After a pioneering study of Jamaican coral reefs, the Cuban archipelago was the second to be surveyed by SCUBA for scleractinian corals and reef life to a depth of 90m, sampling all phenotypes. Regrettably, the published data on the mesophotic coral ecosystems (MCEs) of Cuba, collected 1970 to 1973, have been ignored. This is also true for the published data on the MCEs of the Mexican Yucatán Peninsula, collected 1983 to 1984. These two investigations described immense areas exhibiting a rich continuum of coral life, from shallow reefs into MCEs without scleractinian faunal break, and no depth-specialists species complex. Instead, a morphological changeover of three-dimensional corallum into two-dimensional corallum was observed and documented. The existing data on the Cuban and Mexican MCEs (now 45 and 34 years old, respectively) present a unique opportunity for long-term status and ecosystem trends analysis. MCEs require terminological clarification from collaborative efforts to effectively use the globally available data.