Re: Fossil Fish With "Limbs" Is Missing Link, Study Says


"George" <george@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:ZtWYf.909406$xm3.508689@xxxxxxxxxxxx
http://news.nationalgeographic.com/news/2006/04/0405_060405_fish.html

James Owen
for National Geographic News

April 5, 2006
Fossil hunters may have discovered the fish that made humans possible.

Found in the Canadian Arctic, the new fossil boasts leglike fins,
scientists say. The creature is being hailed as a crucial missing link
between fish and land animals-including the prehistoric ancestors of
humans.

Researchers say the fish shows how fins on freshwater species first began
transforming into limbs some 380 million years ago. The change was a huge
evolutionary step that opened the way for vertebrates-animals with
backbones-to emerge from the water.

"This animal represents the transition from water to land-the part of
history that includes ourselves," said paleontologist Neil Shubin of the
University of Chicago.

Shubin was co-leader of a team that uncovered three nearly complete
fossils measuring up to nine feet (three meters) long on Ellesmere Island
in 2004.

The new species, Tiktaalik roseae, had a flattened, crocodile-like head
and strong, bony fins.

The large fish probably flexed and extended these fins like legs to help
it move through shallow, subtropical waters or even on land, the team
says.

The discovery marked the culmination of a five-year, 400-mile
(650-kilometer) fossil hunt across the Arctic's frozen tundra. The
National Geographic Society partially funded the project, which is to be
detailed tomorrow in the journal Nature.

The fish shows other features characteristic of land animals, including
ribs, a neck, and nostrils on its snout for breathing air.

The previously unknown creature is the closest known fish ancestor of land
vertebrates, Shubin said.

It likely used its fins "to prop its body, much like we do when we do a
push-up," he said.

Likewise, the animal's broad ribs would have supported its long, scaly
trunk, adds team member Farish Jenkins of Harvard University in Cambridge,
Massachusetts.

Land Excursions

Water supports the bodies of submerged fish, making strong ribs largely
unecessary, "so this animal must have developed these structures for life
in the shallows and making excursions on to land," Jenkins said.

Shubin says the fish's wide head and sharp teeth suggest it hunted much
like a crocodile and that it also breathed air.

"Look at the side of the snout. It has a nice big pair of external
nostrils," he said.

Tiktaalik could become an icon of evolution in action, write
paleontologists Per Ahlberg of Sweden's Uppsala University and Jennifer A.
Clack of the University of Cambridge in the United Kingdom in an
accompanying commentary.

The paleontologists say the new fish form goes a long way toward filling
the evolutionary gap between fish and the earliest amphibians.

"Our remote ancestors were large, flattish, predatory fishes," they write.
"Strong limblike pectoral fins enabled them to haul themselves out of the
water."

Evolutionary scientists agree that all four-limbed land vertebrates,
including dinosaurs and mammals, are descended from lobe-fins, a group of
primitive fishes with fins suggesting limbs.

__________________________________

One question: If it had the ability to make excursions on land like a
crocodile, possibly to hunt, what was it hunting?

George


It ate ET, when the Aliens came down to cut crop circles into the ancient
forests. Fortunately, they always left one alien in the saucer, so that is
why we never found any saucer remnants in the rock formations.

"Of all the billions of places in the universe, I had to pick this one."

ET


.

Relevant Pages

  • Re: Fossil Fish With "Limbs" Is Missing Link, Study Says
    ... Found in the Canadian Arctic, the new fossil boasts leglike fins, scientists say. ... The creature is being hailed as a crucial missing link between fish and land animals-including the prehistoric ancestors of humans. ... Researchers say the fish shows how fins on freshwater species first began transforming into limbs some 380 million years ago. ... The large fish probably flexed and extended these fins like legs to help it move through shallow, subtropical waters or even on land, the team says. ...
    (sci.geo.geology)
  • Re: Fossil Fish With "Limbs" Is Missing Link, Study Says
    ... Fossil hunters may have discovered the fish that made humans possible. ... Researchers say the fish shows how fins on freshwater species first ... it move through shallow, subtropical waters or even on land, the team ...
    (sci.geo.geology)
  • Re: Michael Ruses Model
    ... well as lungs to breath and gills to survive under water. ... The swim bladders of teleost fish are modified lungs. ... that walk on their fins. ... This one looks like it could have better locomotion on land then Tiktaalik. ...
    (talk.origins)
  • OT - Gap closed
    ... creationism make is that there are "gaps" in the fossil records. ... sea creatures changing into land creatures. ... Scientists Call Fish Fossil, 375 Million Years Old, 'Missing Link' ...
    (alt.sports.basketball.nba.la-lakers)
  • Re: OT - Gap closed
    ... creationism make is that there are "gaps" in the fossil records. ... demonstrates sea creatures changing into land creatures. ... Scientists Call Fish Fossil, 375 Million Years Old, 'Missing Link' ...
    (alt.sports.basketball.nba.la-lakers)
Loading