Part 79

=Nayarit.= Tepic, 1.

=Jalisco.= Río Santiago, 1; Los Masos, 1; "Artenkiki" (J. A. Allen, 1906, p. 238, writes "Artenkikil" and, on p. 259, "Artenkiki."), 1.

=Michoacán.= Zamora, 1; Los Reyes, 1; Pátzcuaro, 3.

=Mustela frenata perotae= Hall

Long-tailed Weasel

Plates 36, 37 and 38

Mustela frenata perotae Hall, Carnegie Instit. Washington Publ. 473:100, November 20, 1936.

Putorius frenatus, Merriam, N. Amer. Fauna, 11: pl. 3, fig. 2, June 30, 1896.

Type.--Female, adult, skull and skin; no. 54278, U. S. Nat. Mus., Biol. Surv. Coll.; 12,500 feet, Cofre de Perote, Veracruz, México; May 26, 1893; obtained by E. W. Nelson; original no. 4864.

The skull (plates, 37-39) lacks the right zygomatic arch. Left p2 is missing. The skin is fairly well made and in good condition except that the extreme tip of the tail has been broken off and there are two holes in the right hind leg. The underparts show the beginning of a spring molt.

Range.--From 7500 (?) feet (Perote) to 13,500 feet (Popocatépetl), Upper Sonoran, Transition and Boreal life-zones of mountains along Puebla-México boundary, eastward to western central Veracruz and south into Oaxaca. See figure 29 on page 221.

Characters for ready recognition.--Differs from M. f. frenata, its nearest relative, in extension from head of blackish onto anterior fourth of neck; restriction of color of underparts (least width of same less than 37 per cent of greatest width of color of upper parts), height of tympanic bulla less than distance from its anterior margin to foramen ovale; from M. f. macrophonius and M. f. goldmani in presence of, rather than absence of, color of underparts on hind feet; upper parts (black) Brussels Brown rather than Argus Brown or darker; from M. f. tropicalis in larger size (adult female with total length more than 400, basilar length more than 40, weight of skull more than 3 grams); postorbital breadth less than combined length of upper premolars; m1 more than 5.4 long; from M. f. leucoparia in white facial markings so restricted that spot between eyes is not confluent with white stripe in front of ear, or, if so, narrowly (less than 4 wide) confluent; color of upper parts extending onto antipalmar face of forefoot, least width of color of underparts not more than 40 per cent of greatest width of color of upper parts; height of tympanic bulla not more than three-fifths distance from its anterior margin to foramen ovale.

Description.--Size.--Male: A nontypical specimen from Cerro San Felipe, Oaxaca, measures: Total length, 500; length of tail, 205; length of hind foot, 52.

Female: The type specimen, measures: Total length, 418; length of tail, 160; length of hind foot, 45.

In this male the tail is 70, and in the female, 62 per cent as long as the head and body. In each the hind foot is longer than the basal length.

The differences in external measurements between these two specimens, representing the two sexes, are: Total length, 82; length of tail, 45; length of hind foot, 7.

Externals.--As described in Mustela frenata frenata.

Color (based on type specimen).--Color and color pattern as described in Mustela frenata frenata except that: blackish of sides and top of head extends one-fourth of way back to shoulders from ears; throat and breast as well as chin white; remainder of underparts near (16´ c) Ochraceous-Buff; least width of color of underparts equals 36 per cent of greatest width of color of upper parts; black tip of tail equal to 28 per cent of length of tail-vertebrae.

Skull and teeth.--Male (based on a referred specimen from Cerro San Felipe which certainly is nontypical): See measurements. As described in Mustela frenata frenata except that: Weight, 4.9 grams; basilar length, 49.2; postorbital breadth more than distance between posterior borders of P4 and P2; tympanic bulla as far posterior to foramen ovale as width of 5 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale; zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla.

Female (based on type specimen, an adult): See measurements and plates 37-39. As described in Mustela frenata frenata except that: Weight 3.4 grams; basilar length, 43.5; zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth less than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; tympanic bulla as far posterior to foramen ovale as width of 5 or 6 upper incisors; height of tympanic bulla one-half to three-fifths distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer than rostrum.

The skull of the female is 33 per cent lighter than that of the nontypical (and smaller than average) male from Cerro San Felipe.

