''Haliclona caerulea'' is a species of marine sponge 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 ...

Chalinidae Chalinidae is a family of marine demosponges, containing the following genera: * '' Chalinula'' Schmidt, 1868 * '' Cladocroce'' Topsent, 1892 * '' Dendrectilla'' Pulitzer-Finali, 1983 * '' Dendroxea'' Griessinger, 1971 * ''Haliclona ''Haliclon ...

. It is an encrusting tubular sponge that grows anchored on rocky surfaces of

coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. ...

Name

The name of the species comes from the Latin ''caeruleus'' and relates to the sponge's colour:

cerulean The color cerulean (American English) or caerulean (British English, Commonwealth English), is a variety of the hue of blue that may range from a light azure blue to a more intense sky blue. Cerulean may also be mixed with the hue of green. ...

blue, like the sky, or the ocean.

Morphology

''Haliclona caerulea'' takes the form of an encrusting mass of cylindrical to volcano-shaped projections between 2 and 15 cm, with oscula at the high end. The oscula are circular or oval, and between 1.3 and 5.0 mm in diameter. The body has radial symmetry and consists, on the outside, of flattened cells known as

pinacocytes The pinacoderm is the outermost layer of body cells (pinacocytes) of organisms of the phylum Porifera (sponges), equivalent to the Epidermis (skin), epidermis in other animals. Structure The pinacoderm is composed of pinacocytes, flattened epitheli ...

. The inner part is formed by cells called

choanocytes Choanocytes (also known as "collar cells") are cells that line the interior of asconoid, syconoid and leuconoid body types of sponges that contain a central flagellum, or ''cilium,'' surrounded by a collar of microvilli which are connected by ...

, equipped with a

flagellum A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

. These cells have a dual function: ingesting food particles, and maintaining the flow of water through the sponge's body. Between the two layers a more or less gelatinous substance called

mesohyl The mesohyl, formerly known as mesenchyme or as mesoglea, is the gelatinous matrix within a sponge. It fills the space between the external pinacoderm and the internal choanoderm. The mesohyl resembles a type of connective tissue and contains ...

. Sclerocyte cells are responsible for secreting a kind of skeleton for supporting the sponge's body, formed of spongin fibers. As its name suggests, the most common color is blue, but individuals may be beige or white.

Distribution

Its geographic distribution includes the western tropical Atlantic, from

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

, to the Caribbean Sea, reaching the

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

and the Pacific coast of Mexico and Panama. is also found on the islands of

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 ...

and

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 ...

, where it has been introduced probably via unintended

biofouling Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...

on the hulls of ships.

Habitat and ecological roles

It is commonly seen growing in beds of the seagrass '' Thalassia'', and in rocky coral rubble habitats. Studies reported their symbiosis with calcareous alga '' Jania adhaerens''.

Aquaria

A sponge going by the name of ''Haliclona caerulea'' can sometimes be found in the

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

trade, though this appears to be ''Amphimedon texotli''.

References

{{Taxonbar, from=Q2140487

caerulea ''Caerulea'' is a genus of butterflies in the family Lycaenidae. It is a small genus with only two species. *'' Caerulea coeligena'' (Oberthür, 1876) western China, central China. *'' Caerulea coelestis'' (Alphéraky, 1897) Tibet, western Chi ...

Animals described in 1965