Calcarea

From Palaeos

o Metazoa 
`--o PORIFERA
   |--Hexactinellida 
   `--+--+--Demospongiae 
      |  `?-Archaeocyatha
      |==Sclerospongiae (polyphyletic)?
      |==Stromatoporoidea (polyphyletic)?
      `--+--Calcarea 
         `--Radiata / Eumetazoa

This class consists of marine calcareous sponges with a skeleton composed of separate calcareous spicules, one-rayed (monaxonid), three-rayed (triaxonid) or four-rayed (tetraxonid), not divisible into megascleres (larger) and microscleres (smaller). They have an asconoid, syconoid or leuconoid construction. Many are dull coloured, although brilliant red, yellow, and lavender species are also known. In size they are generally smaller than representatives of other classes, most are less than 10 cm in height. They have a world-wide distribution, mostly restricted to shallow coastal waters.

Credits

MAK030430