dinosaurs?  Turtles?

stay tuned…

UPDATE

SPOILER ALERT! :

It’s a California Whiptail (Aspidoscelis tigris munda)

I kill children, can hardly wait for yours…

1 March 2010

Sculpture by Tyler Keillor and original photography by Ximena Erickson (image modified by Bonnie Miljour and, uh, me).

There is an old cliché amongst journalists, which I am sure you have heard before, “If it bleeds, it leads.” There is a slightly less familiar version: “If it ate baby dinosaurs it…well I can’t think of a rhyme but trust me, people go crazy for this stuff.”

Okay, so maybe nobody has ever actually said that, but it’s true.  Witness the widely celebrated accusations of dino infanticide recently leveled against the corpulent Jabba the Hutt wannabe Beelzebufo, those protarded Azhdarchoids, and some middling theropod I cannot seem to remember the name of right now. Each of these charges is built more or less on sound scientific inference, based on comparisons with living animals, but they aren’t exactly trial-worthy.  Even more compelling is the case against the dino-munching Mesozoic mammal Repenomamus, discovered with a chewed up and partially digested juvenile Psittacosaurus (sort of a low-rent Triceratops knockoff) in its gut.

And then there’s Oviraptor, whose very name transliterates to “egg-thief”, branded for half a century as a heartless baby killer when it was discovered near a clutch of dinosaur eggs, until scientists worked out that the eggs were actually its own.  This PR transformation is nicely, uh, summed up by this YouTube Tribute:

Which, now that we have veered so radically off track, is a good enough time as any to drop the news about this un-FREAKING-believable fossil described today in PLoS Biology:

Figures 1 (top) and 2 (bottom) from Wilson et al. 2010 'Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India' PLoS Biology

In 1984(!) this fossil was first uncovered in the Indian state of Gujarat.  In 2007, the Geological Survey of India announced the discovery.  Three short years, and who knows how many hours of preparation and study, later this new paper finally presents a full description of the fossil and gives it a name: Sanajeh indicus. The genus name is derived from Sanskrit for “giant gape” for those of you keeping score at home.  In fact, by the strict rules of zo0logical nomenclature, electronic publications don’t count at valid descriptions to establish a new name.  Following a lesson learned during the Darwinius debacle, PLoS is selling a limited run of print copies of the paper: $10 a pop if you want to invest in a little paleophiliogical memorabilia.

While certainly not the oldest snake fossil yet discovered as erroneously claimed in the 2007 report (we’ll see if any enterprising journalists pick up this non-fact), Sanajeh indicus does have important implications for the early evolutionary history and paleobiogeographic origins of snakes.  Snakes evolved from lizard ancestors some time in the Mesozoic, but precisely where, when, how and from whom has been a matter of some debate.  Sanajeh probably won’t settle any of these questions, but it certainly will allow us to push them a bit further.

But, who cares really, because, oh yeah did I mention? IT ATE BABY DINOSAURS! Expect to hear plenty on this elsewhere so I won’t belabor the issue but, something to think about the next time you reach for the carton of cage-free AA dinosaur eggs in your fridge:

We behold the face of nature bright with gladness, we often see superabundance of food; we do not see or we forget that the birds which are idly singing round us mostly live on insects or seeds, and are thus constantly destroying life; or we forget how largely these songsters, or their eggs, or their nestlings, are destroyed by birds and beasts of prey. – some dude.

REF

Wilson JA, Mohabey DM, Peters SE, Head JJ, 2010 Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India. PLoS Biol 8(3): e1000322. doi:10.1371/journal.pbio.1000322

Why is a protarded boa constrictor like a writing desk, I mean, thermometer?

5 February 2009

“In a word, the form of the tooth entails the form of the condyle; the forms of the shoulder blade and the claws, just like the equation of a curve, entail all their properties. Just as in taking each property seperately as the basis for a particular equation, one would find both the ordinary equation and all the other properties of any kind, so likewise the claw, the shoulder blade, the condyle, the femur, and all the other bones taken seperately, determine the teeth, and each other reciprocally. Beginning with each of them in isolation, he who possesses rationally the laws of organic economy would be able to reconstruct the whole animal.” — Cuvier 1812, trans. Martin Rudwick.

