Plate [30]
Mustela affinis Gray, Ann. and Mag. Nat. Hist., 14(ser. 4):375, 1874.
Putorius (Gale) brasiliensis frenatus, Coues, Fur-bearing animals, p. 142, 1877 (part).
Putorius affinis, Merriam, N. Amer. Fauna, 11:31, June 30, 1896.
Mustela affinis affinis, Allen, Bull. Amer. Mus. Nat. Hist., 35:100, April 28, 1916; Allen, Bull. Amer. Mus. Nat. Hist., 35:220, May 31, 1916.
Mustela frenata affinis, Hall, Carnegie Instit. Washington Publ. 473:110, November 20, 1936; Hall, Physis, 16:175, 1939.
Type.—Male, adult, skull with skin; no. 54.1.11.3 (skull originally numbered 195d, later 54.6.3.4), Brit. Mus. Nat. Hist.; Colombia [given as new Granada in original description]; purchased from Mr. S. Stevens. Type locality restricted by Allen (1916:99) to Bogotá, Colombia.
The skin is in a good state of preservation and has been made over into a conventional study specimen from a mount on exhibition. Exposure to light when mounted probably accounts for the faded color. The skull (plate [30]) lacks the middle 9 mm. of the right zygomatic arch, occiput, basioccipital and posterior two-thirds of the left tympanic bulla. The teeth all are present and entire.
Range.—Four thousand six hundred feet (Quetame) to 9154 feet (El Carmen), Tropical to Temperate life-zones of eastern Andes of Colombia. 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, by presence of p2 and by two roots rather than one root on P2; from M. frenata meridana, in case of males, by, on average, greater breadth and length of skull and lesser actual and relative size (see measurements) of facial part of skull; from M. f. aureoventris by lighter-colored upper parts (tone 2 rather than tone 4, pl. 344, Reddish Black of Oberthür and Dauthenay); from M. f. macrura by darker color (Reddish Black, tone 2, pl. 344, Ober. and Dauth., rather than Chocolate, tone 3, pl. 343, Ober. and Dauth.).
Description.—Size.—Male: Measurements in life, estimated from dried skins, are: Total length, 455; length of tail, 175; length of hind foot, 52. Proportions of parts supposedly as described in Mustela frenata meridana.
Female: Estimates from two dried skins: Total length, 365; length of tail, 135; length of hind foot, 43. Proportions of parts supposedly as described in Mustela frenata meridana.
The estimated differences in external measurements of the two sexes are: Total length, 90; length of tail, 40; length of hind foot, 9.
Externals.—As described in Mustela frenata meridana.
Color.—As described in Mustela frenata panamensis except that: posterior fourth of each upper lip and spot in front of each ear white in approximately half of the specimens; black of head proper not extending back of ears and grading insensibly into color of upper parts; upper parts near (n) Bay, or tone 2 of Reddish Black (pl. 344, Oberthür and Dauthenay). Least width of color of underparts (in five males from vicinity of Bogotá) 24 (15-29) per cent of greatest width of color of upper parts. Black tip of tail, in same series, 60 to 75 mm. long, thus longer than hind foot and averaging 38 per cent as long as tail-vertebrae.
Skull and teeth.—Male (based on three adults and two subadult topotypes): See measurements and plate [30]. As described in Mustela frenata meridana except that: Weight, 4.5 grams (estimated); basilar length 45.8±; interorbital breadth not greater than distance between foramen opticum and anterior margin of tympanic bulla (type as in meridana where interorbital breadth is more than distance between foramen opticum and anterior margin of tympanic bulla); least width of palate not less than length of P4; masseteric fossa confined to posterior two-fifths (38 to 40 per cent; average 39 per cent) of mandible and not extended anteriorly to middle of m2.
Female: No adults examined.
As compared with M. f. meridana the skull of the male is larger, to the average amount of 2.2 mm. in basilar length and 1.2 mm. in zygomatic breadth of adults; length of tooth-rows and mastoid breadth average greater but relatively less; breadth of rostrum, interorbital breadth and orbitonasal length average actually and relatively less. Thus the skull of affinis is longer and broader, but the facial region is actually, as well as relatively, smaller. As compared with the skull of the male of M. f. aureoventris, that of M. f. affinis is about the same in basilar length. However, in no specimen of affinis are the measurements of length of tooth-rows or breadth of rostrum, actually, or relatively, as great as in aureoventris. The same is true of all measurements taken of M1, P4 and m1. The specimens from the vicinity of Quito and north of there, although referred to macrura, are nearly as dark as typical affinis, approach affinis in cranial characters, and indicate intergradation of affinis with macrura.
Remarks.—Mustela affinis was named by John Edward Gray in 1874 (p. 375) on the basis of a specimen from New Granada. Although usually synonymized with Mustela brasiliensis by later authors until 1896 when Merriam (1896:31) applied the name to weasels from Costa Rica, nearly all the South American and several of the Central American weasels have, at one time or another, had Gray's name, affinis, applied to them. Gray, in 1865 (p. 115) when giving measurements of Mustela aureoventris, probably mentioned the specimen, that later became the holotype. In 1916 (p. 98) Allen restricted the type locality to Bogotá, Colombia. Allen's action was a necessary procedure in clearing up the systematics of South American weasels and was based on good grounds. As set forth by Allen (loc. cit.), and more in detail by Chapman (1917:642), Bogotá has long been the shipping point for Colombian vertebrate specimens, many of which were obtained in the mountains to the east. Allen (1916A:220) quotes Thomas as saying that the type specimen was purchased from Stevens at about the same time that a number of Colombian birds were purchased from the same dealer. Also, specimens from Bogotá agree with Gray's description of the type specimen.
Mustela frenata affinis, as here defined, constitutes one of the several slight geographic variants met with, on the sides of, and between, the three north and south mountain chains of Colombia. The others are lumped under the name Mustela frenata meridana. M. f. affinis, in common with specimens from the northern part of the range of macrura has large teeth. Weasels of all of the region from Quito to Bogotá have large teeth. To the north there is the smaller-toothed meridana and to the south the smaller-toothed macrura grading into the still smaller-toothed agilis, and boliviensis.
Two skins, without corresponding skulls, from Caqueta are lighter colored than any others of affinis; possibly the skins are faded by exposure to light. Since they probably come from an elevation of less than 1000 feet in the Amazonian region, they may pertain to another subspecies.
Complete, unbroken, skulls of affinis are needed to ascertain the degree to which affinis and meridana differ in cranial features. The several specimens from the immediate region of Bogotá show well the color and the color pattern but lack collectors' measurements.