The starfish Astropecten spinulosus is a member of the Astropectinidae family, which in turn is part of the order Paxillosida. It is a species that inhabits sandy, muddy and even pebbly bottoms, and during the day it usually remains buried in the sediment and in the late afternoon and at night, they come out of the substrate in search of prey, among which we mainly find bivalves. The geographical distribution range of this starfish includes waters up to 50 meters deep in the Mediterranean Sea, where it is frequently associated with Posidonea oceanica or Cymodocea nodosa meadows.
Astropecten spinulosus has a body with the characteristic shape of starfishes, that is a pentadial symmetry in which from a central pentagon-shaped disk 5 conical arms ending in blunt points emerge. On the edges of the arms, we can observe conical appendages that run along the margin of the entire specimen. The dorsal surface of the body of Astropecten spinulosus is relatively rough. They can grow up to a maximum of 10 cm in diameter, the most frequent size observed being between 6 and 8 cm.
The diet of Astropecten spinulosus consists mainly of small molluscs and other echinoderms. As is the case with the vast majority of asteroids, Astropecten spinulosus specimens evest their stomachs to the outside, which allows them to digest their food. Another feature also present in this species and very frequent in this class of species is the great capacity for regeneration that they possess. They are able, when attacked by a predator, to detach one or more of their arms as a strategy to avoid compromising their life and that the predator only captures one of their arms. Astropecten spinulosus will completely regenerate all of its lost arms.
Regarding reproduction, Astropecten spinulosus is a sequential protandric hermaphrodite species, that is, the specimens start their lives as males and at some point in their lives they have the ability to become females.
Photos:
from