Male Ocellated Quail in the northern portion of their range (Mexico and Guatemala) are much paler on the midbreast and upper abdominal areas, these regions being generally buffy or slightly tawny; additionally, in these populations the flanks are chestnut with black and gray cross-markings, rather than gray with chestnut spotting. Some males in Honduras have tawny or chestnut lateral spotting instead of white (Eitniear et al. in press).
Described as Ortyx ocellatus Gould 1836 (= 1837); type locality Guatemala; differens Griscom 1932, type locality Hatillo, Honduras, now usually is regarded as a synonym.
Three groups of Cyrtonyx quail occur from the United States into Mexico and Central America. The northernmost group, Montezuma Quail (Cyrtonyx montezumae), includes subspecies mearnsi, montezumae, and merriami, and occurs from the southwestern United States (Arizona, New Mexico, and Texas) south into northern Oaxaca in south central Mexico. A second group, represented by subspecies sallei and rowleyi, occurs in southwestern Mexico (Michoacán, Guerrero and Oaxaca). This group usually is included under Montezuma Quail, but some authors (Davis 1972, del Hoyo and Collar 2014) recognize this group as a separate species, Spot-breasted or Salle's Quail (Cyrtonyx sallei). "Spot-breasted Quail" is somewhat intermediate in appearance between northern populations of Montezuma Quail and Cyrtonyx ocellatus; males are distinguished from males of northern C. montezumae by the bronzy-chestnut vs white lower flank spots; rather broad bronzy-brown vs narrow buff long streaks and narrow vs broad black bars on wing-coverts; white spots on upper breast sides and flanks smaller, duller and on paler gray; and paler chestnut mid-breast to belly. The sallei group differs from ocellatus in white, not pale tan, spots on upper breast sides and flanks; chestnut vs buff-tan top to central stripe down underparts; and black-edged pale tan streaks vs rich chestnut long streaks on lower upperparts. Cyrtonyx ocellatus is separated from the sallei group by the Isthmus of Tehuantepec, but occurs in similar habitat from south of the Isthmus to Nicaragua. An alternative treatment would be to recognize only a single species of Cyrtonyx.