Waterwereld

The common sunstar


This a large sunstar is an omnivore but prefers preying on other echinoderns. For this reason it can be found in mosselbanks in the Norhsea were its main prey is the common seastar. But it also feeds on other animals, including dead ones.

The common sunstar movements


The common seastar is a fast mover, using all its 8 to 14 arms to move about half a meter a minute. These arms are also called rays. Sometimes the common seastar is missings some rays. This can happen when it meets a lobster or an edible crab or Cancer pagurus. The arms can regenerate. The rays are covered whith brushlike spines, making is hard for fishes to come near.

The common sunstar distribution


The sunstar live in all the shallow seas of the Artic and Atlantic ocean. The sunstar can be found at depths between 10-50m in shallow seas with a rocky bottom.

The common sunstar in rockpools


The common sunstar can sometimes be found in rockpools , but only when they are very small.


Some echinoderms from the Arctic ocean.
1 sunflower seastar or Pycnopodia helianthoides
2 Distolasterias nippon
3 purple sea urchin or Strongylocentrotus purpuratus
4 Creeping Pedal Sea Cucumber or Psolus chitonoides
5 Amphiodia fissa,a brittle star
6 apanese sea cucumber or Apostichopus japonicus
7 Brisaster townsendi
8 The Fragile Rainbow Star or Astrometis sertulifera
9 Strongylocentrotus nudus, a sea urcin
10 common sunstar or Crossaster papposus
11 Evasterias retifera
12 the blue bat star or Patiria pectinifera
13 Amphiophiuria, a brittle star



Echinoderms of the North Sea.
1 Common Starfish or Asterias rubens. (twice)
2 Sand Sea Star or Astropecten irregularis
3 Common Sun Star or Crossaster papposus or Solaster papposus.
4 Common Brittlestar or Ophiothrix fragilis.
5 brittle star or Ophiura albida
 6 Amphiura filiformis
7 European Edible Sea Urchin or Echinus esculentus
8 Green Sea Urchin or Echinus miliaris
9 Sea Potato or Echinocardium cordatum




Autotomy or self-amputation

Some animals are able to regenerate new body parts. Lizards and crabs, daddy-long-legs and some spiders can throw off a limb to escape.
from an enemy. Autotomy is also common in animals that live between rocks, like seastars, brittle stars and worms.
It is also used as a form of asexual reproduction, this can be seen in flatworms. Have a look :
seacucumber
brittle star
starfish