User:Drangini/articlesandbox

Halityle regularis, also known as the Mosaic Cushion Star, is a species of sea star in the family Oreasteridae, and the sole species in the genus Halityle. It is named for its brightly colored, intricately patterned surface, large domed body, and stubby arms. H. regularis can be found in the coastal waters of the Indo-Pacifc.

Taxonomy
H. regularis was first taxonomically defined and described in 1913 by W.K. Fisher. It is the only member of the genus Halityle, and typical of most members of the family Oreasteridae, it is brightly colored with a convex, five-armed body. The genus Halityle is defined from others in the Oreasteridae by a lack of spines on all plates other than the adambulacral and mouth plates; visible marginal plates in the adult form; and the distinctive triangular arrangement of the papulae. Fisher’s original holotype for the species resides in the Smithsonian Institution's invertebrate collection in Washington D.C.

Description
Mosaic Cushion Stars are so named for the dazzling patterns on their dorsal surface and bright distinctive colors. All members of H. regularis have 5 short, broadly based arms, which coupled with their massive size and domed bodes gives them their “cushiony” appearance. Sizes vary geographically, but adult specimens have been found with radii (measured from center to arm tip) ranging from 54 to 162 mm.

The mosaic pattern arises from the distinctive colorful raised trabeculae, which divide the dorsal surface of the sea star into separate triangular papular areas. The coloration of the trabeculae has been seen to range from bright red to deep violet, and the papular areas range from pale yellow, to red, to deep purple. The rest of the body has been found in brown and purple varieties, with the color most often growing lighter towards the ends of the arms. The ventral side tends to be lighter in color, however there are still instances of bright coloration, particularly around the oral plates.

Distribution and habitat
H. regularis is wide ranging in the Indian and Pacific tropical oceans. Individuals have been found as far north as the Philippines and also appear along the coasts of southern Vietnam and India. Individuals have been found as far southwest Madagascar and as far east as Queensland, Australia.

Very little has been recorded about the life history and ecology of the species. It is presumed H. regularis prefer sandy to pebbled substrate as this is where most specimens are collected, but it has also been found of corals. There are conflicting accounts of which depth the species prefers to live at, with specimens having been collected in waters anywhere from 3 to 275 meters deep.

Symbionts and parasites
Though relatively little is known about the ecology of this species, it is known to be a host to multiple species of smaller invertebrates, both parasitic and commensal. The starfish shrimp (Periclimenes soror) lives commensally on H. regularis, picking off smaller parasites. Some species of polycheate worms (Hololepidella millari) have also been found on H. regularis but the nature their relationship is unknown. Multiple species of parasites use H. regularis as a host including the cyclopid copepods Asterocomes indica and Stellicomes tumidulus.

Asterosaponins
Asterosaponins are a subclass of saponins only found in Asteroidea. Saponins are traditionally amphipathic glycosides found in plant species, but multiple steroidal varieties can be found exclusively in echinoderms. The suspected use of these toxic compounds range from predator avoidance and stunning prey, to serving as an antifungal. Human interest in these compounds is high, as they have been discovered to have many medicinal properties, such as anti-inflammation.

Multiple unique asterosaponins, have been discovered in H. regularis making them a valuable species for possible pharmaceutical applications. Asterosaponins present in the mosaic cushion star include regularoside A and B, named after the sea star they were derived from.