Pterasteridae is a family of sea stars in the order Velatida, consisting of eight genera.
Pterasterids are primarily deep-water, and have an inflated aboral surface. Like many other members of the ordo Velatida, they have a hole in the middle of the central disc called "osculum", from which they can expel mucus for defending against predators.[2]
Many species brood their young in an internal chamber flushed with seawater.
Fossil pterasterids have been found as early as the upper Campanian of the Cretaceous period.[3]
According to the World Register of Marine Species :
Hymenaster echinulatus (both faces)
Hymenaster sp.
Pteraster stellifer (both faces)
Pteraster sp.
