12 Sep 2008, 12:33 pm
Quote:
The first whales once swam the seas by wiggling large hind feet, research now suggests.
These new findings shed light on the mysterious shift these leviathans made away from land.
The ancestors of whales once strode on land on four legs, just as other mammals do. Over time, as they evolved to dwell in water, their front legs became flippers while they lost their back legs and hips, although modern whales all still retain traces of pelvises, and occasionally throwbacks are born with vestiges of hind limbs.
A great deal of mystery surrounds how the anatomy of the first whales changed to propel them through the water. A key piece of that puzzle would be the discovery of when exactly the wide flukes on their powerful tails arose.
"The origin of flukes is one of the last steps in the transition from land to sea," explained vertebrate paleontologist Mark Uhen of the Alabama Museum of Natural History in Tuscaloosa.
To shed light on this mystery, Uhen analyzed new fossils that amateur bone hunters discovered exposed along riverbanks in Alabama and Mississippi. These bones once belonged to the ancient whale Georgiacetus, which swam along the Gulf Coast of North America roughly 40 million years ago, back when Florida was mostly submerged underwater. This creature reached some 12 feet in length and likely used its sharp teeth to dine on squid and fish.
The first whales known to possess flukes are close relatives of Georgiacetus that date back to 38 million years ago. But while only about 2 million years separate Georgiacetus from these other whales, Uhen now finds that Georgiacetus apparently did not possess flukes. The new 2-inch-long tail vertebra he analyzed - one of some 20 tail vertebrae the ancient whale had - is not flattened as the vertebrae near whales flukes are.
Instead, Uhen suggests that Georgiacetus wiggled large back feet like paddles in order to swim. Past research showed this ancient whale had large hips, which suggested it also had large hind legs. Oddly, scientists had also found that its pelvis was not attached to its spine. This meant its hind legs could not paddle in the water or support the whale's body weight on land, leaving it a puzzle as to what they were for until now.
"The idea we are now helping confirm is that this ancient whale wiggled its hips to swim, moving its feet like hydrofoils or paddles. So it swam rather like a modern whale, which undulates its body up and down," Uhen told LiveScience.
The scientists detailed their findings in the latest issue of the Journal of Vertebrate Paleontology.
These new findings shed light on the mysterious shift these leviathans made away from land.
The ancestors of whales once strode on land on four legs, just as other mammals do. Over time, as they evolved to dwell in water, their front legs became flippers while they lost their back legs and hips, although modern whales all still retain traces of pelvises, and occasionally throwbacks are born with vestiges of hind limbs.
A great deal of mystery surrounds how the anatomy of the first whales changed to propel them through the water. A key piece of that puzzle would be the discovery of when exactly the wide flukes on their powerful tails arose.
"The origin of flukes is one of the last steps in the transition from land to sea," explained vertebrate paleontologist Mark Uhen of the Alabama Museum of Natural History in Tuscaloosa.
To shed light on this mystery, Uhen analyzed new fossils that amateur bone hunters discovered exposed along riverbanks in Alabama and Mississippi. These bones once belonged to the ancient whale Georgiacetus, which swam along the Gulf Coast of North America roughly 40 million years ago, back when Florida was mostly submerged underwater. This creature reached some 12 feet in length and likely used its sharp teeth to dine on squid and fish.
The first whales known to possess flukes are close relatives of Georgiacetus that date back to 38 million years ago. But while only about 2 million years separate Georgiacetus from these other whales, Uhen now finds that Georgiacetus apparently did not possess flukes. The new 2-inch-long tail vertebra he analyzed - one of some 20 tail vertebrae the ancient whale had - is not flattened as the vertebrae near whales flukes are.
Instead, Uhen suggests that Georgiacetus wiggled large back feet like paddles in order to swim. Past research showed this ancient whale had large hips, which suggested it also had large hind legs. Oddly, scientists had also found that its pelvis was not attached to its spine. This meant its hind legs could not paddle in the water or support the whale's body weight on land, leaving it a puzzle as to what they were for until now.
"The idea we are now helping confirm is that this ancient whale wiggled its hips to swim, moving its feet like hydrofoils or paddles. So it swam rather like a modern whale, which undulates its body up and down," Uhen told LiveScience.
The scientists detailed their findings in the latest issue of the Journal of Vertebrate Paleontology.
Somebody needs to photoshop some kicking rockette legs on a whale and send that bugger 'round the interweb...
Prof_Pretorius
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12 Sep 2008, 1:31 pm
12 Sep 2008, 2:22 pm
12 Sep 2008, 2:22 pm
12 Sep 2008, 2:22 pm
12 Sep 2008, 2:37 pm
12 Sep 2008, 2:41 pm
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12 Sep 2008, 5:10 pm
12 Sep 2008, 5:12 pm
12 Sep 2008, 5:23 pm
ShawnWilliam wrote:
show me a whale with legs and i might believe it
Ask and ye shall receive:
The inaccurately named basilosaurus with hind legs (now extinct).
Additionally, leg remnants can be found in the skeletons of modern whales as well.
12 Sep 2008, 5:30 pm
Whales are mammals for a reason, they didn't go from fish to whale. They got out of the water before getting back in. 
12 Sep 2008, 9:11 pm
twoshots wrote:
ShawnWilliam wrote:
show me a whale with legs and i might believe it
Ask and ye shall receive:
The inaccurately named basilosaurus with hind legs (now extinct).
Additionally, leg remnants can be found in the skeletons of modern whales as well.
this doesn't prove anything.. they find bones in a body that look similar to the bone of another creature and assume we are all evolved from something else.. it does seem odd that every creature on this planet is built in pretty much the same way.. what it all boils down to is a test of conscience from God OR true magnum evolution.. if this were solid evidence then it might be enough, but it's not.. have they found a half evolved whale/land animal fossil to prove it?.. no. Mind you also that little bone thing that looks like a foot, don't you think that they might actually NEED it for something?.. like isn't it supposed to be a fin? whales have similar bone structures for fins that look like hands
12 Sep 2008, 9:17 pm
ShawnWilliam wrote:
twoshots wrote:
ShawnWilliam wrote:
show me a whale with legs and i might believe it
Ask and ye shall receive:
The inaccurately named basilosaurus with hind legs (now extinct).
Additionally, leg remnants can be found in the skeletons of modern whales as well.
this doesn't prove anything.. they find bones in a body that look similar to the bone of another creature and assume we are all evolved from something else.. it does seem odd that every creature on this planet is built in pretty much the same way.. what it all boils down to is a test of conscience from God OR true magnum evolution.. if this were solid evidence then it might be enough, but it's not.. have they found a half evolved whale/land animal fossil to prove it?.. no. Mind you also that little bone thing that looks like a foot, don't you think that they might actually NEED it for something?.. like isn't it supposed to be a fin? whales have similar bone structures for fins that look like hands
Ever seen a kid with a cleft palate? How about Dwarfism? Downs Syndrome? Webbed fingers? These are the so-called 'half evolved' organisms you're looking for... A human with all four would look nothing like a 'typical' human, and might be classified as a different species by an observer not familiar with the human race...
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