Mustela frenata inyoensis Hall
Long-tailed Weasel
Mustela frenata inyoensis Hall, Carnegie Instit. Washington Publ. 473:99, November 20, 1936.
Putorius xanthogenys, Merriam, N. Amer. Fauna, 11:25, June 30, 1896 (part).
Mustela xanthogenys xanthogenys, Miller, U. S. Nat. Mus. Bull., 79:99, December 31, 1912.
Type.—Male, adult, skull (with skeleton) and skin; no. 25907, Mus. Vert. Zoöl.; Carl Walter's Ranch, 2 mi. N Independence, Inyo County, California; June 26, 1917; obtained by A. C. Shelton; original no. 3143.
The skull (plates [22]-[24]) is complete and unbroken. All teeth are present and entire. The skin is well made and in good condition.
Range.—From 3700 feet (Lone Pine) to at least 4000 feet (Alvord); Lower Sonoran Life-zone of the floor of Owens Valley in Inyo County, California. See figures [29] and [30] on pages 221 and 314.
Characters for ready recognition.—Differs from M. f. nevadensis in presence of white facial markings; from M. f. pulchra in near (l) Brussels Brown rather than near (16 j) Buckthorn Brown to near (h) Yellow Ocher color of upper parts and basilar length of less than 45 in males; from M. f. latirostra in brownish rather than blackish color of inside of ear and orbitonasal length of more than 15.
Description.—Size.—Male: Two adults, the type specimen and no. 25392/32805, measure, respectively, as follows: Total length, 423 and 390; length of tail, 170 and 145; length of hind foot, 42 and 44. Tail is 67 and 59 per cent as long as head and body. Length of hind foot less than basal length.
Female: No. 12400, Field Mus. Nat. Hist., which is young, has the following measurements: Total length, 390; length of tail, 150; length of hind foot, 39. Tail is 63 per cent as long as head and body. Length of hind foot less than basal length.
The differences in external measurements between the two sexes, as represented by the male type specimen and by the young female, are: Total length, 33, length of tail, 20; length of hind foot, 3.
Externals.—Longest facial vibrissae black or dark brown and reaching beyond ear; carpal vibrissae same color as underparts and extending to apical pad of fifth digit; hairiness of foot-soles (in summer pelage) slightly less than shown in figure [19].
Color.—Large spot between eyes, band confluent with color of underparts, on each side of head extending anterodorsally anterior to each ear, upper throat, chin, lower lips and in some specimens part or all of upper lips white; patch between eyes and bars in front of ears tinged with some shade of yellowish in one specimen; dark spot posterior to each angle of mouth present in four of five specimens; tip of tail black; remainder of upper parts, in summer, near (l) Brussels Brown or tones 1 to 2 of Raw Umber of Oberthür and Dauthenay, pl. 301; slightly darker brown on forehead, nose and about eyes. In winter near (j) Snuff Brown or lighter than Brussels Brown with a smoked effect. Underparts Buff-Yellow, winter and summer. Color of underparts extends distally on posterior sides of forelegs over toes onto antipalmar faces of feet and wrists and on medial sides of hind legs over antiplantar faces of toes. Least width of color of underparts averaging, in 5 available specimens 34 (24-42) per cent of greatest width of color of upper parts. Black tip of tail, in two adult males, averaging 53 (45 and 60) mm. Thus longer than hind foot and averaging 34 per cent of length of tail-vertebrae.
Skull and teeth.—Male (based on the type): See measurements and plates [22]-[24]. As described in M. f. nigriauris except that: Weight, 4.4 grams; basilar length, 44.7; postorbital breadth not less than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; length of tympanic bulla less than length of lower molar and premolar tooth-row.
Female: Adult unknown.
Compared with the skull of the male of nevadensis, no single difference not covered by individual variation in nevadensis has been detected. Selected differences of inyoensis in comparison with latirostra are larger size, less inflated tympanic bullae and relative narrowness of the postorbital, interorbital and preorbital parts of the skull. Comparison of the skull with that of M. f. pulchra is made in the account of that subspecies.
Remarks.—Although two specimens of this subspecies were taken during the Death Valley Survey conducted by Dr. C. Hart Merriam, only three additional individuals are known to have been saved as study specimens since that time.
M. f. inyoensis as now known may be thought of as closely similar to M. f. nevadensis except for the presence of well-developed white facial markings like those found in the weasels of the San Joaquin Valley and coastal region of California south of San Francisco Bay. The nonwhite areas of the head are almost the same color as the back and not distinctly blackish as in M. f. latirostra and M. f. nigriauris. The one specimen in the winter coat, no. 25392/32805, U. S. Nat. Mus., from Lone Pine, is brown rather than white. The brown has the pale smoke-tinge common in the winter pelage of subspecies whose members are either brown or white in winter. The range of this subspecies is thought to include the floor and lower elevations of Owens Valley although it may occur in limited numbers southwestward along the base of the Sierra Nevada and through the mountains in places of low elevation like Walker Pass its range may meet that of pulchra.
The type specimen was taken in an alfalfa field by ranch hands, who, according to A. C. Shelton (MS), stated that the species was common at the type locality. None of the five specimens shows infestation of the frontal sinuses by parasites.