New Fossil Helps Fill Missing Link In Sea-Land Evolution

A primitive fish that swam in tropical reef systems before life
clambered up on land had more advanced features than prev-
iously thought, a new study finds.

Scientists led by John Long of the Museum Victoria in Melbourne,
Australia, discovered the first complete fossil of a Gogonasus
fish last year in a limestone formation in Western Australia.
Prior to the new discovery, only parts of Gogonasus, including a
snout and part of a skull, had been found.

The newly discovered fossil “has all these remarkable details
preserved that none of the other specimens could show,”
Long said.

The specimen, whose middle ear and limbs resemble those of
land vertebrates, could be one of the missing links between fish
and four-legged land vertebrates, bringing researchers closer
to the point when life reached the water’s edge.

When the scientists unearthed the Gogo fossil, they could still
open and close its mouth. “It’s like it died yesterday,” Long said.

The fish had a big hole in its head.
Called a spiracle opening, the cavity leads down into the gill cham-
ber used for breathing and is thought to be the forerunner for the
middle ear in modern land animals.

The fossil also showed the beginnings of a wrist joint and a complete
front fin, consisting of the same arm bones found in humans and
four-legged animals—the humerus, radius and ulna.
The scientists suspect the fish used the front limb to push off the
sea bottom and lunge at prey.


SOURCE:
LiveScience.com

This is IMO a pretty cool discovery.
I love when discoveries like this are made, it helps
to fill in the tree of evolution on our faire planet.


Comments, Opinions?

[edit on 10/18/2006 by iori_komei]

posted by iori_komei

A primitive fish . . before life on land . . had advanced features . . The fossil “has remarkable details preserved that other specimens could not show” The middle ear and limbs resemble those of land vertebrates . . the missing link . . between fish and four-legged land vertebrates . . close to when life reached the water’s edge . . the Gogo fossil’s mouth could still be opened and closed . . “It’s like it died yesterday” the fish had a hole in its head called a spiracle opening . . the cavity leads into the gill chamber and is thought to be the forerunner for the middle ear in modern land animals . . the fossil showed a wrist joint and front fin consisting of the same arm bones found in humans, the humerus, radius and ulna. [Edited by Don W]

This is IMO a pretty cool discovery. I love when discoveries like this are made, it helps to fill in the tree of evolution on our faire planet. Comments, Opinions?

I love it. To learn of the past. Especially the very distant past. I always found Pangea, Gondwanaland and Laurasia more fascinating then the stories about Atlantis by Ignatius Donnelly written in 1882 or The Lost Continent of Mu by James Churchward written in 1930s. Neither book would be written today, what with plate tectonics and all that. I recall well the groundbreaking work - no pun intended - of the Leakey’s at the Olduvai Gorge and the later discovery of Lucy, our oldest known ancestor, perhaps 6.5 million years ago. It seems the discussion now centers whether humans migrated into Africa or the more traditional view, out of Africa.

www.world-science.net...



[edit on 10/19/2006 by donwhite]