Calcaxonia

Calcaxonia (1981 - 1999 known only under the informal name restricted Holaxonia) was, in some systems, an Octocorallian suborder of the order Gorgonacea, or alternatively of the broadly conceived order Alcyonacea. Before its formal erection in 1999, it was usually included inside the suborder Holaxonia. ^{[1] [2] [3]}

According to a 2022 revision of Octocorallia, former Calcaxonia is part of the newly created order Scleralcyonacea, with the exception of the Calcaxonian genus Isis which is included in the order Malacalcyonacea. Within Scleralcyonacea, almost all former Calcaxonia taxa form together one unnamed clade, only Ellisellidae and Dendrobrachiidae (and possibly also Chelidonisididae) are parts of other clades of Scleralcyonacea. ^[4]

Composition

The following taxa were included in Calcaxonia: ^{[4] [1]}

• family Chelidonisididae
• family Chrysogorgiidae
• family Dendrobrachiidae (before 2019, this taxon was classified as part of Holaxonia, rather than Calcaxonia)
• family Ellisellidae
• family Ifalukellidae
• genus Isis (the current family Isididae includes only this genus plus two genera formerly included in Gorgoniidae being part of Holaxonia; prior to 2021, the family Isididae included this genus plus what are now the families Keratoisididae and Mopseidae)
• family Isidoidae (before 2021, this taxon was classified either as incertae sedis or as part of Chrysogorgiidae)
• family Keratoisididae (before 2021, this taxon was classified as part of Isididae)
• family Mopseidae (before 2021, this taxon was classified as part of Isididae)
• family Pleurogorgiidae (before 2021, this taxon was classified as part of Chrysogorgiidae)
• family Primnoidae

Note that while some of the above families were (re)created by various studies in 2021, all the above families were moved to the new order Scleralcyonacea one year later, i.e. in 2022.

Calcaxonia sensu lato

In 2019, G. C. Williams proposed that the name Calcaxonia be applied to the whole clade which, since 2022, has been known as Scleralcyonacea, i.e. the clade composed mainly of Calcaxonia proper, Pennatulacea and Helioporacea. ^[5] Other authors did not adopt this proposal.

References

1. Lesser, Michael (2011-11-16). Advances in Marine Biology. Academic Press. p. 43-46. ISBN   978-0-12-385529-9 . Retrieved 2025-07-09.
2. 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
3. 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
4. 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.
5. Williams, Gary. (2019). A new genus and species of enigmatic gorgonian coral from the Ryukyu Archipelago, northwestern Pacific, with a discussion of calcaxonian systematics (Cnidaria, Anthozoa, Octocorallia). Zootaxa. 4701. 417-433. 10.11646/zootaxa.4701.5.2.