Speirogorgia Williams 2019, gen. nov.

Genus Speirogorgia gen. nov.

(Figs. 1–8, 10)

Diagnosis. Gorgonian octocoral. Axis solid, continuous, presumably highly calcareous. Interior of axis uniform throughout in transverse section, without concentric lamellae or radiating pattern of wedge-shaped columns of calcareous material. Axis unjointed, quadrangular to quadrate in cross section. Polyps completely retractile into coenenchyme, calyces absent. Retracted polyps form very low conical mounds along the polypary. Coenenchymal sclerites include elongated spindles with acute ends and narrower medial waists, as well as shorter radiates. Anthocodial sclerites are small rods. Colonies azooxanthellate.

Type species. Speirogorgia robertbollandi sp. nov.

Etymology. The generic name is derived from the Greek, speira (a winding, coil, or twist—something wound, rolled or coiled), and the suffix –gorgia (a commonly used ending in octocoral nomenclature), in reference to the coiled or spiral growth form of the holotype.