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Family Rhizangiidae: (Gk. rhizon, root).... probably relating to the polyps that are liked to neighbouring polyps by rootlets. Small distinct family of azooxanthellate corals which may become infected by endosymbionts if sufficient light is available. The colonies are encrusting, usually plocoid, and occur in clusters linked by rootlets. The colonies consist of scattered corallites that are united by a basal coenosteum. The corallites are small and tubular, with very solid walls. Budding in all genera is extratentacular or occurs from the stolon.

This family consisting only of three genera that are restricted to Atlantic waters, where it can be found north of Bermuda and occasionally at the west coast of Africa.
The colonies are encrusting, usually plocoid, and occur in clusters linked by rootlets. The colonies are usually scattered corallites that are united by a basal coenosteum. The corallites are small and tubular, with very solid walls. The septa are in three or more distinct orders.


Some members of the familyRhizangiidae (60kB)

Key to the family Rhizangiidae Genus Astrangia
Genus Colangia
Genus Culicia
Zooxanthellate genera are only found in Atlantic waters: -------------------------------------------------

Astrangia (?. ?):

Colonies are encrusting, submassive, plocoid, and occur in clusters linked by rootlets. Corallites are tightly compacted and up to 10 mm in diameter. Corallite walls are well defined. Septal margins are beaded. T he septa are in three or more distinct orders. Columellae are well developed. Depending on the presence of endosymbiontic algae, the colony color can range from translucent to brown. Prefers rocky shores and jetty pilings. Tolerates a wide range of temperatures.
PRESENT DISTRIBUTION: zooxanhtellate species are found in the north-western Atlantic, Bermuda and east African shoreline.
GENERAL ABUNDANCE: common.
FOSSIL RECORD: Miocene of eastern USA.
NUMBER OF EXTANT SPECIES: 1 known species. Colangia (?,?) Usually found intermixed with other encrusting fauna in caves and shipwrecks. C.immersa forms red-brownish discs and is often found to thrive among ascidians and sponges. Culicia (?,?) A common coral of intertidal rocky shores.