New fossils of fish with limblike fins excavated from arctic Canada now serve as a missing link in the evolution of animals from water onto land. Three nearly complete specimens of a flattened, alligatorlike fish species dubbed Tiktaalik roseae possess the scales, fins, snout and lower jaw of a fish, but they have the ribs, neck, skull, wrists and fingerlike bones of a land animal. Scientists had to dig the up to three-meter-long fossils out from icy rock in polar bear country, but they say the tundra resembled a subtropical version of today's Mississippi River delta when the fish was alive some 375 million years ago. The sharp-toothed predator's overlapping ribs would have produced a stiff trunk not required by fish buoyed up by water, suggesting it lived in the shallows, perhaps with excursions onto land, the researchers write in the April 6 Nature.
This article was originally published with the title "Fish Out of Water" in Scientific American 294, 6, 27 (June 2006)