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American Weasels · E. Raymond Hall — chapter 69 of 157 · ~2,025 words · public domain

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Several specimens of the smaller, inland variant (see under "Remarks") are near (l) Antique Brown rather than near (14 l) Sudan Brown above and hence do not differ in this respect from nigriauris.

Skull and teeth.--Male (based on 3 adults from Mendocino County): See measurements and plates 19-23, 30. As described in Mustela frenata nigriauris except that: Weight, 6.0 (5.4-6.3) grams; basilar length, 47.6 (46.5-48.2); length of tympanic bulla more than length of lower molar and premolar tooth-row.

Female (based on no. 19723, M.V.Z., from Point Arena): See measurements and plates 34-36, 40. As described in M. f. nigriauris except that: Weight, 3.0 grams; basilar length, 42.3.

The skull of the female is 50 per cent lighter than that of the average male.

Compared with the skull of the male of nevadensis that of munda averages larger in every part measured and specimens from Point Arena are nearly as heavy again, have relatively more expanded zygomata and mastoid processes but are relatively narrower anteriorly as shown by the breadth of the rostrum, interorbital breadth and postorbital breadth. Also the braincase is less inflated anteriorly, the tympanic bullae are lower and the skull is more angular. Females show the same differences although in different degree. Compared with the skull of the male of M. f. nigriauris, that of munda from Point Arena averages larger in every part measured except for the length of the upper tooth-rows. Relative to the basilar length, the skull of munda averages broader across the mastoids and across the zygomata, is deeper through the braincase at the anterior end of the basioccipital, and has a greater development of the lambdoidal crest.

Remarks.--The skin and part skull, no. 536/1849, U. S. Nat. Mus., taken by Lieutenant W. P. Trowbridge at San Pablo Bay, is the first specimen known to have been saved of this subspecies. Since 1899 when O. Bangs diagnosed munda as of small size, the weasel of the humid costal belt north of San Francisco Bay has been regarded as smaller than bridled weasels from farther south in the State. Actually, however, the weasel of the humid costal belt shares with M. f. pulchra the distinction of being one of the two largest weasels in California.

M. f. munda may be a composite subspecies, for the variation in facial markings, in coloration otherwise, in external measurements and in size and shape of skull is great. At one time in the course of the present study, manuscript accounts of two subspecies were prepared for the animals now all called munda and there is still much justification for recognizing two subspecies, one, along the coast proper, the larger, darker-colored animal with reduced white facial markings and large, wide, heavily ridged skull from Point Arena, and 6 miles south of Laytonville, Mendocino County, along with the specimens from 5 and 6 miles west of Inverness, Marin County, and the other, an inland race, which is a smaller, lighter-colored animal with more extensive white facial markings and a smaller, narrower, skull, known by specimens from Point Reyes [station?], Nicasio, 15 mi. north of San Rafael, Freestone, Vallejo, and Mount Sanhedrin. The differences between these two lots of specimens are of great degree. However, a female from Fort Bragg proves to be no larger than three females labeled as from Point Reyes. Also, a male from 2 miles south and one mile east of Stewarts Point on the coast has a skull no larger than the animal from Vallejo, whereas the skin alone of an adult female from 3 miles south of Stewarts Point is large and agrees with the specimens from Point Arena. Consequently, no logical ranges can be worked out for the two variants with the material now available.

Finally, the type specimen of munda is a "runt," smaller than any other male seen. This specimen, purchased by E. A. and O. Bangs from C. A. Allen, who collected and sold specimens widely, was labeled as from Point Reyes. So far as this place-name is concerned, it might refer to: (1) The point of land by that name which projects out into the Pacific Ocean, (2) an abandoned ranch house bearing that name at the head of Drakes Bay, 6 miles north and 3-3/4 miles east of the actual point, or (3) the railway station by the same name at the head of Tomales Bay, 12 miles east and 4-3/4 miles north of the actual point. Allen, himself, lived near San Geronimo (then Nicasio) about nine miles southeast of the Point Reyes railway station. All these places are in Marin County, but differ markedly as regards climate and flora. The first two are treeless, windswept and have much fog, whereas Point Reyes Station is more often sunny, and is situated in a shallow valley, inland, where the open grass-covered west-facing slopes meet the east-facing wooded ones. From which one of these three places the type specimen came, I do not know. The same may be said of the three female specimens labeled Point Reyes; two of these are in the United States National Museum and one in the Field Museum.

The specimens in the Museum of Vertebrate Zoölogy from 5 and 6 miles west of Inverness and those from near the same place in the collection of John Cushing come from within a couple of miles or less of the Point Reyes represented by the abandoned ranch house. These specimens, as remarked above, agree with those from Point Arena in large size, reduced facial markings and wide skull. These are points of difference from the smaller variant suspected of being a recognizable subspecies. It is the smaller variant which the type specimen approaches in size, and with which it agrees in relatively well-developed white facial markings. This suggests that the type specimen came from Point Reyes Station rather than from either of the two other places bearing the name "Point Reyes," from one of which, as just stated, the variant of large size is known. The three females labeled "Point Reyes" also have well-developed white facial markings and are of lesser size than the female of similar age from Point Arena, Mendocino County. The presumption is that these three females also came from Point Reyes Station.

