Lesser Brain Coral

zooxanthellate

Valleys are particularly long, often winding but with extensive straight sections. Valleys are usually narrower than those of the meandroid Platygyra species. Its columella is a laminar ribbon, or is a thick keel with vertical undulations. This separates it from Platygyra. The range of valley, wall and septa widths is considerable, and is greater than the span encompassed by the two meandroid Playtgyra species but despite this it is now generally considered to be a single variable species. The species is largely restricted to water less than about 6 m deep. It occurs principally on exposed and moderately exposed reef crests and seaward facing reef slopes, or on deeper patches of reef flats subjected to good water exchange. Within this shallow, fairly turbulent habitat it is abundant and a consistent component. It is always grey in colour. (Sheppard, 1998 ) Colonies are massive with an even surface and dense skeleton. Corallite valleys are highly meandroid and very uniform. Septa are uniformly spaced and are of equal size. Columellae are wall-like with lobed upper margin and do not form centres. Paliform lobes are absent. Polyps are extended only at night. Colour: cream, brown or green, with walls and valleys of different colours. Abundance: occurs in most reef environments except where the water is turbid. Often common in upper reef slopes. (Veron, 1986 ) Forms irregularly humped, massive colonies with meandering surface pattern of corallites very similar to Platygyra and Oulophyllia but with more pronounced ribs on the walls. Colour: walls of corallites are brown with green or cream valleys. Habitat: in lagoons and on clear water reef slopes. (Richmond, 1997)