Orbicella faveolata

Orbicella faveolata, also called mountainous star coral, is a colonial stony coral belonging to the family Merulinidae. This species is found along the coral coast of the Caribbean Sea and the Gulf of Mexico, and the International Union for Conservation of Nature lists it as endangered. It was previously classified under the genus Montastraea as Montastraea faveolata.

Description

The colonies are solid and very large, forming a mound with a skirt-like edge. The surface is smooth and wavy, dotted with small bumps, bulges, or lobes. The corallites—the stony cups housing the polyps—measure about 5 mm across and cover the entire colony.

Colors range from pale brown, yellowish green, or grey to deep brown, often with fluorescent green highlights. This coral is part of a species complex that includes the closely related Orbicella annularis and Orbicella franksi. Orbicella annularis has more distinct nodules or small columns, while Orbicella franksi has a more irregular, lumpy surface.

Distribution and habitat

Orbicella faveolata lives in shallow waters of the Caribbean Sea and the Gulf of Mexico, including Florida (United States), the Bahamas, Venezuela, and possibly Bermuda. It grows on both back reef and fore reef slopes of fringing reefs, down to depths of 40 meters. On fore reef slopes between 10 and 20 meters, it is often the most abundant coral species.

Biology

Like other corals, Orbicella faveolata has a symbiotic relationship with dinoflagellates from the family Symbiodiniaceae, commonly called zooxanthellae. These symbionts live in large numbers within the coral’s living tissue. Different species of Symbiodiniaceae associate with the coral depending on light intensity reaching the surface. When researchers artificially shaded parts of the coral for weeks, the endosymbionts in the shaded area died.

After light was restored, zooxanthellae returned, but often a different species of Symbiodiniaceae replaced the original one. The coral also hosts a diverse microbiome of bacteria, archaea, and other microorganisms, which shift with the coral’s health. Orbicella corals are affected by several diseases, including yellow-band disease.

This species is related to lobed star coral (Orbicella annularis) and boulder star coral (Orbicella franksi), all found in the Caribbean Sea and Gulf of Mexico, including the Bahamas and Bermuda.