Chrysogorgia Duchassaing and Michelotti, 1864

Cairns, Stephen D., 2018, Deep-Water Octocorals (Cnidaria, Anthozoa) from the Galapagos and Cocos Islands. Part 1: Suborder Calcaxonia, ZooKeys 729, pp. 1-46 : 20

Genus Chrysogorgia Duchassaing and Michelotti, 1864

Chrysogorgia Duchassaing and Michelotti 1864: 13; Versluys 1902: 17-33; Kükenthal 1919: 505-511 (key to species); 1924: 388-390 (key to species); Bayer 1956: F216; Bayer and Stefani 1988: 259 (key to genus and some species); Cairns 2001: 754-756; Pante and France 2010: 600 (key to genus); Pante et al. 2012: fig. 2.

Dasygorgia Verrill 1883: 21.

Type species.

Chrysogorgia desbonni Duchassaing and Michelotti, 1864, by monotypy.

Diagnosis.

Branching from main branch sympodial in an ascending spiral, clockwise (R) or counterclockwise (L), usually following a repeated geometric branching formula, producing a bottlebrush colony, or dichotomous in one or more parallel planes. Branchlets repeatedly dichotomously branched, resulting in short terminal segments. Polyps large in relation to branchlets, standing perpendicular to branchlets and usually well separated. Sclerites consist of rods and scales. Axis with a brilliant metallic luster, usually golden or yellow in color, and thus referred to as the golden corals.

Distribution.

Cosmopolitan, including off Antarctica ( Pante et al. 2012: figs 4-5), 100-3860 m deep.

Remarks.

In order to manage the relatively large number of species in the genus, now standing at 70, Versluys (1902) divided the genus into three group based on the presence of rods or scales in the body wall and tentacles of each species, which he referred to as Groups A-C. Table 1 is a graphic representation of the four permutations of these two characters as divided between the two regions of the polyp. This table also lists the number of species currently assigned to each group, their geographic and depth ranges, and the branching formulas encountered within the group. A species having the fourth permutation, Group D, was not reported until 2015 ( Cordeiro et al. 2015). Recent molecular evidence ( Pante et al. 2012), based on three genes, supports the monophyly of the genus as well as groups B and C, but results in Group A being paraphyletic. Regardless of the true phylogeny of the species, the grouping of Versluys (1902), along with the branching formula, served to help distinguish the various species.