M. f. costaricensis is well differentiated from M. f. nicaraguae and M. f. goldmani which occur to the northward and from M. f. panamensis which occurs to the southward and is a large, heavy-skulled, dark-colored animal with white facial markings restricted or absent. In the type specimen and the female from the Candelaria Mountains the white facial markings are only narrow facial bars or a few white hairs, but in the young male from Cervantes there is a well developed bar 6 millimeters wide on each side of the face and a separate nasofrontal spot, 10 x 12 mm. The young female from Cachí has a V-shaped frontonasal spot, on the right side of the face a white bar 5 mm. wide and 17 mm. long connected with the color of the underparts, and on the left side a white spot in front of the ear and another between the ear and eye. White facial markings were not recorded in the other specimens. The color of the upper parts is only a little less dark than those of M. f. panamensis. Owing to the numerous white hairs on the dorsal side of the neck, the nape of the female from the Candelaria Mountains has a frosted appearance not present in other specimens.
M. f. costaricensis is a large animal and among its geographic neighbors is approached in size only by a specimen of panamensis from Boquete, Panamá. Also the young male from Cervantes suggests panamensis in the less flattened interorbital region, but even so is more like costaricensis. The small size of two young males, one from Navarro and the other from the vicinity of San José, is suggestive of M. f. nicaraguae. However, the large size of most of the specimens and the configuration of the skull are more as in M. f. goldmani than in M. f. nicaraguae and thus suggest that the known specimens are of high mountain subspecies. The long black tip of the tail is another point of resemblance to M. f. goldmani, the high mountain subspecies to the north. Perhaps in the lowlands of Costa Rica, there are weasels of another subspecies.
Of the eight skulls examined for malformation of the frontal sinuses, each of the two adults and two subadults shows signs of having the frontal sinuses infested with parasites.
Specimens examined.—Total number, 14, listed by localities from north to south.
Costa Rica: Irazú (Frasu or Irasu on label), 3000 M., 1[4]; Cervantes, 1[2]; San José, 1[91]; vicinity of San José, 2[7]; Azahar Cartago, 1[78]; Tucurrique, 1[7]; Cachí, 1[7]; El Muñco [= Muñeco?] (Río Nivarro [= Navarro?]), 4000 ft., 10 mi. S Cartago, Caribbean Slope, 1[76]; Navarro, 1[91]; Candelaria Mts., 1[75]; no locality more definite than Costa Rica, 3[91].
Mustela frenata panamensis Hall
Long-tailed Weasel
Plates [1], [25], [26], [27], [28], [29] and [30]
Mustela frenata panamensis Hall, Proc. Biol. Soc. Washington, 45:139, September 9, 1932; Hall, Carnegie Instit. Washington Publ. 473:109, November 20, 1936.
Mustela brasiliensis, Alston, Biol. Cent. Amer., Mammalia, p. 78, 1879.
Putorius affinis, Bangs, Bull. Mus. Comp. Zoöl., 39:49, April, 1902; Hollister, Proc. Biol. Soc. Washington, 28:143, July 10, 1914.
Mustela affinis, Goldman, Proc. Biol. Soc. Washington, 25:10, January 23, 1912; Hollister, Proc. Biol. Soc. Washington, 28:143, July 10, 1914.
Mustela affinis costaricensis, Allen, Bull. Amer. Mus. Nat. Hist., 35:101, April 28, 1916; Goldman, Smithsonian Miscel. Col., 69 (no. 5): 161, 1920.
Type.—Female, subadult, skull and skin; no. 170970, U. S. Nat. Mus., Biol. Surv. Coll.; Río Indio, Canal Zone, near Gatún, Panamá; February 17, 1911; obtained by E. A. Goldman; original no. 20897.
The skull is complete and unbroken. The left lower incisor is broken off but all the other teeth are present and entire. The skin is well made and seems to be in faded, worn, first, adult pelage.
