Rana pipiens complex: hemoglobin phenotypes of sympatric and allopatric populations in Arizona.

Electrophoretic comparison of hemoglobin samples from numerous populations of Rana pipiens in Arizona reveals three distinct phenotypes that closely correlate with morphological differences. Hemoglobin samples from sympatric locations contain parental phenotypes with only the occasional occurrence of a hybrid. These data support the contention that the Rana pipiens complex consists of several species.