Orbicella annularis
Spot lobed star coral across the Caribbean, from the Yucatán Peninsula to Bonaire. Best seen May, January in water from 26-29°C.
Colonies form large, dome-shaped or lobed mounds that can grow to several metres across, typically in shades of tan, olive-green, or yellowish-brown. The surface is covered in evenly spaced, circular corallites (the individual polyp cups) arranged in a regular pattern, giving the colony a bumpy, almost cobblestone texture. Where colonies grow adjacent to each other, distinct valleys or ridges form between the lobes, which is the key feature to key on when distinguishing it from similar massive corals.
As a sessile (permanently fixed) organism, it does not move or respond to your presence. What you are actually watching when you hover over a colony is a living structure: the tiny polyps filter nutrients from the water column, while the colony itself provides shelter and attachment points for dozens of other reef species. The most rewarding way to observe it is to slow down and look closely at the corallite surface, where you may catch feeding polyps extended, particularly on night dives.
Colonies can live for several centuries, making any large lobed mound you encounter one of the oldest individual organisms on the reef. A colony a metre across may have been growing since before the first European explorers arrived in the Caribbean.
Sightings concentrate from May through January and again in March, broadly tracking the warm-water season across the Caribbean. Water temperatures in the observed range of roughly 26-29°C align with peak Caribbean diving conditions, so any visit during that window gives solid odds.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most commonly logged in the Caribbean basin, with the strongest concentration of records from the Yucatán Peninsula in Mexico, making it the single best region to encounter this coral. Strong populations are also documented across the Caribbean Coast of Colombia, Grand Cayman, Jardines del Rey in Cuba, Klein Bonaire, and the Florida and southeast United States coastline.
Mapping where Lobed Star Coral is logged…
The best place to look is the Yucatán Peninsula in Mexico, which holds by far the most logged sites. It is also reliably found across Grand Cayman, the Caribbean Coast of Colombia, Klein Bonaire, Jardines del Rey in Cuba, and the Florida coastline of the United States.
Sightings are most frequent from May through January and again in March across Caribbean sites. This broadly corresponds to the warm season when water temperatures sit in the 26-29°C range where the species thrives.
Look for large dome or lobed mounds in tan to olive-green tones, covered in evenly spaced circular corallite cups. Where lobes meet, you will see valleys between them rather than the continuous brain-like ridges of true brain corals. The regular, dot-like pattern of the corallites is the most reliable field mark.
Colonies commonly grow into large, multi-lobed mounds that can reach several metres in diameter. Because growth is extremely slow, any colony of significant size is likely many decades or even centuries old.
Yes, it is listed as Endangered on the IUCN Red List. Populations have declined significantly due to coral bleaching caused by rising sea temperatures, outbreaks of stony coral tissue loss disease, and broader reef degradation. Divers can help by avoiding contact with colonies and practising careful buoyancy control.
The Lobed Star Coral is listed as endangered by the IUCN. Observe from a distance, avoid touching or feeding it, and report sightings to local marine research organisations.
Lobed star coral is listed as Endangered on the IUCN Red List, having suffered significant population declines due to bleaching events, disease, and habitat degradation. Divers should maintain good buoyancy and never touch or rest on colonies, as even minor physical contact can damage or kill polyps that may have taken decades to grow.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Plate Coral
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