Distinguished from two other Cyprinodon species on San Salvador Island by the following characters: anterior process of the maxillary head extends up to or beyond the most anterior point on the dentigerous arm of the premaxilla with oral jaws retracted (vs. most anterior point on the maxillary head is always posterior to the most anterior point on the dentigerous arm of the premaxilla in C. variegatus and C. desquamator); externally, this skeletal extension presents as a fleshy protuberance nearly encasing the upper jaw when retracted (vs. lacking any fleshy protuberance surrounding the maxillary head in C. variegatus and C. desquamatory); paired nasal bones are not enlarged, but form a more acute angle (approximately 120") with the dorsal margin of the neurocranium (vs. approximately 180" in C. variegatus and C. desquamatory); with either pale or complete absence of banding along the body in both sexes and shortened lower jaws jaws relative to C. variegates and C. desquamator, which always show dark banding along the body and either typical jaw length for the genus or enlarged jaws, respectively (Ref. 94405).