|
filthy
SFN Die Hard
USA
14408 Posts |
 Posted - 06/04/2002 : 08:51:00
|
Since Kacey found urgent business elsewhere, things seem to have gotten pretty quiet. So, I thought maybe I'd try and liven it up a bit.
Serpent evolution: Wassup wid dat?
For as long as I can remember, snakes were considered to have evolved from a burrowing lizard, and that was the end of it. Then, some years back, there began a discussion of whether snakes came from an aquatic ancestor, perhaps something similar to a mosasaur. http://www.anomalous-images.com/news/news578.html
Now, there are some problems, here: A( snakes are most un-lizard-like and B( they are also most un-mosasaur-like. And C( good snake fossils are not all that easy to come by.
Today, there are several species of legless lizard. These are called Glass snakes in the US and Slow Worms in the UK (don't know what they're called elsewhere). At a glance, they look for all the world like a snake. Indeed, they have snake-like habits. But unlike snakes, they have eyelids (proves nothing - many species of gecko lack eyelids), ear holes, a detachable tail that can be regenerated, and are, for the most part, insectivores (also proves nothing - a few snakes also are insectivores). But, all lizards lack one, important feature than only snakes have. They cannot crawl on their bellies...... Say what??
The scales on a snakes belly go all the way across the animal and are linked into a network of muscle that allows them to be advanced and contracted. The snake can sort of caterpillar it's self along and is the primary means of locomotion for many species, especially larger, heavy-bodied ones like Gaboon Vipers (Bitis gabonica). Some, like the Rat Snakes (Genus Elaphe) and many of the Boids, also climb rough-barked trees using the same, excellent method.
NO other creature in the world has evolved this remarkable and efficient means of getting about. Today's legless lizards do not have it and I would not think that they‘d ultimately evolve it.
If I were forced to speculate, I'd say that snakes did not evolve from lizards. I think there was a different ancestor all together and it probably was a relatively small, aquatic reptile that came ashore, but not a mosasaur. (More speculation) Could it have possibly been the common ancestor of lizards and snakes?
Or did the Great and Caustic Mojo wake up with a hangover and accidentally create it all whilst searching for the aspirin?
Thoughts?
f
If I do not return to the pulpit this weekend, millions of people will go to hell.
-- Rev. Jimmy Swaggart, 20 May 1988
|
|
Topic Locked
