Taxonomy of the Chipmunks, Eutamias quadrivittatus and Eutamias umbrinus

The differences in anatomy and color between many species of chipmunks are subtle, and refined techniques are required to discover them. When measuring chipmunks taxonomically, it is necessary to use a chipmunk scale and not, for example, a pocket-gopher scale. In explanation, some species of pocket gophers closely allied to each other, and even some subspecies of the same species, differ markedly in color and in size and shape of parts of the skeleton; comparable differences are not so pronounced among many species of chipmunks.
Merriam (1905) was the first to show clearly that Eutamias quadrivittatus is a distinct species, and pointed out that E. amoenus operarius (= E. minimus operarius ) is a small species which resembles, and is found in some areas together with, E. quadrivittatus .
Howell (1929) placed under E. quadrivittatus the following subspecies: E. q. quadrivittatus , E. q. hopiensis , E. q. inyoensis , E. q. frater , E. q. sequoiensis , and E. q. speciosus .
Hardy (1945) placed E. adsitus under E. quadrivittatus as E. q. adsitus , and Kelson (1951) placed E. umbrinus under E. quadrivittatus as E. q. umbrinus .
Johnson (1943) re-established E. speciosus as a separate species, and in California left only E. q. inyoensis in E. quadrivittatus .
Thus, since 1943 the recognized subspecies of E. quadrivittatus have been: E. q. quadrivittatus , E. q. hopiensis , E. q. inyoensis , E. q. nevadensis , E. q. umbrinus , and E. q. adsitus .
Capitalized color terms, which are used in descriptions and comparisons, are of Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912.
In the synonymy of each subspecies there appears only the first usage of a name, second the first usage of the name combination now employed unless a new combination is proposed by me, and third pure synonyms. The last is recognizable as such because the type locality is appended to each.
Unless otherwise specified, all specimens are in the Museum of Natural History, University of Kansas. The various collections of institutions and of private persons are indicated by the following symbols: