Tiktaalik prehistoric fish, illustration. This extinct lobe-finned fish lived around 375 million years ago during the Late Devonian. A Tiktaalik roseae fossil was found in the Canadian Arctic in 2004. When scientists later analysed its skull, it was found to demonstrate a key transitional stage between fish and tetrapods (four-limbed vertebrates). It had fish-like fins with thin ray bones and scales, but also a flattened skull (similar to a crocodile), a mobile neck, sturdy shoulders, lungs, and ribs, features characteristic of tetrapods.