Boulder star coral
(Ellis & Solander, 1786)
The colonies grow in several morphotypes, that were originally described as separate species. The species occurs as long, thick columns with enlarged, dome-like tops; large, massive mounds; sheets with skirt-like edges; irregularly bumpy mounds and plates or as smooth plates. Colonies up to 3 meter in diameter. The surface is covered with distinctive, often somewhat raised, corallites.
Shades of green to brown, yellow-brown and gray.
Corallites 2.1-3.5 mm in diameter, with 24-26 septa. The distance between neighboring corallites is between 0.6 and 1.2 mm. Septa and theca raised (M. annularis-corallite). Septa with small teeth. Columella trabecular.
Inhabit most reef environments and the species is often the predominant coral between 7 and 25 m. The flattened plates are most common at deeper reefs, down to 50 m.
Common to abundant Florida, Bahamas and Caribbean.
Recent investigations suggest that this species consists of three or more separate species:
Montastrea annularis , corallite diameter 2.1-2.7 mm, with 24 septa, 1-1.2 mm between neighboring corallites, raised septa and theca and moderately well developed costae. Grows mostly in clusters of long, thick columns with enlarged, dome-like tops.
Montastrea faveolata , corallite diameter 2.1-2.7 mm, with 24 septa, 0.6-0.9 mm between neighboring corallites and poorly developed costae. Grows mostly in large, massive mounds and sheets with skirt-like edges.
Montastrea franksi , corallite diameter 2.5-3.5 mm, with 24-26 septa, 1-1.2 mm between neighboring corallites and well developed costae. Grows mostly in irregularly bumpy mounds and plates.