[I]f life on Earth originated in water, then there must have once been fish species possessing primitive limbs, which enabled them to spend some part of their lives on land. And these species, in turn, must be the ancestors of four-limbed, land-living vertebrates like us.

Tiktaalik roseae, a 375 million-year-old Devonian period specimen [was] discovered in the Canadian Arctic by paleontologist Neil Shubin and his colleagues. Tiktaalik, explains Shubin, is an “anatomical mix between fish and a land-living animal.”

“It has a neck. No fish has a neck. When you look inside the fin, and you take off those fin rays, you find an upper arm bone, a forearm, and a wrist.”

Via Mother Jones.