ACANTHOAXIIDAE, van Ofwegen & McFadden, 2010

van Ofwegen, Leen P. & McFadden, Catherine S., 2010, A new family of octocorals (Anthozoa: Octocorallia) from Cameroon waters, Journal of Natural History 44 (1 - 2), pp. 23-29 : 23-24

Order ALCYONACEA Lamouroux, 1812 Family ACANTHOAXIIDAE fam. nov.

Diagnosis

Alcyonacea with an arborescent colony form and a proteinaceous axis with a narrow, hollow, soft, cross-chambered central core, and prominent spines on its surface. Polyps and coenenchyme without calcareous sclerites.

Type genus

Acanthoaxis gen. nov., here designated.

Remarks

In the literature, four different families of alcyonaceans are described with a skeletal axis of mainly scleroproteinous gorgonin and without sclerites in this axis; they are diagnosed on the axis morphology: Acanthogorgiidae have an axis with a wide, hollow, soft, cross-chambered central core; Plexauridae have a similar central core to the Acanthogorgiidae , but also with numerous hollow spaces that can be filled with non-scleritic calcite; Gorgoniidae have a narrow, hollow, soft, cross-chambered central core; and Dendrobrachiidae have a purely proteinaceous axis lacking a hollow core.

The last two families most resemble the Acanthoaxiidae . The Gorgoniidae have a narrow, hollow, soft, cross-chambered central core in common with the Acanthoaxiidae , but lack the spines on the axis surface; the Dendrobrachiidae have spines on the axis surface in common with the Acanthoaxiidae , but differ in lacking a narrow, hollow, soft, cross-chambered central core.

Very few alcyonaceans with a gorgonin axis and lacking sclerites have been reported in the literature. Opresko and Bayer (1991) mentioned two species belonging to Trichogorgia (Chrysogorgiidae) , and the three species described for Dendrobrachia (Dendrobrachiidae) . The Chrysogorgiidae have a highly calcified axis, quite unlike the Acanthoaxiidae and Dendrobrachiidae .

An ongoing molecular study based on the mitochondrial genes msh1 and COI placed the genus described below in the Holaxonia– Alcyoniina clade of Octocorallia ( McFadden et al. 2006) closest to Carijoa and Cryptophyton , both in the family Clavulariidae , but without particularly strong support for that relationship. Carijoa and Cryptophyton both lack an axis, therefore, morphologically the Acanthoaxiidae have no relationship with the Clavulariidae .