''Balanophyllia elegans'', the orange coral or orange cup 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 ...

of solitary cup coral, a

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 ...

Dendrophylliidae Dendrophylliidae is a family of stony corals. Most (but not all) members are azooxanthellate and thus have to capture food with their tentacles instead of relying on photosynthesis to produce their food. The World Register of Marine Species incl ...

. It is native to the eastern Pacific Ocean. As an azooxanthellate species, it does not contain

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 ...

dinoflagellates 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 ...

in its tissues in the way that most corals do.

Description

''B. elegans'' is a solitary species of cup coral. The polyps are mostly bright orange and about in diameter, though a yellow form also exists. The polyp is large and fleshy with tapering tentacles bearing groups of stinging cells. The polyp can almost completely retract into its stony

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 ...

cup. This coral can be distinguished from the corallimorph ''

Corynactis californica ''Corynactis californica'' is a brightly colored colonial anthozoan corallimorph. Unlike the Atlantic true sea anemone, '' Actinia fragacea'', that bears the same common name, strawberry anemone, this species is a member of the order Corallimor ...

'', which it somewhat resembles, by its stony skeleton, and from ''

Caryophyllia alaskensis ''Caryophyllia'' is a genus of solitary corals in the family Caryophylliidae. Members of this genus are azooxanthellate (do not contain symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") ...

'', another stony coral found in this habitat, by its brighter colour (''C. alaskensis'' is beige).

Distribution and habitat

The species is native to the western seaboard of North America, from

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

. It occurs on rocky coasts from the low intertidal zone down to about . It appreciates habitats with vigorous water movement, such as surge channels, and often grows in caves and under overhangs. It is often found living amongst

kelp Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "underwat ...

such as ''

Macrocystis integrifolia Macrocystis integrifolia was considered a distinct species of giant kelp in the genus ''Macrocystis ,'' based on blade and holdfast morphology. As of 2009, phycologists have collapsed ''Macrocystis integrifolia'' and the various other giant kel ...

''.

Biology

Being an azooxanthellate coral, that is, not containing symbiotic

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 ...

algae that photosynthesise, ''B. elegans'' feeds on whatever the tentacles can catch, with the aid of their

nematocyst A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this ce ...

s (stinging cells) and spirocysts (cells containing hollow adhesive threads which coil around the prey). The mouth is large and slit-shaped, and it is possible that some prey is caught by use of the

mesenteries In zoology, a mesentery is a membrane inside the body cavity of an animal. The term identifies different structures in different phyla: in vertebrates it is a double fold of the peritoneum enclosing the intestines; in other organisms it forms co ...

in the

gastrovascular cavity The gastrovascular cavity is the primary organ of digestion and circulation in two major animal phyla: the Coelenterates or cnidarians (including jellyfish and corals) and Platyhelminthes (flatworms). The cavity may be extensively branched into ...

while opening the mouth wide, however its main prey is

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 ...

caught by the tentacles. This coral can also extract

dissolved organic carbon Dissolved organic carbon (DOC) is the fraction of organic carbon operationally defined as that which can pass through a filter with a pore size typically between 0.22 and 0.7 micrometers. The fraction remaining on the filter is called particu ...

from sea water, and during the winter months, when there is a scarcity of zooplankton, this source of nutrition may be critical for the coral's survival. The sexes are separate in this coral. Fertilisation takes place inside the female's gastrovascular cavity, and the larvae are brooded there. They are later released as worm-like orange larvae and settle nearby.

References

External links

* {{Taxonbar, from=Q3955389 Dendrophylliidae Corals described in 1864