Part 26

=Zapus hudsonius hudsonius= (Zimmerman)

Dipus hudsonius Zimmerman, Geog. Geschichte d Menschen u. vierfussigen Thiere, 2:358, 1780.

Dipus labradorius Kerr, Animal Kingdom:276 (based on the Labrador Jerboid Rat of Pennant, 1781--but Preble, N. Amer. Fauna, 15:11, August 8, 1899, states that the specimen came from Hudson Bay), 1792.

Gerbillus canadensis, Desmarest, Mammalogie, 2:321, 1822.

Gerbillus labradorius, Harlan, Fauna Amer., p. 157, 1825.

Meriones labradorius, Richardson, Fauna Boreali-Americana, 1:144, 1829.

Jaculus labradorius Wagner, Suppl. Schreber's Saugthiere, 3:294, 1843.

Zapus hudsonius hudsonius, Preble, N. Amer. Fauna, 15:15, August 8, 1899 (part--the part from Northwest Territory, Ontario, Michigan, northern Wisconsin and northern Minnesota).

Zapus hudsonius alascensis, Osgood, N. Amer. Fauna, 19:38, October 6, 1900.

Type.--Type specimen not known to be in existence; from Hudson Bay, locality now considered to be Fort Severn, Ontario (see Anderson, 1942:37).

Range.--Central Alaska southeastward to central Ontario, northern Minnesota, northern Wisconsin, and upper peninsula of Michigan. See fig. 47. Zonal range: Hudsonian, Canadian, and into Transition.

Description.--Size medium; back dark, from near Tawny-Olive to near Cinnamon with heavy admixture of black hair forming dorsal band; sides lighter than back and from near Tawny-Olive to near Cinnamon, sometimes with admixture of black hair giving sides streaked appearance; lateral line usually distinct, clear Ochraceous-Buff; underparts white, sometimes with slight suffusion of Ochraceous-Buff; tail bicolored, brown to brownish-black above, grayish-white to yellowish-white below; ears dark, usually edged with ochraceous; feet grayish-white above; incisive foramina relatively short and broadly rounded; zygomata relatively short; braincase relatively broad; auditory bullae flat, long, and relatively broad; pterygoid fossae relatively narrow; nasals relatively broad and short.

Comparisons.--From Zapus hudsonius alascensis, Z. h. hudsonius differs as follows: upper parts generally darker, more black tipped hair; sides darker with greater suffusion of dark hair; lateral line brighter, more distinct; size averaging smaller; zygomatic arches less bowed outward; distance from incisors to postpalatal notch shorter; zygomata shorter; occipitonasal length less; mastoid region narrower.

From Zapus hudsonius intermedius, Z. h. hudsonius differs in: color darker, more tawny dorsally; sides averaging darker, more black-tipped hairs; size averaging larger; braincase averaging broader; distance from incisors to postpalatal notch averaging slightly shorter; zygomata averaging longer; mastoid region averaging broader; incisive foramina averaging shorter.

From Zapus hudsonius tenellus, Z. h. hudsonius differs as follows: upper parts averaging darker; tail averaging shorter; condylobasal length averaging more; braincase averaging broader; auditory bullae broader and less inflated; interparietal averaging broader; incisive foramina more broadly rounded and averaging longer.

For comparison with Zapus hudsonius canadensis and Zapus hudsonius campestris see accounts of those subspecies.

Remarks.--Preble (1899:16) had available for study five specimens of Zapus hudsonius hudsonius from Hudson Bay. Four were preserved in alcohol and one as an incomplete skin (prepared from an alcoholic specimen). All were unreliable for comparative purposes owing to the effects of the preservative. Preble, therefore, (loc. cit.) selected as a fairly typical sample a series of specimens from Tower, St. Louis County, Minnesota; these formed the basis of comparison between Z. h. hudsonius and other subspecies of Zapus hudsonius. Now that additional material (well prepared skins and skulls) is available from the Hudson Bay region and from other localities in northern and western Canada it is evident that the specimens from Tower, although here considered to be Z. h. hudsonius, are not typical Z. h. hudsonius but are intergrades between hudsonius and specimens of Zapus hudsonius intermedius. Comparisons made in the present account are based on specimens from the vicinity of Hudson Bay (Fort Severen, Ontario, York Factory, Shamatawa River, and Robinson Portage, Manitoba). These individuals are considered typical of this subspecies. With these new data available the range of Z. h. hudsonius is now understood to include all of the region from eastern Alaska to the northern parts of Minnesota, Wisconsin, and Michigan.

