DIVERSITY OF LIFE

HIERARCHICAL CLASSIFICATION OF THE PHYLUM PORIFERA

EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>PARAZOA>PORIFERA

Taxonomy of the Phylum after the systems of Brusca and Brusca (2003) and Bergquist (2001).  Descriptions of the following taxa were taken from: Barnes (1984), Bergquist (2001), Brusca and Brusca (2003), Hickman (1973), Storer and Usinger (1965), and Tudge (2000).  

CLASS HEXACTINELLIDA (ALSO CALLED SYMPLASMA; 4 ORDERS DISTRIBUTED IN 2 SUBCLASSES)

Skeleton of silicaceous spicules; usually 6-rayed. No epidermis but covered by syncytium of amoebocytes. Choanocytes in finger-like chambers. Spicules large (megascleres) and small (microscleres).  >400 extant species.

SUBCLASS HEXASTEROPHORA

Microscleres 6-rayed (hexasters), megascleres fused into a skeleton.

Aphrocallistes, Caulophacus, Euplectella, Hexactinella, Leptophragmella, Lophocalyx, Rosella, Sympagella.

SUBCLASS AMPHIDISCOPHORA

Microscleres 2-rayed, megascleres never fused into a skeleton.

Hyalonema, Monorhaphis, Pheronema.

 

CLASS CALCAREA (7 ORDERS DISTRIBUTED IN 2 SUBCLASSES)

Spicules of calcite or aragonite, free or fused. Spicules variable, megascleric, but not of two distinct size classes. Epidermis of pinacocytes.  >500 extant species.

SUBCLASS CALCINEA

3-rayed spicules usually not fused into a skeleton.  Larva forms a flagellated ball of cells (hollow or solid).

Clathrina, Dendya, Leucascus, Leucetta, Murrayona, Soleniscus.

SUBCLASS CALCARONEA

Spicules may be fused or not.  Larva forms hollow ball of cells, about half of which are flagellated.

Amphoriscus, Grantia, Leucilla, Leucoselenia, Petrobiona, Scypha (Sycon).

 

CLASS DEMOSPONGIAE (15 ORDERS DISTRIBUTED IN 3 SUBCLASSES)

Skeleton of spongin; sometimes with silicaceous spicules in megasclere and microsclere size classes; some genera without skeleton. Epidermis of pinacocytes.  Important as source of commercial sponges. >8,000 extant species.

SUBCLASS HOMOSCLEROMORPHA

Spicules numerous and very small.  Not differentiated into mega and microscleres.  

Corticium, Oscarella, Plakina, Plakortis, Pseudocorticium.

SUBCLASS TETRACTINOMORPHA

Very large group.  Distinct differences between mega and microscleres.  Megascleres organized into distinct patterns.

Acanthochaetes, Asteropus, Chondrilla, Chondrosia, Cliona, Cryptotethya, Geodia, Merlia, Polymastia, Rhabdermia, Stelletta, Superites, Tethya, Tetilla.

SUBCLASS CERACTINOMORPHA

Very large group. Distinct micro and megascleres, but megascleres not organized into distinct patterns. Spongin present in most.

Adocia, Agelas, Aplysilla, Aplysina (Verongia), Asbestopluma, Astrosclera, Axinella, Axociella, Calcifibrospongia, Callyspongia, Ceratoporella, Clathria, Coelosphaera, Goreauiella, Halichondria, Haliclona, Halisarca, Hispidopetra, Hymeniacidon, Ircinia, Lissodendoryx, Microciona, Mycale, Myxilla, Spongia, Spongilla, Stromatospongia, Tedania, Valceletia.

 

LITERATURE CITED

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Leys, S. P. 1995. Cytoskeletal Aachitecture and organelle transport in giant syncytia formed by fusion of hexactinellid sponge tissues. The Biological Bulletin. 188:241-254.

Leys, S. P. 2003. The significance of syncytial tissues for the position of the Hexactinellida in the Metazoa. Integrative and Comparative Biology. 43:19-27.

Margulis, L. and K. Schwartz. 1998. Five Kingdoms, an Illustrated Guide to the Phyla of Life on Earth. 3rd Edition. W. H. Freeman and Company.  New York.

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Sperling, E.A., D. Pisani, and K.J. Peterson. 2007. Poriferan paraphyly and its implications for Precambrian palaeobiology. In: Vickers-Rich, P. and P. Komarower, eds. The Rise and Fall of the Ediacaran Biota.  Geological Society, London, Special Publications. 286: 355-368.

Storer, T. I. and R. L. Usinger. 1965. General Zoology. 4th Edition. McGraw-Hill Book Company. New York.

Tudge, C. 2000. The Variety of Life, A Survey and a Celebration of all the Creatures That Have Ever Lived. Oxford University Press. New York.

 

By Jack R. Holt and Carlos A. Iudica.  Last revised: 01/30/2012