Part 49

_Skull and teeth._--Male (based on type specimen and no. 562): See measurements and plates 27-30; weight, not known; basilar length, 43.2 (40.8 and 45.5); zygomatic breadth more or less than distance between condylar foramen and M1 and more than that between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth more or less than postpalatal length; postorbital breadth more than length of upper premolars and greater than width of basioccipital, measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth more than distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum less than length of tympanic bulla; least width of palate more than inside length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 4 (including I3) upper incisors; height of tympanic bulla not 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; anterior margin of masseteric fossa below or behind m2.

Female (based on no. 564, from Cutervo, Perú, type specimen of _Mustela jelskii_ Taczanowski): See measurements and plates 37-40; weight, not known; basilar length, 38±; zygomatic breadth less than distance between condylar foramen and Ml and not greater than that between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth more than alveolar length of upper premolars and (probably) more than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate more than inside length of P4; tympanic bulla as far posterior to foramen ovale as width of at least 5-1/2 upper incisors; height of tympanic bulla less 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.

As compared with that of _helleri_, the skull of the male of _macrura_ from Junín southward has a lesser mastoid breadth, notably smaller teeth, and a flatter skull which averages lighter throughout. The skulls of females available indicate that the skull and teeth are larger than in _agilis_.

_Remarks._--Seven years after Taczanowski named this subspecies, he applied the name _jelskii_ to a female taken farther north than the original examples of _macrura_. As indicated in synonymy, various other names have been applied to animals included by the present author in this subspecies.

_Mustela frenata macrura_ intergrades with _M. f. affinis_ as shown by practically all the referred specimens from north of Junín. As one proceeds northward the color of the weasels becomes progressively darker and the teeth become larger until the conditions found in _affinis_ are met with near the northern border of Ecuador. From the material available it appears that the light-colored upper parts found in _macrura_ characterize weasels of, at least, the Temperate Zone, from Marcapata, Perú, to near Quito, Ecuador. West of the range of _macrura_ there exists the still lighter-colored subspecies, _M. f. agilis_. Immediately adjacent on the north, east, and south, darker-colored weasels occur. So far as color is concerned, the geographic range of the subspecies _M. f. macrura_ is not difficult to define. However, the small size of the teeth characterizes only that part of this light-colored subspecies from Junín southward including the subspecies _boliviensis_ at the southern extremity of the range of the species. From Cutervo northward the light-colored weasels of the Temperate Zone have teeth similar in size to those of the darker, more northern _affinis_. To designate the slightly larger-toothed, light-colored animals from Ecuador as a subspecies distinct from _affinis_ and _macrura_ is one solution but at present it seems best to refer all of these light-colored animals to _macrura_.

The type specimen and topotype no. 562 differ more in the amount of inflation of the tympanic bullae than adult males of comparable ages from a given locality usually do. In other respects, the differences between the two skulls are not greater than those ordinarily found in specimens from the same locality. No. 562 has the tympanic bullae greatly, relative to the other South American weasels, inflated posteriorly. Otherwise, the bullae agree with those of the type specimen.

Specimens from southwestern Ecuador, average large, and include the largest specimens of the species _Mustela frenata_ seen from South America. A subadult male, no. 61406, in the American Museum of Natural History, is the largest. Its external measurements are 482, 191, 56. The basilar length of the skull is 48.2 and the zygomatic breadth is 30.3. Although not so large as this specimen, the corresponding measurements of specimens from Alamor, El Chiral, and even from as far away as Sigsig also are distinctly large.

The skull of the female from Ollantaytambo and that of the male from Marcapata have teeth equally as small as do the specimens from Lake Junín.

The skin alone, no. 194328, from Ollantaytambo has the color of the underparts extended over the entire upper sides of the forefeet. The male from Marcapata has less of this color on the forefeet and is in this respect intermediate between the specimens from Lake Junín and the one from Ollantaytambo.

In size of teeth the female, type specimen of _M. jelskii_, from Cutervo, shows an approach to the larger-toothed weasels of the northern part of the range of _macrura_.

The specimens in the Riksmuseum from the vicinity of Quito, Ecuador, have been rather fully described by Lönnberg (1921:11-17) and need little comment here, except to say that they show, as he suggested, that the weasel of the Temperate Zone of Ecuador is an intermediate link between _M. f. macrura_ and _M. f. affinis_.

