''Comaster schlegelii'', the variable bushy feather star, is a

crinoid Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...

in the family

Comatulidae Comatulidae is a family of comatulid crinoids. Since 2015, it replaces the family Comasteridae. Description and characteristics This family is of recent restoration, and still has no consensual description. However the description of the fam ...

. It was previously classified as ''Comanthina schlegeli'' but further research showed that it was better placed in the genus '' Comaster''. It is found on shallow water reefs in the

western Pacific Ocean 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 contine ...

Description

The variable bushy feather star often keeps its body concealed in a crevice and the only visible part is its array of arms, especially when it is young. There are in fact five rays attached to the upper part of the body but these subdivide into a number of arms and when one of these is lost, two grow in its place. The arms are flexible, being formed from many jointed calcareous small plates known as ossicles, and can be coiled up. On either side of each arm are short side branches known as pinnules. On the underside of the body are about twenty clawlike appendages known as cirri which are used to cling on to the underlying surface, but they are lost in older specimens, which attach directly using the underarms. The colour is very variable, some specimens being plain golden yellow, pale brown or black and others being multicoloured, often green with bands of orange, white and black on the arms and pinnules.

Distribution and habitat

The variable bushy feather star is found in shallow waters in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

. Its range includes

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

and

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, the

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 ...

and

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

. It is most common on reef crests down to a depth of about .

Biology

Like other feather stars, the variable bushy feather star is a

suspension feeder Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a spec ...

and spreads out its arms and pinnules to feed.

Plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

or other organic particles that drift past are caught by

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 pinnules and passed to the mouth down ciliated grooves. Feather stars are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, each individual being either male or female. The

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s are produced in specialised pinnules on the arms and fertilisation is external. The larvae drift with the plankton and pass through several developmental stages before settling on the

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

and anchoring themselves with a stalk. After metamorphosis the stalk remains intact at first but later breaks and the juvenile feather star can move around independently. The variable bushy feather star is sometimes sold for display in

reef aquaria A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriately in ...

, however it is not easy to meet its food requirements and most aquarium specimens sooner or later die of

starvation Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, de ...

. It can be fed with

brine shrimp ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp or ''Sea-Monkeys, sea monkeys''. It is the only genus in the Family (biology), family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to t ...

larvae,

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s and

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s after turning off the particulate filter on the tank.

References

{{Taxonbar, from=Q3457867 Comatulidae Animals described in 1881 Echinoderms of the Pacific Ocean