Two new subspecies are described from the southern part of the distribution of Thamnophis elegans: T.e. arizonae from the Little Colorado River basin of Arizona and New Mexico and T. e. vascotanneri from the Upper Colorado River basin of Utah.
Tanner, Wilmer W. and Lowe, Charles H.
"Variations in Thamnophis elegans with descriptions of new subspecies,"
Great Basin Naturalist: Vol. 49
, Article 6.
Available at: http://scholarsarchive.byu.edu/gbn/vol49/iss4/6