What is the common name of the critically endangered coral Acropora palmata?

The common name of Acropora palmata is elkhorn coral.

Its thick, branching colonies resemble the antlers of an elk, giving the species its memorable name. Elkhorn coral is a major reef-building coral of the Caribbean, Bahamas, Florida, and nearby waters. Its branching form creates shelter and nursery habitat for fish and other reef organisms.

The species can grow relatively quickly for a coral—about 5 to 10 centimetres per year—and can reproduce sexually or by fragmentation when broken branches develop into new colonies. That ability once helped it dominate shallow Caribbean reefs.

Elkhorn coral suffered an estimated 97% decline between 1980 and 2006. Disease, warming seas, ocean acidification, algae, storms, pollution, and physical damage all contribute to its critically endangered status. A common mix-up is staghorn coral, another Caribbean Acropora with narrower branches; fire coral is not a true stony coral of the same genus.