Long-tailed Weasel
Mustela frenata boliviensis Hall, Proc. Biol. Soc. Washington, 51:67, March 18, 1938.
Mustela frenata macrura, Hall, Carnegie Instit. Washington Publ. 473:110, November 20, 1936; Hall, Physis, 16:176, 1939 (part).
Type.—Male, adult, skull and skin; no. 72587, Amer. Mus. Nat. Hist.; Nequejahuira, 8000 feet, Bolivia; May 19, 1926; obtained by G. H. H. Tate; original no. 4135 (see plates [28]-[30]).
Range.—As now known 8000 to 9500 feet in the Andes from Limbaní, Perú, south to Nequejahuira, Bolivia; upper Subtropical and Temperate life-zones. See figure [29] on page [221].
Characters for ready recognition.—Differs from Mustela africana stolzmanni by absence of median, longitudinal, abdominal stripe of same color as upper parts; presence of p2 and two roots rather than one root on P2; from Mustela frenata macrura by darker color of upper parts (tone 4 or darker of Carbon Brown, pl. 342 rather than tone 3 of Chocolate, pl. 343, Oberthür and Dauthenay) and lesser size (in males hind foot less than 45 and m1 less than 5.6); from Mustela frenata agilis by darker color of upper parts (as given above rather than tone 2 of Chocolate, pl. 343, of Oberthür and Dauthenay).
Description.—Size.—Male: The type and two young specimens from Limbaní, Perú, measure respectively, as follows: Total length, 383, 368, 304; length of tail, 140, 132, 115; length of hind foot, 43, 44, 41. Tail 55 per cent as long as head and body. Length of hind foot approximately equal to basal length.
Female: Unknown.
Externals.—As described in Mustela frenata macrura.
Color.—Top of head blackish posteriorly to behind ears; upper lips same color as upper parts of head; dark area at angle of mouth not separated from upper parts as a distinct spot; tip of tail black; remainder of upper parts near (n) Mars Brown of Ridgway and tone 4 or darker of Carbon Brown (pl. 342, Oberthür and Dauthenay); underparts Cream-Colored with strong wash of Ochraceous-Buff; whitish on insides of forelegs to just below elbow; color of underparts extended distally on forelegs over ankles onto antipalmar faces of inner toes, and on hind legs to knees. Least width of color of underparts averages 15 (11-19) per cent of greatest width of color of upper parts. Black tip of tail in type longer than hind foot and amounting to 36 per cent of length of tail-vertebrae.
Skull and teeth.—Male (based on the type): See measurements and plates [28]-[30]. As described in Mustela frenata macrura except that: Weight, 2.8 grams; basilar length, 41.6; zygomatic breadth less than distance between anterior palatine foramen and anterior margin of tympanic bulla; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 5 upper incisors.
Female: Skull unknown.
Remarks.—Apparently the first specimens of this race to find their way into a zoölogical collection were the two young males taken on February 17, 1904, at Limbaní, by Geo. Ockenden [sic.].
M. f. boliviensis is smaller than any other South American weasel except possibly agilis. Better material of the two races probably will show even agilis to be larger.
Early in my study of Mustela after examination of the one young specimen, from Limbaní, in the United States National Museum, an account of this race was drawn up, but the account was discarded for want of satisfactory material and the animal was referred to macrura. Then, in 1937, when the two other specimens were studied, the race was formally characterized as different from previously recognized kinds.
The collector has noted on the labels of the two young from Limbaní that they were shot in the afternoon when running together beneath bushes. The frontal sinuses of the type are malformed as a result of infestation by parasites.