Comparison of the skull with that of M. f. tropicalis is made in the account of that subspecies. Compared with the skull of M. f. macrophonius, that of the female of perotae is more flattened, has the longitudinal dorsal outline distinctly concave rather than flat just behind the postorbital processes, and much wider tympanic bullae. Accordingly, the basioccipital is slightly narrower in perotae. The more marked postorbital constriction of the type specimen of perotae possibly is due to its relatively greater age. As compared with the skull of M. f. leucoparia, that of the female of perotae has less inflated tympanic bullae, the height of each being half as great as distance from its anterior margin to foramen ovale, whereas, in leucoparia (as represented by no. 26153) the two distances are equal. As compared with that of M. f. frenata, the skull of the female of perotae differs mainly in the lesser inflation of the tympanic bullae and their relative position. The height of each bulla is in perotae only half as much as, but in frenata more than, the distance from its anterior margin to foramen ovale. The anterior margin of the bulla is much less projected from the floor of the braincase in perotae. The squamosal anterior to each bulla is convex ventrally in perotae but flat or concave ventrally in frenata.

Remarks.--The type specimen and a juvenal female from the town of Perote were taken in the spring of 1893 by E. W. Nelson. Of these two, the type specimen was mentioned and figured by Merriam (1898:30, fig. 16 [= fig. 15], pl. 3, fig. 2) as Putorius frenatus. The referred nontypical specimen from Cerro San Felipe, Oaxaca, was referred by Merriam (op. cit.:29) to Putorius frenatus goldmani with the comment that it was intermediate ". . . both in coloration and cranial characters, between typical frenatus and goldmani;. . . ." No other published references to this subspecies, or specimens of it, have been seen. In 1941 and 1942, W. B. Davis and associates took four specimens along the boundary between the states of Puebla and México.

Although the specimen from Cerro San Felipe, Oaxaca, is referred to Mustela frenata perotae, to the description of which it answers best, that specimen, on account of its structural characters and geographic position relative to adjacent races, is in reality an intergrade between several of the adjacent races. Some of its intermediate characters are pointed out in the discussion of M. f. goldmani. In the specimens from 45 and 55 kilometers ESE of México (city) the black color of the top of the head does not extend so far behind the ears as in the holotype of M. f. perotae and in this feature the two specimens show intergradation between the two subspecies, perotae and frenata.

The type specimen taken on May 26, is acquiring new hair on the belly and lower sides which appears to be the result of a normal molt.

As would be expected from its geographic position, M. f. perotae resembles M. f. frenata of northern México and the high mountain forms of southern México more than it does the lowland tropical forms. This is true as regards size of entire animal, proportions of its parts, and size, general angularity and major proportions of its skull. The marked postorbital constriction, convex supralacrymal face of rostrum, width of tympanic bullae and angularity of the braincase place it nearest M. f. frenata as does also the color and color pattern. The ventrally convex squamosal anterior to each tympanic bulla and the slight degree of projection from the cranium of the anterior margin of each tympanic bulla are intermediate in degree between the condition in M. f. macrophonius and that in M. f. frenata. Thus M. f. perotae combines several characters of M. f. frenata on the one hand with some of M. f. macrophonius on the other and in some features, for instance in the size, shape and degree of inflation of the tympanic bullae, presents intermediate stages of development.

On the eastern plain below the high mountain, Cofre de Perote, there ranges the similarly colored, smaller, tropical weasel, Mustela frenata tropicalis. Between M. f. perotae and M. f. tropicalis there is marked differentiation in the skulls with much less differentiation in coloration. The differences in typical skulls of the two subspecies are so pronounced that one would, at first glance, hardly believe it possible for direct intergradation to occur between them on the sides of this mountain. Merriam (1896:30) thought that it did not. The two skulls figured by him (op. cit.:31) are a topotype of M. f. tropicalis from Jico and the one which now is the type specimen of M. f. perotae. They show the great difference in size and proportions and are females of comparable ages, not of different ages as I suspected before examining the skulls. However, despite this marked difference in the skulls, there is some, although not conclusive, evidence of intergradation furnished by a young female from Xuchil, Veracruz. This specimen is described in connection with M. f. tropicalis (see p. 366).

None of the seven skulls shows marked deformity of the interorbital region, but two of the three adults appear to have had these parts infested with nematodes.