Taxonomy of Chubs (Teleostei, Cyprinidae, Genus Gila) in the American Southwest with Comments on Conservation
Chubs of the Gila River basin have been variously classified as nominal species, subspecies of Gila robusta, or a “complex.” Three full species, robusta, intermedia, and nigra are here recognized, the last possibly arising through more than one hybrization event between robusta and intermedia. Following resolution of a nomenclatural problem, G. nigra is characterized in a key for species identification. Listing under the Endangered Species Act is suggested for all species of Gila in the Colorado River basin.Abstract

Drainage map of the Gila River basin, Arizona, New Mexico, and Sonora, with place names used in text and localities for Gila robusta (circles), G. intermedia (squares), and G. nigra (diamonds). Symbols denote records for museum specimens and in the primary literature and, when darkened, are for material examined by Rinne (1969, 1976), DeMarais (1986), and/or WLM. Localities in close approximation may be included within a single symbol