Part 77

The average differences in external measurements of the two sexes are: Total length, 65; length of tail, 29; length of hind foot, 7.

Externals.--Longest facial vibrissae black and reaching beyond ear; carpal vibrissae same color as underparts and extending to apical pad of fifth digit; hairiness of foot-soles as shown in figure 20.

Color.--Spot between eyes, broad band, confluent with color of underparts, on each side of head extending anterodorsally anterior to each ear, and posterior two-thirds to one-half of each upper lip, white; remainder of sides and top of head, posteriorly to line connecting posterior margins of ears, blackish; dark spot posterior to angle of mouth present on both sides in about half the specimens; tip of tail black; remainder of upper parts Brussels Brown; chin white; remainder of underparts near (16´a) Ochraceous-Buff (same color in juveniles and young), which color extends distally on posterior sides of forelegs over forefeet and on medial sides of hind legs to feet and sometimes onto upper sides of toes. Least width of color of underparts averaging, in a series of seventeen males from Brownsville, Texas, 47 (extremes 38-53) per cent of greatest width of color of upper parts. Black tip of tail, in same series, averaging 49 (extremes 40-55) mm. long, thus about equal to length of hind foot and averaging 24 per cent of length of tail-vertebrae.

Skull and teeth.--Male (based on ten adults from Brownsville): See measurements and plates 22-24; weight (three adults, one topotype and two from Brownsville, Texas), 6.2 (5.3-7.2) grams; basilar length, 49.8 (48.2-51.3); zygomatic breadth more than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; mastoidal breadth less than postpalatal length; postorbital breadth less than length of upper premolars (less than distance between posterior borders of P4 and P2) and not greater (usually less) than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth not greater 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 or less than length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 3 or 4 (including I3) upper incisors; height of tympanic bulla 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 (usually longer) than rostrum; anterior margin of masseteric fossa just behind m2.

Female (based on two adults from Brownsville, Texas): See measurements and plates 36-38, 40; weight, 3.4 (3.3-3.5) grams; basilar length (six, adult to young) 43.3 (41.3-47.3); zygomatic breadth more or less than distance between condylar foramen and M1 and more than distance between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth less than length of upper premolars and more or less than (about equal to) width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate less than outside length of P4; tympanic bulla as far posterior to foramen ovale as width of 2 to 3-1/2 (including I3) upper incisors; height of tympanic bulla 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.

The skull of the female averages 45 per cent lighter than that of the average male.

Comparison of the skull with those of M. f. arthuri, tropicalis, perotae, leucoparia and neomexicana has been made in accounts of those subspecies. As compared with M. f. texensis (known only from males), the only difference detected is smaller size.

Remarks.--As Merriam (1896:27) has said: "In 1813 a Russian naturalist, Sevastianoff, gave the name 'Mustela brasiliensis' to a weasel brought to St. Petersburg by Capt. A. J. Krusenstern on his return from a voyage around the world. The animal was said to have come from Brazil, but no definite locality was given." This name was long applied by many European naturalists to American weasels which had white facial markings, and several American naturalists adopted the name. However, Lichtenstein in 1832 applied the name Mustela frenata to the weasels of the vicinity of México City and that name was used for bridled weasels from México and the southwestern United States by most subsequent German writers and by several Americans. In 1896 Merriam (1896:27) showed that Sevastianoff's Mustela brasiliensis, 1813, although probably the same as Mustela frenata, was preoccupied by Gmelin's Mustela brasiliensis, 1788, applied to an otter and that Lichtenstein's name must be used as the next available one. Since that time, 1896, frenata has been the name applied to the large bridled-weasels of Texas and the high table land of México south to México City. It may be added that in 1937 search by the writer among the specimens and records at the Russian Academy of Sciences, in Leningrad, failed to reveal any trace of the type specimen of Sevastianoff's Mustela brasiliensis.