From our irregular series - Bloggers half-assedly opining about peer-reviewed papers when, really no one asked them in the first place anyway

From our irregular series, "Bloggers half-assedly opining about peer-reviewed papers when, really no one asked them in the first place anyway."

Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier was a man of strong opinion and bold statement. In the most dramatic articulation of his “Principle of the Correlation of Parts” Cuvier argued that anatomy, like God, bows to math. Given a single isolated bone, he claimed, one might be able to infer what the entire animal looked like, at least in principle. In following paragraphs Cuvier hedges his bold assertion just a bit, but this is the idea for which Cuvier is remembered, and misremembered, the most.

Creationsists love to bring this up, “scientists find a few scraps of bone and make up a dinosaur.”  Ironically, it was Cuvier’s own vision of “intelligent design” and “irreducible complexity” that informed his view. On the opposite side of the spectrum, Thomas Henry Huxley took Cuvier’s claim to task in his lecture “On Natural History, as Knowledge, Discipline, and Power” (see also Hugh Falconer’s rebuttal). In a later, and tremendously entertaining essay, “On the Method of Zadig” Huxley argues that Cuvier’s principle can be of some use, as long as it is conducted cautiously and in an explicitly evolutionary context.

These days most paleontologists would claim that they aren’t so bold as Cuvier, and that they wouldn’t seriously attempt to reconstruct an animal based upon a single bone (though they certainly might do so for a laugh). I would argue, however, that we’ve actually gone far beyond Cuvier’s wildest dreams. Correlation and exrapolation are largely the name of the game. This is how we sex the brooding theropod, draw out the fetal leviathan, and diagnose the dueling dinosaur.

The much publicized recent discovery of Titanoboa is significant not only because it’s a freaking huge-ass snake, though admittedly it is one ginormous, redonkulus, totally protarded animal. Even more amazing than the snake is what Jason Head and coauthors* do with the fossils. Given a handful of vertebrae from several individuals, they first extrapolate the body size of the animal based on the anatomical proportions found in the largest living snakes, python and anaconda. Then, and this is the really amazing part, they use the size of the snake to calculate paleo temperature based on the relationship between geographic distribution, temperature and body size among living reptiles. In fact, the authors even propose a pole to equator temperature gradient–based on the size and shape of the backbone of an extinct snake!!

If the scientists were simply saying “big snake = tropical weather,” as most news outlets are basically reporting it, that wouldn’t be very noteworthy. But this may be the first time that a fossil vertebrate has been used to calculate a numerical paleotemperature estimate. At last year’s Society of Vertebrate Paleontology Conference I saw one of the authors, David Polly, give a pretty amazing lecture using ankle bone shape to estimate paleoenvironment and paleoclimate.

Taking the temperature of the tropics with a snake – Head et al. 2009

This kind of claim is certain to draw criticism and skepticism within the paleontological community and, probably especially, from neontologists and paleoclimatologists. That’s not neccesarily a bad thing, radical new ideas in science need to be tested. I’m certainly not totally convinced. Still, for a science as old and dusty as comparative anatomy, it’s pretty exciting to see this kind of novel and creative work. It gives me hope that there are plenty of new surprises out there still waiting to be discovered. Cuvier would be proud I think.

For more huge-ass snakes see: Snake Handlin’

* – full disclosure, I’m friends with one of the authors and have worked with him in the field.

LIFE, with reptiles

20 November 2008

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Photo Tony Linck,  1948

Matt from HMNH recently posted some gems from the amazing LIFE photo collection that is going up on Google.

Here are some amazing images filed under “Reptiles.”  Each, warrants pages of minor musings, but of course each is worth volumes alone so I’ll spare you.  Keep your eye out for gliders in glight and stone, safety-conscious crocodilians, A. S. Romer in a jam, and of course various feats of snake handlin.    Happy Hunting!

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Photo Ralph Crane, Los Angeles 1972