Silicarea
Encyclopedia
The siliceous sponges form a major group of the phylum Porifera, consisting of classes Demospongiae and Hexactinellida. They are characterized by spicules made out of silicon dioxide
, unlike calcareous sponge
s.
Individual siliachoates (silica skeleton scaffolding) can be arranged tightly within the sponginocyte or crosshatched and fused together. Siliceous spicules come in two sizes called megascleres and microscleres.
The group, as a part of the phylum Porifera, has been named Silicispongia Schmidt, 1862 and Silicea Bowerbank, 1864. Silicarea is a proposed new phylum based on molecular studies of the phylum
Porifera. It consists of the Poriferan classes Demospongiae and Hexactinellida. Some scientists believe that Porifera is polyphyletic/paraphyletic, and that some sponges, the Calcarea, are a separate phylum which was the first to diverge from the main line of kingdom Animalia. Silicarea is considered the next phylum
to diverge from the primary animal lineage.
Silicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
, unlike calcareous sponge
Calcareous sponge
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...
s.
Individual siliachoates (silica skeleton scaffolding) can be arranged tightly within the sponginocyte or crosshatched and fused together. Siliceous spicules come in two sizes called megascleres and microscleres.
Systematics
Most studies support the monophyly of siliceous sponges.The group, as a part of the phylum Porifera, has been named Silicispongia Schmidt, 1862 and Silicea Bowerbank, 1864. Silicarea is a proposed new phylum based on molecular studies of the phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
Porifera. It consists of the Poriferan classes Demospongiae and Hexactinellida. Some scientists believe that Porifera is polyphyletic/paraphyletic, and that some sponges, the Calcarea, are a separate phylum which was the first to diverge from the main line of kingdom Animalia. Silicarea is considered the next phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
to diverge from the primary animal lineage.