Sympodium Ehrenberg, 1834

Benayahu, Yehuda, Ekins, Merrick & Mcfadden, Catherine S., 2021, Overview of the genus Sympodium Ehrenberg, 1834 (Octocorallia, Alcyonacea, Xeniidae), with the description of new species, revealing regional endemism, Zootaxa 5072 (4), pp. 324-350 : 328

Sympodium Ehrenberg, 1834

Type species Sympodium caeruleum Ehrenberg,1834: 285

Klunzinger 1877: 42; May 1898: 46–51; Wright & Studer 1889: 270–271; Cohn 1908: 241–242; Kükenthal 1916: 453; Hickson 1931: 174–175; Roxas 1933: 106–107; Macfadyen 1936: 23; Gohar 1940: 106–107; Tixier-Durivault 1966: 371; Reinicke 1997: 22–23.

Diagnosis. Colonies encrusting. The encrusting part is a membrane of variable thickness. It can be either mat-like or with ribbon-like extensions; when thicker, it features irregularly shaped low mounds. Polyps monomorphic, commonly retractile, mostly found over the entire surface of the colony, but some parts of the encrusting membrane have very few polyps. Commonly, the polyps arise individually from the membrane or the mounds and can be either spaced or closely set. In the latter case, they can appear as clusters comprising polyps that bud off at different levels to form small branched groups. The sclerites are ellipsoid platelets, abundant throughout the colony. They reach up to ca. 0.03 mm maximal diameter, with each composed of densely packed calcite rods. The tips of the rods are distinct on the surface of the sclerites and commonly provide a granular microstructure. Zooxanthellate.