Tiktaalik fossil reveals how fish evolved into four-legged land animals

A fish called Tiktaalik that lived 375m years ago already had strong hind limbs – even though it still lived in waterThe fossilised remains of an ancient beast have revealed how prehistoric life hauled itself from the water and took its first unsteady steps along the path that led to four-legged land animals.Clues to the seminal moment in the history of life were found in the bones of Tiktaalik, a 375m-year-old freshwater creature that grew to three metres long and had aquatic features mixed with others more suited to life on land.Scientists first discovered Tiktaalik in 2004 while hunting fossils on Ellesmere Island in the Canadian Arctic. Its extraordinary blend of gills, scales, fins and lungs, combined with a movable neck, sturdy ribcage and crocodile-like head, placed Tiktaalik half way between fish and the earliest four-legged land animals.In work published on Monday, researchers describe fossils of the back half of Tiktaalik for the first time. The report shows that the animal had a large, robust pelvic girdle, a prominent hip joint, and long hind fins. The powerful fins could have propelled the beast in the water, but also helped it walk on riverbeds, or scramble around on mudflats.Neil Shubin, professor of anatomy at the University of Chicago and the first author on the paper, said the most surprising find was the size of the pelvis. "To give you a sense of how giant it is, the pelvis of this animal is the same size as the shoulder, so it's very clear from understa...

Source: Guardian Unlimited Science - January 13, 2014 Category: Science Authors: Ian Sample Tags: The Guardian Evolution Biology Americas World news Canada Fossils Science Source Type: news