Equatorial bulges should not be confused with [[equatorial ridge|equatorial ridges]]. Equatorial ridges are a feature of at least threefour of Saturn's moons: the large moon [[Iapetus (moon)|Iapetus]] and the tiny moons [[Atlas (moon)|Atlas]], [[Pan (moon)|Pan]], and [[Daphnis (moon)|Daphnis]]. These ridges closely follow the moons' equators. The ridges appear to be unique to the Saturnian system, but it is uncertain whether the occurrences are related or a coincidence. The first three were discovered by the [[Cassini-Huygens|''Cassini'' probe]] in 2005; the Daphnean ridge was discovered in 2017. The ridge on Iapetus is nearly 20 km wide, 13 km high and 1,300 km long. The ridge on Atlas is proportionally even more remarkable given the moon's much smaller size, giving it a disk-like shape. Images of Pan show a structure similar to that of Atlas, while the one on Daphnis is less pronounced.