The first fossil of Tiktaalik roseae was uncovered in the Canadian Arctic in 2004. Tiktaalik likely lived in shallow water close to the shore. It is a remarkable creature that owes its nickname “fishapod” to the anatomical features it shares with fish and four-legged animals, or tetrapods. Like a fish, it has scales, fins, and gills. But it also has tetrapod features like a neck, a flat head with eyes on top, strong ribs to support its body weight, and limb-like bones with a wrist, that clearly distinguish Tiktaalik from early fish. Its fossilized body tells us that many tetrapod features first arose in animals still living in water.
To learn more about the discovery of Tiktaalik, its place in the history of life on earth, and what it reveals about our fishy past, go to the Your Inner Fish website on PBS, and watch the Great Transitions: The Origin of Tetrapods short film on BioInteractive.
Image courtesy of Ted Daeschler, PhD, The Academy of Natural Sciences, Philadelphia