Speirogorgia, Williams, 2019

Williams, Gary C., 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 (5), pp. 417-433 : 419

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.

Figures

FIGURE 1. Speirogorgia robertbollandi gen. & sp. n. A. Two photographic views of the entire holotype; scale bar=45 mm. B–C. Dissecting microscope views of external morphology. B. Two views of a portion of the colony showing placement of polyp mounds; scale bar=2.50 mm. C. Details of surface of colony showing polyp mounds and partially exserted polyps; scale bar=2.50 mm.

FIGURE 2. Speirogorgia robertbollandi gen. & sp. n. A. Scanning electron micrograph of a portion of the polypary showing a single polyp mound, and sclerites of the surface coenenchyme; scale bar=0.4 mm. B–C. Two photographic views of a portion of the polypary; scale for B=1.0 mm; scale bar for C=2.5 mm.

FIGURE 3. Speirogorgia robertbollandi gen. & sp. n. Scanning electron micrographs of morphological features. A. A portion of the external surface of the holotype showing a polyp mound (center) and dense arrangement of sclerites in the surface coenenchyme; scale bar=1.0 mm. B–D. Oblique views of portions of the axis showing distinctive quadrangular shape in transverse section, and solid calcified material distributed throughout the axial interior; scale bars=0.2 mm.

FIGURE 4. Speirogorgia robertbollandi gen. & sp. n. Scanning electron micrographs of axial structure. A–B. Longitudinal views of two portions of axis; scale bar=1.0 mm. C. Transverse section of axial portion in A; scale bar=0.2 mm.

FIGURE 5. Speirogorgia robertbollandi gen. & sp. n. Scanning electron micrographs of sclerites from the surface coenenchyme—elongated spindles with median waists; scale bar=0.10 mm.

FIGURE 6. Speirogorgia robertbollandi gen. & sp. n. Scanning electron micrographs of sclerites from the subsurface coenenchyme—radiates; scale bar=0.05 mm.

FIGURE 7. Speirogorgia robertbollandi gen. & sp. n. Scanning electron micrographs of coenenchymal sclerites. A. Sclerites from the surface coenenchyme. B. Sclerites from the subsurface coenenchyme; scale bar=0.05 mm.

FIGURE 8. Speirogorgia robertbollandi gen. & sp. n. Camera lucida illustrations of polyp sclerites (rod-like structures presumably from the tentacles); scale bar=0.02 mm.

FIGURE 10. Map of a portion of the eastern Pacific, Ryukyu Archipelago, and Okinawa; arrows point to the type locality of Speirogorgia robertbollandi gen. & sp. n.