The gravitational pull of tiny Daphnis (7 km, or 4.3 miles across) perturbs the orbits of particles of Saturn's A ring -- sculpting the edge of the Keeler Gap into waves. Material on the inner edge of the gap orbits faster than the moon, so the waves there lead the moon in its orbit. Material on the outer edge moves slower than the moon, so waves there trail the moon.
Daphnis was discovered by the Cassini mission team on 1 May 2005.
How Daphnis Got its Name:
Formerly known as S/2005 S1, Daphnis is named for a shepherd, and pipes player who is a pastoral poet in Greek mythology. Daphnis was the son of Hermes, the brother of Pan and a descendent of the Titans.