The calcareous sponges of class Calcarea are members of the animal phylum Porifera, the cellular sponges. They are characterized by spicules made out of calcium carbonate in the form of calcite or aragonite. While the spicules in most species have three points, in some species they have either two or four points.
|"Calcispongiae" from Ernst Haeckel's Kunstformen der Natur, 1904|
All sponges in this class are strictly marine, and, while they are distributed worldwide, most are found in shallow tropical waters. Like all other sponges, they are sedentary filter feeders.
All three sponge body plans are represented within class Calcarea : asconoid, syconoid, and leuconoid. Typically, calcareous sponges are small, measuring less than 10 cm (3.9 in) in height, and drab in colour. However, a few brightly coloured species are also known.
Calcareous sponges vary from radially symmetrical vase-shaped body types to colonies made up of a meshwork of thin tubes, or irregular massive forms. The skeleton has either a mesh or honeycomb structure.
Of the 15,000 or so species of Porifera that exist, only 400 of those are calcareans.
Calcarean sponges first appeared during the Cambrian, and their diversity was greatest during the Cretaceous period. Recent molecular analysis suggests the class Calcarea should be designated as a phylum, in particular the first to have diverged in the Animalia; the other sponges belong to the phylum Silicarea.
The calcareous sponges are divided into two subclasses and six orders:
Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 104. ISBN 0-03-056747-5.
Arturia africana is a species of calcareous sponge from South Africa.Arturia alcatraziensis
Arturia alcatraziensis is a species of calcareous sponge from Brazil. It is named after the Alcatrazes Islands where it was discovered.Arturia canariensis
Arturia canariensis, commonly known as the yellow calcareous sponge, is a species of sponge in the family Clathrinidae. It is found in shallow seas in the Canary Islands, Cape Verde, the Adriatic Sea and the Caribbean Sea. The specific epiphet "canariensis" was given to this species because it was first described from Lanzarote in the Canary Islands.Arturia compacta
Arturia compacta is a species of calcareous sponge in the family Clathrinidae found in Mauritius. This species is very likely to be synonymous with Arthuria canariensis, differing only in its larger and thicker triactines. However, the type and only known specimen is lost.Arturia sueziana
Arturia sueziana is a species of calcareous sponge from Egypt. The species is named after the Egyptian city of Suez where the holotype was discovered.Ascandra atlantica
Ascandra atlantica is a species of calcareous sponge from Cape Verde.Ascandra corallicola
Ascandra corallicola is a species of calcareous sponge in the family Leucaltidae.Borojevia
Borojevia is a genus of calcareous sponge in the family Clathrinidae. The genus is named after sponge researcher Radovan Borojevic.Clathrina
Clathrina is a genus of calcareous sponge in the family Clathrinidae. Several species formerly in Clathrina were transferred to the newly erected genera Arturia, Ernstia, Borojevia, and Brattegardia in 2013. The name is derived from the Latin word "clathratus" meaning "latticed".Clathrina aurea
Clathrina aurea is a species of calcareous sponge from Brazil. Specimens of this species were previously misidentified with Clathrina clathrusClathrina clathrus
Clathrina clathrus is a species of calcareous sponge belonging to the family Clathrinidae.
This yellow (occasionally white) sponge, up to 10 cm in diameter, usually appears cushion-shaped at a distance (its close relative Clathrina coriacea is normally flatter in appearance). Close-up the sponge can be seen to consist of a tangled mass of tubes (these tubes are thicker and less tightly knit than in C. coriacea and there is no osculum as found in that species). Like C. coriacea, the spicules are exclusively three-pointed triactines.
This is a shallow-water species found in the Mediterranean and on Atlantic coasts of Europe as far north as the British Isles.Clathrina primordialis
Clathrina primordialis is a species of calcareous sponge from Croatia.Clathrina rotunda
Clathrina rotunda is a species of calcareous sponge from South Africa.Clathrina sinusarabica
Clathrina sinusarabica is a species of calcareous sponge from Egypt.Clathrina wistariensis
Clathrina wistariensis is a species of calcareous sponge from Australia.Dendya clathrata
Dendya clathrata is a species of calcareous sponge in the family Dendyidae.Guancha apicalis
Guancha apicalis was thought to be a species of calcareous sponge in the genus Guancha from Antarctica. It actually never existed.Raphidonema (sponge)
Raphidonema is an extinct genus of calcareous sponges.Sycon raphanus
Sycon raphanus is a species of marine invertebrate, a calcareous sponge belonging to the family Sycettidae. The name derives from the Greek, "raphanus", meaning radish, and presumably refers to the sponge's shape.
Sponges are composed of a jellylike mesohyl sandwiched between two layers of cells. They have a fragile skeleton composed of stiff spicules. They are filter feeders, maintaining a flow of water through their structure which passes out through large openings called oscula.
Extant Porifera classes