Land Fish Linkage

'Link' Between Fish and Land Animals Found
Discovery Called Key Evidence Of Vertebrates' Ocean Origins

By Guy Gugliotta
Washington Post Staff Writer
Thursday, April 6, 2006; Page A03

Scientists yesterday reported discovering an evolutionary "missing link" between fish and land animals -- an ancient, river-dwelling predator with arm joints in its fins, an alligator-like head and ribs heavy enough to support its body on dry land.

Researchers found several fossils between four and nine feet long. The creature was a fish -- with scales, fins and gills -- but it moved its head independently of its body, could drag itself along on land as today's seals do, and may have walked, although the research team did not find fossil hindquarters to test that hypothesis.

Here's hoping they find those back hips sometime soon. This is still freakin' amazing. When you think of the range of new information and empirical stats on one of the most significant evolutionary steps of life on earth... Wow! lol

I especially like the detail of where they found these, and where the fossils actually lived and died.

The fish lived 375 million years ago in what had been an equatorial river delta before continental drift moved the land mass northward. The team dubbed it Tiktaalik roseae . "Tiktaalik" is an Inuktitut word for "large, shallow water fish," and Shubin said "roseae" refers to one of the patrons of the project who wants to remain anonymous. The research was reported today in the journal Nature.

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Hans Sues (of the Museum of Natural History at the Smithsonian) said scientists first subscribed to a theory that the red sedimentary rock where most of the transitional fossils were found indicated an ancient desert climate, and that legs evolved because fish were trapped in evaporating ponds and "had to move out or die."

"That became passe, when scientists in recent years found good lakes for the creatures," Sues said. "It seemed likely that they never left the water, and instead evolved limbs for the purpose of running along under the surface. One idea is that they developed limbs to navigate lakes choked with vegetation."

That's another bit o' new understanding that's been garnered from the dedicated and intelligent collection of data scientists are always performing in their craft. The critters learned how to walk before even leaving the water! I think it makes such a transition appear more likely to occur than the older idea.

These findings, like so many others awaiting discovery, are really providing some o' that missing linkage.