Common starfish

Regenerating lost arms is not what you might expect

Author: Pat
16th January 2015
 

Extruding their stomach out of their body to digest their prey and regenerating lost limbs sounds like something from a nightmare. However, this is actually what the starfish are capable of.

polka dots covering it are actually blunt spines

Starfish belong to the Echinoderms. Echinoderm, which simply means ‘spiny skin’, is a phylum that consists of the starfish, sea cucumber, sea lilies and the sea urchins, all having their own unique abilities. The common starfish (Asterias rubens) is one of 32 species of starfish found in British waters, but it is the most familiar to divers.

Although they can reaching a size anywhere up to 50 centimetres, the common starfish usually remains fairly small, averaging between 10 to 30 centimetres. In shallow water the colour will vary from orange, brown or pale yellow; in the deep sea they will remain pale. The top of this starfish looks like it has white polka dots covering it, but these are actually blunt spines which are part of the exoskeleton. If turned upside down, tubular projections can be seen these are called tube feet. Tubed feet are how the starfish move around and prey capture.

Unfortunately, this species is also a common souvenir item sold alongside seashells. They are occasionally taken from the sea and left out to dry, having their dried exoskeletons painted before being sold.

Habitat

  • Lower shore to depth
  • Variety of sea floor material
  • North-east Atlantic, all around the UK and Ireland

Key Identifying Features

  • Up to five arms, can be six
  • Upper surface covered with small blunt spines
  • Orange or pale yellow/brown, cream underside

Conservation Status

  • Not evaluated

Compiled by Ellie Richards, a marine biologist and enthusiastic UK diver. Check out Ellie’s page on Instagram

 
 
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