Animal Species:Eleven-armed Sea Star

The Eleven-armed Sea Star is the largest species of sea star in Sydney and is commonly seen at low-tide levels, either on the rocky shore or in sandy bays.

Eleven-armed Sea Star

Dr Isobel Bennett © Australian Museum

Standard Common Name

Eleven-armed Sea Star

Identification

The upper surface of the Eleven-armed Sea Star is covered in small spines.The number of arms varies from seven to 14 but, as the name suggests, it is usually found with 11 arms.

Size range

40 cm

Distribution

The Eleven-armed Sea Star is found in Southern Queensland, New South Wales, Victoria, South Australia, Western Australia and Tasmania. Also found in New Zealand.

Habitat

The Eleven-armed Sea Star lives in intertidal rocky shores, coastal waters to a depth of 150 m.

Feeding and Diet

The Eleven-armed Sea Star feeds on small crabs or marine worms.

Other behaviours and adaptations

Using a hand lens, you can see small protuberances like miniature jaws around the spines on the body of the Eleven-armed Sea Star. These are called pedicellariae, and they not only defend the sea star from predators, but also move up and down to catch food, which usually consists of small crabs or worms. These tiny jaws hang on until the prey is dead or until it can be reached by an arm or tube feet and passed to the mouth.

 

Classification

Species:
muricata
Genus:
Coscinasterias
Family:
Asteriidae
Order:
Forcipulatida
Class:
Asteroidea
Phylum:
Echinodermata
Kingdom:
Animalia

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Tags sea stars, starfish, echinioderms, invertebrates, identification, wildlife of sydney,