Branched Cup Coral

zooxanthellate

This is the smallest mussid, but has the typical fleshy polyps of the family. Colonies rarely exceed a diameter of 25-30 cm. Calices are 4-9 mm diameter, and septa contain few strong but blunt spines, commonly one on each near the wall. Colonies are cerioid, phaceloid, or with both conditions occurring in the same colony. When the cerioid growth form exists, colonies are low and encrusting. Even here, there may be little or no organic tissue connecting adjacent polyps, and phaceloid corallites usually occur near the perimeter of the colony. Wholly phaceloid growth forms have a greater thickness, with individual corallites reaching 6 cm tall, of which the top 15 mm is enveloped by tissue (see the 3 b/w photos for variation). This species favours small crevices or steep parts of reef slopes. It can be found equally on exposed reef slopes and slightly sedimented areas, and may be recorded down to at least 50 m depth in fairly dark and cryptic conditions as well as in moderately lit areas. It is very rarely encountered in shallow or exposed conditions. The cerioid condition becomes more common in the western Indian Ocean region. (Sheppard, 1998 <308>). Corallites are less than 7 mm in diameter. Septa are in three cycles, of which only the first two reach the columella. Colour: dark red or greenish-brown (two colour morphs). Abundance: uncommon. (Veron, 1986 <57>) Always distinctive. Corallites in the colony are widely spaced providing room for the fleshy mantles of the polyp to expand. Colour: mantles red or green with a bright green centre, making the red variety a spectacular find underwater. Habitat: diverse reef areas, but never common. (Richmond, 1997)