Type.—Male, subadult, skull and skin; no. 32019/43828, U. S. Nat. Mus., Biol. Surv. Coll.; Grants Pass, Rogue River Valley, Josephine County, Oregon; December 19, 1891; obtained by C. P. Streator; original no. 1404.
The skull (plates [19]-[21], [30]) is complete and unbroken. P3 on the left side is missing. Otherwise the teeth all are present although worn probably as a result of gnawing at the trap which captured the specimen. The skin, in brown, winter pelage, is fairly well made.
Although the label on the skin and the label in the skull vial each give the sex of the specimen as female, and although Merriam (1896:25) regarded the specimen as a female, the present writer regards the specimen as a male.
It is as large as other undoubted males and larger than any known female of this subspecies. The labels with the skull and skin give the locality as "Rogue River Valley, Oregon." The listing here of the more restricted locality, Grants Pass, is made on the basis of Merriam's (1896:25) original description of the subspecies.
Range.—Transition and Canadian life-zones along coast of northern California and southern Oregon from Humboldt County, California, north through Curry County, Oregon, thence inland, west of the Cascades, north to the Columbia River. See figures 29 and 30 on pages 221 and 314.
Characters for ready recognition.—Differs from M. f. altifrontalis in presence of frontonasal white patch, lighter color above (tone 2 to 3 of Raw Umber, pl. 301, rather than tone 4 of Brownish Drab, pl. 302, Oberthür and Dauthenay), wider extent of light color of underparts which is extended distally beyond knee, and in females, longer tooth-row which amounts to more than 38 per cent of basilar length; from M. f. munda in shorter hind foot of males which is less than 50, and in both sexes, smaller, less rugose skull (see measurements and plates); from M. f. saturata in presence of frontonasal white patch, in having color of underparts extended uninterruptedly over ankle onto foot; from M. f. nevadensis in presence of frontonasal white patch, lack of light color of underparts on ventral face of tail, and longer skull, which relative to its length in males, is shallower through braincase; from M. f. effera in presence of frontonasal white patch, lack of light color of underparts on ventral face of tail, and larger skull with basilar length averaging more than 41.7 in males; from M. f. washingtoni in presence of frontonasal white patch, shorter skull in males, which in percentage of basilar length has, on the average, orbitonasal length amounting to less than 35, mastoid breadth more than 55, and zygomatic breadth more than 63; and in females larger skull with least width of palate more than length of P4, upper tooth-rows more than 38-1/2 per cent of basilar length, bullae larger and averaging more than 13.4 long.
Description.—Size.—Male: Five males (3 adults and 2 subadults from Eureka, Ferndale, and Carlotta, California) yield average and extreme measurements as follows: Total length, 392 (347-430); length of tail, 138 (110-160); length of hind foot, 46 (43-50). Tail averages 54 (46-61) per cent as long as head and body. Length of hind foot more or less than basal length. The type specimen, and an adult from Goldbeach measure, respectively, as follows: Total length, 412, 386; length of tail, 155, 137; length of hind foot, 44, 46.
Female: Three adults (2 from Fortuna and 1 from Carlotta, California) yield average and extreme measurements as follows: Total length, 367 (360-374); length of tail, 130 (123-134); length of hind foot, 40 (39-40). Tail averages 55 (52-57) per cent as long as head and body. Length of hind foot less than basal length. A subadult from Goldbeach, an adult from 13 mi. SW Grants Pass, and an adult from Medford, measure, respectively, as follows: Total length, 316, 344, 294; length of tail, 114, 120, 122; length of hind foot, 36, 40, 38.
The average differences in external measurements of the two sexes in the vicinity of Carlotta, are: Total length, 25; length of tail, 8; length of hind foot, 6. Corresponding differences, at Goldbeach, are: 70, 23, 10. Probably the females at Fortuna reflect the large size of munda more than do the males at Carlotta and the differences between the measurements of the two sexes probably, therefore, are actually more than are indicated by the figures above.
Externals.—Longest facial vibrissae black, brown or white (often all three colors in same specimen) and extending beyond ear; carpal vibrissae same color as underparts and extending to apical pad of fifth digit; hairiness of foot-soles, in summer pelage, as shown in figure [20].
Color.—Upper parts, in summer, near (16 l) Brussels Brown or tone 2 of Raw Umber of Oberthür and Dauthenay, pl. 301, to slightly darker than tone 3 of same plate. Darker on nose and top of head, usually with frontonasal white patch but lacking white bar in front of each ear, except in the type and 2 specimens from Salem. Chin, lower lips, angle of mouth, and usually posterior seventh of upper lip white. Remainder of underparts Pale Orange-Yellow. In winter usually lighter above with underparts Warm Buff to Straw Yellow. Tip of tail at all times black. Color of underparts extends distally on posterior sides of forelegs over toes onto antipalmar faces of feet and wrists, on medial side of hind leg, typically over ankle in extremely narrow line which widens out over distal phalanges of antiplantar faces of toes but sometimes interrupted at ankle. Least width of color of underparts averaging, in twenty available specimens, 39 (27-54) per cent of greatest width of color of upper parts. Black tip of tail in five adults averaging 50 (43-60) mm. long; thus averaging longer than hind foot and 33 per cent of length of tail-vertebrae.
Skull and teeth.—Male (based on 4 adults and subadults from Eureka, Requa, Goldbeach, and Grant Pass): See measurements and plates [19]-[21], [30]. As described in Mustela frenata nevadensis except that: Weight, 3.5 (3.5-4.1) grams; basilar length, 42.9 (41.8-44.0); least width of palate more or less than medial length of P4.
