Mussa (coral)
Monotypic stony coral genus with aggressive, large polyps.
Mussa is a genus of stony coral belonging to the family Faviidae, and it contains just one species: *Mussa angulosa*, often called the spiny coral or large flower coral. This coral lives on shallow reefs across the Caribbean Sea, the Bahamas, and the Gulf of Mexico.
The species grows in colonies that form low domes up to 50 centimeters wide. Its corallites are tubular and grow from a shared base, usually in groups of one to three, sometimes up to five. Each corallite is large, measuring 25 to 45 millimeters across and up to 6 millimeters high, with four cycles of narrow, curved septa that are spaced widely apart. The polyps themselves are very large—sometimes 12 centimeters long and 4 centimeters wide—and they completely cover the short, stony branches of the skeleton. By day, the polyps look fleshy; at night, they expand further and are edged with a ring of short tentacles. Their color varies, ranging from gray or pale brown to shades of green, pink, and purple. Inside the coral’s tissues live symbiotic algae called zooxanthellae, which use sunlight to produce organic compounds that feed the coral.
*Mussa angulosa* is found in the Caribbean Sea, the Gulf of Mexico, the Bahamas, and on reefs and banks off Texas and southern Florida. It lives at depths of 3 to 60 meters, most commonly between 10 and 30 meters.
This coral is a reef builder and is aggressive, attacking fast-growing corals that come too close and risk overgrowing or shading it. Its stinging cells are so strong that no other Caribbean coral can successfully fight back. As it grows, it leans away from the current, and it does poorly with increased sedimentation.
No specific threats target this coral, but the IUCN Red List classifies it as near threatened. It is likely declining due to coral reef degradation from mechanical damage, climate change, and ocean acidification. It is vulnerable to coral bleaching and diseases that affect stressed corals. Off U.S. coasts, it is found in several marine parks and conservation areas, where it is protected.
Quick Facts
- Taxon
- Mussa angulosa
Facts from the source article.
Lore & Background
Mussa angulosa is a colonial species forming low domes up to 50 cm across. Its corallites are phaceloid, tubular, in series of one to five, each 25–45 mm in diameter. The polyps are very large, sometimes reaching 12 cm long and 4 cm wide, completely obscuring the short branches of the skeleton. During the day the polyps appear fleshy; at night they expand further, fringed by a rim of short tentacles. Color varies from grey to pale brown with green, pink, and purple shades. The tissues contain symbiotic zooxanthellae, which photosynthesize and provide organic compounds to the coral.
This coral occurs in the Caribbean Sea, Gulf of Mexico, Bahamas, and off Texas and southern Florida, at depths of 3 to 60 m, most often between 10 and 30 m. It is a reef-building species and is aggressive, attacking other fast-growing corals that grow nearby. Its cnidocytes are so powerful that no other Caribbean corals can successfully attack it. It leans away from the current as it grows and reacts adversely to increased sedimentation.
Reader's Guide
Mussa angulosa is notable as the sole species in its genus and for its aggressive reef-building behavior. Its powerful cnidocytes make it dominant over other Caribbean corals, preventing overgrowth or shading. The species is listed as near threatened on the IUCN Red List, though no specific threats are identified. It is likely declining due to general reef degradation from mechanical damage, climate change, and ocean acidification. It is susceptible to coral bleaching and diseases that affect stressed corals. Off U.S. coasts, it occurs in marine parks and conservation areas where it is protected. Its large, fleshy polyps and variable coloration make it a distinctive component of shallow Caribbean reefs, and its reliance on zooxanthellae ties it to sunlight availability. The coral's adverse reaction to sedimentation and its growth leaning away from currents indicate sensitivity to environmental conditions.
Did You Know?
- Mussa is a monotypic genus, represented only by Mussa angulosa.
- Its polyps can reach 12 cm in length and 4 cm in diameter.
- No other Caribbean coral can successfully attack Mussa angulosa due to its powerful cnidocytes.
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