Siderastrea radians, the lesser starlet coral (family Siderastreidae), is a small, encrusting to dome-shaped scleractinian coral endemic to the Caribbean Sea and Gulf of Mexico, typically forming small hemispherical colonies with characteristic star-shaped corallites on shallow reef pavements, rubble, and rocky substrates. The species is notably tolerant of turbid, warm, and low-salinity conditions, colonizing marginal reef environments including seagrass beds and mangrove prop roots where other corals cannot survive. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.