Part 14

Zapus princeps idahoensis Davis, Jour. Mamm., 15:221, August 10, 1931.

Jaculus hudsonius, Allen, Bull. Essex Inst., 6:61, April, 1874 (part--the part in Carbon County, Wyoming).

Zapus hudsonius, Merriam, N. Amer. Fauna, 5:72-73, July 30, 1891.

Zapus princeps princeps, Preble, N. Amer. Fauna, 15:22-23, August 8, 1899 (part).

Type.--Male, adult, skin and skull; No. 54845, Mus. Vert. Zool.; 5 mi. E Warm Lake, 7000 ft., Valley County, Idaho; obtained on July 9, 1932, by Robert T. Orr; original No. 660.

Range.--From Banff, Alberta, southward through extreme southwestern Alberta and extreme southwestern British Columbia, most of the panhandle of Idaho, Kamiak Butte in eastern Washington, western Montana, and western Wyoming (Green, Wind River and Absoroka ranges of the Rocky Mt's). See fig. 46.

Description.--Size, medium; back from near Clay Color to near Warm Buff, usually overlaid with black hairs forming broad dorsal band; sides lighter than back; lateral line indistinct or wanting; belly pure white, occasionally faintly tinged with Ochraceous-Buff; tail indistinctly bicolored, tan to grayish-white below and pale brown above; hind feet grayish-white above; ears dark, edged with white or yellowish-white; postpalatal notch anterior to posterior border of last molars; proximal part of inferior ramus of zygomatic process of maxillary relatively narrow and usually without enlarged median projection; auditory bullae well inflated; incisive foramina relatively narrow.

Comparisons.--From Zapus princeps kootenayensis, Z. p. idahoensis differs as follows: Size averaging larger; upper parts with greater suffusion of ochraceous, not grayish or dusty; skull larger; incisive foramina longer and relatively wider; zygomatic breadth averaging greater; nasals broader at tips; auditory bullae more inflated.

From Zapus princeps oregonus, Z. p. idahoensis differs in: Size averaging smaller; upper parts generally more suffused with black hairs, on the average more yellowish with less ochraceous; skull smaller; incisive foramina narrower (breadth less, instead of more, than 52 per cent of length); palatal bridge shorter; zygomatic arch shorter; pterygoid fossae narrower.

From Zapus princeps utahensis, Z. p. idahoensis can be distinguished by: Size less; color slightly darker; skull averaging smaller in zygomatic breadth, least interorbital constriction, and occipitonasal length; palate narrower; upper tooth-rows nearly parallel as opposed to diverging anteriorly.

From Zapus princeps minor, Z. p. idahoensis differs in: Size larger; color of underparts less ochraceous; lateral line indistinct or wanting; skull averaging larger in all measurements taken except that the two subspecies are approximately same in least interorbital constriction, length of zygomatic arch, and distance from anterior face of incisors to postpalatal notch; nasals, in profile, straight instead of with proximal third depressed; postpalatal notch anterior to posterior face of last molar, instead of even with, or usually posterior to, same.

From Zapus princeps saltator, Z. p. idahoensis differs as follows: Size averaging slightly larger; color darker, being less ochraceous and more yellow dorsally and laterally; auditory bullae more inflated; zygomatic arches less bowed laterally; incisive foramina narrower.

For comparison with Zapus princeps princeps and Zapus princeps cinereus see accounts of those subspecies.

Remarks.--Intergradation occurs at almost all of the places where the range of Z. p. idahoensis is known to touch that of any other geographic race. Nevertheless, each of the populations studied has characters which make this subspecies recognizable as a taxonomic unit, although its characters are not yet stabilized even in the central part of its range.

Among named subspecies of Zapus princeps, Zapus p. idahoensis most closely resembles Zapus princeps kootenayensis, its nearest geographic neighbor to the north. Three specimens from 2 mi. NE Weippe, 3000 ft., Idaho, are best referred to Z. p. idahoensis but show relationship to Z. p. kootenayensis in size and shape of the tympanic bullae. The relationship of individuals from Idaho, here referred to Z. p. idahoensis, from Glidden Lakes, Enaville, Cascade Creek, and 13 mi. E and 5 mi. N Coeur d'Alene, is discussed in the account of Z. p. kootenayensis. British Columbian specimens from Newgate and Crows Nest Pass, 4450 ft., as well as Albertan specimens from Crows Nest Pass and various places in Waterton Lake Park, resemble Z. p. kootenayensis in color but cranially are more nearly like Z. p. idahoensis.

