Thursday, April 20, 2017

[Cnidaria • 2017] Flagelligorgia gracilis • A New Genus and Species of Golden Coral (Anthozoa, Octocorallia, Chrysogorgiidae) from the Northwest Atlantic

Flagelligorgia gracilis 
 Cairns & Cordeiro, 2017 

A new genus and species of unbranched golden coral, Flagelligorgia gracilis, is described based on several specimens collected off the southeastern coast of the United States. The genus is provisionally included in the family Chrysogorgiidae, pending molecular confirmation. Flagelligorgia morphologically resembles other unbranched chrysogorgiids, such as Distichogorgia, Chalcogorgia, Helicogorgia and Radicipes, to which it is compared. The type species is illustrated and its distribution mapped.

Keywords: Flagelligorgia gracilis, unbranched octocoral, biserial polyp arrangement, Radicipes, southeastern USA

Figure 1.: Diagnostic characters of Flagelligorgia gracilis sp. n. 
A general view of the holotype (USNM 49503) attached to a rocky substrate B detail of the holotype showing the biserial arrangement of polyps C,E cross-section of the stem of the holotype showing its four rounded longitudinal cords D detail of undulating concentric layers of the stem in cross-section.
Scale bars: A: 10 mm, B: 5 mm, C, E: 0.1 mm, D: 0.01. 

Subclass Octocorallia Haeckel, 1866

Order Alcyonacea Lamouroux, 1812
Suborder Calcaxonia Grasshoff, 1999

Family Chrysogorgiidae Verrill, 1883
Type genus: Chrysogorgia Duchassaing & Michelotti, 1864.

Diagnosis: (after Cairns (2001) and Pante et al. (2012)). Calcaxonians having an unjointed, solid (non-spicular), concentrically layered scleroproteinous axis. The axial layers are usually smooth (not undulated) and thus not longitudinally grooved externally; the axis usually displays metallic or iridescent reflections. The colony may be branched or unbranched (flagelliform), arising from a root-like or discoidal, strongly calcified holdfast. Polyps are contractile but not retractile, arranged in rows (uniserial, biserial or multiserial), but never in whorls. Sclerites predominantly flat, smooth scales, in some species warty rods and spindles.

Flagelligorgia gen. n.
 Type species: Flagelligorgia gracilis, here designated. Gender: feminine.

Diagnosis: Colonies unbranched (flagelliform), loosely coiled, attached by a holdfast; axis composed of undulating concentric layers (Figs 1C–E, 2D). Polyps arranged biserially. Body wall and coenenchymal scales elongate, smooth scales. Polyps lack an operculum.

Distribution: Off Southeastern United States from North Carolina to Florida, 196–567 m depths.

Etymology: The name is a combination of flagellum (Latin for small whip) and gorgia (a common octocoral suffix and once the name of the order Gorgonacea, the name derived from the mythical female monster, the Gorgon), in reference to the flagelliform nature of the colony.

Flagelligorgia gracilis sp. n.

Distribution: Southeastern coast of United States from off Outer Banks, North Carolina to off Carysfort Reef (near Key Largo, Florida) (Fig. 4), 196–567 m depths.

Etymology: Named gracilis (Latin for slendergracile), in allusion to the very slender aspect of the colony.

 Stephen D. Cairns and Ralf T. S. Cordeiro. 2017. A New Genus and Species of Golden Coral (Anthozoa, Octocorallia, Chrysogorgiidae) from the Northwest Atlantic.
 ZooKeys. 668: 1-10.  DOI: 10.3897/zookeys.668.12203

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