261: Surprising Footprints in Old Sand

The New York Times > Science > Surprising Footprints in Old Sand:

Today, a barefoot walk on one of the North Atlantic beaches of Nova Scotia is a chilly experience. But 350 million years ago, Nova Scotia lay near the Equator, and scientists have found thousands of footprints left by animals trundling across this tropical paradise.

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The very first four-legged creatures to flop ashore did so only about 370 million years ago, and, while capable of occasional forays on land, they nevertheless spent most of their lives in water. Fossils of these earliest land animals show that their fins-turned-feet had as many as eight toes.

On the other hand, the feet that tromped across Blue Beach, on the north central coast of Nova Scotia, all had five toes and appear to be those of amphibians and reptiles that lived largely out of the water.

This is evolution, some tectonics, and speciation.