''Coscinasterias muricata'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Asteriidae. It is a large 11-armed starfish and occurs in shallow waters in the temperate western Indo-Pacific region.

Description

''C. muricata'' is the largest starfish in southern Australia and can reach a diameter of . It has seven to fourteen arms, with eleven being the commonest number. The

aboral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

(upper) surface of the arms has longitudinal rows of short spines along the surface and margins and the oral (lower) surface has two rows of

tube feet Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...

. The colour is orange mottled with shades of blue, green, grey and reddish-brown. This starfish is prone to shedding its arms, making it asymmetric until new arms have grown.

Distribution and habitat

''C. muricata'' is native to temperate parts of the western Indo-Pacific region. Its range extends in Australia from Houtman Abrolhos in Western Australia to southern Australia, Tasmania and eastern Australia as far north as Port Denison in Queensland. It is also found in New Zealand,

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

and

Norfolk Island Norfolk Island (, ; Norfuk: ''Norf'k Ailen'') is an external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia, directly east of Australia's Evans Head and about from Lord Howe Island. Together with ...

. It is common around southern Australia and New Zealand where it is found on rocks, under boulders and in sandy habitats to depths of about .

Ecology

In sheltered baylets in Australia, the tunicate ''

Pyura stolonifera ''Pyura'' is a large genus of sessile ascidians that live in coastal waters at depths of up to 80 m (260 feet). Like all ascidians, ''Pyura'' are filter feeders. A few species, including Pyura chilensis are commercially fished. Specie ...

'' can dominate the shallow seabed to the exclusion of other sessile organisms. This provides suitable habitat for

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

s such as

sea cucumber Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothuria ...

s, brittle stars, and bivalve molluscs, and among them can be found carnivorous starfish such as ''C. muricata'', a specialist feeder on bivalves. It is often to be found on

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

beds, as well as eating

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s and scavenging for

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

. This starfish can reproduce by binary fission; a groove appears on the surface of the disc and the two halves of the starfish pull apart from each other. Each part will then regenerate its missing tissues. This is a form of

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the fu ...

, and smaller individuals often divide in this way, while larger individuals have an extended breeding season, releasing sperm and eggs into the sea during spring and summer. The larvae are

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic, and when sufficiently developed, settle onto the seabed in

coralline algae Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of re ...

habitats.

References

{{Taxonbar, from=Q2495521 Asteriidae Fauna of the Indian Ocean Fauna of the Pacific Ocean Taxa named by Addison Emery Verrill Animals described in 1867