Fish fossil holds clue to the evolution of hind limbs

The discovery of pelves and a partial pelvic fin from Tiktaalik roseae, a 375 million-year-old transitional species between fish and the first legged animals, reveals that hind legs actually evolved from enhanced hind fins. This finding reveals that a key step in the evolution of hind limbs happened in fish and challenges existing theories that such appendages evolved only after the move to land. Read more in PNAS.