''Fromia nodosa'', commonly called elegant sea star, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of marine

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

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Goniasteridae Goniasteridae (the biscuit stars) constitute the largest family of sea stars, included in the order Valvatida. They are mostly deep-dwelling species, but the family also include several colorful shallow tropical species. Description Goniast ...

Description

The elegant

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

has five triangular arms radiating around an apparent central disc. its coloration is reddish, sometimes blueish to orange, and more or less densely covered with large, embossed creamy rounded plates, which are slightly angular at their top and whose size decreases towards the end of the arms. These plates leave a normally open pentagonal area on the central disc, but they also can sometimes completely cover it. Adult animals measure a maximum of 10 cm in diameter. This species is sometimes very difficult to differentiate from closely related species such as '' Fromia monilis'' or '' Fromia heffernani'': ''F. monilis'' has no relief plates and ''F. heffernani'' has more rounded plates which line the outside of the arms and also the geographic distribution differs. Image:Starfish, Mauritius.jpg, In

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

. Image:Fromia nodosa 4 bras Baa Atoll - Dhigu Thila.JPG, In

Maldives The Maldives, officially the Republic of Maldives, and historically known as the Maldive Islands, is an Archipelagic state, archipelagic country in South Asia located in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, abou ...

Distribution and habitat

The elegant

is present in the tropical waters of the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

, from

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...

, where it is relatively common. It can be observed from surface to 35 m depth.

Biology

This

has a nocturnal activity and feeds mainly on

bivalve molluscs Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...

corals Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

and

microalgae Microalgae or microphytes are microscopic scale, microscopic algae invisible to the naked eye. They are phytoplankton typically found in freshwater and marine life, marine systems, living in both the water column and sediment. They are unicellul ...

. To ingest its food, it needs as all other

sea stars A sea is a large body of salt water. There are particular seas and the sea. The sea commonly refers to the ocean, the interconnected body of seawaters that spans most of Earth. Particular seas are either marginal seas, second-order section ...

to externalize its stomach, this action is also called devagination, and has to make an external digestion.

References

External links

* {{Taxonbar, from=Q2052293 nodosa Animals described in 1967