Part 28

Marginal records.--North Dakota: Fish Lake; Pembina. Wisconsin: Danbury; Ogema; Lakewood. Illinois: Fox Lake. Indiana: La Fayette; New Harmony. Illinois: 6 mi. S Pinckneyville (near Pyatt). Iowa: Ames; Arthur; Ireton. Montana: Yellowstone River, 7 mi. NE Glendive, 2000 ft. North Dakota: Grinnell.

=Zapus hudsonius ladas= Bangs

Zapus hudsonius ladas Bangs, Proc. New England Zool. Club, 1:10, February 28, 1899.

Type.--Female, adult, skin and skull, No. 4169, E. A. and O. Bangs Coll. (now in Mus. Comp. Zool.); Rigoulette, Hamilton Inlet, Labrador; obtained on July 18, 1895, by C. H. Goldthwaite.

Range.--Eastern Quebec north of Gulf of St. Lawrence, Labrador, and Newfoundland. See fig. 47. Zonal range: Canadian and Hudsonian.

Description.--Size medium; back relatively dark, near Ochraceous-Tawny with admixture of black-tipped hair; dorsal band relatively wide but not sharply defined against color of sides; side lighter than back, from near Ochraceous-Tawny to near Cinnamon and lined with black-tipped hair; lateral line distinct of clear Cinnamon-Buff or Light Ochraceous-Buff; underparts white, often suffused with Ochraceous-Buff; tail distinctly bicolored, dark brown to black above and yellowish-white to grayish-white below; ears dark, usually flecked with Tawny Ochraceous and edged with ochraceous; feet grayish-white above; incisive foramina relatively short and broad; pterygoid fossae relatively broad; auditory bullae broad and well inflated; mastoid region relatively broad; zygomata relatively short; inferior arm of zygomatic process of maxillary relatively broad.

Comparison.--From Zapus hudsonius acadicus, which Z. h. ladas closely resembles, it differs in: Color darker, dorsal band much less distinct, underparts more frequently suffused with Ochraceous-Buff; auditory bullae relatively broader and more inflated; pterygoid fossae broader; zygomata averaging shorter; incisive foramina relatively shorter; inferior arm of zygomatic process of maxillary relatively broader.

From Zapus hudsonius canadensis, Z. h. ladas differs as follows: Color darker, more richly tawny, dorsal band less distinct; auditory bullae relatively shorter, more inflated; pterygoid fossae averaging broader; zygomata averaging broader; incisive foramina averaging longer.

Remarks.--This subspecies retains all of its diagnostic characters throughout nearly all parts of its geographic range. Specimens from Nova Scotia are like Z. h. ladas in their darker color and less distinct dorsal band, but in the remainder of their characters they are distinct and best referable to Z. h. acadicus.

Zapus h. ladas, with its relatively large size, poorly defined dorsal band, and broad, well inflated auditory bullae, is one of the better marked subspecies of the species Zapus hudsonius.

Specimens examined.--Total, 41, distributed as follows:

LABRADOR: Mahkovik, 1 (USNM); Etagaulet Bay, Lake Melvikl, 2 (USNM); 3 mi. above mouth of Naskaupi River, 1 (USNM); Northwest River, 6, (USNM); Cartwright, 1 (USBS); Muskrat Falls, Hamilton River, 1 (USNM); Hamilton River, Flour Lake, 3 (USNM); Hawke Harbor, 4 (USNM); Goose Bay, 3 (USNM); Niger Sound, Islet Bay, 1 (USNM); Red Bay, 5 (USNM); Mecklenburg Harbor, 2 (USNM); Mary Harbor, 1 (USNM).

NEWFOUNDLAND: Hare Harbor, 3 (USNM).

Quebec: northwest Ungava, 1 (NMC); Moise Bay, 5 (NMC); Trout Lake, near Moise Bay, 1 (NMC).

Marginal records.--Labrador: Mahkovik; Red Bay. Newfoundland: Hare Harbor. Quebec: Trout Lake, near Moise Bay; northwest Ungava.

=Zapus hudsonius pallidus= Cockrum and Baker

Zapus hudsonius pallidus Cockrum and Baker, Proc. Biol. Soc. Washington, 63:1, April 26, 1950.

Jaculus hudsonius, Baird, Repts. Expl. and Surv. 111, 8 (pt. 1):433, July 14, 1858 (part--the part from Platte River, Nebraska, and Cass County, Missouri).

Zapus hudsonius, Coues, Bull. U. S. Geol. and Geog. Surv. of the Territories, 2nd ser. No. 5:260, 1877 (part--the part from Platte River, Nebraska).

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, 5-1/2 mi. N, 1-3/4 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.