Acropora, Oken, 1815

Sola, Erwan, Silva, Isabel Marques da & Glassom, David, 2015, An annotated and illustrated checklist of species of the coral genus Acropora (Cnidaria: Scleractinia) from Vamizi Island, Mozambique, African Invertebrates 56 (3), pp. 807-807 : 837

Acropora robusta (Dana, 1846)

Fig. 27

Colony growth form: Irregular with large and thick prostrate branches (> 30 mm basal diameter) which are usually contorted in different directions with either pointed or rounded extremities; different parts of the colony look different; peripheral branch often prostrate with upturned ends while those in the centre of colony may be long, conical and upward projected; formation of branchlets is rare and irregular and these are often short and clumpy.

Axial corallites: Outer diameter 2.1–3.7 mm; inner diameter 0.75–1.8 mm; short and tubular, they are not conspicuous, but can be distinguished from radials from their round opening; two complete cycles of dentate septa; two well defined directives are blade-like. Radial corallites: Mixture of sizes, crowded; on main branch, most are immersed to sub-immersed; only have one cycle of septa. On branchlets, rounded, tubular and slightly appressed with clearly dimidiate opening and some longer ones have hooked upper lip; septation usually in two cycles but second cycle may be incomplete; one or two directives present.

Coenosteum: Neatly costate on corallites and reticulate with numerous simple spinules in between; all corallite are highly calcified and branches are very hard and robust.

Figures

Fig. 27. Acropora robusta. (A) live colony; (B) main branch tip; (C, D) radial corallites on branchlets; (E) axial corallite; (F) sub-immersed radials and intercorallite area.