''Acropora secale'' 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 branching staghorn stony

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

. It is found in shallow parts of the Indo-Pacific Ocean and the type locality is Sri Lanka. The oldest fossils found date back to the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Description

''Acropora secale'' is a

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 ...

coral that forms low hummocks. The branches can grow to a diameter of and length of . They are cylindrical but gradually taper towards the tips. They grow in a

corymb Corymb is a botanical term for an inflorescence with the flowers growing in such a fashion that the outermost are borne on longer pedicels than the inner, bringing all flowers up to a common level. A corymb has a flattish top with a superficial re ...

ose fashion with the lower branches being longer than the upper ones so that the coral has a level-topped appearance. 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 of varying sizes and arranged in vertical rows, often with alternate rows of larger and smaller corallites. The axial corallites are up to in diameter while the radial corallites either have long tubular openings or nariform (noselike) openings. The skeleton is covered by a thin

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...

al layer of tissue. When feeding, the polyps protrude from the corallites. Each has a single ring of twelve tentacles, one of which is longer than the others. The polyps have a mouth which opens into the coelenteron. This interconnects with other polyps through a complex system of channels, the

coenenchyme Coenenchyme is the common tissue that surrounds and links the polyps in octocorals. It consists of mesoglea penetrated by tubes (''solenia'') and canals of the gastrodermis and contains sclerites, microscopic mineralised spicules of silica or of ca ...

, inside the porous skeleton. Several colour schemes occur in this coral, purple with yellow tips to the branches, pale brown with blue tips, plain green or plain brown.

Distribution

''Acropora secale'' is found in the tropical waters of the west Indo-Pacific including the coasts of East Africa, Mozambique,

Rodrigues Rodrigues (french: Île Rodrigues, link=yes ; Creole: ) is a autonomous outer island of the Republic of Mauritius in the Indian Ocean, about east of Mauritius. It is part of the Mascarene Islands, which include Mauritius and Réunion. Rodr ...

Aldabra Aldabra is the world's second-largest coral atoll, lying south-east of the continent of Africa. It is part of the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120 k ...

and

Chagos The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archi ...

. It is also found further east around Singapore, Thailand, Indonesia, Japan, the Philippines, Taiwan and north and west Australia. It is a reef-building coral and occurs at depths down to on outer reef flats, reef slopes, reef edges and walls.

Biology

''Acropora secale'' 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. This means that it has

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 living within its tissues. These, combined with pigments in the tissue, are responsible for the colour of the colony. ''Acropora secale'' 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 ...

and both female gonads and testes are present and mature once a year. The colonies release

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

and sperm simultaneously, usually six days after the full moon, in November in the Southern Hemisphere and in June in the Northern Hemisphere. Fertilisation is external; the developing larvae form part of the

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

and drift with the current before settling on the seabed.

References

{{Taxonbar, from=Q3314172 Acropora Animals described in 1878 Near threatened animals