About Electra pilosa (Linnaeus, 1767)
Electra pilosa forms colonies that grow as broad mats or star-shaped patches on the frond surfaces of large algae including Laminaria and Fucus serratus. Its zooids can also grow in small patches or tufts on the surfaces of shells and stones, and encircle the fronds of red algae such as Mastocarpus stellatus. Zooids are packed tightly together, are cylindrical in shape, and measure approximately 0.5 by 0.3 mm (0.020 by 0.012 inches). Each zooid has a mineralized exoskeleton that features a transparent, membranous oval window. The calcified protective covering of the zooid carries around nine spines, with a range of four to twelve total spines. The central spine is much longer than the other spines, which gives the entire colony a hairy appearance matching its species name pilosa, which means hairy in Latin. This species is native to the northeastern Atlantic Ocean, northwestern Atlantic Ocean, Mediterranean Sea, North Sea, Wadden Sea, White Sea, and Barents Sea. It also occurs in Australia and New Zealand, where it is classified as an introduced species. It can be found from the intertidal zone of sheltered rocky shores down to depths of approximately 50 m (164 ft).
