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American Weasels · E. Raymond Hall — chapter 65 of 157 · ~1,583 words · public domain

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Compared with M. f. nevadensis, the skull of the male of washingtoni averages more slender, as shown by the mastoid and zygomatic breadths and has the preorbital part longer, on the average, as shown by the greater ratio (to the basilar length) of the length of the tooth-rows and orbitonasal length. Also, on the average, the postorbital constriction is longer than in nevadensis and the tympanic bullae are smaller. In females, the skull is lighter, the tooth-rows are shorter, the tympanic bullae are smaller, and the preorbital part of the skull is shorter and narrower as shown by the orbitonasal length and interorbital breadth. Except that the tympanic bullae are actually, although not relatively, smaller in males of effera, it differs from washingtoni in the same way as does nevadensis as regards relative proportions, but, of course, the actual difference in size is greater since effera is smaller than nevadensis. Comparison of the skull with that of oregonensis is made in the account of that subspecies.

Remarks.--M. f. washingtoni was described and named in 1896 by Merriam as a distinct species. Subsequently, specimens which here are regarded as intergrades between altifrontalis and nevadensis, were classified as washingtoni.

The external measurements given for the specimens from Mount Adams are those recorded on the labels in inches and fractions thereof. Instead of total length there sometimes is written "tip to tip." In the series of 19 winter-taken topotypes the hairs project beyond the end of the caudal vertebrae for an average distance of 28 (19-40) millimeters. If the hairs on the end of the tail were included in the measurements, 28 millimeters should be subtracted from the averages. Probably the measurements should stand as given, since an adult male topotype, no. 226758, U. S. Nat. Mus., taken subsequently by Walter P. Taylor measures 405; 152; 51.

Mustela frenata washingtoni is not a strongly marked geographic race. In many features it is intermediate between M. f. altifrontalis and M. f. nevadensis. This is especially true of coloration. In the series from Mount Adams and that from Mount Rainier, some individuals have the light color of the underparts extended down the hind legs over the feet and over the proximal face of the ventral third of the tail as in nevadensis, whereas others from the same place have the light color of the underparts absent from the tail and extending no farther down the hind limbs than the knees. The light color of the underparts in the series of topotypes is so restricted that the transverse extent at the narrowest place amounts to only 24 (10-37) per cent of the greatest width of the color of the upper parts. This narrowness of the color of the underparts has been likened by Merriam (1896:18) to the condition in Mustela frenata noveboracensis. So it is, but it is similar to the condition found also in the geographically adjoining M. f. altifrontalis.

Of the 37 skulls of subadults and a few adults, 11 had the frontal sinuses malformed as a result of infestation by parasites.

Specimens examined.--Total number, 56, arranged within each state by localities from north to south. Unless otherwise indicated specimens are in the collection of the United States National Museum.

=Oregon.= Mt. Jefferson, Permilia Lake, 1.

=Washington.= Pierce County: 5500 ft., Spray Park, Mt. Rainier, 1; Spray Park, 1; 5935 ft., Glacier Basin, Mt. Rainier, 5 (1); 5051 to 5100 ft., Owyhigh Lakes, Mt. Rainier, 7 (1), Tahoma Creek, 1; Nisqually entrance, 1; Longmire, 1; Mt. Rainier Nat'l Park, 2. Klickitat County: Trout Lake, S Base Mt. Adams, 35; 3500 ft., Gotchen Creek, Mt. Adams, 1.

=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.

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