Description ⁵

This sea star has five stout rays that range in length from 10 to 25 centimeters (4 to 10 in). The rays are arranged around an ill-defined central disk. While most individuals are purple, they can be orange, orange-ochre, yellow, reddish, or brown. The aboral surface contains many small spines (ossicles) that are arranged in a netlike or pentagonal pattern on the central disk. The ossicles are no higher than 2 mm. In Pisaster the tube feet have suckers on their distal ends which allow them to attach to the rocky substrate and live in heavily wave-swept areas.

Two species that can be mistaken for Pisaster ochraceus are Pisaster giganteus, which has blue rings around white or purple spines, and Pisaster brevispinus, which is pink with small white spines. These two species have different aboral spines and coloration which allows one to distinguish between the species. Evasterias troscheli may be confused with Pisaster ochraceus at times as well. It can be distinguished by its smaller disk size and longer, tapering rays which are often thickest a short distance out from their base rather than at the base as in Pisaster ochraceus.

Sources and Credits

1. (c) Steven Pavlov, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Starfish,_Oregon_coast.jpg
2. (c) minustide, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/outershores/17458061335/
3. (c) Alison Young, some rights reserved (CC BY-NC), uploaded by Alison Young
4. (c) bioproject, some rights reserved (CC BY-NC), uploaded by bioproject
5. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Pisaster_ochraceus

More Info

• iNat taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
• BOLD Systems BIN search
• CalPhotos
• Global Biodiversity Information Facility (GBIF)
• NatureServe Explorer 2.0
• SeaLifeBase
• World Register of Marine Species

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