Elliptical Star Coral

Our species in the spotlight has been around for quite some time; fossil records date back to the Eocene period, some 33 to 55 million years ago! No, it’s not a dinosaur, but the beautiful Elliptical Star Coral (Dichocoenia stokesi), easily identified by its distinct extended and oval corallites; the corallites are widely spaced apart, and the surface between them is grainy. Elliptical Star Coral forms cream to orange-brown spherical colonies. It occasionally forms thick flattened plates; this flattened plate morph was until recently classified as a separate species, Pancake Star Coral (D. stellaris).

Colonies of Elliptical Star Coral reproduce both sexually and asexually. They reproduce sexually through spawning events, during which eggs and sperm (gametes) are released into the water column. Colonies in one area typically spawn at the same time to increase the chances of fertilisation. Few of the resulting larvae survive; the few that do drift for a few days until they find adequate substrate to settle on. Post-settlement growth rates are very slow. Elliptical Star Coral also reproduces asexually through budding; an adult polyp splits into two, forming a new individual that is an identical replica of itself.

Elliptical Star Coral is still a common sight within the Dutch Caribbean’s reefs thanks to our successful marine protected areas. Overall, however, the population of this coral is declining throughout its range, which includes Florida, the Gulf of Mexico, the Bahamas, Bermuda and the Caribbean. The IUCN Red List currently classifies Elliptical Star Coral as Vulnerable. It is especially affected by disease (white plague, black-band disease), bleaching and sedimentation.

Photo by MyFWC on flickr via Creative Commons
 
Sources:
Arkive—Elliptical Star Coral
Coralpedia—Elliptical Star Coral
EDGE—Dichocoenia stokesii
IUCN Red List of Threatened Species—Dichocenia stokesii