Intergradation between Zapus hudsonius canadensis and Z. h. hudsonius is noted in specimens from 30 mi. NE Port Arthur and also in those from Silver Islet, Thunder Cape, Ontario. These individuals resemble Z. h. canadensis in size and shape of the auditory bullae and in the shape of the nasals, but in their darker coloration, broadly rounded incisive foramina, and relatively narrow pterygoid fossae they are more nearly like Z. h. hudsonius to which they are here referred.

Specimens from Minaki, Ontario, are tending toward Zapus hudsonius intermedius in lighter coloration but in the size and shape of the auditory bulla, size and shape of the incisive foramina, and in the width of the pterygoid fossae they are more nearly like Z. h. hudsonius to which they are here referred. Specimens from various localities in Menominee County, Michigan, are like Z. h. intermedius in shape of the incisive foramina and shape of the postpalatal notch, but in color of pelage, size and shape of the auditory bullae, and breadth of the pterygoid fossae they closely resemble Z. h. hudsonius.

In Wisconsin, intergradation occurs in color and in cranial characters in specimens from Mercer, Solon Spring, and in a single individual from Basswood Lake. All these specimens, however, are best referable to Z. h. hudsonius.

Specimens from one mile southwest of Fairbanks and from Fairbanks, Alaska, show intergradation with Zapus hudsonius alascensis in coloration (more brown, less black), but in small size, short, broadly rounded incisive foramina, and in size and shape of the auditory bullae are nearest to Z. h. hudsonius to which they are here assigned.

Intergradation with Zapus hudsonius alascensis is noted also in specimens from McIntyre Creek, Yukon. They are like Z. h. alascensis in the size and shape of the auditory bullae and in the more elongate incisive foramina, but in the coloration, size of the pterygoid fossae, and breadth of the braincase are more nearly like Z. h. hudsonius and are here referred to this geographic race.

In British Columbia, in specimens from 1 mi. NW junction of Irons Creek and Laird River as well as in those from Hot Springs, 3 mi. WNW junction of Trout River and Laird River, and in those from 1/4 mi. S of the junction of the same rivers, three way intergradation occurs. These animals are like Zapus hudsonius alascensis in color and in length of tail. They agree with Zapus hudsonius tenellus in shape of nasals. In degree of inflation of auditory bullae, in length and width of incisive foramina, and in shape of pterygoid fossae they are as in Z. h. hudsonius to which they are here assigned.

Specimens examined.--Total, 230, distributed as follows:

ALASKA: Fairbanks, 1 (USNM); 1 mi. SW Fairbanks, 440 ft., 1.

ALBERTA: Conibear Lake, Wood Buffalo Park, 1 (NMC); Assineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 1; Mountain Rapid, Athabasca River, 1 (USBS); Brule Rapid, Athabasca River, 1 (USBS); 25 mi. above Pelican Rapid, Athabasca River, 1 (USBS); Lac la Nonne, 7 (NMC); Swift Current, Athabasca River, 1 (USBS); junction Lac la Biche River and Athabasca River, 1 (USBS); 30 mi. above Athabasca Landing, Athabasca River, 1 (USBS).

BRITISH COLUMBIA: 1 mi. NW junction Irons Creek and Laird River, 3; Hot Springs, 3 mi. WNW junction Trout River and Laird River, 1; 1/4 mi. S junction Trout River and Laird River, 1.

MANITOBA: York Factory, 2 (USBS); Shamatawa River, 1 (USBS); Oxford House, 15 (USBS); Robinson Portage, 4 (USBS); Echamamish, 1 (USBS); Norway House, 1 (USBS); Swan River, 1 (NMC); Bird, 1 (NMC); Aimie Lake, 2 (NMC); Albert's Lake, Flin Flon, 2 (NMC); Portage La Prairie Prov., Delta, 1 (UM).