''Dactylotrochus'' is a genus of large polyp

stony corals 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 ...

from the Red Sea and western Pacific Ocean. It is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

with a single species, ''Dactylotrochus cervicornis''. It inhabits the deep sea and is believed to be azooxanthellate.

Description

Dactylotrochus cervicornis is a sturdy solitary coral with a short pedicel measuring 15 millimeters (0.6 in) in diameter and an encrusting base. The maximum size is in diameter and high. The fossa (central depression) is elongated and the calyx is deep. As the coral grows, certain parts of 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 ...

wall and

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

develop more than others and two or more petal-like lobes grow, often recurving. The septa are very numerous; they are narrow except near the corallite wall and there is no central columella.

Taxonomy

This species was originally classified in the family

Caryophylliidae The Caryophylliidae are a family (biology), family of stony corals found from the tropics to temperate seas, and from shallow to very deep water. Genera *''Africana (coral), Africana'' Ocana & Brito, 2015 *''Anomocora'' Studer, 1878 *''Aste ...

but

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

studies show that it should be included in Agariciidae, even though other members of this family are shallow water, colonial corals. The ancestor of the family was probably solitary and azooxanthellate, and such solitary fossil species as '' Trochoseris'' can now be better accommodated in this family.

Distribution and habitat

''D. cervicornis'' is known from the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

and from various oceanic islands in the Indo-Pacific region; it occurs in

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

Palau Palau, officially the Republic of Palau, is an island country in the Micronesia subregion of Oceania in the western Pacific Ocean. The Republic of Palau consists of approximately 340 islands and is the western part of the Caroline Islands ...

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (; ), is an island country in Melanesia located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of northern Australia, northeast of New Caledonia, east o ...

and

Wallis and Futuna Wallis and Futuna, officially the Territory of the Wallis and Futuna Islands (), is a French island territorial collectivity, collectivity in the Oceania, South Pacific, situated between Tuvalu to the northwest, Fiji to the southwest, Tonga t ...

, and also from the eastward slope of

Bikini Atoll Bikini Atoll ( or ; Marshallese language, Marshallese: , , ), known as Eschscholtz Atoll between the 19th century and 1946, is a coral reef in the Marshall Islands consisting of 23 islands surrounding a central lagoon. The atoll is at the no ...

and the Baie de Sandal in

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

. Its depth range is . It is not considered to be a

hermatypic Hermatypic corals are those corals in the order Scleractinia which build reefs by depositing hard calcareous material for their skeletons, forming the stony framework of the reef. Corals that do not contribute to coral reef development are referred ...

(reef building) coral.

Biology

The polyp secretes the

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

from which the skeleton is built. It spreads its

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 to catch the

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

on which it feeds and can also absorb dissolved organic matter from the water. Although this is assumed to be a solitary coral, new polyps can bud from the base.

References

{{Taxonbar, from1=Q20804596, from2=Q3940613 Agariciidae Taxa described in 1954 Monotypic cnidarian genera Scleractinia genera