''Montastraea'' is a genus of colonial

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 ...

found in the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

seas. It is the only genus in the monotypic family Montastraeidae and contains a single species, ''Montastraea cavernosa'', known as great star coral. It forms into massive boulders and sometimes develops into plates. Its polyps are the size of a human thumb and fully extend at night.

Description

Great star coral colonies form massive boulders and domes over 5 feet (1.5 m) in diameter in waters of shallow and moderate depths. In deeper waters, this coral has been observed growing as a plate formation. It is found throughout most reef environments, and is the predominant coral at depths of 40–100 feet (12.2–30.5 m). This coral occasionally has a fluorescent red or orange color during daytime; it has recently been suggested that this hue is due to

phycoerythrin Phycoerythrin (PE) is a red protein-pigment complex from the light-harvesting phycobiliprotein family, present in cyanobacteria, red algae and Cryptomonad, cryptophytes, accessory to the main chlorophyll pigments responsible for photosynthesis.The ...

, a

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

. It appears that, in addition to

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

zooxanthella 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 ...

, this coral harbors endocellular symbiotic cyanobacteria, possibly to help it fix

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

. However more recently, Oswold ''et al.'' (2007) showed an absence of functional phycoerythrin in ''M. cavernosa''. The species is gonochoric (colonies can be either male or female) and spawns one week after the full moon in late August. Skeletons show sex-related differences, with females having a less dense skeleton compared to males, which is presumably due to reallocating energy to egg production.

Bleaching

The distinction of bleaching in reefs of ''M. cavernosa'' from merely white-coloured corals was shown to be difficult using standard reflectance techniques. A survey in the

Bay of All Saints The Bay of All Saints (), also known as All Saints' Bay and Todos os Santos Bay, is the principal bay of the Brazilian state of Bahia, to which it gave its name. It sits on the Brazilian coast, eastern coast of Brazil, surrounding part of Bahia' ...

concluded that this may lead to nearly two-fold overestimation of bleaching.

References

{{Authority control Scleractinia Scleractinia genera Fauna of the Caribbean Monotypic cnidarian genera