''Porites astreoides'', commonly known as mustard hill coral or yellow porites, is a colonial

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 mo ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Poritidae Poritidae is a family of stony corals. Members of the family are colonial hermatypic (reef-building) corals. They are variable in size and form but most are massive, laminar or ramose as well as branching and encrusting. The corallites are co ...

. It is a common species in the

Caribbean Sea The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba ...

and western tropical Atlantic Ocean in North, Central, and South America; and the eastern tropical Atlantic Ocean in western Africa.

Description

When it grows in fast-flowing, shallow water, ''Porites astreoides'' is encrusting but in calmer water at medium depths it is a massive coral with a smooth, mounded, semi-spherical form and can grow to in diameter. At greater depths it is usually plate-like and in caves and under overhangs the plates are angled to receive the maximum amount of light. It is the only species within the genus ''

Porites ''Porites'' is a genus of stony coral; they are small polyp stony (SPS) corals. (Also referred to as finger coral or hump coral) They are characterised by a finger-like morphology. Members of this genus have widely spaced calices, a well-de ...

'' not to have a finger-like form. 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 are small and tightly-packed and give the coral a porous appearance. The polyps each have six

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 and are generally retracted during the day. This coral is yellow, yellowish-green, pale grey or pale brown, a colour given to it by the dinoflagellate

zooxanthellae Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthell ...

, microscopic algae that live

symbiotically Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term

IUCN Red List ver 3.1: ''Porites astreoides''

Least Concern species A least-concern species is a species that has been evaluated and Conservation status, categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still p ...

(2008) . accessed 2017-06-27. It is a common species on all parts of a reef and in lagoons. It usually grows in water less than deep but may occasionally be found at depths of up to . It is sometimes free-living, growing on loose bits of coral, pebbles or mollusc shells. Large domed colonies sometimes appear to be separated into several lobes. This happens when part of the coral has died, and the living tissue in between the dead patches continues to develop, giving a clumped effect.

Biology

The polyps of ''Porites astreoides'' feed mostly at night, extending their tentacles to catch

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

and

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

. The coral also obtains an important part of its nutritional needs as a result of the

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

performed by the zooxanthellae in sunlight. Some colonies of ''Porites astreoides'' are female while others are

hermaphroditic A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

. Sexual reproduction occurs with male gametes being released into the sea around the time of the new moon. The sperm gets drawn into other polyps where fertilization takes place. The

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e are initially brooded but are liberated into the sea at about the time of the full moon. The

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores, which are not related to cnidarians at all. Some groups of Nemerteans also produce larva ...

larvae then drift with the currents for some time before settling onto 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 metamorphosing into new polyps. Each of these grows into a new colony by secreting a

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

skeleton and

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is kno ...

. This is initially extratentacular budding, taking place at the side of the polyp, but at a later stage in the development of the colony, the budding is intratentacular, taking place within the ring of tentacles.

Ecology

''Porites astreoides'' often has the sponge ''

Mycale laevis ''Mycale laevis'', the orange icing sponge or orange undercoat sponge, is a species of marine demosponge in the Family (biology), family Mycalidae. ''Mycale'' is a large genus and this species is placed in the subgenus ''Mycale'' making its full ...

'', with prominent osculi, growing on its underside. This coral is also often associated with

fan worm Sabellida is an order of annelid worms in the class Polychaeta. They are filter feeders with no buccal organ. The prostomium is fused with the peristomium and bears a ring of feathery feeding tentacles. They live in parchment-like tubes made of ...

s. The polyps contain stinging cells known as

nematocyst A cnidocyte (also known as a cnidoblast) is a type of cell containing a large secretory organelle called a ''cnidocyst'', that can deliver a sting to other organisms as a way to capture prey and defend against predators. A cnidocyte explosively ...

s to try to ward off the stoplight parrotfish, other reef fish,

snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

worms The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

and

starfish Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

that feed on it. It is also important to the coral to be in an unshaded position where its zooxanthellae can function fully. Sedimentation may limit this but under good conditions, this coral can grow at the rate of about per year. The

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...

ranks this coral as being of "

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

" as, within its range, it is widespread and common. Compared to other members of its genus, it is resistant to disease and

bleaching Bleach is the generic name for any chemical product that is used industrially or domestically to remove color from (i.e. to whiten) fabric or fiber (in a process called bleaching) or to disinfect after cleaning. It often refers specifically t ...

and lives in deeper water so may be less affected by rising sea temperatures.

References

{{Taxonbar, from=Q3333980 Poritidae Cnidarians of the Atlantic Ocean Cnidarians of the Caribbean Sea Marine fauna of Africa Marine fauna of North America Marine fauna of South America Invertebrates of Central America Biota of the Gulf of Mexico Invertebrates of Brazil Fauna of Mexico Fauna of the Southeastern United States Invertebrates of Venezuela Least concern biota of Africa Least concern biota of North America Least concern biota of South America Least concern biota of the United States Corals described in 1816 Taxa named by Jean-Baptiste Lamarck