''Goniastrea favulus'', also known as the lesser star coral, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

stony coral Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Merulinidae Merulinidae is a family of reef-building stony corals. Characteristics All the genera in this family are colonial, reef-building corals. Skeletal structures are similar to those of Faviidae but are highly fused, without paliform lobes. The vall ...

. It occurs in shallow water in the Indo-Pacific region. This is an uncommon species of coral and the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has rated its conservation status as being "

near threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

Description

Colonies of ''Goniastrea favulus'' usually form greenish or brownish massive boulder-like structures. The polyps are either arranged in groups within a common

corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can retract. The cup is composed of aragonite, a crystalline form of calcium carbonate, and is secreted by the polyp. Corallit ...

wall, or are in meandroid valleys. The walls of the corallites are thin, the

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five coun ...

bear large paliform lobes and there is a small central collumella.

Distribution and habitat

''Goniastrea favulus'' is native to theIndo-Pacific region. Its range extends from northern Madagascar and the eastern coast of Africa to the Maldive Islands, southeastern Asia, Japan, Australia and island groups in the Pacific Ocean. It is found in the intertidal and subtidal zones on fore and hind reef slopes, and in lagoons. It is generally uncommon and is seldom found deeper than .

Ecology

''Goniastrea favulus'' is a

zooxanthellate Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus ''Symbi ...

species of coral, containing in its tissues many microscopic

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s which during the day provide the coral with the products of

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. During the night, the polyps expand and extend their

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 to catch

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. Colonies of ''Goniastrea favulus'' are simultaneous

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

s and spawn once a year. Spawning is a synchronised event with all the colonies in a locality releasing their gametes into the sea at much the same time. The sperm is released in a jet while the eggs are negatively buoyant and surrounded by mucous and adhere to the colony. Although a majority of the eggs are cross-fertilised, a large number are self-fertilised. This is in contrast to the closely related '' Goniastrea aspera'', in which species both eggs and sperm are released in discrete buoyant packets which float to the surface. The clusters soon break apart and fertilisation then occurs, resulting in a much higher percentage of cross-fertilised eggs.

References

{{Taxonbar, from=Q3934180 Merulinidae Corals described in 1846