Three new species of Cyprinodon (Teleostei, Cyprinodontidae) are described, each long recognized as distinct. Cyprinodon pisteri occupies a variety of systems and habitats in the Lago de Guzmán complex basin in northern Chihuahua, México. It is distinguished by its dusky to black dorsal fin and narrow or inconspicuous terminal bar on the caudal fin in mature males. Cyprinodon albivelis is distributed largely in relatively high elevation sites in the upper Río Papígochic (Río Yaqui basin), with a single occurrence in the Río Santa María basin. It is distinguished most notably by the striking white dorsal and anal fins displayed by breeding males. Cyprinodon arcuatus is a distinctive form most similar to Cyprinodon macularius and Cyprinodon eremus and is restricted to the upper Santa Cruz River basin in southern Arizona and Northern Sonora. It is distinguished in having a sharply convex dorsal body profile form the head to dorsal fin origin and in lacking yellow or orange pigmentation on the part of nuptial males. Extensive and careless human alterations to this system drove C. arcuatus to extinction, with the last natural population perishing in Monkey Spring (Santa Cruz County, Arizona), devoured by introduced sport fish. Where appropriate, biogeography and conservation issues are discussed with regard to these species.

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