A new genus and species of enigmatic gorgonian coral from the Ryukyu Archipelago, northwestern Pacific, with a discussion of calcaxonian systematics (Cnidaria, Anthozoa, Octocorallia)

A new genus and species of flagelliform gorgonian coral is described from mesophotic depth in the western Pacific Ocean. The new taxon exhibits calcaxonian morphological characters and shares affinities to both the clade that includes the Chrysogorgiidae, Primnoidae, and Isididae, as well as the clade that includes the Ellisellidae and the Pennatulacea. Based on morphology alone, placement in a new family is likely justifiable, since it exhibits some characters similar to several diverse calcaxonian taxa, and has unique features as well, but such an outcome awaits supporting molecular evidence. The new genus and species is remarkable among most octocorals in that it has an axis that is quadrangular in transverse section as in the calcaxonian Flagelligorgia gracilis and the pennatulacean Funiculina quadrangularis, and an apparently uniform, solid, highly calcified axial structure that lacks concentric layers or prismatic radiating wedges. In addition, it has distinctive sclerites of the surface coenenchyme that are predominantly elongate warty spindles with median waists, some of which superficially resemble sclerites found in some species of ellisellid gorgonians, but also exhibit ultrastructural features that differentiate them.