Tuesday, 27 January 2015

Oh Creation! Now It's Transitional Snake Fossils!

Source: Nature Communications
Fossils of oldest known snakes unearthed | Science/AAAS | News: "DOI: 10.1126/science.aaa6402"

Thanks to Science Magazine's excellent content sharing initiative, I'm able to embarrass creationists with another piece of science for them to ignore or lie about. This time it's news of the discovery of four very early snakes which push the known evolution of snakes back by almost 70 million years and they show unmistakable signs of transition from lizards with whom they are known to share a common ancestor.

So that's transitional snakes living between 143 and 167 million years ago, and already showing considerable diversification, suggesting an origin many millions of years earlier. It must be embarrassing having to try to force-fit facts like that into a superstition which claims Earth is only a few thousand years old and all the animals were created as they are today in a single day. In fact, it's hard to see creationism being more detached from reality than it needs to be to maintain a belief in it in the face of such overwhelming contrary evidence.

Abstract
The previous oldest known fossil snakes date from ~100 million year old sediments (Upper Cretaceous) and are both morphologically and phylogenetically diverse, indicating that snakes underwent a much earlier origin and adaptive radiation. We report here on snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous). These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter). The paleobiogeography of these early snakes is diverse and complex, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic. Phylogenetic analysis of squamates recovers these early snakes in a basal polytomy with other fossil and modern snakes, where Najash rionegrina is sister to this clade. Ingroup analysis finds them in a basal position to all other snakes including Najash.



Source: Nature Communications
The fossils were discovered when a systematic examination was made of museum specimens stored away for decades in draws and cupboards. Two were originally found in Southern England, one in Portugal and one in the USA. One of them had evidence in its vertebrae indicating it may have had hind legs.

As the authors go on to discuss at the end of this article, the evidence now is that snakes evolved from a lizard which first evolved a head which we would now recognise as distinctly snake-like. This was probably the founder of a new clade which increased in body length and reduced or lost limbs altogether over the succeeding millions of years.

These four fossils were all found in locations which, when plate tectonic movements are wound back to the time when this radiation began, places them all within the same geographical region of Pangea. In fact the authors predict that there should have been a short-bodied, four-legged 'stem' snake pre-dating these fossils by several million years. I wonder how creationists will dismiss it if just such a fossil is ever found.

By contrast, the standard creationist explanation for snakes is that they used to walk about and talk to humans but because one of them spilt the beans about God lying to Adam, they were made to crawl about on their bellies and eat dust (Genesis 3:14). No known species of snake has the apparatus for speech and no evidence for it has ever been found in the fossils of extinct species. None has ever been known to eat dust and no evidence has ever been found to support the story. Creationists regard this as a far more plausible account of how snakes arose than the scientific one based on evidence such as that presented in this Nature Communications article.

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