The fossils were of the prehistoric fish, Tiktaalik roseae, which is known as a transitional species between fish and land animals. The discovery of a well-preserved pelvis and a partial pelvic fin of the fish suggest that the development of hind legs started in fishes and not in land dwelling animals.
The pelvis had features comaprable to early tetrapods. It had a ball and socket hip joint and a highly mobile femur. Crests on the hip for muscle attachment indicated strength and advanced fin function. And although no femur bone was found, pelvic fin material, including long fin rays, indicated the hind fin was at least as long and as complex as its forefin.
The Tiktaalik roseae has a broad flat head and sharp teeth. Looking like a cross between a fish and a crocodile, the lobe finned fish can grow up to nine feet in length. Aside from having gills, scales, and fins, the prehistoric fish also had features found in land animals such as a mobile neck, robust ribcage and primitive lungs.
Tiktaalik roseae also had shoulders, elbows and partial wrists in its large forefins to provide support when it hunted in shallow freshwater environments. The researchers believe that aside from using the fins to swim like a paddle, the fish can also use it to walk with them as well.