The geographic range of this subspecies is relatively large and, as might therefore be expected, specimens show geographic variation. The specimens from Tlalpam, which Merriam (op. cit.:27) regards as topotypes, differ in certain respects from specimens from Texas. The skull of the adult male "topotype," no. 50826, differs from any other adult male seen in that the basilar length, the length of the upper tooth-rows, the orbitonasal length, the ratio of the same to the basilar length, the mastoidal breadth, the zygomatic breadth, the depth of the skull at the posterior margins of the upper molars, and the length and breadth of M1, are greater. The height of the tympanic bullae is less than the average height for these structures in more northern specimens. The specimens from Tlalpam have also larger external measurements than the average of more northern specimens. All of these features show an approach to the subspecies of more southern distribution. On the other hand, the blackish of the head is not more intense or more extended posteriorly onto the neck than in specimens from Brownsville, Texas. The skin, with skull crushed, no. 767, in the Paris Museum, from 3200 meters elevation near Toluca, does have the black color of the head extended 30 millimeters posteriorly to the ears. In this feature, and also in the extensively white face on which the white bar in front of each ear connects with the frontal spot, as well as with the color of the underparts, the specimen resembles leucoparia. Better material from the western part of the state of México may show the range of leucoparia to extend eastward almost or quite to Toluca.

An adult male, taken on July 15 at Miquihuana, Tamaulipas, is unique in several respects. The top of its head is black, rather than blackish, and this color extends posteriorly on the top and sides of the neck almost halfway to the shoulders. All of the upper parts are much more darkly colored than in other specimens of this race. The least width of the color of the underparts is 63 per cent of the greatest width of the color of the upper parts; thus the color of the underparts is considerably more extensive than in any other specimen seen. The underparts are more intensely colored than in the average specimen. The mastoidal breadth is greater than in any other adult male and amounts to more than the postpalatal length. On available maps the elevation of Miquihuana is given as 1892 meters (about 6200 feet). Thus the dark colors can hardly be ascribed to more tropical conditions than those under which animals from Brownsville, Texas, live. Brownsville is only a few feet above sea level and only 235 miles farther north. The difference noted, therefore, seems to be of geographic significance. However, there is from Alvarez, San Luis Potosí, approximately 115 miles south of Miquihuana, a young (nearly subadult) female, no. 21968, which is as light colored as specimens from Brownsville, Texas, or Tlalpam, México. The only distinctive feature of this specimen is the much greater extent of its white facial markings; they are more extensive even than in the specimen from Miquihuana.

Finally, the series from Brownsville, Texas, indicates that the animal there is smaller than frenata from the vicinity of México (city). The skull is similarly proportioned except that relative to the basilar length the orbitonasal length is more. Several other measurements of the skull of the adult male from Tlalpam, as pointed out above, are actually, although not relatively, greater than in any specimen from Brownsville. The similarities between specimens from the two localities, Tlalpam and Brownsville, are striking; since the two localities lie at opposite, extreme ends of the range more geographic variation would be expected. All that is known of the characters of populations from intermediate localities is that the one specimen from Alvarez shows no peculiarities whereas the one from Miquihuana suggests the existence there of a geographic variant.

None of the specimens seen shows actual intergradation with M. f. neomexicana or with M. f. arthuri but it is supposed that frenata intergrades with each of these subspecies. The difference between frenata and arthuri is greater than between frenata and neomexicana. Bailey (1905:198) records tracks of a weasel seen just below El Paso which he supposed had been made by a weasel of the neomexicana type. He also cited the taking of a weasel at Langtry which suggested to him (op. cit.) ". . . a continuous range from the country of frenatus up the Rio Grande to the type locality of neomexicanus at Mesilla Valley," New Mexico. Other records of occurrence in Texas cited by Bailey, in addition to those provided by specimens examined by the writer, are San Diego, Beeville, and Port Lavaca. The Port Lavaca record is the easternmost one assigned to the subspecies frenata; possibly specimens from there would be referable to arthuri.

