Title: Geographic Range of the Hooded Skunk, Mephitis macroura
Author: Walter Woelber Dalquest
E. Raymond Hall
Release date: November 13, 2010 [eBook #34311]
Most recently updated: January 7, 2021
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The hooded skunk, Mephitis macroura Lichtenstein, can be distinguished from the only other species in the genus, Mephitis mephitis Schreber, by the larger tympanic bullae, in the white-backed color phase by having some black hairs mixed with the white hairs of the back, and in the black-backed phase by having the two white stripes widely separated and on the sides of the animal instead of narrowly separated and on the back of the animal. The starting point for taxonomic work with Mephitis is A. H. Howell's "Revision of the skunks of the genus Chincha (N. Amer. Fauna, 20, 1901)." Of the species Mephitis macroura, Howell (op. cit.) recognized three subspecies: M. m. macroura, M. m. milleri, and M. m. vittata.
The species M. macroura is restricted to the arid region made up mostly of the Mexican Plateau. Also, wherever the species occurs beyond this Plateau, as for example in Guatemala, at San Mateo del Mar in Oaxaca, in the vicinity of Piedras Negras in Veracruz, and in southern Arizona, aridity is marked. Whether the species has a continuous distribution from the southern end of the Mexican tableland southward to Dueñas in Guatemala is not known but it is unlikely that the lowland population at San Mateo del Mar on the Pacific slope of Oaxaca has contact with M. m. macroura of the Mexican Plateau and it is almost certain that the population, which is here named M. m. eximius, from the arid coastal plain of eastern Mexico in Veracruz, has no connection with the upland population, M. m. macroura. The lowest elevation on the eastern slope of the Plateau from which we have record of the occurrence of this species is 4,500 feet at Jico. All along the eastern slope of the Plateau, between the elevations of approximately 2,000 and 4,500 feet, the belt of lush, dense vegetation of the upper humid division of the Tropical Life-zone constitutes a barrier to Mephitis and tends to exclude the hooded skunk from the arid territory below the humid belt. Another kind of skunk, Conepatus tropicalis, lives in the humid belt, at least on the eastern side of the Mexican tableland. How the population of Mephitis, which was sampled by us from  west and west-northwest of Piedras Negras, arrived there is unknown but we think that its geographic range is not now connected with that of the population on the Plateau. The same can be said of the lowland population at San Mateo del Mar in Oaxaca. There, on the Pacific slope of the Mexican tableland, the lower humid division of the Tropical Life-zone probably has tended to restrict the spread southward and westward of Mephitis; however, on this Pacific slope the humid belt is less humid and it is less continuous, we think, than on the Atlantic slope.
Four subspecies of Mephitis macroura may be recognized. They are as follows:
Mephitis macroura milleri Mearns
1897. Mephitis milleri Mearns, Proc. U. S. Nat. Mus., 20:467, 1897.
1901. Mephitis macroura milleri, Bull. Amer. Mus. Nat. Hist., 14:334, November 12, 1901.
Type locality.—Fort Lowell, Pima County, Arizona.
Range.—Northwestern Mexico and southeastern Arizona. See figure 1. Marginal occurrences (unless otherwise indicated, after Howell, N. Amer. Fauna, 20:42, 43, 1901) are: Arizona: Santa Catalina Mountains; Tucson; Fort Lowell. Chihuahua: Casas Grandes; Chihuahua (City). Coahuila: La Ventura. Chihuahua: Guadalupe y Calvo (mountains near). Sonora: Camoa; Hermosillo; Sierra Cubabi (Burt, Miscl. Publ., Mus. Zool., Univ. Michigan, 39:30, 1938).
Characters.—Long skull (♂ 60 mm, ♀ 56 mm) and large m1.
Mephitis macroura macroura Lichtenstein
1832. Mephitis macroura Lichtenstein, Darstellung Säugethier, pl. 46, with accompanying text, 1832.
Type locality.—Mountains northwest of the City of Mexico.
Range.—Southern half of Mexican Plateau and south to Guatemala. See figure 1. Marginal occurrences (all from Howell, N. Amer. Fauna, 20:41, 42, 1901) are: Tamaulipas: Jaumave. Veracruz: Las Vigas; Jico; Orizaba. Puebla: Tehuacan. Guatemala: Dueñas (vicinity). Oaxaca: 15 mi. W Oaxaca. Colima: Hacienda Magdalena. Jalisco: San Sebastian. Tepic: Santa Teresa. Zacatecas: Valpariso.
