''Seriatopora hystrix'' 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 ...

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

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

Pocilloporidae The Pocilloporidae are a family of stony corals in the order Scleractinia occurring in the Pacific and Indian Oceans. Description Pocilloporids are colonial and most species are reef-building. They are very variable in size and shape, some being ...

. It forms a branching clump and is commonly known as thin birdsnest coral. It grows in shallow water on fore-reef slopes or in sheltered lagoons, the type locality being the Red Sea. It is native to East Africa, the Red Sea and the western Indo-Pacific region. It is a common species 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 assessed its conservation status as being of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

Description

Colonies of ''Seriatopora hystrix'' formed a tangled, bushy clump of fragile, slender, tapering branches with pointed tips. These clumps can grow to a metre (yard) across. In shallow positions with strong water movement the branches are thicker than they are in deeper or turbid habitats in sheltered positions. The

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 ...

s form neat rows of oval cup-shaped depressions with raised rims from which the polyps protrude at night. This coral can be cream, pink, yellow, brown or blue.

Distribution and habitat

''Seriatopora hystrix'' is native to the Indo-Pacific region. Its range extends from East Africa, Madagascar and the Red Sea through the Indian Ocean to tropical Australia, Japan, the South China Sea and the island groups in the West and Central Pacific. It occurs on reefs and reef flats, mostly at depths between .

Ecology

''Seriatopora hystrix'' is a

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 ...

, mature polyps producing both sperm and eggs. The sperm are liberated into the sea and get drawn into other polyps of the same or other colonies, and the developing larvae are brooded maternally. Self-fertilisation may be an important strategy for this species. When eventually released, the larvae settle within about 24 hours which suggests a limited dispersal range. Many settle within a few tens of metres of the parent colony, but others are probably swept along in warm currents and end up further afield. ''S. hystrix'' 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, housing

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 within its tissues. It has been found that these symbionts are transferred during the brooding of the larvae and that different species of ''

Symbiodinium : ''This is about the genus sometimes called Zoox. For the company, see Zoox (company)'' ''Symbiodinium'' is a genus of dinoflagellates that encompasses the largest and most prevalent group of endosymbiotic dinoflagellates known. These unicellul ...

'' are associated with the coral in different parts of its range, a likely example of

coevolution In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well ...

and specialization. Another means of reproduction is by asexual means; fragments of coral that become detached from branches can form new colonies if they are deposited in suitable locations. At times of stress, another form of

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the fu ...

takes place that may allow some of the polyps to survive even though the parent colony dies. This has been termed "polyp bail-out" and involves growth of the

coenosarc In corals, the coenosarc is the living tissue overlying the stony skeletal material of the coral. It secretes the coenosteum, the layer of skeletal material lying between the corallites (the stony cups in which the polyps sit). The coensarc is comp ...

(the living tissue covering the skeleton) to isolate the polyp, detachment of the polyp, and settlement of the polyp on the seabed followed by its attachment and growth of a new skeleton. In the laboratory, about 5% of these polyps survived to found a new colony. This coral exhibits a high growth rate, high reproductive output and short life-span. It is a very successful species and is often the first scleractinian coral to colonise a disturbed area. The tangled bushy form of this coral provides a suitable habitat for other animals. A number of symbiotic decapod crustaceans find shelter and protection here and they also obtain food in the form of mucus secreted by the coral. Two species of alpheid shrimps and three species of xanthid crabs are thought to be

obligate symbiont 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 ...

s and not found living anywhere else. The coral benefits from their presence as they may attack and prevent predators from feeding on the coral. Any one coral colony is likely to house a single species of symbiotic crustacean, including both adults and juveniles, but a large colony may house two species.

Status

The threats faced by ''Seriatopora hystrix'' and other corals include

ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxid ...

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

and habitat loss. It is gathered for the

reef aquarium 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 ...

trade and in 2005, the total number of pieces exported worldwide was about 15,000. However ''S. hystrix '' has a wide range and is a common species, and may be more resilient than other species of coral. The

has assessed its conservation status as being of "

References

{{Taxonbar, from=Q117568 Pocilloporidae Corals described in 1846