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Amphibious Aquatica

  1. Apr 2, 2004 #1
    Researchers digging along a rural Pennsylvania highway have unearthed what they say is the world's oldest known arm bone, once used by a slithery creature to raise itself out of a prehistoric swamp.

    The bone formed the upper arm of an animal about 3 feet long that looked like a flat-headed salamander and lurked in swamps and shallow waters 365 million years ago.

    The size and shape of the thumb-sized bone indicate that the animal was a four-limbed creature -- a tetrapod -- and used its arms to raise the front end of its body, push-up style.

    Many experts agree that fins on fish evolved into legs as primitive amphibians began to move from one waterway to another during dry seasons. But researchers say this discovery could help resolve a long-standing question among evolutionary biologists: did limbs develop on land or in the water?

  2. jcsd
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