Open Brain Coral

zooxanthellate

Colonies are flabello-meandroid and free-living. They are usually bilaterally symmetrical, up to 80 mm in length with one to three separate mouths. Large, fully flabello-meandroid colonies are uncommon. Valleys have large, regular septa and paliform lobes and a large columella tangle. Polyps are fleshy. When retracted during the day, a large mantle extends well beyond the perimeter of the skeleton, but this retracts if disturbed. At night, tentacles in several rows are extended from the expanded oral disc inside the mantle. The mouth is about 10 mm across. Colour: polyps, especially the mantles, are brightly coloured and are commonly yellow, brown, blue or green. Abundance: rare on reefs, common around continental islands and some inter-reef areas. Frequently found with other free-living corals. Large colonies are found only in certain protected shallow island embayments. (Veron, 1986 )