Characters.—Skull of medium size (basal length, ♂ 56, ♀ 54); tail averaging shorter than head and body.
Mephitis macroura vittata Lichtenstein
1832. Mephitis vittata Lichtenstein, Darstellung Säugethier, pl. 47, with accompanying text, 1832.
1901. Mephitis macroura vittata, Allen, Bull. Amer. Mus. Nat. Hist., 14:334, November 12, 1901.
Type locality.—"San Matteo el Mar" [= San Mateo del Mar], Oaxaca.
Range.—Known only from the type locality. See figure 1.
Characters.—Skull short (♂ 54.6, ♀ 52.3); narrow across mastoid processes; tail long; body short.
Mephitis macroura eximius new subspecies
Type.—Female, adult, skin with skull, No. 19272, Mus. Nat. Hist., Univ. Kansas; 15 kilometers west of Piedras Negras, 300 feet elevation, Veracruz, Mexico; 13 January 1947; obtained by J. Mazza and Walter W. Dalquest; original No. 7017, W. W. Dalquest.
Range.—From the vicinity of the type locality on the arid coastal plain of the lowlands of central Veracruz. See figure 1.
Diagnosis.—Size small (see measurements); tail long, ranging from 110 to 133 percent of length of head and body; color black, with white areas containing a few black hairs, and in non-hooded phase with white lateral stripes low on sides of body and in some specimens almost absent; skull small but broad across mastoid processes.
Comparisons.—From Mephitis macroura macroura of the southern part of the Mexican Plateau, M. m. eximius differs in shorter head and body, relatively (to body) longer tail, and smaller skull. From Mephitis macroura vittata of the tropical lowlands of the Pacific slope of Oaxaca, M. m. eximius differs in slightly larger average size throughout and relatively longer tail.
Remarks.—M. m. eximius is regarded as a subspecies of M. macroura because there is some overlap in size between larger individuals of M. m. eximius and smaller individuals of M. m. macroura. Actually, as indicated above, we doubt that the geographic ranges  of the two subspecies are continuous or that the geographic range of M. m. eximius is continuous with the geographic range of M. m. vittata. Small size and relatively long tail characterize both of the lowland, tropical subspecies, eximius and vittata, whereas the two upland subspecies of the temperate areas are larger and have relatively shorter tails.
Habitat closely resembling that at the type locality extends from the southern base of the first mountains north of Jalapa southward as far as the north base of the Tuxtla Mountains—a distance of approximately 110 miles from northwest to southeast along the gulf coast. None of our 5 skins shows the hooded color-pattern so common on the Mexican Plateau and in vittata of Oaxaca. One of our five specimens has well-developed lateral stripes; three have greatly reduced lateral stripes and one is black except for a white spot on the right hip.
Measurements.—An adult male (University of Kansas Museum of Natural History Catalogue Number, 17900), a subadult male (19273), and adult female (19272, the holotype) and a subadult female (19902), measure, in millimeters, respectively, as follows: Total length, —, 599, 578, 583; length of tail, —, 319, 335, 305; length of hind foot, 58, 62, 58, 60; basal length of skull, 56.1, 55.0, 52.8, 53.1; basilar length of Hensel, 53.6, 52.6, 50.3, 51.2; greatest zygomatic breadth, 41.6, 38.0, 39.0, 37.0; greatest mastoid breadth, 34.6, 34.3, 33.3, 31.5; breadth across postorbital processes, 22.2, 20.2, 20.5, 21.0; least interorbital breadth, 20.3, 18.2, 19.0, 18.5; palatal length, 24.2, 25.1, 24.2, 24.0; postpalatal length, 31.5, 29.6, 28.8, 29.0; foramen magnum to plane of last molars, 30.8, 29.4, 27.5, 29.0.
Specimens examined.—Total number, 5, all from Veracruz, Mexico, as follows: Rió Blanco, 20 km. WNW Piedras Negras, 3; 15 km. W Piedras Negras, 300 ft., 2.
University of Kansas Museum of Natural History, Lawrence, Kansas.
Transmitted October 31, 1949.