Echinodermata (echinoderms), class: Asteroidea

Collection Highlights | Updated 1 decade ago

Asteroids lack a distinctive central body (disc) - they have arms that connect together at the base in such a way that it is difficult to tell where the arms end and the disc begins. They have the ability to regenerate arms as long as part of the central disc remains.

Although there are a few exceptions, arms of seastars usually occur in multiples of five. Asteroids have an “eye-spot” at the end of each arm to detect light.

Interestingly, their mouth is located on the bottom-side, and the anus is located at the top, some species can also invert their stomach to digest food – including sending their stomach into clams and mussels to digest their flesh even when the shell is closed.

Once called starfish, their accepted common name is seastar as they are not fish.

Marine Invertebrates Section