''Luidia savignyi'' is a species of

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 ...

belonging to the family

Luidiidae ''Luidia'' is a genus of starfish in the family Luidiidae in which it is the only genus. Species of the family have a cosmopolitan distribution. Characteristics Members of the genus are characterised by having long arms with pointed tips frin ...

. The species is found in the tropical and subtropical Indo-Pacific region. It is a large starfish and preys on other echinoderms.

Description

''Luidia savignyi'' is a large starfish, with the distance between the tips of extended arms sometimes reaching about . There are usually six or seven slender arms with pointed tips attached to a relatively small central disc. The aboral (upper) surface is rough and granular, with numerous skeletal appendages known as paxillae. These are vertical columns tipped by clusters of tiny spines, often with a single larger orange spine in the centre. The colour of the aboral surface is very variable between individuals, being greyish with beige, burgundy, greenish or brownish spots and patches. On the oral surface, an ambulacral groove runs along each arm, terminating at the central mouth. This is lined on either side by tube feet tipped with suckers. The oral surface of the arms is clad with clawed pedicellaria, and a rim of large, thick spines grows on the margin between the aboral and oral surfaces.

Distribution and habitat

''Luidia savignyi'' is native to the tropical and subtropical Indo-Pacific region, its range extending from the Red Sea and East African coast to the Philippines and New Caledonia. Its typical habitat is uncompacted sandy-mud, but it also frequents rock slabs covered with coral rubble and algae. It is found at depths down to about .

Ecology

''Luidia savignyi'' is largely nocturnal. It is able to move very quickly because of its long arms, and can bury itself efficiently in the sediment. It is a predator and feeds on

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

s, irregular urchins and starfish, particularly ''

Astropecten polyacanthus ''Astropecten polyacanthus'', the sand sifting starfish or comb sea star, is a sea star of the family Astropectinidae. It is the most widespread species in the genus ''Astropecten'', found throughout the Indo-Pacific region. The armspread is up t ...

''. It almost appears to run after its prey, and other species flee at its approach. It does not invaginate its stomach as many starfish do, but stretches its mouth wide and swallows its prey whole; the small disc becomes swollen and distorted after a large meal. When it attacks certain starfish such as ''

Protoreaster nodosus ''Protoreaster nodosus'', commonly known as the horned sea star or chocolate chip sea star, is a species of sea star found in the warm, shallow waters of the Indo-Pacific region. They are sometimes seen in the marine aquarium trade or dried and ...

'' and the small ''

Nardoa gomophia ''Nardoa'' is a genus of sea stars in the family Ophidiasteridae The Ophidiasteridae (Greek ''ophidia'', Οφιδια, "of snakes", diminutive form) are a family of sea stars with about 30 genera. Occurring both in the Indo-Pacific and Atla ...

'', it soon abandons the potential prey. In contrast to the closely related ''

Luidia maculata ''Luidia maculata'' is a species of starfish in the family Luidiidae in the order Paxillosida. It is native to the Indo-Pacific region. It is commonly known as the eight-armed sea star because, although the number of arms varies from five to nine ...

'', no useful chemical substances have been discovered in the tissues of ''Luidia savignyi''.

References

{{Taxonbar, from=Q2114073 Luidia Fauna of the Indian Ocean Fauna of the Pacific Ocean Animals described in 1826 Taxa named by Jean Victoire Audouin