GEOGRAPHIC-VARIATION IN MORPHOLOGY OF SPIKEDACE, MEDA-FULGIDA, IN ARIZONA AND NEW-MEXICO

Meda fulgida (Pisces: Cyprinidae) is a species endemic to the Gila Riv er basin of Arizona, Mexico, and New Mexico. The extent of geographic variation in morphology within this species has not been explored alth ough evidence indicates that subpopulations have long been isolated. W e examined samples from the four restricted areas within the Gila Rive r basin where subpopulations persist, and used principal components an alysis, regression against PC1 (to eliminate variation due to size), a nd ANOVA to demonstrate that individuals from the Verde River (Arizona ) have smaller mouths in proportion to body length as compared to indi viduals from Aravaipa Creek (Arizona). Subpopulations from New Mexico and Eagle Creek in Arizona have intermediate measurements. Additional analyses confirm that females have shorter pre-pectoral measurements, greater mid-body size, and shorter pectoral fins than do males.