Dipsastraea lacuna (Knob coral)
Dipsastrea lacuna forms substantial colonies, usually more than one metre across. Corallites are circular to irregular in shape, and crowded, with separated walls. The walls are beige to brown in color, with white centers (or columellae). The inner walls of corallites plunge vertically. Septa (the inner corallite ridges) are thin, uniformly spaced and subequal, most reaching deep within the center of the corallite. Costae (the outer corallite ridges) of adjacent corallites do not meet, leaving a narrow ambulacral groove. There are no paliform lobes. Columellae are small and compact.
Unassessed by the IUCN Red list, but an uncommon species. Only known from the Red Sea.
They can be found only in the Red Sea. They prefer shallow reefs with exposure to waves, and clear water. They grow in a depth range of 1-15 meters.
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Corallites are up to 1 cm. in width, the entire colony can reach over 1 meter in size.
Dipsastrea lacuna relies on capturing sunlight with its zooxanthellae to produce energy.
This species was renamed to Dipsastrea in 2014, but is still widely referred to as Favia lacuna. They are the same species though.
