Part 40

Remarks.--As early as 1858 (p. 159) Baird recognized an individual of this race from Pembina, Minnesota, as pertaining to a distinct species. Although he used for it the specific name pusillus originally proposed by DeKay for a small weasel from the state of New York, Baird wisely noted that the specimen he described "may be different from the New York species. . . ." After preparing this account, Baird included a second specimen, from Fort Steilacoom, Washington Territory, which he thought might be the same, but the differences that he was careful to point out, in the light of later knowledge, show it to be of the species Mustela erminea. Only a few other naturalists followed Baird in distinguishing the least weasel as a separate species until Bangs in 1896 (p. 21) clearly differentiated it and proposed for it the name Putorius rixosus, which continues in use today and applies to the species.

The accumulation at the National Museum of Canada, through the energy of Dr. R. M. Anderson, of a good series of specimens from Saskatchewan in the general vicinity of the type locality allows for the first time an adequate conception of the amount of secondary sexual variation and individual variation and permits recognition of subspecific characters to differentiate between M. r. rixosa and the subspecies eskimo and campestris. In comparison with the subspecies allegheniensis the basis for segregation is less clear and will remain somewhat in doubt until additional adults of allegheniensis from, say, Pennsylvania, become available with accurate external measurements taken in the flesh and especially with complete skulls.

Intergradation with the subspecies eskimo is suggested by the short tail of the specimen from fifteen miles east of Atlin, British Columbia; in other particulars that specimen, a skin-alone, agrees with the subspecies rixosa. Intergradation with campestris is indicated by increased size of some specimens from North Dakota, and is suggested with allegheniensis by the color of specimens from Wisconsin and Illinois. Three specimens from Winona County, in southeastern Minnesota, unfortunately are skulls-alone without external measurements. Also, two of these skulls are of young animals. The one adult, unsexed, is from Crystal Springs. Selected cranial measurements are: basilar length, 28.5; length of tympanic bulla, 10.9. These measurements accord with those of males of the subspecies rixosa to which the specimens from Winona County, therefore, are here assigned. The possibilities have not been excluded, however, that the adult is an unusually large female of the subspecies campestris or a male of allegheniensis that has tympanic bullae longer than average for that subspecies.

Some hesitation is felt in assigning the specimens, 8 in all, from eastern Canada to the subspecies rixosa. The skin-alone from Eagle River and the skin, with part of the skull, from St. Michael Bay, are in transitional pelage and are of no help in appraising subspecific characters. The one adult specimen which does have a complete skull is from an island south of the Comb Hills. This animal in all respects agrees with selected individuals of M. r. rixosa from Saskatchewan, but each of the five other skins in summer pelage has spots of dark brown color on the breast. Only about one specimen in three of rixosa from Saskatchewan is similarly marked. Furthermore, on some of the specimens from eastern Canada the spots are larger than on any of the animals from farther west. The greater frequency of brown spots on the breast, the larger average size of these spots, and the darker average coloration of the upper parts are suggestive of geographic variation, the existence of which has to be proved by additional and more complete specimens from eastern Canada. For the time being, specimens from there are tentatively assigned to the race rixosa.

Of 56 subadult and adult skulls only 3 (1 North Dakota; 1 Calgary, Alberta; and 1 Island S Comb Hills, Queb.) display lesions resulting from infestation of the frontal sinuses by nematode parasites. None of the young skulls shows such infestation.

Specimens examined.--Total number, 87 as follows. Arranged alphabetically by provinces and states and within each from north to south. Unless otherwise indicated, specimens are in the United States National Museum.

=Alberta.= Miette River, 1; 5 mi. NW Camrose, 1; Camrose, 2 (1, 1); "near Camrose," 2; Forks Blindman and Red Deer rivers, 1; Innisfail, 1; Veteran, 1; Diddsbury [= Didsbury], 1; Calgary, 2 (1, 1); Shepard, 1.

=British Columbia.= Clarks Ranch, Halfway River, Peace River Dist, 1; 15 mi. E Atlin, 1; Wistaria, P. O., 3 (2, 1); Ootsa Lake, 1.

=Labrador.= Davis Inlet, 1; 30 mi. upriver and 20 mi. toward Groswater Mts., Eagle River, 1; St. Michael Bay, 1.

=Mackenzie.= Old Fort Reliance, 1; Fort Resolution, 2; Fort Smith, 1.

=Manitoba.= Gypsumville, 1; Lake St. Martin Reserve, 1.

=Minnesota.= Roseau County: Cedarbend, 2; Grimstad, 1; America, 2 (1, 1); Malung, 1; Norland, 1; Falun, 3 (1, 1, 1); Palmville, 1; Spruce, 1; Stokes, 1. No locality more definite than Marshall County, 1. Clay County: Moorhead, 1. Winona County: "near" Whitman, 1; Altura, 1; Crystal Springs, 1.

=Montana.= Sun River Valley, 1; Wibaux in Wibaux County, 1.

=North Dakota.= Walsh County: Grafton, 15 (3, 1, 5, 2, 1, 1, 1). McHenry County: 4 and 4-1/2 mi. N Upham, 2. Wells County: 1. Morton County: Mandan, 1.

=Ontario.= Algoma Dist: Tatnall, near Oba, 1. Moose Factory, 1.

=Quebec.= Island S of Comb Hills, James Bay, 1. Saguenay County: Natashkwan, 1.

=Saskatchewan.= Osler, 1; "near Regina," 1; Dollard, 2; Shaunavon (and "near" and 1 mi. NE), 9; Klintowel P. O. (about 15 mi. N of Eastend), 1; Eastend and "near" Eastend, 2.

=Mustela rixosa allegheniensis= (Rhoads)

Least Weasel

Plates 14, 15 and 41

Putorius allegheniensis Rhoads, Proc. Acad. Nat. Sci. Philadelphia, 1900:751, March 25, 1901.

Putorius rixosus allegheniensis, Cory, Mamm. Illinois and Wisconsin, p. 378, 1912.

Mustela allegheniensis, Miller, U. S. Nat. Mus. Bull., 79:96, December 31, 1912.

Mustela rixosa allegheniensis, Swenk, Journ. Mamm., 7:328, November 23, 1926.

Type.--Probably male adult, skin and skull, no. 6195, Acad. Nat. Sci. Philadelphia; near Beallsville, Washington Co., Pa.; about 1885 or 1886; obtained by Robert Hawkins.

Type not seen by me.

Range.--Wisconsin, northern Illinois, northern Indiana, Michigan, Ohio, Pennsylvania east to Dauphin County and south in the mountains to northwestern North Carolina. See figure 28 on page 180.

Characters for ready recognition.--Distinguished from M. r. rixosa by three average differences, namely, darker color, shorter tympanic bullae, and smaller size of males; from M. r. campestris in smaller size: hind foot less than 25 in males and less than 22 in females; in males total length less than 216 and tail averaging less than 34, color averaging darker; from M. frenata and M. erminea of same region by basilar length less than 31, tail less than 45, and lacking black pencil.