Long-tailed Weasel

Plates [22], [23], [24], [34], [35], [36] and [41]

Mustela frenata nigriauris Hall, Carnegie Instit. Washington Publ. 473:95, November 20, 1936.

Putorius xanthogenys, Baird, Mamm. N. Amer., 1858, p. 176 (part).

Mustela xanthogenys Gray, Ann. and Mag. Nat. Hist., 14(ser. 4):375, 1874 (part?).

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

Putorius xanthogenys xanthogenys, Grinnel, Proc. California Acad. Sciences, fourth series, 3:292, August 28, 1913.

Mustela xanthogenys xanthogenys, Miller, U. S. Nat. Mus. Bull., 79:99, December 31, 1912; Grinnell, Univ. California Publ. Zoöl., 40:102, September 26, 1933.

Type.—Male, adult, skeleton and skin; no. 32820, Mus. Vert. Zoöl.; Half Moon Bay, San Mateo County, California; received at Museum of Vertebrate Zoölogy, May 4, 1922, through A. L. Hagedoorn, after having been in captivity a few days where death occurred owing to injuries received in trap; original no. 1590.

The skull has each of the zygomatic arches and the anterior end of the nasals broken through. The only part missing is the central two millimeters of the left zygomatic arch. The teeth all are present and entire. The skeleton appears to be complete except for the bones of the feet, which are preserved within the skin. The skin is well made and in good condition.

Range.—Altitudinally, sea level to more than 4000 feet; Sonoran and Transition life-zones of Coast Range and coast of California from San Francisco Bay south to Point Conception, Santa Barbara County, California. See figures [29] and [30] on pages 221 and 314.

Characters for ready recognition.—Differs from M. f. munda, xanthogenys, and pulchra by having inside of ears darker than back rather than same color as back, and from xanthogenys and pulchra in near (l) Antique Brown color of upper parts rather than Buckthorn Brown or near (16 j) Buckthorn Brown to near (h) Yellow Ocher respectively; from M. f. latirostra by postorbital breadth, of adult males and females, less, rather than more, than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite.

Description.—Size.—Male: Five adults from Palo Alto, Santa Clara County, yield average and extreme measurements as follows: Total length, 447 (412-465); length of tail, 167 (147-175); length of hind foot, 46 (45-47). Corresponding measurements of four adults from San Francisco are: 412 (394-435); 153 (145-160); 43.5 (41-46). Corresponding measurements of five adults and subadults from Berkeley, Alameda County, are: 419 (390-448); 148 (135-160); 44 (42-47). Tail averages 59 per cent as long as head and body in series from Palo Alto and in one from San Francisco. The average of 55 for the Berkeley series probably reflects a lesser average age. Length of hind foot less than basal length. The type specimen measures, 415, 150, 43. It is smaller than the mean.

Female: A subadult from Palo Alto measures: Total length, 368; length of tail, 126; length of hind foot, 39. An adult and two subadults from Berkeley measure, respectively, as follows: Total length, 347, 365, 340; length of tail, 134, 123, 125; length of hind foot, 37, 38.4, 36.5. In these four females the tail averages 55 per cent as long as head and body. Length of hind foot less than basal length.

The average differences in external measurements of the two sexes, as represented by specimens from Berkeley, Alameda County, are: Total length, 68; length of tail, 21; length of hind foot, 7. Eight adult males weigh 249 (217-335) grams and one adult female 123 grams.

Externals.—Longest facial vibrissae brownish like dark color of head and extending beyond ear; carpal vibrissae mostly color of underparts and extending to apical pad of fifth digit; hairiness of foot-soles slightly more than shown in figure [20].

Color.—Spot between eyes, band, confluent with color of underparts, on each side of head extending anterodorsally anterior to ear, and posterior third of each upper lip tinged with color of underparts or, less often, pure white; chin and lower lips white; remainder of sides and top of head posteriorly to, or a little behind, a line connecting posterior margins of ears, blackish; inside of pinna of ear, and sometimes outside of pinna, blackish; dark spot posterior to each angle of mouth present on each side in three-fourths of specimens; tip of tail black; remainder of upper parts near (l) Antique Brown, and with more yellow than tone 3 of Raw Umber of Oberthür and Dauthenay, pl. 301. Often with more blackish and red in winter. Underparts near (a to c) Ochraceous-Buff or Ochraceous-Salmon. Ochraceous-Salmon in some juveniles. 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 limbs over antiplantar faces of toes. Least width of color of underparts averaging, in 17 adult males (Berkeley, 5; San Francisco, 5; Palo Alto, 7), 55 (40-73) per cent of greatest width of color of upper parts. Black tip of tail in same series of males averaging 51 (35-60) mm., thus averaging longer than hind foot and 33 per cent of length of tail (Palo Alto and San Francisco, 31 per cent; Berkeley, 35 per cent). In 8 adult females, least color of underparts amounts to 55 (47-62) per cent of greatest width of color of upper parts. Black tip of tail averages 41.5 (28-50) mm., thus averaging longer than hind foot and 32 per cent of length of tail-vertebrae.

