There’s a journal out there called Proceedings of the National Academy of the Sciences. Apparently, it published a paper recently discussing the fossilized remains of a prehistoric fish that scientists discovered at Ellesmere Island in northern Canada in 2004. The species was Tiktaalik roseae. 2.7 m in length, it looked like a cross between a fish and a crocodile and hunted in shallow fresh-water environments around 375 million years ago.
It was heralded at the time as a significant find — a key bridge in the evolution of land-based animals from the sea. And after six plus years of scientific study it’s turned out to be precisely that.
In fact, the fossil has caused scientists to rethink the process by which the fins of fish type species gradually evolved into the legs necessary to permit movement on land. You can read more on what the scientists found here. But in a nutshell, when they examined the tail-end of the fossil they discovered a pelvic girdle and ball-and-socket hip joint.
Previously, scientists believed that the front fins of fish had developed first enabling the animals to drag themselves out of water and on to land. Now, it looks like the mechanism may have been more of a “rear wheel drive”.