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.
Description.—Size.—Male: An adult or subadult from Fair Oaks, Pa., a subadult from Finleyville, Pa., and an adult from Huttonsville, W. Va., measure, respectively as follows: Total length, 206, 194, 191 (average 197); length of tail, 37, 32, 28 (32); length of hind foot, 23 in each. An adult from Roanoke, Indiana, weighs 40.6 grams.
Female: Two young from Leasuresville, Pa., and Middle Paxton Twp., Pa., measure, respectively, as follows: Total length, 188, 172; length of tail, 33, 30; length of hind foot, 20.5, 21. An adult from Monroeville, Ohio, weighs 40.5 grams and a young individual from Middle Paxton Twp., Pa., 39.3 grams, and a subadult from Swan Creek Exp. Station, Allegan Co., Mich., weighs 49 grams.
Color.—Winter pelage either all white, or brown as in summer; upper parts about Raw Umber, or tone 2 of Carbo Brown of pl. 342 of Oberthür and Dauthenay. Underparts white at least on thoracic region; approximately three-fourths of specimens with brown rictal spot at angle of mouth or with this area covered by brown upper parts which extend down on each side and meet on the underparts in about one specimen out of three; upper lips and hind feet ordinarily brown; toes of forefeet ordinarily white (see under remarks for details of color pattern). Least width of color of underparts in the specimens in which the dark color of the upper parts does not encircle the body averages 60 per cent of greatest width of color of upper parts, or including all specimens the percentage is 42.
Skull (based on specimens from Pa. listed in table of cranial measurements, which see and plates [14] and [15]).—Basilar length 29.7 and 28.6 in male and 28.0 in female; weights unavailable; otherwise as described in M. e. richardsonii. The length of the tympanic bullae seems to be actually less, and less in relation to the basilar length, than in other American subspecies of M. rixosa.
Remarks.—Robert Kennicott's mention in 1859 (p. 245) of what seems to be this subspecies is the earliest reference to it that I can identify in the literature. He used the specific name pusillus and it was not until 1900 that Samuel N. Rhoads proposed the name Putorius allegheniensis. Since 1900, several records of occurrence have been published which have made the geographic range of this race better known.
An adequate number of specimens has been gathered only from Ohio and from western Pennsylvania. Many from Ohio are without accurate external measurements taken in the flesh. The majority of the specimens from Pennsylvania owe their preservation to the willingness of local officials, who pay bounties on weasels, to save the skins of Mustela rixosa. These specimens ordinarily comprise the skin with locality but because the feet, external measurements in the flesh, and skulls are unavailable, the material is far from adequate and to give an accurate notion of the usual or average cranial characters of allegheniensis in Pennsylvania, skulls from there are especially desirable.
A smaller percentage of the specimens from Ohio than from Pennsylvania have the brown color of the upper parts meeting on the underparts. Also, more of the specimens from Ohio are lighter colored and this suggests intergradation with the subspecies campestris and rixosa to the westward.
From Pennsylvania 23 animals in brown pelage are available. In 5 there is a rictal spot at the angle of the mouth; in 5 the area is white and in 13 the brown color of the upper parts is continuous over the area in question. Only 2 of 23 have the upper lips white. Eight have the color of the upper parts meeting on the venter thus restricting the white of the underparts to the chin, throat, and pectoral region, and 6 of these have a white area in the inguinal region as well. The toes of the forefeet are white in 3 of 4 animals suitable for examination in this regard and the hind feet are marked with white in 3 of the 8 animals which have the hind feet preserved. Mustela rixosa in Pennsylvania parallels the species Mustela frenata in that in this relatively humid area of the northeastern United States the color of the upper parts is darker and the area of the dark-colored upper parts is increased at the expense of the area of the light-colored underparts. Also Mustela erminea in this same region (range of the subspecies Mustela cicognanii) shows the same tendency to darker color of upper parts and their extension in area at the expense of the area of the light-colored underparts, or was mentioned above.
It is difficult to account for the seeming absence of the species from New England and all that part of Canada and the United States south of the St. Lawrence River and northeastward from Pennsylvania. The size of females of M. erminea cicognanii in that territory is so little more than in rixosa that the latter possibly cannot successfully compete with the erminea stock which may already occupy the ecologic niche to which rixosa is adapted. It will be remembered that in western North America in territory seemingly climatically suitable for rixosa it occurs no farther southward than the line below which M. erminea has become reduced to a size comparable with that of M. rixosa.
Of 41 subadult and adult skulls assigned to this subspecies 24 have obvious lesions in the frontal sinuses evidently resulting from infestation by nematodes. More in detail, none of the specimens from Illinois (3 individuals), Pennsylvania (3 barely subadult), or West Virginia (2) displays lesions. From Wisconsin, Indiana, Virginia and North Carolina there is one specimen each and each specimen displays lesions. From Ohio, 17 of 23 specimens display lesions. From Michigan 3 of 8 specimens display lesions; 2 adults and one subadult have lesions and 5 subadults do not have lesions.