Comments: Formerly regarded as a subspecies of Ambystoma tigrinum. See Kraus (1988), Shaffer et al. (1991), and Jones et al. (1993) for phylogenetic analyses of North American Ambystoma; these analyses treated californiense as a distinct species.
Based on genetic analysis, there are six populations of California tiger salamanders, distributed as follows: (1) Santa Rosa area of Sonoma County; (2) Bay Area (central and southern Alameda, Santa Clara, western
Stanislaus, western Merced, and the majority of San Benito counties); (3) Central Valley (Yolo, Sacramento,
Solano, eastern Contra Costa, northeast Alameda, San Joaquin, Stanislaus, Merced, and northwestern Madera
counties); (4) southern San Joaquin Valley (portions of Madera, central Fresno, and northern Tulare and Kings
counties); (5) Central Coast Range (southern Santa Cruz, Monterey, northern San Luis Obispo, and portions
of western San Benito, Fresno, and Kern counties); and (6) Santa Barbara County (Shaffer and Trenham 2002).
USFWS (2000, 2002) reviewed the biogeographical and genetic information supporting the recognition of the Santa Barbara County population and Sonoma County population as distinct population segments under the U.S. Endangered Species Act.