The adult female and juvenal male labeled as from Ambato have little left of the skulls except some of the teeth and the assignment of the specimens to the subspecies _macrura_ is made mainly on geographic grounds. These two specimens probably are part of the shipment of birds and mammals of which Chapman (1926:703) speaks as follows: "A small collection of native-made skins purchased by the American Museum from a commission merchant in New York City as from 'Ambato' proved to be from the eastern slope of the Andes." Another skin in the same Museum, labeled by a native collector as from "Baeza arriba" [= above Baeza] is so dark colored and has the color of the underparts so much restricted, as to suggest that it belongs to the race _aureoventris_. Possibly, therefore, it was taken not at Baeza, Ecuador, which I find to the eastward of Quito at 77° 55' W and O° 25' S, but at some place of the same name on the Pacific Slope, unless the locality has been altogether wrongly recorded on the label. If the specimen was taken near the Baeza above referred to, then it gives evidence of an unnamed race of _Mustela_ on the eastern slope of the Andes, characterized by its dark color. Unfortunately the specimen is young and its skull therefore offers insufficient basis for the judging of its subspecific relationships.

Other specimens, in the British Museum of Natural History, recorded as taken "near Quito" and here tentatively listed under _macrura_, mostly, include specimens so dark colored as to lead me to think they came from country, lower than Quito, adjacent to the range of _aureoventris_.

Nematodes taken from the right frontal sinus of no. 562 from Junín proved to belong to the superfamily Oxyuriodea according to Professor W. B. Herms and Mr. O. L. Williams, who have independently identified them. Because these worms had been dried fifty-five years in the mounted specimen and were later boiled in cleaning the skull, a more accurate determination was impossible and whether or not they pertain to the same species found in North American weasels cannot be said. Of 18 adult skulls examined for this type of infestation, 13 were found affected as judged by the evident malformation of the frontal region.

_Specimens examined._--Total number, 74, arranged by localities from north to south and unless otherwise indicated in the American Museum of Natural History.

=Ecuador=: Ibarra, 6600 ft., and 7500 ft., 2[7]; San Antonio, 8000-8500 ft., 5 mi. N Quito, 4 (2[7], 2[78]); Nono, 10000 ft., 1; Mindo, 1[78]; Zambiza, 8000-8100 ft., NE Quito, 4 (2[78], 2[95]); Carapungo, 8500 ft, NE Quito, 1[78]; Panecillo, 10000 ft., near Quito, 2[78]; Guapulo, 8800 ft., 3 mi. E of Quito, 1[78]; Pichincha, 10500 ft., and 12000 ft., 2 (1[78], 1[95]); San Ignacio, 11500 ft., Pichincha, 1; Santa Rosa, 9600 ft., Río Pita, 2; near Santa Rosa, 9000 ft., 1; Río San Rafel, 9000 ft., 1; N side Quito, 9000 ft., 1[78]; Quito, 1[4]; near Quito, 5[7]; Nára Papallacta, 11000 ft., 1[78]; below Papallacta, 9000 ft., 1[78]; Chillo Valley, 1[78]; "Hacienda Hda," 10000 ft., Pintag, Valencia, 1; Baeza arriba, 1; Ambato, 2; San Francisco, 8000 ft., E of Ambato, 1; Chunchí, Pagma Forest, 6400 ft., 1[1]; Canar, 2600 M., 1[7]; Malletura, 7600 ft., 1; Contrayerbas, 11000 ft., 1; Sisig, 8500 ft., 3[7]; El Chiral, 1; Almor, 1; Guainche, 3200 ft., 1; no locality more definite than Ecuador, 4[95]; "Received from Quito," 1[7]; Quisaya, 6000 ft. (locality not found), 1[7]; La Carolina (locality not found), 1[78].

=Perú=: La Lejía, 1; Huancabamba, 4 (2[75]); Cutervo, 9000 ft., 1[73]; Condechacha, 7000 ft., Río Utcubamba, 1[7]; San Pedro, 8600-9400 ft., S of Chachapoyas, 1; Celendín, 1[7]; Junín, 2[73]; Yana Mayo, Río Tarma, 1[7]; Ollantaytambo, 9000 ft., 3 (1[7], 2[91]); Ocabamba, 1[7]; Anta Cuzco, 3400 and 3500 M., 2[4]; Marcapata, 1[91].

=Mustela frenata boliviensis= Hall

Long-tailed Weasel

Plates 28, 29 and 30

_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.