Skull and teeth.—Male (based on six adults from Stanford Univ. and vicinity): See measurements and plates [22]-[24]; weight (four adults), 5.4 (5.0-5.9) grams; basilar length, 47 (46.1-48.1); zygomatic breadth more than distance between condylar foramen and M1, or than between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth more than postpalatal length; postorbital breadth less than length of upper premolars (less than distance between posterior borders of P4 and P2) and less than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth not greater than distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum less than length of tympanic bulla; least width of palate less than lateral length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 3 or 4 (including I3) upper incisors; height of tympanic bulla more than distance from its anterior margin to foramen ovale; length of tympanic bulla more or less than (about equal to) length of lower molar and premolar tooth-row and longer or shorter (usually shorter) than rostrum; anterior margin of masseteric fossa below anterior half of m2.

Female (based on three adults, Hayward, Palo Alto, and Morro): See measurements and plates [34]-[36]; weight (no. 43574, from Morro) 2.7 grams; basilar length, 41.2 (40.2-42.2); zygomatic breadth more or less than distance between condylar foramen and M1 and more or less than distance between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth less than length of upper premolars and less than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate less than lateral length of P4; tympanic bulla as far posterior to foramen ovale as width of 3 (including I3) upper incisors; height of tympanic bulla more than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer or shorter than rostrum.

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

Comparisons of the skull of the male with those of M. f. latirostra, pulchra, xanthogenys, and munda are made in the accounts of those subspecies.

Remarks.—Like M. f. latirostra, nigriauris long bore the name xanthogenys. The fairly adequate lot of specimens is divided between the collections of several institutions. The most satisfactory material in any one collection is in the Stanford University Natural History Museum where local specimens have been accumulated over a period of many years.

No actual intergrade between nigriauris and xanthogenys has been seen, although the specimens from Los Banos, referred to xanthogenys, have large skulls as in nigriauris. Intergradation with latirostra is shown by specimens, referred to latirostra, from the Los Angeles area. Also the one adult male from 5 miles southeast of Santa Margarita, San Luis Obispo County, is of small size and in this respect approaches latirostra. The range of nigriauris is separated from that of munda by San Francisco Bay, Carquinez Straits, and I suppose by the lower part of the San Joaquin River. On the basis of color of the inside of the pinna of the ear, the two subspecies are uniformly distinct. Intergradation is assumed to occur through the subspecies xanthogenys.

None of the 26 adult and subadult specimens examined for evidences of infestation of the frontal sinuses by parasites shows malformation of the sinuses.

Specimens examined.—Total number, 103, arranged by counties from north to south. Unless otherwise indicated specimens are in the Museum of Vertebrate Zoölogy.

California. Contra Costa County: Glen Frazer Station, 1; 2 mi. W Pinole, 1[13]; 1 mi. E Pinole, 1; Richmond, 1[13]; Lafayette, 1; 7 mi. E Clayton, 1; Moraga Valley, 1; Pinehurst, Redwood Canyon, 1; Concord, 1. Alameda County: Berkeley, 11; Oakland, 1; Piedmont, 1; Haywards, 2; near Haywards, 2; 10 mi. E Haywards, 1[91]; Redwood Canyon, 1; Calaveras Dam, 1. San Francisco County: San Francisco, 11 (5[8], 2[91], 1[60], 1[7]); Ocean View, 1[68]; Visitation Valley, 1. San Mateo County: Moss Beach, 1; Half Moon Bay, 1; Redwood City, 1[87]; Menlo Park, 9 (5[87], 2[68]); no locality more definite than county, 1[8]. Santa Clara County: 1/4 mi. N Milpitas, 1; 1/4 mi. S Milpitas, 1; Stanford University, 6 (4[68], 2[91]); Palo Alto, 11 (6[41], 2[60], 1[75], 1[87]). Santa Cruz County: 3 mi. E Santa Cruz, 1; 2-1/2 mi. E Santa Cruz, 1; Santa Cruz, 6 (2[91], 1[68], 1[4]). Monterey County: 1 mi. E mouth Salinas River, 10 ft., 1[37]; Pacific Grove, 1[8]; Monterey, 2 (1[7]); Carmel, 1[8]; Carmel Valley, 1[68]; Point Lobos, 1; Gonzales, 1. San Luis Obispo County: 5 mi. SE Santa Margarita, 1; Morro, 1[91]; 3-1/2 mi. S Oceano, 6. Santa Barbara County: Santa Maria, 1[87]; 5 mi. N Las Cruces, 1; 7 mi. W Gaviota, 1; Gaviota, 1.