Tiktaalik roseae in shallow water. This fossil fish was a 375 million-year-old large aquatic predator with flattened head and body, represents an important intermediate step in the evolutionary transition from fish to animals that walked on land. A fossil of a Tiktaalik roseae was found in the Canadian Arctic in 2004. Results from a research study funded by the National Science Foundation show that the transition from aquatic to terrestrial lifestyle involved complex changes not only to appendages (fins to limbs) but also to the internal head skeleton.