Tiktaalik is a genus of extinct sarcopterygian (lobe-finned "fish") from the late Devonian period, with many features akin to those of tetrapods (four-legged animals). It is an example from several lines of ancient sarcopterygian "fish" developing adaptations to the oxygen-poor shallow-water habitats of its time, which led to the evolution of tetrapods. Well-preserved fossils were found in 2004 on Ellesmere Island in Nunavut, Canada.
Tiktaalik lived approximately 375 million years ago. Paleontologists suggest that it is representative of the transition between non-tetrapod vertebrates ("fish") such as Panderichthys, known from fossils 380 million years old, and early tetrapods such as Acanthostega and Ichthyostega, known from fossils about 365 million years old. Its mixture of primitive "fish" and derived tetrapod characteristics led one of its discoverers, Neil Shubin, to characterize Tiktaalik as a "fishapod".
The name Tiktaalik is an Inuktitut word meaning "burbot", a freshwater fish related to true cod. The "fishapod" genus received this name after a suggestion by Inuit elders of Canada's Nunavut Territory, where the fossil was discovered. The specific name roseae cryptically honours an anonymous donor.
Tetrapod footprints found in Poland and reported in Nature in January 2010 were "securely dated" at 10 million years older than the oldest known elpistostegids (of which Tiktaalik is an example) implying that animals like Tiktaalik were "late-surviving relics rather than direct transitional forms, and they highlight just how little we know of the earliest history of land vertebrates" possessing features that actually evolved around 400 million years ago.