Characters: Sometimes zooxanthellate. Corals are solitary, free-living, and have a flat base. They have a commensal relationship with a sipunculid worm (Aspidosiphon corallicola) which moves the coral about on soft substrates and prevents it from becoming buried. Tentacles are usually extended only at night. Larvae initially settle on a microgastropod shell which they usually envelop during subsequent growth. Corals have only one corallite which is circular. They have prominent costae.
Colour: Pale brown, often with a greenish oral disc.
Similar Species: Heterocyathus and the dendrophylliid Heteropsammia cochlea are structural and ecological equivalents. Heteropsammia lacks the prominent costae of Heterocyathus.
Habitat: Always found on soft horizontal substrates at depths of 20 metres or more, usually in association with Heteropsammia cochlea and Cycloseris cyclolites.
Abundance: May be locally abundant (commonly 40 individuals per square metre).
Taxonomic Note: The type species of Heterocyathus Milne Edwards and Haime, 1848. A species complex. Azooxanthellate forms of this species may occur outside the distribution record.
Taxonomic References: Hoeksema and Best (1991); Veron (2000a);
Identification Guides: Veron (1986a); Sheppard and Sheppard (1991); Carpenter, Harrison, Hodgson et al. (1997);