Intergradation with Zapus princeps oregonus was noted by Davis (1939:340) in a specimen from Cedar Mountain in Idaho. I have not seen this individual which he referred to Z. p. idahoensis but have seen a specimen from the N Fork of Potlatch River (15 mi. SE Cedar Mt.), which, in color, closely resembles Z. p. oregonus but cranially (shape of incisive foramina, size, and inflation of auditory bullae) is more nearly like Z. p. idahoensis to which it is referred. Davis (loc. cit.) indicates that specimens from summit of Smith Mt., from 1 mi. N Bear Creek R. S., from 1/2 mi. E Black Lake, and from 3 mi. W Payette Lake, Idaho, are in an area of intergradation between Z. p. oregonus and Z. p. idahoensis, but he referred them to Z. p. idahoensis on the basis of cranial characters and length of hind foot. Seven specimens from Alturas Lake, 7000 ft., Idaho, were likewise so allocated by Davis (loc. cit.). I concur with him and in addition refer the following intermediate individuals from Idaho to Z. p. idahoensis: New Meadow, 1; Warren, 1; Perkins Lake, 7000 ft., Sawtooth Nat'l Forest, 1; Prairie Creek, 12 mi. W Ketchum, 2400 ft., 3. All are more nearly like Z. p. oregonus in color but cranially they show more resemblance to Z. p. idahoensis.

In the eastern part of the range of Z. p. idahoensis, intergradation occurs with Zapus princeps minor, as at 15 mi. S Heath, N Fork Flat Willow Creek, Big Snowy Mt's, Montana. Specimens from there have the lateral line enlarged and the maximum seen in this species of Ochraceous color ventrally. The pterygoid fossae are large and the bullae are reduced as in Z. p. minor, but in the sum total of the characters the mice more closely resemble Z. p. idahoensis. At Lewistown, 7 mi. NE Judith Mt's, Lime Kiln Gulch, Montana, the animals are colored as are Z. p. minor but cranially are like Z. p. idahoensis to which they are referred. Specimens from the Highwood Mt's, Montana, also are intergrades; they have a relatively distinct lateral line as in Z. p. minor but show no ventral suffusion of Ochraceous; they have large bullae, nasals that are straight in lateral profile and other cranial characters of Z. p. idahoensis to which they are here referred.

A single specimen from Kamiak Butte, Whitman County, Washington, has been referred to Z. p. idahoensis by Dalquest (1948:373). I have not seen this individual, but, on geographic grounds, it is likely to be of this subspecies.

Specimens examined.--Total, 342, distributed as follows:

ALBERTA: Boom Creek, 5600 ft., 27 mi. W Banff, 2 (NMC); Banff, Cascade Basin, 2 (NMC); Bryant Creek, Banff Park, 1 (NMC); Spray River, 7 mi. Cabin, Banff Park, 3 (NMC); Crows Nest Pass, 2 (NMC); Waterton Lakes Park, 16 (NMC); Linnets Pond, Waterton Lakes Park, 4 (NMC); Bertha Creek, Waterton Lakes Park, 8 (NMC).

BRITISH COLUMBIA: Vermilion Crossing, Kootenay, 1 (ROM); Paradise Mine, 3 (PM); Crows Nest Pass, 4450 ft., 3 (NMC); Newgate, 10 (NMC).

IDAHO: Adam Co.: 1/2 mi. E Black Lake, 6800 ft., 8; summit of Smith Mtn., 7500 ft., 9 (3 MVZ); 1 mi. N Bear Creek R. S., SW Slope Smith Mtn., 5400 ft., 13; New Meadows, 1 (USBS); 3 mi. W Payette, 5400 ft., 4 (MVZ). Blaine County: Perkins Lake, 7000 ft., Sawtooth Nat'l Forest, 1; Alturas Lake, 7000 ft., 3 (MVZ); Prairie Creek, 12 mi. NW Ketchum, 2400 ft., 3. Clearwater County: 2 mi. NE Weippe, 3000 ft., 3 (MVZ). Custer County: Loon Creek R. S., 6000 ft., Challis Nat'l Forest, 2; Head Pahsimeroi River, 2 (MVZ); Mill Creek, 14 mi. WSW Challis, 8370 ft., 1 (MVZ). Fremont County: 7 mi. W West Yellowstone, 7000 ft., 3; 17 mi. E and 4 mi. N of Ashton, 6275 ft., 9 (MVZ). Idaho Co.: Packers Meadow, near state line, South Lobo Hot Springs, 5150 ft., 7 (USBS); Warren, 1 (USBS). Kootenai Co.: 13 mi. E and 5 mi. N Coeur d'Alene, 5; Cascade Creek, 36 mi. E Coeur d'Alene, Coeur d'Alene Nat'l Forest, 1 (USBS). Latah Co.: N Fork Potlatch River, 1 (USBS). Lemhi County: Salmon River Mts., 3 (USBS). Shoshone Co.: Enaville 1 (USBS); Glidden Lakes, 5700 ft., 4 (MVZ). Valley County: 5 mi. E Warm Lake, 7000 ft., 6 (MVZ); 5 mi. W Cape Horn, 7000 ft., Sawtooth Range, 1 (MVZ).

