Holaxonia

Holaxonia
Pinnigorgia sp.
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Cnidaria
Subphylum: Anthozoa
Class: Octocorallia
Order: Alcyonacea
Suborder: Holaxonia
Studer, 1887
Families

See text

Paramuricea sp.
Eunicea sp.

Holaxonia (English name: holaxonians) is a former Octocorallian suborder of the order Gorgonacea (English names: gorgonians or sea fans), or alternatively of the broadly conceived order Alcyonacea. Before 1981/1999, Holaxonia usually also included the taxon Calcaxonia (informal name: restricted Holaxonia).

Since a 2022 revision of the Octocorallia, the content of the former Holaxania has been included in the new order Malacalcyonacea, within which it does not form a monophyletic group (clade) and has no name. The two Holaxonian genera Dendrobrachia a Ideogorgia are an exception in that they have been included not in the order Malacalcyonacea, but in the order Scleralcyonacea.

Vernacular names of certain members of Holaxonia include: sea fan, sea whip, sea rod, and sea blade.

Characteristics

Members of Holaxonia are soft corals. They are colonial, sessile organisms and are generally tree-like in structure. They do not have a hard skeleton composed of calcium carbonate but have a firm but pliable, central axial skeleton composed of a fibrous protein called gorgonin embedded in a tissue matrix, the coenenchyme. In some genera this is permeated with a calcareous substance in the form of fused spicules. Members of Holaxonia are characterized by having an unspiculated axis and often a soft, chambered central core. The polyps have eight-fold symmetry and in many species, especially in the families Gorgoniidae and Plexauridae, contain symbiotic photosynthetic algae called zooxanthellae. These soft corals are popular in salt water aquaria.

Families and genera

In 2018, the World Register of Marine Species listed the following families and genera in Holaxonia:

See also

References

  1. ↑ Orejas, Covadonga; Jiménez, Carlos (2019-07-10). Mediterranean Cold-Water Corals: Past, Present and Future: Understanding the Deep-Sea Realms of Coral. Springer. p. 142. ISBN 978-3-319-91608-8. Retrieved 2025-07-10.
  2. ↑ Daly, Marymegan & Brugler, Mercer & Cartwright, Paulyn & Collins, Allen & Dawson, Michael & Fautin, Daphne & France, Scott & McFadden, Catherine & OPRESKO, DENNIS & Rodriguez, Estefania & Romano, Sandra & Stake, Joel. (2007/2006). The Phylum Cnidaria: A Review Of Phylogenetic Patterns And Diversity 300 Years After Linnaeus *. Zootaxa. 1668. 10.5281/zenodo.180149.
  3. ↑ Lesser, Michael (2011-11-16). Advances in Marine Biology. Academic Press. p. 43-46. ISBN 978-0-12-385529-9. Retrieved 2025-07-09.
  4. ↑ GOFFREDO, Stefano; DUBINSKY, Zvy. The Cnidaria, Past, Present and Future (The world of Medusa and her sisters). [s.l.] : Springer, 2016. ISBN 978-3-319-31305-4. pp. 109-111
  5. ↑ BAYER, F. M. Key to the genera of Octocorallia exclusive of Pennatulacea (Coelenterata: Anthozoa), with diganoses of new taxa. PROC. BIOL. SOC. WASH. 94(3), 1981, pp. 902-947
  6. ↑ McFadden, Catherine S.; Ofwegen, Leen P. van; Quattrini, Andrea M. (14 October 2022). "Revisionary systematics of Octocorallia (Cnidaria: Anthozoa) guided by phylogenomics". Bulletin of the Society of Systematic Biologists. 1 (3). doi:10.18061/bssb.v1i3.8735. ISSN 2768-0819.
  7. ↑ Suborder Holaxonia Guide to the Shallow Water (0-200 m) Octocorals of the South Atlantic Bight. Retrieved 2011-12-05.
  8. ↑ Gorgonians (Holaxonia) Saltcorner. Retrieved 2011-12-03.
  9. ↑ Gorgonians Animal-World. Retrieved 2011-12-03.
  10. ↑ "WoRMS - World Register of Marine Species - Holaxonia". marinespecies.org. Retrieved 2018-03-30.