Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide. They are sponges with a soft body that covers a hard, often massive skeleton made of calcium carbonate, either aragonite or calcite. They are predominantly leuconoid in structure. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges. Some species, in particular from the Antarctic, obtain the silica for spicule building from the ingestion of siliceous diatoms.
Geodia is a genus of sea sponge belonging to the family Geodiidae. It is the type genus of its taxonomic family.
Polymastia is a genus of sea sponges containing about 30 species. These are small to large encrusting or dome-shaped sponges with a smooth surface having many teat-shaped projections (papillae). In areas of strong wave action, this genus does not grow the teat structures, but instead grows in a corrugated form.
Halichondriidae is a family of sea sponges belonging to the order Suberitida. These sponges have a skeleton consisting of dense bundles of spicules occurring in a more or less random pattern.
Spongia is a genus of marine sponges in the family Spongiidae, originally described by Carl Linnaeus in 1759, containing more than 60 species. Some species, including Spongia officinalis, are used as cleaning tools, but have mostly been replaced in that use by synthetic or plant material.
Acanthotetilla is a genus of demosponges belonging to the family Tetillidae. They are distinguished from others in the family by the presence of distinctive, heavily spined skeletal structures called "megacanthoxeas".
Clionaidae is a family of demosponges which are found worldwide. This family is known for parasitically boring holes in calcareous material such as mollusc shells and corals, using both chemical and mechanical processes.
Pseudospongosorites is a genus of sea sponges belonging to the family Suberitidae. Currently, the genus is considered as monotypic, consisting of a single species Pseudospongosorites suberitoides. It is found in the Caribbean Sea, the Gulf of Mexico and on the Atlantic coast of the United States as far north as North Carolina. This species is known by the common name Florida hermit crab sponge, so named because hermit crabs often use it as shelter.
Ancorinidae is a family of marine sponges belonging to the order of Tetractinellida.
Pachymatisma is a genus of sponges belonging to the family Geodiidae.
Cliona viridis, commonly called the green boring sponge, is a species of demosponge in the family Clionaidae. Its form varies according to the nature of the surface on which it grows. In limestone and other calcareous substrates it excavates channels and chambers while on other types of rock it encrusts the surface or forms massive structures. It is native to the eastern Atlantic, the Mediterranean Sea and the Indo-Pacific Ocean.
Tetractinellida is an order of sea sponges belonging to the class Demospongiae. First described in 1876, this order received a new description in 2012 and replaced the two orders Astrophorida and Spirophorida, which then became sub-orders as Astrophorina and Spirophorina.
Calthropella is a genus of sea sponges in the order Tetractinellida. It is the only genus in the monotypic family Calthropellidae.
Craniella is a genus of marine sponges in the family Tetillidae.
Tethyida is an order of sea sponges in the subclass Heteroscleromorpha.
Azoricidae is a family of marine sponges belonging to the order of Tetractinellida.
Jean Vacelet is a French marine biologist who specialises in the underwater fauna of the Mediterranean. After earning his licence at the Faculté des Sciences de Marseille and learning to dive in 1954, he specialised in the study of sponges at the Marine station of Endoume, and there he has stayed faithful to both sponges and place for more than half a century. His research has included all aspects of sponges: taxonomy, habitat, biology, anatomy, their bacterial associations, and their place in the evolution of multi-celled animals. He has studied them not only in the Mediterranean but in the Indian Ocean and the Pacific. Exploration of underwater grottoes, together with Jacques Laborel and Jo Hamelin, revealed the existence of sponges dating from very ancient geological periods and the unexpected existence of carnivorous sponges, and surprisingly, the grottoes in some ways mimicked life at much greater depths.
Ascaltis is a genus of sponges in the family Leucascidae, first described in 1872 by Ernst Haeckel.
Tetilla is a genus of demosponges in the family Tetillidae. It is widely distributed. They are mainly found in deeper habitats.