MONTANA: Beaverhead County: Birch Creek, 18 mi. NE Dillon, 7100 ft., 14 (MVZ). Carbon Co.: Pryor Mts., 1 (USBS); 2 mi. E Shriver, 6500 ft., 6 (MVZ). Cascade Co.: Neihart, 1 (USBS). Chouteau Co.: Upper Muddy, 1 (USBS); Highwood Mts., 2 (USBS). Fergus Co.: Lime Kiln Gulch, 7 mi. NE Judith Mts., 3 (USBS); 15 mi. S Heath, N Fork Flat Willow Creek, 8 (USBS); 10 mi. W Tyler, N Fork Flat Willow Creek, 1 (USBS); Crystal Lake, 6000 ft., Big Snowy Mts., 3 (UM). Flathead Co.: Waterton Lake, 1 (USBS); Crosley Lake, Glacier Nat'l Park, 1 (USBS); Paola, 1 (USBS); Summit, 2 (USBS); 1 mi. W and 2 mi. S Summit, 5000 ft., 12. Gallatin Co.: 4 mi S Logan, Camas Creek, Big Belt Mts., 5 (USBS); Gallatin Gateway, 5 (SDM); west fork West Gallatin River, 6500 ft., 6 (USBS). Glacier Co.: Babb, 1 (LMH); 2-1/2 mi. W and 1-1/2 mi. S Babb, 4700 ft., 1; Many Glaciers, 4900 ft., Glacier Nat'l Park, 5 (MVZ); 6 mi. S St. Marys, 6500 ft., 1; St. Marys Lake, 7 (USBS); McDermit Lake, 1 (USBS); Blackfoot Agency, 1 (USBS). Golden Valley County: Swimming Woman Canyon, 3/4 mi. S Fergus County line, Big Snowy Mts., 4 (UM). Judith Basin Co.: Little Belt Mts., Dry Wolf Creek, 20 mi. SW Stanford, 4 (USBS); 13 mi. W Buffalo, 1 (USBS). Madison Co.: 12 mi. SW Alder, Hinch Creek, Ruby Mts., 2 (USBS). Meagher Co.: 16 mi. N White Sulphur Springs, Little Belt Mts., 7 (USBS). Park County: West Boulder Creek, 18 mi. SE Livingston, 1 (USBS); Emigrant Gulch, 3 mi. SE Chico, 6500 ft., 4 (USBS); 2 mi. NE Cooke, 8000 ft., 22 (MVZ). Ravalli County: 3 mi. SW Florence, 3700 ft., 1; 6 mi. E Hamilton, 3700 ft., 1. Sanders Co.: Prospect Creek, near Thompson, 1 (USBS). Sweet Grass Co.: near head of Big Timber Creek, 5200 ft., Crazy Mts., 11 (USBS); Brannin Ranch, Sweet Grass Creek Canyon, 6 (UM); Big Timber, 1 (USBS). Teton County: 17-1/2 mi. W and 6-1/2 mi. N Agusta, 5100 ft., 2.

WYOMING: Fremont County: Moccasin Lake, 19 mi. W and 4 mi. N of Lander, 10,000 ft., 1; 23-1/2 mi. S and 5 mi. W Lander, 8600 ft., 4. Park County: 31-1/2 mi. N and 36 mi. W Cody, 6900 ft., 7; 28 mi. N and 30 mi. W Cody, 7200 ft., 1; 16-1/4 mi. N and 17 mi. W Cody, 5625 ft., 14; 2 mi. S and 42 mi. W Cody, 6400 ft., 5; 12 mi. W Wapiti, 6 (LMH); 25 mi. S and 28 mi. W Cody, 6350 ft., 5. Sublette County: E end Island Lake, 10,600 ft., 3 mi. S Fremont Park, 1; N side Halfmoon Lake, 7900 ft., 3; W end Halfmoon Lake, 7900 ft., 2; 10 mi. NE Pinedale, 8000 ft., 1; 5 mi. E and 8 mi. N Pinedale, 7500 ft., 1; 3 mi. E and 5 mi. N Pinedale, 7500 ft., 4; 19 mi. W and 2 mi. S Big Piney, 7700 ft., 3.

Marginal records.--Alberta: Boom Creek, 5600 ft., 27 mi. W Banff; Crows Nest Pass; Waterton Lakes Park. Montana: Highwood Mts.; 15 mi. S Heath, N Fork Flat Willow Creek; 2 mi. E Shriver, 6500 ft. Wyoming: 23-1/2 mi. S and 5-1/2 mi. W Lander, 8600 ft.; 10 mi. W and 2 mi. S Big Piney, 7700 ft. Idaho: 7 mi. W West Yellowstone, 7000 ft.; Prairie Creek, 12 mi. NW Ketchum, 2400 ft.; 5 mi. W Warm Lake, 7000 ft.; 1 mi. N Bear Creek R. S., SW slope Smith Mtn., 5400 ft.; N Fork Potlatch River; 13 mi. E and 5 mi. N Coeur d'Alene. British Columbia: Newgate; Vermilion Crossing, Kootenay.

=Zapus princeps kootenayensis= Anderson

Zapus princeps kootenayensis Anderson, Ann. Rept. Nat. Mus. Canada for 1931:108, November 24, 1932.

Zapus princeps princeps, Preble, N. Amer. Fauna, 15:23, August 8, 1899 (part).