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PALEONEWS:New Species Fills Evolutionary Gap

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New Species Fills Evolutionary Gap

LONDON, April 4 (Reuters) - British scientists said on Tuesday they had
identified a new species that fills a crucial gap in the evolutionary
transition from fish to land animals about 370 million years ago. 

Fossils of the creature were found embedded in rocks excavated from
Latvia and Estonia in Eastern Europe. 

They consist of two small pieces of lower jaw, showing a bone
arrangement half-way between those of fish and prehistoric four-legged
land animals known as tetrapods. 

The arrangement of the jaw changes greatly at the fish-tetrapod

"This fossil shows just about a perfect intermediate condition between
fish and amphibian," Dr Per Ahlberg, of London's Natural History Museum,
told a press conference. 

"We've had fossils with very advanced fishes. We've had fossils with
very primitive land animals called tetrapods. But there had been a gap
in the middle until now. This is where the new fossil fits in." 

Ahlberg said this evolutionary route gives us a better understanding of
where we have come from and also who we are. 

The unnamed creatures had a crocodile-like body, long head, eyes close
together on top of its head and a tail fin at the rear. Most of the
advanced fishes and the most primitive amphibians have those
characteristics, Ahlberg said. 

All amphibians, reptiles, birds, mammals and humans are ultimately
descended from one small group of fishes that left the water about 365
million years ago, according to Ahlberg. 

But until recently, the evolutionary transition from fish to tetrapod
was poorly understood by scientists. 

Ahlberg also believes it may be possible to find complete skeletons,
which could show how tetrapod features like limbs originated. 

"It's going to be extremely important in terms of explaining the most
dramatic step in the actual physical transformation, the emblem that
goes from fish to land animal, turning your fins into limbs," he added. 

The announcement was made on the first day of Nature's Treasurehouses, a
wide ranging four day conference on the future role of natural history
museums at the Natural History Museum. 

Flying Goat Graphics
(Society of Vertebrate Paleontology member)