Mustela frenata saturata (Merriam)
Long-tailed Weasel
Plates [19], [20], [21] and [30]
Putorius saturatus Merriam, N. Amer. Fauna, 11:21, June 30, 1896.
Mustela saturata, Miller, U. S. Nat. Mus. Bull., 79:98, December 31, 1912.
Mustela arizonensis saturata, Grinnell, Univ. California Publ. Zoöl., 40:102, September 26, 1933.
Mustela frenata saturata, Hall, Carnegie Instit. Washington Publ. 473:106, November 20, 1936.
Type.—Male, adult, skull and skin; no. 65930, U. S. Nat. Mus., Biol. Surv. Coll.; Siskiyou, Jackson County, Oregon; June 6, 1894; obtained by C. P. Streator; original no. 3905.
The skull (plates [19]-[21], [30]) lacks the middle part of each zygomatic arch. The teeth all are present although much worn, probably from gnawing at the trap which captured the animal. The skin, in fresh summer pelage, is fairly well made.
Range.—Transition and Boreal life-zones of Siskiyou and Trinity mountains in southern Oregon and northwestern California. See figures [29] and [30] on pages 221 and 314.
Characters for ready recognition.—Differs from M. f. nevadensis in lacking light color of underparts on tail and ankle and in greater average breadth across mastoid processes of skull (see measurements); from M. f. oregonensis in lacking white nasofrontal spot, in having color of underparts interrupted at ankle; from M. f. munda in lacking white nasofrontal spot, in smaller and relatively deeper skull of males and smaller skull of the female.
Description.—Size.—Male: Four adult males (the type, 1 from Mt. Ashland and 2 from Jackson Lake) yield average and extreme measurements as follows: Total length, 414 (402-437); length of tail, 150 (136-160); length of hind foot, 46 (43-50). Tail averages 57 (49-62) per cent as long as head and body. Length of hind foot more or less than basal length.
Female: One young from the summit of the Trinity Mountains east of Hoopa and one nontypical adult from 5500 feet elevation on South Fork Mountain, Humboldt County, measure respectively as follows: Total length, 330, 325; length of tail, 115, 123; length of hind foot, 37, 37. Tail is 53 and 61 per cent as long as head and body. Length of hind foot less than basal length.
Average differences in external measurements between the two sexes, indicated by the unsatisfactory material available, are: Total length, 86; length of tail, 31; length of hind foot, 9.
Externals.—Longest facial vibrissae black or dark brown and extending beyond ear; carpal vibrissae same color as underparts and extending as far as apical pad of fifth digit; hairiness of foot-soles, in summer pelage, as shown in figure [19].
Color.—Upper parts, in summer, Brussels Brown to near (n) Brussels Brown or lighter than tone 3 of Raw Umber of Oberthür and Dauthenay, pl. 301, usually darkest on nose and forehead. Chin white. Remainder of underparts Buff-Yellow to Warm Buff. Tip of tail black. Winter pelage unknown. Color of underparts extends distally on posterior sides of forelegs over toes onto antipalmar faces of feet and sometimes wrists, on medial sides of hind legs only to ankles, but toes sometimes with isolated white markings. Least width of color of underparts in the type and 2 adults from Jackson Lake averaging 35 (30-40) per cent of greatest width of color of upper parts. Black tip of tail averaging 54 (53-55) mm. long; thus longer than hind foot and averaging 37 per cent of length of tail-vertebrae.
Skull and teeth.—Male (based on 4 adults: Type, Mt. Ashland, 1; Jackson Lake, 2): See measurements and plates [19]-[21], [30]. As described in Mustela frenata nevadensis except that: Weight, 3.8 (3.5-4.3) grams; basilar length, 44.4 (42.6-45.8); zygomatic breadth more or less than distance between condylar foramen and M1 or than distance between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth more than postpalatal length; least width of palate less than medial length of P4 (except in one specimen).
Female (based on one adult possibly not typical, from 5500 ft., South Fork Mt.): See measurements. As described in Mustela frenata nevadensis except that: Weight, 2.2 grams; basilar length, 38.1; zygomatic breadth less than distance between condylar foramen and M1 and less than distance between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth more than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite.
The skull of the male of saturata, relative to the basilar length, is broader across the mastoids and narrower across the rostrum and interorbital region than that of nevadensis. Skull not known certainly to differ from that of oregonensis. Compared with the skull of munda, that of the male of saturata is smaller in every part measured except depth of tympanic bullae which averages 3.6 millimeters, rather than 3.5 as in munda. Also, the skull of saturata has a less-marked postorbital constriction, is less heavily ridged, less angular, does not have the impressions of the temporal muscles carried so far forward on the frontal bones and is relatively much narrower across the zygomatic arches.
Remarks.—In 1896, Merriam named M. f. saturata as a distinct species on the basis of one specimen, taken by Clark P. Streator at Siskiyou, Oregon, and a second specimen taken the year previously by Allan C. Brooks at Chilliwack, British Columbia. On the basis of these two specimens, Merriam (1896:22) ascribed to the race a range ". . . on the Cascade and Siskiyou mountains of Oregon and Washington, reaching a short distance into British Columbia." Since that time, this name, saturata, has been employed for the dark-colored weasels, of the coastal region of Oregon, Washington, and extreme southwestern British Columbia, which here are arranged under the name M. f. altifrontalis. M. f. saturata proves to be restricted to the humid mountainous region inland from the coast in northern California and in the Siskiyou Mountains of southern Oregon. Its range is separated by that of M. f. oregonensis from the range of the darker-colored, deeper-skulled, M. f. altifrontalis of the humid costal region proper.
On May 5, 1933, Mr. Clark P. Streator, informed the writer that he remembered taking the type specimen of Mustela frenata saturata (Merriam) in the town of Siskiyou, Oregon. The exact place, he said, was reached, at the time of his work there, by going one or two blocks east of the depot, then through a garden into the thick woods where there were springs and numerous burrows of the rodent, Aplodontia. Two other weasels labeled as taken at Siskiyou, on September 28 and 29, 1893, by Mr. Streator, are much lighter colored than the type of saturata and have the color of the underparts extended distally on the hind legs to the tips of the toes and in other features of coloration are more like nevadensis, the subspecies to which they are referred, than saturata. Probably these did not come from exactly the same place that the type specimen of saturata did. Although Mr. Streator does not remember the taking of these particular specimens in 1893, he does remember that on this visit to Siskiyou, he walked southward through the railroad tunnel and collected on the opposite side of the ridge from Siskiyou. Here on more southern exposures, the country was markedly different than in the thick forest at Siskiyou. Probably these two specimens taken in 1893, and referred to nevadensis, came from a little way south of Siskiyou and from a different habitat and life-zone than the type specimen of M. f. saturata.
Of the 6 specimens examined, only one, the type, shows malformation of the frontal sinuses such as result from infestation by parasites.