The series of thirty-four specimens from Brownsville, Texas, permits measuring the amount of individual and age variation in several features. For instance, the material is sufficient to show that external measurements of subadults and those that fall in the upper part of the category designated as "young" may be included with the measurements of adults, because the mentioned measurements are not appreciably greater in adults. The series of skulls, although not providing more than six of any one age, shows the range of variation in size and proportion of certain parts and enables the student the better to evaluate cranial characters of nearby races known from only a few specimens. For example, not one of the twenty skulls of males from Brownsville and immediate vicinity is as large as either of the two specimens of texensis from Kerr County.

The white facial markings vary much in size and shape. In the series of thirty-four skins from Brownsville the broad white bands in front of the ears are confluent with the white patch between the eyes on both sides in three specimens and on one side only in six other specimens. These bands are confluent with the color of the underparts in all but two specimens. In one specimen the connection is lacking on both sides and in the other on one side only. A white patch between the ears is present in two specimens. The dark spot at each angle of the mouth is absent on both sides in eleven specimens and absent on one side only in ten others.

In six other specimens from parts of Texas north of Brownsville, the broad white bands in front of the ears are confluent with the white patch between the eyes on both sides in one specimen. A white spot between the ears is present in one specimen. The dark spot at each angle of the mouth is absent on both sides in six specimens and on one side only in three other specimens.

In eleven specimens from México, the broad white bands in front of the ears are confluent with the white spot between the eyes on both sides in two specimens and on one side only in one other specimen. The white spot between the ears is present in one specimen. The dark spot at each angle of the mouth is absent on both sides, in six specimens, and on one side only in one other specimen.

Thus, in 51 specimens the broad bands (one in front of each ear) are confluent with the white patch between the eyes in nineteen out of 100 instances, and not with the color of the underparts in three instances. A white spot between the ears is present in four specimens. The dark spot at each angle of the mouth is present 47 out of a possible 98 times.

Four juvenal specimens from Brownsville, Texas, with their dates of capture and probable age, are as follows: no. 58574, , three weeks old, taken on February 15; no. 17318/24239, , four weeks old, taken on March 16; no. 45899, , forty days old, taken on May 21; no. 21778/36481, , thirty days old, taken on October 20. In the order given, the dates of birth of these four juveniles would be approximately as follows: January 25, February 15, April 1, and September 20. The dates of birth of other specimens less than three months old as judged by the stage of development of the skull, and reckoning backward from the dates of capture, are as follows: April 1, April 30, May 25, October 12, and December 21. Thus, young appear to be brought forth at Brownsville, Texas, in the fall, winter and spring, that is to say from the latter part of September until the latter part of May.

Mustela frenata frenata is either free of the parasites that infest the frontal sinuses of most weasels, or withstands their presence remarkably well, for only one skull shows a definite pathological condition of the frontal sinuses.

Allen (1896:74) quotes H. P. Attwater, with respect to this species in Bexar County, Texas, as follows: "Not common, but occasionally met within the chaparral and cactus lands, where Wood Rats, Rabbits and Quail abound. They were frequently met with around San Antonio during the great 'Tramp Rat' [= Sigmodon hispidus texianus, see Bailey (1905:116)] invasion of 1889-90."

Specimens examined.--Total number, 63, arranged by counties, and in México by states, from north to south. Unless otherwise indicated specimens are in the collection of the United States National Museum.

=Texas.= Bexar County: San Antonio, 2 (1). Goliad County: Charco, 1. Nueces County: Corpus Christi, 1. San Diego County (not found), 1. Hidalgo County: La Hacienda, 1. Duval County: San Diego, 2. County in question: Lower Rio Grande, 1. Cameron County: Brownsville, 34 (3, 4, 3, 2, 1, 1, 1); no locality more definite than county, 2.

=Nuevo León.= Río Ramis, 20 mi. NW Montemorelos, 1.

=Tamaulipas.= Matamoros, 6; Miquihuana (now in Nuevo León), 1.

=San Luis Potosí.= Alvarez, 1.

=México=: Region montagneuse des environs de Toluca, Nevada Toluca, 3200 M., 1

=Distrito Federal.= City of México, 2 (1); Tlalpam, 2. No locality more definite than México, 4 (1, 3).

=Mustela frenata leucoparia= (Merriam)