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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)

  • Homoscleromorpha Bergquist, P.R. 1978. Sponges. London : Hutchinson 268 pp. 12 pls 81 figs 15 tables. [33].
  • Homosclerophorides Lévi, C. 1973. Systématique de la classe des Demospongiaria (Démosponges). pp. 577-631 in Brien, P., Lévi, C., Sarà, M., Tuzet, O. & Vacelet, J. (eds). Traité de Zoologie, Anatomie, Systématique, Biologie. III. Spongiaires. (Series ed. P.-P. Grassé). Paris : Masson et Cie. [591] [invalid name; Lévi (1973) used the name 'Homosclerophorides' to encompas what we now call Homoscleromorpha, but the name is 'imperfect', undifferentiated from Order Homosclerophorida Dendy, and hence Bergquist (1978) is presently credited with the subclass, now class Homoscleromorpha].

 

Introduction

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.

 

Diagnosis

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)

 

Diagnosis References

Gazave, E., Lapébie, P., Renard, E., Vacelet, J., Rocher, C., Ereskovsky, A.V., Lavrov, D.V. & Borchiellini, C. 2010. Molecular Phylogeny Restores the Supra-Generic Subdivision of Homoscleromorph Sponges (Porifera, Homoscleromorpha). PLoS ONE (Public Library of Science) 5(12): 1-15 [e14290. doi:10.1371/journal.pone.0014290] [2]

 

General References

Bergquist, P.R. 1978. Sponges. London : Hutchinson 268 pp. 12 pls 81 figs 15 tables.

Brien, P., Lévi, C., Sarà, M., Tuzet, O. & Vacelet, J. 1973. Spongiaires. pp. 1-716 485 figs in Grassé, P.P. (ed.). Traité de Zoologie. Anatomie, Systématique, Biologie. Paris : Masson et Cie Vol. 3(1).

Dendy, A. 1905. Report on the sponges collected by Professor Herdman, at Ceylon, in 1902. 57-246 pls 1-16 in Herdman, W.A. (ed.). Report to the Government of Ceylon on the Pearl Oyster Fisheries of the Gulf of Manaar. London : Royal Society Vol. 3 Suppl. 18. [64]

Gazave, E., Lapébie, P., Renard, E., Vacelet, J., Rocher, C., Ereskovsky, A.V., Lavrov, D.V. & Borchiellini, C. 2010. Molecular Phylogeny Restores the Supra-Generic Subdivision of Homoscleromorph Sponges (Porifera, Homoscleromorpha). PLoS ONE (Public Library of Science) 5(12): 1-15 [e14290. doi:10.1371/journal.pone.0014290] [e14290] (http://www.marinespecies.org/porifera/porifera.php?p=taxdetails&id=131587 (on 2011-12-28))

Hooper, J.N.A., Van Soest, R.W.M. & Pisera, A. 2011. Phylum Porifera Grant, 1826. In: Zhang, Z.-Q. (Ed.) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness. Zootaxa 3148: 13-18 [13]

Hooper, J.N.A. & Soest, R.W.M. Van 2002. Class Demospongiae Sollas, 1885. pp. 15-18 in Hooper, J.N.A. & Van Soest, R.W.M. (eds). Systema Porifera: A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 1.

 

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)