Orbicella faveolata, commonly known as mountainous star coral, is a colonial stony coral in the family Merulinidae. This coral is native to the coral coast of the 🌊 Caribbean Sea and the 🌊 Gulf of Mexico and has been classified as "endangered" by the International Union for Conservation of Nature. Previously known as Montastraea faveolata, it forms large, solid colonies that take the shape of mounds with a skirt. The surface of the coral is smooth and undulating, featuring small lumps, bulges, or lobes. The entire surface is covered in corallites, which are stony cups that serve as home to the polyps. These corallites have a diameter of about 5 mm (0.2 in). The typical coloration of Orbicella faveolata ranges from pale brown to yellowish green and grey, but it can also be deep brown with fluorescent green highlights. This coral is part of a species complex that includes closely related species like Orbicella annularis and Orbicella franksi, although the former displays more distinct nodules or small columns, and the latter has a more irregular and lumpy surface.
Orbicella faveolata can be found in shallow waters throughout its range in the 🌊 Caribbean Sea and the 🌊 Gulf of Mexico, including locations such as 🇺🇸 Florida, the 🇺🇸 United States, the 🇧🇸 Bahamas, 🇻🇪 Venezuela, and possibly 🇧🇲 Bermuda. It is commonly found on both the back reef and fore reef slopes of fringing reefs, typically at depths of up to 40 m (131 ft). In fact, it often dominates the fore reef slopes between depths of 10 and 20 m (33 and 66 ft).
Similar to other corals, Orbicella faveolata maintains a symbiotic relationship with dinoflagellates in the genus Symbiodinium, commonly referred to as zooxanthellae. These organisms are abundant in the coral's living tissue. The specific species of Symbiodinium associated with the coral depends on the intensity of light reaching particular regions on the coral's surface. If artificial shading is applied to corals, the Symbiodinium that reside in the shaded areas die off. However, when light is restored, zooxanthellae are reintroduced. In many cases, a different species of Symbiodinium replaces the original species. The surface of the coral can be considered a microbiome, a community of microorganisms. The composition of zooxanthellae, bacteria, and archaea present on the coral surface varies throughout the year. Additionally, the health of the coral and the presence of yellow-band disease can also influence the microbial composition, particularly during the spring season.
Orbicella faveolata is closely related to other coral species such as lobed star coral (Orbicella annularis) and boulder star coral (Orbicella franksi), which are also found in the 🌊 Caribbean Sea and the 🌊 Gulf of Mexico, including regions like the 🇧🇸 Bahamas and 🇧🇲 Bermuda. The species Paramontastraea saleborsa and Astrea curta have similar-sized corallites and share a taxonomic history with Orbicella faveolata, having also been placed in the coral genus Montastraea.
Due to its slow growth rate, the formation of new colonies is outpaced by the rate at which mature colonies perish. Orbicella faveolata is vulnerable to bleaching as well as several coral diseases, including yellow-band disease, black band disease, and plague. Over the past thirty years, population numbers have declined by more than 50%, leading to its classification as an "endangered" species by the International Union for Conservation of Nature.
Why it's threatened
Threat classification from the IUCN Red List.
