Zapus hudsonius campestris Preble, N. Amer. Fauna, 15:20, August 8, 1899 (part—the part from Columbus in Nebraska and Jackson County in Missouri).
Type.—Male, adult, No. 22953, Univ. Kansas Mus. Nat. Hist.; NW corner sec. 4, T. 12S, R. 20E, 51/2 mi. N, 13/4 mi. E Lawrence, Douglas County, Kansas; obtained on May 4, 1948, by E. Lendell Cockrum and Rollin H. Baker, original No. 916 of Cockrum.
Range.—Southern South Dakota, Nebraska, Kansas, Missouri, and northeastern Oklahoma. See [fig. 47]. Zonal range: Upper Austral (Upper Sonoran and Carolinian).
Description.—Size small; back near Cinnamon-Buff with admixture of dark-tipped hair forming distinct, broad, dorsal band; sides bright Cinnamon-Buff with sparse mixture of dark-tipped hair; lateral line usually distinct, of clear Cinnamon-Buff; belly white, sometimes with suffusion of color of sides, tail bicolored, brownish to brownish-black above, grayish-white to yellowish-white below; ears dark, narrowly edged with color of sides; feet white to grayish-white above; mastoid region relatively narrow; maxillary tooth-row relatively short; zygomata relatively short; zygomatic arch relatively broad; interorbital region relatively broad; auditory bullae relatively small and narrow; lateral margins of nasals not constricted posteriorly.
Comparisons.—From Zapus hudsonius preblei, Z. h. pallidus differs as follows: Coloration brighter and richer, more buff, less black; zygomatic arch more broadly bowed; condylobasal length averaging less; braincase narrower; interorbital region broader; incisive foramina shorter.
For comparisons with Zapus hudsonius pallidus and Zapus hudsonius intermedius see accounts of those subspecies.
Remarks.—The characters that distinguish this jumping mouse from neighboring kinds are relatively stable throughout most of its geographic range. Zapus hudsonius pallidus is one of the best defined subspecies of Z. hudsonius.
One specimen from Batesland, South Dakota, is referred to Z. h. pallidus but shows evidence of intergradation with Zapus hudsonius campestris in the shape of the nasals, incisive foramina, and in breadth of the zygomatic arch. An animal from 3 mi. NE Ponca, Nebraska, is intermediate between Z. h. pallidus and Zapus hudsonius intermedius in size and shape of the auditory bullae and in the breadth of the pterygoid fossae, but since this individual shows more resemblance to Z. h. pallidus in coloration and in the majority of cranial characters it is here referred to Z. h. pallidus. Specimens from Beemer, Nebraska, show an intergrading tendency toward Zapus hudsonius intermedius in the reduced lateral bowing of the zygomatic arch and in shorter zygomata. Since these individuals resemble Z. h. pallidus in the majority of characters they are referred to that race. An individual of Z. h. pallidus from Pevely, Missouri, is to some extent an intergrade with Z. h. intermedius of neighboring southern Illinois. Two individuals of Z. h. pallidus from Mohawk Park, Oklahoma, are darker dorsally than, but otherwise similar to, specimens from the type locality.
Zapus hudsonius pallidus seems to be the terminus of a cline; this is a southward trend toward smaller size and lighter, brighter color. There is a similar clinal tendency in the jumping mice in eastern North America, and Z. h. americanus from North Carolina, pronouncedly resembles Z. h. pallidus from Kansas.