About Solaster endeca (Linnaeus, 1771)
Solaster endeca usually reaches an adult size of about 20 centimetres (7.9 inches), though some individuals can grow to 40 cm (16 inches). It is a robust starfish with 9 or 10 arms, and occasionally can have between seven and 13 arms, arranged around a large central disc. Its aboral, or upper, surface is made of calcareous plates densely covered in paxillae, which are peg-like projections covered in tiny spinelets. This species has no pedicellariae, but groups of two to three gills are located between the calcareous plates. On its oral, or under, surface, the row of plates on either side of the ambulacral groove bear two or three spines and several rows of shorter spines, and there are two rows of tube feet. S. endeca’s colour ranges from greyish-cream to pinkish-purple. The tips of its arms are often turned upwards, exposing the pale oral surface. It can be mistaken for Crossaster papposus, the only British species with a similar number of arms, but S. endeca has a smoother aboral surface. This species, called the purple sun star, occurs in the northeastern Atlantic Ocean and the North Sea, at depths down to 450 m (1,480 ft). Its typical habitats include muddy sand, gravel, and rocky areas with deposited sediment. It can be found in both sheltered and fairly exposed locations. It has a circumboreal distribution, occurring around the coasts of Greenland, northeastern Canada, and the East Coast of the United States as far south as the Gulf of Maine. In the Baltic Sea it is classified as a vulnerable species. It is also found in the northeastern Pacific Ocean between northern Alaska and Puget Sound.
