Australian Biological Resources Study

Australian Faunal Directory


Regional Maps

Class HOMOSCLEROMORPHA Bergquist, 1978

Compiler and date details

2012 - John N.A. Hooper, Queensland Museum, Brisbane (1994, updated 1999, 2004, 2011); Felix Wiedenmayer Naturhistorisches Museum Basel, Basel, Switzerland (1994)



The Homoscleromorpha has until recently been treated as a subclass of Demospongiae, with a single order and family. The taxon has been attributed to Lévi (1973) by Hooper & Van Soest (2002: 16) based on his use of the term Homosclerophormes for a clade containing Homosclerophorids sensu Dendy (1905), but was subsequently emended by Bergquist (1978).

Recent molecular evidence, together with other data from embryology, cytology and morphology, show that although homoscleromorphs share synapomorphies with both Calcarea and Demospongiae, their possession of some unique features and molecular evidence justified their promotion to a separate fourth class of the Porifera (Gazave et al. 2010).

This class contains two families (Plakinidae and Oscarelllidae) differentiated by the presence and absence of a spicule skeleton, respectively. There are less than 100 described species. The current systematics is as follows (from Hooper, Van Soest & Pisera 2011):

Class Homoscleromorpha Bergquist, 1978 (1 order: no apparent fossil record)
Order Homosclerophorida Dendy, 1905 (2 families)
Family Plakinidae Schulze, 1880 (5 genera, 68 species)
Family Oscarellidae Lendenfeld, 1887 (2 genera, 17 species)

Database Notes

Other names. Microsclerophora Sollas, 1887, Carnosa Carter, 1875c.



Porifera with cinctoblastula larvae and viviparous reproduction; skeleton composed of tetraxonid siliceous spicules and derivatives with equal rays (diods, triods, lophate spicules), arranged around choanocyte chambers reflecting the canal structure; no differentiation between megascleres and microscleres although size differences do occur between types of spicules; spicules usually small (100µm or less), not localised to any particular region; choanocyte chambers with large numbers of choanocytes. There are <100 described species of exclusively marine sponges worldwide, traditionally subdivided into 7 genera based on morphological characters.


ID Keys

(1) Homoscleromorpha containing species with spicules .............................. Plakinidae Schulze, 1880 (genera Plakina, Plakortis, Plakinastrella and Corticium, Plakinolopha)
–. Homoscleromorpha containing species lacking spicules .............................. Oscarellidae Lendenfeld, 1887 (genera Oscarella and Pseudocorticium)


History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
28-Feb-2012 28-Feb-2012 MODIFIED
28-Feb-2012 13-Apr-2011 MODIFIED
12-Feb-2010 (import)