Sunflower starfish
| Sunflower starfish | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Forcipulatida |
| Family: | Asteriidae |
| Genus: | Pycnopodia |
| Species: | P. helianthoides |
| Binomial name | |
| Pycnopodia helianthoides Brandt, 1835 [1] |
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The sunflower seastar (Pycnopodia helianthoides) is a large predatory sea star usually with 16–24 limbs called rays[citation needed]. It is the largest sea star in the world. Sunflower sea stars can grow to have an arm span of 1 metre (3 ft 3 in) in diameter.[2] The color of the sunflower sea star ranges from bright orange, yellow and red to brown and sometimes to purple, with soft, velvet-textured bodies and 16–24 arms with powerful suckers.[2][3] Most sea star species have a mesh-like skeleton that protects their internal organs.[4] Easily stressed by predators such as large fish and other sea stars, they can shed arms to escape, which will grow back within a few weeks. They are preyed upon by the king crab.[4]
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[edit] Feeding
Sunflower sea stars are quick, efficient hunters, moving at a speed of one metre per minute,[3] using 15,000 tube feet which lie on the undersides of the body.[2] They are commonly found around urchin barrens, as the sea urchin is a favorite food. They also eat clams, snails, abalone, sea cucumbers and other sea stars.[2] In Monterey Bay, California, they will feed upon dead or dying squid.[5] Although the sunflower sea star can greatly extend its mouth, for larger prey, the stomach can extend outside the mouth to digest prey, such as gastropods like abalone.[6] Their feeding behavior was filmed for the BBC in the 2006 nature documentary Planet Earth and again in 2009 for Life.
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[edit] Reproduction
Sunflower sea stars can reproduce either asexually or sexually through broadcast spawning.[clarification needed By fragmentation like most starfish or through some other method?]. They also have separate sexes.[6] Sunflower sea stars breed from May through June. In preparing to spawn, they arch up using a dozen or so arms to hoist its fleshy central mass free of the seafloor and release gametes into the water for external fertilization.[6] The microscopic sea star larvae float and feed near the surface for two to ten weeks. After the planktonic larval period, the larva settles to the bottom and transforms into a juvenile sunflower starfish.[4] Juvenile sunflower sea stars begin life with five arms, and grow the rest as they mature.[5] The life span of most sea stars is 3–5 years.
[edit] Habitat
Sunflower sea stars are common in the Pacific from Alaska to Southern California,[2] and are largest in Puget Sound, British Columbia and Alaska.[4] They generally inhabit low subtidal and intertidal areas rich in seaweed[7] or kelp.[8] They do not venture into high- and mid-tide areas because the body structure is fleshy and requires water to support it.[9]
[edit] References
- ^ "Pycnopodia helianthoides". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=157274. Retrieved 9 April 2007.
- ^ a b c d e Sunflower sea star - NOAA
- ^ a b Telnack, Jennifer. Intertidal Marine Invertebrates of the South Puget Sound. NW Marine Life.[dead link]
- ^ a b c d Sunflowerstar. Scott Boyd's Emerald Sea Photography.
- ^ a b Monterey Bay Aquarium: Online Field Guide - Sunflower star. Monterey Bay Aquarium.
- ^ a b c Sea stars and relatives Edmonds Discovery Programs, City of Edmonds, Washington.
- ^ North Coast Intertidal Guide: Seastars & Urchins. North Coast Intertidal Guide. Humboldt State University. Arcata, CA.[dead link]
- ^ Sunflower Star. Channel Islands National Park. National Park Service.
- ^ Sunflower Star. North Island Explorer.
[edit] External links
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Wikimedia Commons has media related to: Pycnopodia helianthoides |
