Ancient Fish Found Had Front And Back Legs


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A strange looking ancient fish that was discovered off the coast of Canada's Ellesmere Island tells us more than we previously knew about the evolution of limbed animals and their connection to humans.

After further investigation of a 375 million-year-old fish known as Tiktaalik roseae, discovered in 2004, it was revealed that they may have developed rear legs before moving to land.

This newest information challenges previous theories that these limbs evolved only after the move onto land. [ See Images of Tiktaalik Fish Fossils ]

The fossil was definitely a fish, it had gills, scales and fins, however it also had four limbs that only amphibians such as reptiles and mammals possess, including a mobile neck and a robust rib cage.

Previously the only parts of Tiktaalik that researchers examined were its front portions. It is, after all a fossil and was a bit difficult to fully assemble. But once they dug further into the blocks of dirt and rock retrieved where this ancient fish was found, they discovered that the blocks contained more fossils than they had once thought. Plus, it took years to remove the rock surrounding the fragile fossils carefully and properly.

Tiktaalik possesses a broad flat head and sharp teeth and resembled a cross between a fish and a crocodile, estimated to have grown to a length of 9 feet (2.7 meters).

Surprisingly, they found Tiktaalik had big, strong pelvic bones with similarities to early tetrapods and further proof of the evolution theory that all of life came from the ocean.

"I was expecting to find a diminutive hind fin and pelvis," study lead author Neil Shubin, a paleontologist at the University of Chicago, told LiveScience. "Seeing the whopping pelvis set me back a bit — I looked at it again and again, because I was quite surprised."

Shubin cautioned that Tiktaalik is not the ancestor of all limbed vertebrates. It is for now, the closest known relative, "but not the sole, direct ancestor," he said. "It is more like our closest cousin."

Image via Wikimedia Commons #2 #3