21 October 2008

Massive: the sunflower star

Picture yourself as a clam lying on the bottom of Deep Cove bay, Vancouver Island. This starfish approaches you. He likes you, as food. But hey, you're a big and strong clam. So no worries.

Wrong! This is the sunflower star (Pycnopodia helianthoides). Full-grown it can be 1 meter wide, have 24 arms and 15.000 tubefeet and weighing in at about 5 kg.

This specimen was ‘only’ 60 cm.

A juvenile of 6 cm.

A few of the more than 10.000 tubefeet. Have you ever been drunk? Than you know how hard it can be to control your locomotion. How does the sunflower controls that many feet? And he is quick: up to 160 cm in a minute.

Juvenile starfish can look quite different from adult specimens. This one looks even stranger: he has has lost a few arms and is regenerating them (the smaller arms). He walks next to an ochre star (Pisaster ochraceus). N.B. I don't think he has lost his arms: he is growing new ones (click here for a new post about Pycnopodia).

If you want to read more about the starfish of Vancouver Island, here is an excellent book:
Sea stars of British Columbia, Southeast Alaska and Puget Sound, 2000. Philip Lambert. ISBN 0-7748-0825-X. ubcpress.ubc.ca. It is cheap (Can $ 27 = € 19) and describes 43 species of starfish. I think there’s no place on earth with that many species of starfish!

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