Montastraeidae

Lore & Background

Montastraeidae contains a single genus, Montastraea, and a single species, Montastraea cavernosa, known as great star coral. It forms massive boulders and domes over 5 feet in diameter in shallow to moderate depths, and in deeper waters it grows as plate formations. The polyps are the size of a human thumb and fully extend at night. The coral occasionally displays a fluorescent red or orange color during daytime, which has been suggested to be due to phycoerythrin, a cyanobacterial protein, though Oswold et al. (2007) showed an absence of functional phycoerythrin in M. cavernosa. The species is gonochoric, with colonies being either male or female, and spawns one week after the full moon in late August. Skeletons show sex-related differences, with females having less dense skeletons, presumably due to reallocating energy to egg production.

Reader's Guide

The significance of Montastraeidae lies in its sole representative, Montastraea cavernosa, which is a dominant coral in Caribbean reef environments, particularly at depths of 40–100 feet. Its ability to form massive boulders and plates allows it to occupy various reef zones. The coral's potential symbiotic relationship with cyanobacteria, suggested by the presence of phycoerythrin, indicates a possible nitrogen-fixing role, though this is disputed by later research showing an absence of functional phycoerythrin. The species' gonochoric reproduction and sex-related skeletal differences highlight its biological complexity. A survey in the Bay of All Saints found that distinguishing bleaching in M. cavernosa from naturally white corals is difficult using standard reflectance techniques, leading to a nearly two-fold overestimation of bleaching. This underscores challenges in monitoring reef health. The family's monotypic status makes it a unique lineage within stony corals.

Did You Know?

• Montastraeidae contains only one genus and one species, Montastraea cavernosa.
• Females of this species have less dense skeletons than males, likely due to energy allocation to egg production.
• A survey in the Bay of All Saints found that standard reflectance techniques can lead to nearly two-fold overestimation of bleaching in this coral.