Sympodium Ehrenberg 1834

Genus: Sympodium Ehrenberg, 1834

Emended diagnosis

(Chiefly after Benayahu et al. 2021a; The emendation or addition parts are underlined.). 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 dominant sclerites are ellipsoid platelets, abundant in all parts of the colony. In addition to ellipsoid platelets, several other species have hexagonal platelets with a central waist and double-head sclerites. The sclerites are generally 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 or the distal parts of the rods are arranged parallel to the sclerites surface. In a few species, rods are clearly fused and form many nodules at the sclerites surface. Zooxanthellate.

Type species: Sympodium caeruleum Ehrenberg, 1834