The smaller, inland variant seems to agree in size, cranial characters, and coloration with M. f. nigriauris to the southward of San Francisco Bay, but lacks the black on the head which characterizes nigriauris. The larger variant, on which the description here used for munda is based, comprises animals which differ from nigriauris in larger size, darker color, reduced white facial markings, and larger, relatively wider skull. Both of the variants mentioned above are sharply distinct from nigriauris on the basis of coloration of the inside of the ear which is blackish in nigriauris like the dark facial markings, and in munda is colored like the back. M. f. munda lacks the dark facial markings; an occasional specimen has at most, a trace of the markings but this does not extend back so far as the ears. This difference, blackish versus non-blackish face, persists eastward of San Francisco Bay to at least as far as the Carquinez Straits, where a specimen of munda is available from 4 miles north of Vallejo and one of nigriauris from Glen Frazer Station on the south shore opposite Vallejo.

Intergradation with M. f. nevadensis and possibly with M. f. saturata is indicated by specimens from South Yolla Bolly Mountain, Trinity County. In them the external measurements and measurements of the skull are intermediate. Also the white frontal spot is much reduced in size. The white bars in front of the ears are absent in three specimens, and weakly developed in the other two. The relative proportions of the skulls as a whole are nearer those of nevadensis or saturata than munda. The skull of one of the three adult males and the skull of the adult female suggests M. f. oregonensis in certain features; for example, the dorsal outline of the skull in longitudinal axis is slightly convex as it is in oregonensis.

None of the specimens shows malformation of the frontal sinuses such as results from infestation by parasites.

Specimens examined.--Total number, 37, arranged by counties from north to south. Unless otherwise indicated specimens are in the Museum of Vertebrate Zoölogy.

=California.= Trinity County: S. Yolla Bolly Mt., 3; 1/2 mi. S S. Yolla Bolly Mt., 1. Tehama County: 2 mi. S S. Yolla Bolly Mt., 1. Mendocino County: 6 mi. N Laytonville, 1; Mt. Sanhedrin, 1; Ft. Bragg, 1; Gualala, 1; Point Arena, 5. Sonoma County: 2 mi. S and 1 mi. E Stewarts Point, 1; 3 mi. S Stewarts Point P. O., 1; Freestone, 1. Napa County: 6 mi. SSW, Napa, 1; 4 mi. N Vallejo, 1. County in question: San Pablo Bay, 1. Marin County: 6 mi. W Inverness, 2; 5 mi. W Inverness, 2(1); Point Reyes, 4 (2 1, 1); Nicasio, 2 (1, 1); Kehoes Ranch, Pierce Point, 1; Drakes Bay, 1; Tomales Point, about 1/2 mi. SW White Gulch, 1; Point Reyes School, 3-3/4 mi. W Inverness, 1; 15 mi. (by road) N San Rafael, 1; Hurley Ranch, 2 mi. W Tomales, 1. No locality more definite than California, 1.

=Mustela frenata xanthogenys= Gray

Long-tailed Weasel

Plates 21, 22, 23, 28, 30, 34, 35 and 36

Mustela xanthogenys Gray, Ann. and Mag. Nat. Hist., 11:118, 1843.

Putorius (Gale) brasiliensis frenatus, Coues, Fur-bearing animals, p. 142, 1877 (part).

Putorius xanthogenys, Merriam, N. Amer. Fauna, 11:25, June 30, 1896; Bangs, Proc. New England Zoöl. Club, 1:56, June 9, 1899.

Mustela xanthogenys xanthogenys, Miller, U. S. Nat. Mus. Bull., 79:99, December 31, 1912.

Mustela frenata xanthogenys, Hall, Carnegie Instit. Washington Publ. 473:107, November 20, 1936.

Type.--Male, adult, skull and skin; skull no. 197a-43.6.4.55, skin no. 234a-42.11.21.4, British Museum (Nat. Hist.); from the bank of Sacramento River below mouth of Feather River, or from north shore of San Francisco Bay, California; taken in "1837 or 1838"; presented by Captain Edward Belcher.

The skull (plate 28) lacks the occiput, the right mandible posterior to m1, and the right pterygoid; the right zygomatic arch is fractured. The teeth are not greatly worn. The skin was originally mounted for exhibition (R. I. Pocock in Litt.) but in 1937 when I saw the skin, it was prepared as a conventional study skin. The skin is in fairly good condition; some hair is missing on the hind quarters and the skin of the tail is torn at one place.

Range.--Altitudinally, less than 600 feet (Fair Oaks); Lower Sonoran and Upper Sonoran life-zones of all but southern end of the San Joaquin Valley, and probably Sacramento Valley, California. See figures 29 and 30 on pages 221 and 314.

Characters for ready recognition.--Differs from M. f. nevadensis by presence of light facial markings and Buckthorn Brown rather than near (14n to l) Brussels Brown color of upper parts; from M. f. munda by Buckthorn Brown rather than near (l) Sudan Brown, or near (l) Antique Brown color of upper parts and lesser size, in adult males basilar length less than 45 and hind foot less than 47; from M. f. nigriauris by lighter color in same way as from munda and also by having inside of ears same color as back rather than much darker than back; from M. f. pulchra in hind foot of males less than 46 and narrower skull, in males having breadth of rostrum less than 13.9 and mastoid breadth less than 26.0, see comparison of skulls in the account of pulchra.

Description.--Size.--Male: Three adults, from Fresno, Selma and Los Banos, measure, respectively as follows: Total length, 425, 417, 450; length of tail, 152, 154, 180; length of hind foot,--, 43, 44. Tail averages 61 per cent as long as head and body. Length of hind foot less than basal length.

Female: Adults from Selma, Los Banos, and 4 mi. SW Turlock, measure respectively as follows: Total length, 357, 365, 395; length of tail, 133, 132, 145; length of hind foot, 40, 38, 41. Tail averages 58 per cent as long as head and body. Length of hind foot less than basal length.

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