Acropora palmata, the elkhorn coral, is a critically endangered reef-building coral endemic to the Caribbean, historically one of the most important shallow-water reef-builders in the region. Its antler-like, flattened branches can extend over 3 m, providing vital habitat for hundreds of associated marine species. Populations have collapsed by more than 90% since the 1980s due to white-band disease, bleaching, and hurricanes, triggering Critically Endangered status on the IUCN Red List. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.