Ochre Sea Star
Pisaster ochraceus
Marine Life of the Northeast Pacific (MLNEP) notes 4
Summary 5
Pisaster ochraceus, generally known as the purple sea star, ochre sea star, or ochre starfish, is a common starfish found among the waters of the Pacific Ocean. Identified as a keystone species, Pisaster is considered an important indicator for the health of the intertidal zone.
Description 6
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. P. ochraceus has a simple nervous system and does not have a brain. A nerve ring connects and relays impulses between the star's radial nerves.
Two species that can be mistaken for P. ochraceus are P. giganteus, which has blue rings around white or purple spines, and P. 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 P. 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 P. ochraceus.
Fuentes y créditos
- (c) Steven Pavlov, algunos derechos reservados (CC BY-SA), http://commons.wikimedia.org/wiki/File:Starfish,_Oregon_coast.jpg
- (c) Ken-ichi Ueda, algunos derechos reservados (CC BY), subido por Ken-ichi Ueda
- (c) Tony Iwane, algunos derechos reservados (CC BY-NC), subido por Tony Iwane
- (c) Shannon Schmunk, algunos derechos reservados (CC BY-SA)
- Adaptado por Shannon Schmunk del trabajo de (c) Wikipedia, algunos derechos reservados (CC BY-SA), https://hub.toolforge.org/P3151:49699?lang=
- (c) Wikipedia, algunos derechos reservados (CC BY-SA), https://en.wikipedia.org/wiki/Pisaster_ochraceus
