Corals are free-living, with a base that is flat or keeled primarily according to the nature of the substrate. Larvae initially settle on a microgastropod shell which they envelop during subsequent growth. They have an obligate commensal relationship with a sipunculid worm (Aspidosiphon corallicola) and usually have one parasitic mussel (Lithophaga lessepsiana) embedded above the sipunculid. The sipunculid moves the coral about on soft substrates and prevents it from becoming buried. Individual corals are rounded, up to 25 millimetres diameter. They usually have one or two corallites; where there is one it is usually hourglass-shaped. Some populations have colonies with up to 30 corallites. Corallites have well developed septa which follow Pourtalès plan. Columellae are broad, compact, and deep seated. Walls are composed of porous coenosteum. Tentacles are usually fully extended only at night. They are zooxanthellate in tropical localities but are possibly azooxanthellate in temperate locations and in deep water.
Pale grey, orange-brown or greenish.
Almost always found on soft horizontal substrates at depths of 20 metres or more. Usually occurs in association with Heterocyathus aequicostatus and the fungiid Cycloseris cyclolites.
Up to three hundred individuals per square metre have been found on the Great Barrier Reef.
Taxonomic note: Colonies with more than 2 or 3 corallites (illustrated) have been considered a distinct species, Heteropsammia eupsammides (see Hoeksema and Best, 1991). Source reference: Veron (2000). Taxonomic reference: Veron and Pichon (1980). Additional identification guides: Veron (1986), Sheppard and Sheppard (1991), Nishihira and Veron (1995), Carpenter et al. (1997).
displaying probable distribution of species. Points indicate recorded sightings from OBIS.