''Luidia maculata'' 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 ...

in 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 ...

in the order

Paxillosida The Paxillosida are a large order (biology), order of sea stars. Characteristics Paxillosida adults lack an anus and have no suckers on their tube feet. They do not develop the brachiolaria stage in their early development.Matsubara, M., Komatsu ...

. 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, eight arms seems to be the most common.

Description

''Luidia maculata'' is a large starfish, up to in diameter. There are usually seven or eight (sometimes nine) long, slender, pointed arms and a relatively small central disc. 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 is flat, with some granulations, the surface covered with flat-topped, table-like structures known as paxillae. Rows of pale-coloured

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 ...

that end in points rather than suction pads, are visible on the sides of the arms and the oral (lower) surface. There are two different colour forms of this starfish; some individuals are a uniform shade of dark brown or greenish-brown, while others are dark brown with orange-brown chevron-shaped markings, or light brown with dark markings. This starfish could be confused with some other member of the ''

Luidia ''Luidia'' is a genus of starfish in the Family (biology), 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 ...

'' genus, particularly '' L. savignyi'', but that species is spiny whereas ''L. maculata'' is smooth. Another similar species is '' L. magnifica'', but that typically has nine or ten arms.

Distribution and habitat

''Luidia maculata'' is native to the tropical Indian and Pacific Ocean. Its usual habitat is muddy sand on the floor of lagoons, but it may also be found on other soft sediments and in seagrass beds. Its depth range is from a few metres down to about .

Ecology

''Luidia maculata'' partially buries itself in soft sediment rendering itself difficult to spot. It is a

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

, feeding mostly 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, particularly irregular sand dollars and similar echinoderms which also live buried in sand. Unlike some related species which practice external digestion, it draws its prey inside its mouth to consume. When it emerges from hiding, it often leaves behind inedible fragments of

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

from its prey in the hollow it vacated. Other dietary items include

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,

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s and

worms Worms may refer to: *Worm, an invertebrate animal with a tube-like body and no limbs Places *Worms, Germany, a city **Worms (electoral district) *Worms, Nebraska, U.S. *Worms im Veltlintal, the German name for Bormio, Italy Arts and entertainme ...

References

{{Taxonbar, from=Q2246108 Luidia Fauna of the Indian Ocean Fauna of the Pacific Ocean Animals described in 1842 Taxa named by Johannes Peter Müller Taxa named by Franz Hermann Troschel