Zapus princeps minor Preble, N. Amer. Fauna, 15:23, August 8, 1899.
Zapus hudsonius campestris, Bailey, N. Amer. Fauna, 49:117, January 8, 1927 (part).
Type.—Adult female, skin and skull, No. 73673, U. S. Nat. Mus. Biol. Surv. Coll., Wingard, near Carlton House, Saskatchewan; obtained on July 23, 1895, by J. Alden Loring, original No. 3123.
Range.—Most of southern half of Saskatchewan and Alberta, northeastern Montana southeastward to Aweme, Manitoba, and Webster, South Dakota. See [fig. 46]. Zonal range: Transition, Hudsonian, and Canadian.
Description.—Size, small; back dark, usually with a distinct mid-dorsal band of black mixed with Warm Buff; sides lighter, more yellowish, but always with an admixture of black hairs; lateral line distinct, near Ochraceous-Buff, ventral surface characteristically suffused with Ochraceous-Buff; tail bicolored, grayish-white to yellowish-white below and pale brown above; hind feet grayish-white above; ears dark, edged with white or yellowish-white; skull small; postpalatal notch often anterior to posterior part of molars; inferior ramus of zygomatic process of maxillary often with well developed medial projection; auditory bullae flattened; nasals narrower anteriorly and proximal third depressed; base of zygomatic process of squamosal broad.
Comparisons.—From Zapus princeps princeps, Z. p. minor differs as follows: Size averaging smaller in all measurements taken, except least interorbital constriction which is approximately the same; color dorsally and laterally more yellowish, less Ochraceous-Buff; ventrally greater suffusion of Ochraceous-Buff.
For comparison with Zapus princeps idahoensis see account of that subspecies.
Remarks.—This geographic race is notably stable and retains most of its diagnostic characters throughout nearly all parts of its range. Intergradation occurs with Zapus princeps idahoensis at various localities in Montana, as is described in more detail in the account of idahoensis. Crowe (1943:406) gives evidence of intergradation between Zapus princeps idahoensis and Z. p. minor in specimens from Entrance in western Alberta. Crowe (loc. cit.) described these individuals as intermediate in color (lateral line present, under parts washed with buff, sides and dorsal stripe rich in ochraceous), and in cranial characters (smaller skulls, anteriorly narrower nasals, shorter more deflected rostrum, and higher cranium); but he considered them closer to Z. p. minor.
A skin without skull from Kananaskis Valley, Alberta, shows intergradation between Z. p. idahoensis and Z. p. minor. This individual is like Z. p. idahoensis in dorsal and lateral coloring, but is nearer Z. p. minor in ventral coloring and in the presence of a distinct lateral line. External measurements provide basis for tentatively assigning the skin to Z. p. minor.