Range.—Sea level (type locality) to 5800 feet (Boquete, see Bangs [1902:49]); Upper Tropical and Lower Tropical life-zones of Panamá. See figure [29] on page [221].
Characters for ready recognition.—Differs from both M. f. meridana and M. f. costaricensis in darker tone (tone 4 of Oberthür and Dauthenay, pl. 344) of color of upper parts and in convex dorsal outline of skull (Compare figures of mentioned subspecies on plates [25]-[27]).
Description.—Size.—Male: Two adults from Boquete in the Museum of Comparative Zoölogy, nos. 10112 and 10113, measure, respectively, as follows: Total length, 480 and 400; length of tail, 170 and 143; length of hind foot, 52 and 43. Hind feet of two other adult males measure 46 on dried skins. Tail, in two specimens mentioned above, is 55 and 56 per cent as long as head and body. Length of hind foot, in each of three adults, slightly longer than basal length. Corresponding measurements of no. 178970 from Mt. Pirre are: 422, 164, 50. Tail 64 per cent (same per cent as in young male, no. 137514 from Boquete) as long as head and body, and hind foot longer than basal length.
Female: An adult and a young from Chiriquí, nos. 18434 and 18435 (Acad. Nat. Sci. Philadelphia), measure, respectively: Total length, 372, 389; length of tail, 138, 144; length of hind foot, 42, 41. The type specimen measures: Total length, 408; length of tail, 159; length of hind foot, 46.5. Tail 64 per cent as long as head and body, and hind foot longer than basal length.
The average differences in external measurements of the two sexes from the vicinity of Boquete are: Total length, 59; length of tail, 15; length of hind foot, 6.
Externals.—Longest facial vibrissae black and extending beyond posterior border of ear; carpal vibrissae wholly, or in part, black and extending as far as hypothenar pad; hairiness of foot-soles as shown in figure [21].
Color.—Usually, posterior fourth of each upper lip and sometimes few hairs in front of ear, white; sides and top of head and neck posteriorly to, or behind, shoulders, black; dark areas at angles of mouth confluent with color of upper parts; tip of tail, black; remainder of upper parts near (n) Bay of Ridgway and Reddish Black, tone 4, pl. 344 of Oberthür and Dauthenay; chin and lips, whitish; remainder of underparts Warm Buff or near (16´ c) Ochraceous-Buff; near (12) Salmon-Orange in juveniles and small young; color of underparts extending distally on posterior sides of forelegs to wrists, but not to soles, and on hind legs to or slightly below knees. Least width of color of underparts, in seven specimens, averaging 18 (extremes 11-28) per cent of greatest width of color of upper parts; black tip of tail, in five adults and subadults, averaging 45 (extremes 41-50) per cent of length of tail-vertebrae.
Skull and teeth.—Male (based on three adults from Boquete): See measurements and plates [25]-[30]; weight, 5 (4.5-5.4) grams; basilar length, 45.2 (42.8-48.3); zygomatic breadth more or less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth less than postpalatal length; postorbital breadth more than length of upper premolars and more than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth not less than distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum approximately same (more or less than) length of tympanic bulla; least width of palate less than length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 4-1/2 to 5-1/2 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale; length of tympanic bulla more or slightly less than (approximately equal to) length of lower molar and premolar tooth-row or length of rostrum; anterior margin of masseteric fossa directly below posterior fourth of m2.
Female (based on subadult, type specimen and one adult from Siola): See measurements; weight, 3.3 and 2.1 grams; basilar length, 41.3 and 39.3; zygomatic breadth more than distance between condylar foramen and M1 and more or less than (about equal to) that between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth more than combined length of upper premolars or than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate more than length of P4 (less in the adult); anterior margin of tympanic bulla as far posterior to foramen ovale as width of five upper incisors; height of tympanic bulla less than (about half) distance from its anterior margin to foramen ovale; length of tympanic bulla less than length of lower molar and premolar tooth-row or than rostrum.
The skull of the one adult female from Chiriquí is 58 per cent lighter than the average of the two adult males.