Madracis auretenra, new species, is described for a common, shallow-water, zooxanthellate coral species found throughout the wider Caribbean. This new species is distinguished from other species of the genus by a thin branched, dendritic morphology and depth distribution of 1–60 m. Other characteristics include: non-living basal branch portions; a fairly smooth coenosteum; a distinct line of coenosteal spines centrally located between adjacent corallites; no visible secondary septa in corallites; and closely spaced corallites. Individuals of this taxon have been incorrectly referred to Madracis mirabilis (Duchassaing & Michelotti 1860), which is a deep-water species and which is synonymous with Madracis myriaster (Milne-Edwards & Haime 1849), in several publications subsequent to 1973. Herein, a brief explanation of the taxonomic confusion surrounding M. mirabilis and the undescribed species is provided along with a complete description of this new species of Madracis. Records of the new species are confirmed for Puerto Rico, Curaçao, Grenada, and Bermuda. Authors of many recent studies on “Madracis mirabilis sensu Wells” will need to reconsider and reconfirm the identities of their study organisms.