Knob Coral

zooxanthellate

zooxanthellate

This is an easily distinguished Favia, because it forms the largest colonies and has the smallest corallites. Colonies can reach over three metres across and stand 2 metres high; large ones are composed of many upward growing cylinders 10 - 20 cm diameter, and may have a slightly club-head top. Living corallites are usually restricted to the top 20 cm or so of each club in these large colonies, though they may cover all the surface of much smaller colonies. Calices are only about 3 mm diameter which is considerably smaller than any other member of this genus, and they are very neatly formed, being perfectly round, except when budding. They are strongly plocoid, commonly being as tall as they are broad. Favia stelligera has a strong preference to very shallow water. It is rarely found deeper than about 6 m. The very large colonies are also limited to shallow water in sheltered sites such as protected fringing reefs. It is a common component of those coral communities found between shallow patch reefs where the substrate is a mixture of coarse sand and hard substrate (Sheppard, 1998). Colonies are spherical, columnar, hillocky or flat. Corallites are evenly distributed, with small calices. Colour: uniform brown or green. Abundance: seldom common but occurs in a wide range of habitats (Veron, 1986). Large domed colonies made up of numerous lobes or short columns (each 10-20 cm across), with the moderate-sized corallites (2-6 mm across) easily visible on the surface. Colour: usually a uniform pale yellow colour. Habitat: shallow reefs in clear water (Richmond, 1997).