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

crinoid Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which 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 ''Comaster'' is a genus of crinoids. Species The following species are included in the genus by the World Register of Marine Species: * ''Comaster audax'' Rowe, Hoggett, Birtles & Vail, 1986 * ''Comaster multifidus'' (Müller, 1841) * ''Comaste ...

''. It is found on shallow water reefs in the western Pacific Ocean.

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 Giovanni Battista Cirri (1 October 1724 – 11 June 1808) was an Italian cellist and composer in the 18th century. Biography Cirri was born in Forlì in the Emilia-Romagna Region of Italy. He had his first musical training with his brother ...

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. Its range includes Indonesia, Fiji and Japan, the Maldives and Papua New Guinea. 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 and spreads out its arms and pinnules to feed.

Plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

or other organic particles that drift past are caught by

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 br ...

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

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, each individual being either male or female. The

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...

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 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 ...

, 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, dea ...

. It can be fed with

brine shrimp ''Artemia'' is a genus of aquatic crustaceans also known as brine shrimp. It is the only genus in the family Artemiidae. The first historical record of the existence of ''Artemia'' dates back to the first half of the 10th century AD from Urmia L ...

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 (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s and

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s after turning off the particulate filter on the tank.

References

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