Female (based on 2 adults, one from Carlotta and one from 13 mi. SW Grants Pass): See measurements and plates [34]-[36]. As described in Mustela frenata nevadensis except that: Weight, 2.4 (2.2-2.6) grams; basilar length, 37.7 and 39.5; zygomatic breadth less than distance between condylar foramen and M1 and less than distance between anterior palatine foramen and anterior margin of tympanic bulla. See under "Remarks" for additional data on variation in size of skulls of females.
The skulls of the female averages 31 per cent lighter than that of the average male.
Because there is much geographic variation between specimens here referred to oregonensis, the person who is guided by the present account should keep in mind that results, here reported, of comparisons of the skull with those of other races, were obtained by employing specimens of oregonensis from Carlotta and Eureka, California. These specimens from California are judged to have more of the characters of the subspecies munda than do specimens of oregonensis from more northern localities.
Compared with that of M. f. washingtoni the skull of the male is shorter, especially in the preorbital region and is relatively broader across the mastoidal processes and zygomatic arches. The skull of the female is longer in the preorbital region, has a less cylindrical braincase and differs less from the male skull than is the case in M. f. washingtoni. Compared with M. f. effera, the skull of the male is smaller in every part measured and relative to the basilar length is broader across the mastoids and has relatively shorter tympanic bullae. From M. f. nevadensis the skull of the male differs in the same way except that size is about the same. The skull of the female oregonensis is more heavily ridged and is relatively broader across the mastoids than that of effera. From M. f. saturata, oregonensis is not surely known to differ in cranial characters. From M. f. munda, oregonensis differs in having the skull of both sexes smaller, and on the average, in all parts measured, has a less marked postorbital constriction, relatively narrower interorbital region and relatively more expanded zygomata. From M. f. altifrontalis, males of oregonensis differ on the average, in having larger teeth, and relative to the basilar length, a greater mastoid breadth and a shallower braincase as measured at the anterior margin of the basioccipital. Females of oregonensis differ in larger average size of skull, except for breadth of rostrum and interorbital breadth which, therefore, are relatively less in oregonensis, as also is the relative depth of the skull measured at the posterior borders of the upper molars and at the anterior margin of the basioccipital. However, skulls of females of oregonensis have relatively longer tooth-rows and are relatively broader across the zygomata and mastoidal processes.
Remarks.—In 1896, Merriam named oregonensis as a subspecies of the California bridled weasel on the basis of a single specimen taken by Clark P. Streator. Three additional specimens were acquired in later years, by workers of Dr. Merriam's bureau, from near the type locality and specimens from farther north in Oregon have been accumulated at the University of Oregon. The most satisfactory material is that saved from Humboldt County by the late H. E. Wilder, which, when brought together, is adequate to give some idea of the range of variation that can be expected in a given population.
Of two specimens from Goldbeach, one shows approach to altifrontalis in that the color of the underparts stops at the ankle, and in one, the angle of the mouth is dark colored. Specimens from Eugene and vicinity lack the white facial markings, and in this feature approach the adjoining washingtoni-effera-nevadensis stock. A specimen from 6 miles south of Medford shows approach to saturata in the interruption, on the ankle and lower tibial region, of the color of the underparts. One adult female, no. 1413, Univ. Oregon, from the Rogue River Valley, 13 miles southwest of Grants Pass, stands out prominently, among the other specimens from extreme southern Oregon and northwestern California, by reason of the near (18) Apricot Yellow color of the underparts, but this same color occurs in specimens from the more northerly localities of Buchanan, Eugene, Vida Fish Hatchery, and McKenzie Bridge, as well as in no. 2178, Univ. Oregon, from Cresent Lake. The last mentioned specimen is here referred to nevadensis.
Two females referred to oregonensis from southern Oregon differ so greatly in size of skull that they challenge one's imagination in any attempt to provide an explanation for so wide a range of variation in one subspecies. One of these, no. 244520, U. S. Nat. Mus., is an adult female from Medford. The other, no. 224034, U. S. Nat. Mus., is a subadult female (though labeled male) from 43 miles northeast of Grants Pass. The skull of the adult from Medford has a basilar length of 41.5, upper tooth-rows, 16.1 in length, and a weight of 2.75 grams, whereas corresponding figures for the subadult are only 33.8, 12.9, and 1.4. Two other adult females are intermediate in size: No. 1413, Univ. Oregon, from 13 miles southwest of Grants Pass, Oregon, approaches the specimen from Medford in size, and the second specimen, no. 34325, Mus. Vert. Zoöl., from Carlotta, California, is smaller.
Not only is there a difference in length between the skulls of the two extremes of the females but this difference extends to all other dimensions of their skulls, and is most pronounced in the preorbital region. The differences in breadth of the braincase and other parts of the skull are relatively less than the differences in length. Differences of the same nature, although of lesser degree than found in the females, are to be seen in two males. The skull of an adult no. 51590, Mus. Vert. Zoöl., from 6 miles south of Medford, has a basilar length of 46.4, upper tooth-rows, 17.6 mm. long, and a weight of 4.0 grams, whereas corresponding figures for the subadult type specimen from Grants Pass, are only 43.0, 16.2, and 3.3.
The wide range of variation in size of skull of both sexes, together with the considerable variation in color pattern of the specimens here referred to oregonensis raises the suspicion that we are using the name in a composite sense; nevertheless, to recognize more than one subspecies with the material now available would be unwise.