Pisaster
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| Müller & Troschel , 1840 |
Pisaster (from ancient Greek πίσος "pea" and ἀστήρ "star") is a genus of starfish from the family Asteriidae in the order of the pincer stars (Forcipulatida) with three species thatare nativeto the North American Pacific coast between Alaska and southern California .
description
The three types of Pisaster are large starfish with five thick arms and diameters of up to 70 cm, which are covered on the upper side with longer or shorter spines depending on the type. The color varies between ocher, brown, orange and purple. All three species of predatory of mussels , barnacles , sea urchins and snails , but differ in their habitat.
species
- Pisaster ochraceus lives on rocky ground also in the upper areas of the intertidal zone, because it can tolerate longer periods without water. However, it iseatenin larger numbers by predatory seagulls in the longer dry areas, so that here blue mussels ( Mytilus californianus ), its main prey, predominate over other species, while in the deeper zones there are fewer mussels and a greater biodiversity due to the starfish gives.
- Pisaster giganteus , despite its name no bigger than Pisaster ochraceus , also lives on rocky ground, but in deeper waters.
- Pisaster brevispinus can also be found at greater depths and does not tolerate dry phases well, but sandy and muddy soils are its habitat, where it also digs up its prey, sand dollars and burrowing clams .
literature
- Howard M. Feder: Asteroidea , in: Robert Hugh Morris, Donald Putnam Abbott, Eugene Clinton Haderlie: Intertidal Invertebrates of California . Pp. 117–135, here pp. 125ff. ( Pisaster ochraceus, giganteus, brevispinus ). Stanford University Press, 1st ed., Stanford (CA, USA) 1980.
- Edward Flanders Ricketts, Jack Calvin, Joel Walker Hedgpeth, David W. Phillips: Between Pacific Tides . Fifth Edition. Stanford University Press, Stanford (California) 1985. pp. 214ff. ( Pisaster ).
Web links
Commons : Pisaster - collection of pictures, videos and audio files
