''Bohadschia argus'', the leopard sea cucumber, leopardfish, or tigerfish, 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), ...

sea cucumber Sea cucumbers are echinoderms from the class (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...

in 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 ...

Holothuriidae Holothuriidae is a Family (biology), family of sea cucumbers, a type of echinoderm. Description Members of the family Holothuriidae have thick fleshy bodies and several rows of tube feet which are used for moving around and for adhering to the s ...

. It is native to the tropical

Western Indo-Pacific The Western Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the eastern and central Indian Ocean. It is part of the larger Indo-Pacific, which includes the tropical Indian Ocean, the western and centr ...

region.

Description

''Bohadschia argus'' has the same roughly cylindrical

body plan A body plan, (), or ground plan is a set of morphology (biology), morphological phenotypic trait, features common to many members of a phylum of animals. The vertebrates share one body plan, while invertebrates have many. This term, usually app ...

shared by most sea cucumbers. On average, it measures approximately in length and in weight, with a maximum recorded length of . Its tough outer body wall, around in thickness, is firm and leathery to the touch. Its dorsal side is greyish-brown in coloration, and covered in numerous yellow eyespots, similar to those of its vernacular namesake. The underside is usually paler in coloration, although some specimens remain uniformly brown throughout. There are several rows of

tube feet Tube or tubes may refer to: * Tube (2003 film), ''Tube'' (2003 film), a 2003 Korean film * "Tubes" (Peter Dale), performer on the Soccer AM#Tubes, Soccer AM television show * Tube (band), a Japanese rock band * Tube & Berger, the alias of dance/e ...

on the underside, which it uses for locomotion. Surrounding the mouth at the anterior end is a ring of paddle-shaped, black feeding

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s with white fringes. The anus, at the posterior end, has Cuvierian tubules situated at its base, which are readily ejected as sticky threads if the animal is disturbed or handled. These contain toxins which deter predators and are irritating to human skin. ''Bohadschia argus'' appears to be able to hybridize with '' Bohadschia vitiensis''.

Distribution and habitat

''Bohadschia argus'' inhabits shallow tropical waters throughout the eastern

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), ...

and the western

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

. It is commonly found in and around

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s on exposed, sandy areas of the seabed, typically at depths of below the surface.

Ecology and behavior

''Bohadschia argus'' is an

detritivore Detritivores (also known as detrivores, detritophages, detritus feeders or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

. As it moves across the seabed, it sweeps sand grains and

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 ...

into its mouth using its sticky tentacles. It obtains some nourishment from the

biofilm A biofilm is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy ext ...

that coats the grains.

Symbiotic relationships

Pearlfish of the species '' Carapus mourlani'' (star pearlfish) and '' Encheliophis boraborensis'' (pinhead pearlfish) are sometimes found living in the coelomic cavity of ''Bohadschia argus'', typically entering head-first through the sea cucumber's anus. In a study in the

Banda Islands The Banda Islands () are a volcanic group of ten small volcanic islands in the Banda Sea, about south of Seram Island and about east of Java (island), Java, and constitute an administrative district (''kecamatan'') within the Central Maluku ...

in the South Moluccan Sea, a group of 15 star pearlfish were found living within the body cavity of a single ''Bohadschia argus''. '' Carapus mourlani'', which have a mutualistic relationship with ''Bohadschia argus'', will aggressively defend their sea cucumber from the parasitic '' Encheliophis boraborensis'', and in some cases may even fight them to the death. The emperor shrimp ('' Zenopontonia rex'') is often associated with ''Bohadschia argus'', and may help keep it clear of ectoparasites.

Uses

A new

triterpene Triterpenes are a class of terpenes composed of six isoprene units with the molecular formula C30H48; they may also be thought of as consisting of three terpene units. Animals, plants and fungi all produce triterpenes, including squalene, the pre ...

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

, Arguside A, has been extracted from the tissues of ''Bohadschia argus''. This compound appears to exhibit

cytotoxicity Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of d ...

against several different types of human tumor cells.

References

External links

* {{Taxonbar, from=Q3228738 Holothuriidae Echinoderms of the Indian Ocean Echinoderms of the Pacific Ocean Invertebrates of Southeast Asia Marine fauna of Southeast Asia Western Indo-Pacific fauna Symbiosis Echinoderms described in 1833 Taxa named by Wilhelm Friedrich Jaeger