|
How do they look like?
The body has three distinct parts: the calyx, the cirrus and a crown of arms with 5 main branches. In the center of the calyx is the mouth of rather small proportions. The size of the body ranges from 8 to 15 centimeters wide. The crown is formed by 10 arms, although in reality there are only 5 arms, which are divided at the base. The arms are thin, elongated, and very dense, feather-like, and can reach 8 cm in length. The crown can reach a diameter of 20 cm. Each arm has shorter and thinner extensions (called pinnules) on each side, giving the appearance of a feather. Underneath, there are segmented cirri that serve to move forward and for anchoring; the number of segments ranges from 20 to 23. Color ranges from yellow, brown, orange to red. The coloration may be uniform or striped.
Where does it live?
It lives on rocky bottoms, preferably shady, or on white gorgonians (Eunicella) and sometimes in algae meadows and sandy bottoms. Abundant in the Mediterranean, in places exposed to the current, frequent from 10 meters to 40 m depth. They are very abundant in areas rich in plankton.
How do they feed?
They feed on plankton and particles that they filter from the current with their arms. These animals hang onto a sponge, a coral or a gorgonian by means of specialized legs, the cirri, and extend their delicate arms to capture the plankton they feed on. The food filtered by the pinnulae of the arms is transported to the mouth. The comatulae are arranged "upside down", compared to starfish, so the mouth is located above the body, not below.
How does it reproduce?
They have separate sexes, but externally they cannot be differentiated. Males release their sperm into the water. The females filter them by fertilizing the eggs. They then fix the eggs on the thin branches of the arms where they remain sheltered by the mother until the small larvae emerge. The peduncle breaks during the larval stage, so they live a life free of adults and adhere to the substrate with the cirri.
Is a confusion possible?
Yes, it can be confused with Antedon bifida or Leptometra phalangium.
Curiosities
· Outside its active phase, the arms are coiled. They have no visible head. Comatulas can walk with these arms, they can even swim with them. A very beautiful spectacle but not very efficient, to be honest.
· Some feather stars are nocturnal, so during the day we see them hiding in the hollows between corals. At night they come out of their hiding places and go up to the place where the current is stronger.
· It has an extraordinary regeneration power.
· Sometimes they live together with the shrimp Hippolyte prideauxiana, which perfectly hides with its camuflage between the feather stars arms.
· The animals move with the cirri along the bottom when the filtering process becomes impossible due to a change of current, thus looking for a more favorable place.
· When found on land, they decompose in a short time.
Taxonomy
Phylum: Echinodermata, Class: Crinoidea, Order: Comatulida, Family: Antedonidae, Genus: Antedon |