_Specimens examined._--Total number, 3, as follows:

=Perú=: Carabaya, Limbaní, 2 (one in U. S. Nat. Mus. and one in Berlin Zool. Mus.).

=Bolivia=: Nequejahuira, 1 Amer. Mus. Nat. Hist.

=Mustela frenata (?) gracilis= (Brown)

Plates 39 and 40

_Putorius gracilis_ Brown, Mem. Amer. Mus. Nat. Hist., 9(pt. 4):182, pl. 17, 1908.

_Mustela gracilis_, Hay, Iowa Geol. Surv. Bull., 23:32, 1914; Hay, Carnegie Instit. Washington Publ. 322A:252, October 15, 1924; Hay, Carnegie Instit. Washington Publ. 390(vol. 2):528, 1930.

_Mustela frenata gracilis_, Hall, Carnegie Instit. Washington Publ. 473:112, November 20, 1936.

_Type._--Adult skull without lower jaws, probably of a female, no. 12431, Amer. Mus. Nat. Hist.; from Conard Fissure, four miles west of Willcockson, Newton County, Arkansas; obtained sometime in the period 1903 to 1905 inclusive. (See plates 39 and 40.)

_Range._--Known only from the Pleistocene deposit in Conard Fissure, at the type locality in northern Arkansas.

_Description._--Skull. Probably female (based on the type): See measurements and plates 39 and 40; weight unknown; basilar length, 38.1; least width of palate less than greatest length of P4; tympanic bulla as far posterior to foramen ovale as width of 3 to 5 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale; length of tympanic bulla less than length of rostrum.

_Comparison and remarks._--The type specimen was the only individual referred by Brown (1908) to this species. The remaining material of weasels from this deposit was referred by Brown to his _Putorius cicognanii angustidens_. Examination of the original materials convinces the writer, too, that the specimens, except no. 12431, _are_ of the species _erminea_ [= _cicognanii_ of Brown]. No. 12431 itself may possibly be _erminea_ but is far more probably of the species _frenata_. The uncertainty is due to the fact that an occasional skull alone of a subadult male _erminea_ is extremely difficult certainly to distinguish from a skull alone of an adult female _frenata_. This is true among Recent specimens in the northern Mississippi Valley today; more exactly in Iowa and southern Minnesota the females of _frenata_, oftentimes intergrades between the subspecies _Mustela frenata longicauda_, _M. f. noveboracensis_ and _M. f. primulina_, by only the skulls are next to indistinguishable from certain, unusually slender skulls of male _erminea_. At other places where the ranges of the two species meet, this difficulty is not so often encountered. Also, the type of _gracilis_ has the skull broken in such a way that the postglenoid length in relation to the length of the skull as a whole could not be accurately determined in this particular skull.

The type specimen of _gracilis_ surely is an adult and because of its small size is thought to be a female. Of known long-tailed weasels of the species _frenata_, _gracilis_ is structurally nearest to _M. f. primulina_ which occurs in the same region today and to _M. f. noveboracensis_, the long-tailed weasel of the eastern United States. _M. gracilis_ differs from _noveboracensis_ and agrees with _primulina_ in possessing well-marked temporal ridges which fuse to form a low sagittal crest, in having the mastoid processes projecting farther, laterally, beyond the braincase, in having the anterior ends of the tympanic bullae produced below the squamosal rather than on the same plane with the squamosal, and in having the bullae more inflated anteromedially. _M. gracilis_ differs from both _noveboracensis_ (97 [M] and 56 [F] with skulls of comparable age) and _primulina_ (64 [M] and 24 [F] with skulls of comparable age) in that the zygomatic breadth amounts to less than 58 per cent of the basilar length. Another difference from any one of the skulls of females of _primulina_ is the longer rostrum, which, when measured from the posterior base of the postorbital process of the frontal to the anterior end of the nasal on the same side, amounts to more than 35 per cent of the basilar length. As pointed out by Brown (1908:182) this specimen represents the extreme of slender skull among known kinds of American weasels.

Selected measurements of no. 12431, the type specimen of _Mustela gracilis_, are as follows: Basilar length of Hensel, 38.1 mm.; length of upper tooth-rows, 14.3 to 14.4; breadth of rostrum, 11.0; interorbital breadth, 8.5; orbitonasal length, 13.6; mastoid breadth, 18.2; length of tympanic bulla, 13.0; breadth of tympanic bulla, 6.3; depth of tympanic bulla, 3.25; outside length of P4, 4.5; inside length of P4, 4.7; breadth of M1, 3.4; length of inner moiety of M1, 1.8; depth of skull at anterior margin of basioccipital, 12.2; depth of skull at posterior borders of last upper molars, 11.3; distance from foramen ovale to tympanic bulla, 3.6 mm.

