Calcaxonia

Calcaxonia 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.
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 are parts of other clades of Scleralcyonacea.

Composition

The following taxa were included in Calcaxonia:

Note that while some of the above families were 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. Other authors did not adopt this proposal.