The dataset is a composite of morphological data used in the description of a new species of marine fish, Trachinotus macrospilus (Teleostei: Carangidae), endemic to the Marquesas Islands of the Indo-West Pacific. In the addition to the newly described species, three previously named (nominate) species of the same genus are compared and redescribed in this same manuscript. The morphological data include both mensural (morphometric) and meristic (count) data. Synonymies are provided for all species, since many misidentifications have been made in the literature, which dates to the early 1800's.