Python pelvic girdle and snake evolution

Name : Mel McGee
Date : 09.08.04
Email : melnbecky@yah City : lakewood
Country : U.S.A

Message : Hello, Let me start out by saying what a great site you have developed. I just have a quick question. Can you direct me to information regarding the pelvic girdle as found in any snake species, or the yellow python in particular. Anything you can provide would be gteatly appreciated.

Thanks again. Mel McGee melnbecky@yah


Mel,

Thanks for writing.


Lenny Flank is more an expert on snake evolution than I am. He runs a yahoo group on creation and evolution. Here's an article by Lenny on snake evolution, unfortunately no photos:


geocities.com/lflank/


However, I googled:


python "pelvic girdle" evolution


and I found the following excellent letter to NATURE magazine with a photo of the python's pelvic girdle and limb buds that can be seen plainly in the python embryo! Excellent colored pics to use in a creationist debate, and the author of the letter even includes pics of the leg buds in the chick embryo for comparison:


www.mcb.uct.ac.za


----------


I also googled "snake evolution" and "evolution of snakes" and found the following fascinating articles:


How the snake lost its legs: Snakes, researchers once thought, descended from humble burrowing lizards. New evidence suggests a marine pedigree, and a family tree that includes 45-foot reptiles Discover, July, 1997 by Carl Zimmer


"...How did snakes come to be? The distinctiveness of the animals obscures their ancestry. Their scales, eggs, and subtle features of their skulls show them to be descended from lizards, but it's been difficult to link them to any specific group. Unable to pin them down taxonomically, paleontologists have been able to construct only the flimsiest of scenarios for how snakes lost their limbs. But this confusion may now dissolve, thanks to a 100-million-year-old fossil of a snake with legs. The three-foot-long creature, Pachy rachis problematicus (meaning "problematic thick-ribbed animal"), was discovered in the late 1970s by quarryworkers 12 miles north of Jerusalem. After a preliminary study, Hebrew University herpetologist George Haas suggested that while the fossil looked serpentine, there was no evidence that it was closely related to snakes. There matters rested until 1996, when Michael Lee of the University of Sydney in Australia and Michael Caldwell of the Field Museum in Chicago came to Jerusalem to study the fossil more thoroughly. They exposed more of the fossil from its limestone slab and carefully compared its skeleton with those of snakes and lizards. "The first thing you've got to do is look at every possible animal it could be related to, and Haas didn't have access to lots of primitive snake material," says Lee. He and Caldwell conclude that Pachyrachis possesses many characteristics unique to snakes. Its body, for example, is long and sinuous: it has 140 vertebrae in its trunk; most lizards have just 25. And while lizards have open brain cases, Pachyrachis, like snakes, has a completely sealed one. Its jaws are extraordinarily flexible: the lower jaw doesn't fuse at the chin, so the two halves can bend out to the sides to swallow big prey. Many hinges lie along the length of both the upper and lower jaws to expand the gape even more. "They're snakes, no doubt about it," says Lee. Yet Pachyrachis still held on to some primitive bits of anatomy, and in them Lee and Caldwell glimpse the genealogy of snakes. Most obvious, of course, are the legs. The fossil of Pachyrachis bears two hind legs, each about an inch long, that lack only feet. It's possible that Pachyrachis's feet were washed away after it died, but Lee suspects they would have been vestigial at best, perhaps with a few toes. Less obvious but just as significant are its hips, which were outside its rib cage rather than within, and a number of diagnostic details of its spine and skull."...

www.findarticles.com


And see...


news.bbc.co.uk


news.nationalgeographic.com


www.dal.ca


And these fascinating articles on the evolution of snake venom:


www.abc.net.au

And here's an article:

FOSSIL SNAKES OF NORTH AMERICA: ORIGIN, EVOLUTION, DISTRIBUTION, PALEOECOLOGY

Issn: 0272-4634 Journal: Journal of Vertebrate Paleontology Volume: 21 Issue: 1 Pages: 201-202 Authors: ALBRIGHT, L. BARRY


Cheers!


Edward T. Babinski


Make a shorter URL to this article. Highlight link and "Copy To Clipboard"

-->