Elliptical Star Coral

Dichocoenia stokesi is a massive colonial coral that forms rounded humps up to 40 centimetres (16 in) in diameter or thick plates. It is recognisable by the fact that many of the corallites, the stony cups from which the coral polyps protrude, can be oval, or elongated. They can be up to 5 centimetres (2.0 in) long and only 0.5 centimetres (0.20 in) wide. Others are circular or Y-shaped and all have raised rims. The columella, the central axial structure in the corallite, is fragile and spongy. The polyps are large and well-separated with a diameter of about 4 millimetres (0.16 in). The colour is variable and can be white, cream, orange, yellowish-brown, green, olive or brown and the septo-costae, the little ridges that surround the corallites, are white.

Dichocoenia stokesi is found in the western Atlantic Ocean and Caribbean Sea. Its range extends from Bermuda and southern Florida to the southern half of the Gulf of Mexico and along the coast of Central America to Venezuela. The fossil record shows that this species grew in the Caribbean region as long ago as the Oligocene Era (34 to 23 million years ago). It is a relatively uncommon species and tends to grow on fore reefs and back reefs but not on reef crests. It has a wide depth range of 2 to 72 metres (6 to 236 feet) but is commonest at 30 metres (98 ft) or less. The corallites are larger and more prominent in individuals growing at greater depths.

Although Dichocoenia stokesi is susceptible to bleaching, it is considerably more tolerant of thermal stress than many other stony coral species. It is very susceptible to the disease white plague, especially at high water temperatures. In the Florida Keys in 1995 there was an epizootic of white plague type II and 75% of Dichocoenia stokesi colonies were killed. Because of its slow growth rate and low level of recruitment, recovery after this outbreak did not occur and the reef population seems to be permanently diminished. Dichocoenia stokesi is also susceptible to black band disease, ciliate infection and dark-spot syndrome.