=MUSTELA AFRICANA= Desmarest

Tropical Weasel

(Synonymy under subspecies)

_Type._--_Mustela africana_ Desmarest, Nouv. Dict. d'Hist. Nat., vol. 19, p. 376. 1818.

_Range._--Known from the headwaters of the Amazon in eastern Perú and from near the mouth of the same river, on its southern side in Brazil, all within the Tropical Life-zone. See figure 29 on page 221.

_Characters for ready recognition._--Differs from _Mustela frenata_, the only geographically adjacent species of the genus, by: presence of thenar pad on forefoot; presence of a longitudinal, median, abdominal stripe of same color as upper parts; upper lips being broadly edged, entirely round, with color of underparts; failure of longest facial vibrissae to reach posterior margin of ear; absence of p2; relative flatness (see pl. 29, fig. i and pl. 39, fig. _h_) of tympanic bullae.

_Characters of the species._--Size large (total length of adults approximately 500 mm.); foot-soles naked; thenar pad present on forefoot; length of claws, measured on concave sides, less than one and one-fourth times depth of claws measured at bases; longest facial vibrissae not reaching posterior margin of ear; tail relatively long haired; tail at all ages terminating in point as is characteristic of only juveniles and very young of _Mustela frenata_ and _M. erminea_; tip of tail, and muzzle, only slightly darker than remainder of upper parts; upper lips broadly edged with color of underparts; pelage coarse, harsh and sparse; longitudinal, median, abdominal stripe of same color as upper parts present; skull broad and deep; braincase large, rounded, and much inflated anteriorly; palatal region wide; tympanic bullae less inflated than in any other American species of the subgenus; angle of lower jaw reduced; dental formula

3 1 2-3 1 -, -, ---, -; teeth heavy; medial lobe of M1 but slightly larger than 3 1 2 2

lateral lobe. See plates 28, 29, 30, 39 and cranial measurements.

_Geographic variation._--The reddish versus chocolate color of the upper parts constitutes the only variation of a geographic nature so far detected.

_Remarks._--One of the most noteworthy of the several unique characters of this large, tropical weasel is the longitudinal, median, abdominal band. The species exhibits the minimum degree of development of certain features that become progressively less apparent as one proceeds southward from Central America. The relative uniformity of the coloration of the upper parts (reduction in intensity of black color on the muzzle and tip of the tail) and the reduction of the tympanic bullae are two cases in point. Viewed dorsally the general outline of the skull is most nearly matched by that of the skull of _Mustela frenata meridana_ from Venezuela or that of _M. f. helleri_ from Perú. However, the resemblance is not close. The tympanic bullae, although unique among American weasels, are more like those of _M. f. meridana_ from Venezuela than like those of any other kind. The great postorbital width (relatively less in _M. africana_ than in several South American subspecies of _Mustela frenata_) and small angular process of the mandible are characters, in varying degrees, also common to all South American weasels. Structurally _M. africana_ clearly is more nearly like other subspecies of _M. frenata_ from South America than it is like any species or subspecies from North America.

_Mustela africana_ is the most primitive of the American weasels. The distinctive cranial and dental characters, excepting the reduction in number of premolars, are of a primitive nature. For example, the relatively wide postorbital region, the large braincase that is inflated anteriorly, and the flattened, tympanic bullae, are points of resemblance to the holarctic _Mustela erminea_, which species is regarded as nearest the original stem form; also the mentioned characters correspond to ontogenetic stages passed through by other weasels. Mostly on these accounts, one is led to look upon _M. africana_ as a migrant from North America. It may have become isolated from its original stock, by a water barrier in the Central American region, for a length of time sufficient to permit of a degree of differentiation to develop between it and the North American weasels which prevented crossbreeding with the _frenata_ stock when that stock, at a later time, reached South America. This assumption is suggested only by evidence from the Recent specimens. No remains of true weasels (subgenus _Mustela_) have been recorded from deposits in South America older than the Recent period. The alternate possibility, that _M. africana_ intergrades with some race of _M. frenata_ in western or northern South America, has been considered and regarded as highly improbable.