A review of the Mexican stoneroller, Campostoma ornatum Girard (Pisces: Cyprinidae)

A morphological study of the Mexican stoneroller, Campostoma omatum, from throughout its range revealed that the species is distinctive in the genus Campostoma in having very small scales, breeding tubercles in the females as well as the males, and intestinal loops that rarely coil arovmd the bladder. C omatum is extremely variable both in meristics and morphometries, although populations from the southern part of the range tend to be more consistent in having fewer scales and deeper bodies. Because of its extreme and rather irregular variabihty, from drainage to drainage, intraspecific taxa, including C. omatum pricei are not recognized. C. omatum displays several generalized characters and is probably close to the ancestral stock of the genus.