Part 2

#Peromyscus boylii levipes# Merriam

1898. Peromyscus levipes Merriam, Proc. Biol. Soc. Washington, 12:123, April 30, type from Mt. Malinche, 8400 ft., Tlaxcala.

1909. Peromyscus boylei levipes, Osgood, N. Amer. Fauna, 28:153, April 17.

Geographic distribution.--Southeastern Tamaulipas and eastern San Luis Potosi, south through the central states of Mexico to Guatemala.

Diagnosis.--Size medium for the species; tail shorter or longer than head and body (83-112.3%); color variable according to locality but in general ochraceous, having some dusky on upper parts; supraorbital border not angular, almost rounded; auditory bullae large.

Comparisons.--For comparisons see accounts of the subspecies discussed beyond and Osgood (1909:145).

Remarks.--A precise diagnosis for P. b. levipes is difficult to prepare because some geographic variation in color and in the cranial characters is present within the range of the subspecies as here understood. For instance there is a gradual cline of decreasing size to the northward in nearly all measurements, but the ratio of length of tail to length of head and body does not present such a cline; mice from several localities in San Luis Potosi have a relatively shorter tail than do mice from farther north and from farther south. Also, specimens labeled in reference to Zacualpilla, Jacales, Jacala, Tulancingo, and San Miguel Regla average slightly darker dorsally than do typotypes. Some of these specimens are reddish on the cheek and lateral line. Specimens from San Luis Potosi resemble topotypes, but some specimens from northeastern localities in that state have cinnamon or brownish upper parts and are intermediate in coloration between populations of levipes to the south and populations of the same subspecies to the north from the Sierra Madre Oriental and the Sierra de Tamaulipas. Specimens from these two sierras have a cinnamon-reddish color that is more intense in specimens from the Sierra de Tamaulipas.

Osgood (1909:153) recorded P. b. levipes as occurring from central Nuevo Leon south through San Luis Potosi, Hidalgo, and Veracruz to southern Oaxaca. Actually specimens from Nuevo Leon and from most parts of Veracruz differ subspecifically from levipes and also from each other. In Veracruz, P. b. levipes is known only from the northwestern part.

Specimens examined.--Total 179 as follows: TAMAULIPAS: Sierra Madre Oriental, 5 mi. S, 3 mi. W Victoria, 1900 ft., 2; 8 mi. S, 6 mi. W Victoria, 4000 ft., 37; Sierra de Tamaulipas, 2000 ft., 8 mi. S, 11 mi. W Piedra, 13. SAN LUIS POTOSI: Villar, 11 (USNM); 10 km. E Platanito, 19 (LSU); 8 mi. E (by road) Santa Barbarita, 12 (LSU); Agua Zarca, 3 (LSU); 6 km. NE Cd. Maiz, 13 (LSU); Pendencia Region (Puerto Lobos), 1 (LSU); Pendencia, 2-1/2 mi. N Puerto Lobos, 5 (LSU); 3 km. SW San Isidro, 15 (LSU); Cerro Coneja Region, Llano Coneja, 6100 ft., 2 (LSU); Xilitla, 4 (LSU). HIDALGO: 10 mi. NE Jacala, 5050 ft., 7; Regla (San Miguel), 2250 m., 4; Arroyo de las Tinajas, 2370 m., 9.5 km. SSW Tulancingo, 1; 10 mi. NW Apam, 7750 ft., 1. VERACRUZ: 3 km. N Zacualpan, 6000 ft., 1; 3 km. W Zacualpan, 6000 ft., 12; 2 km. N Los Jacales, 7500 ft., 8; 6 km. WSW Zacualpilla, 6500 ft., 5. TLAXCALA: Mt. Malinche, 3 (USNM).

#Peromyscus boylii beatae# Thomas

1903. Peromyscus beatae Thomas, Ann. Mag. Nat. Hist., ser. 7, 11:485, May, type from Xometla Camp, Mt. Orizaba, Veracruz.

Geographic distribution.--East side of the Sierra Madre Oriental in Veracruz, from Jalancingo south to Xuchil.

Diagnosis.--Size large for the species; tail no shorter than head and body (100-114.8%); dorsum dark (near Prout's Brown or Mummy Brown middorsally, Clay Color on sides); supraorbital border rounded; anterior palatine foramina long.

Comparisons.--P. b. beatae differs from other subspecies of P. boylii by the combination of large size, long tail, and dark color.

Remarks.--Thomas (1903:485) described P. beatae on the basis of five specimens from Xometla Camp (lat. 18 deg. 59' N, long. 97 deg. 10' W) and one juvenile from Santa Barbara Camp, both on the Volcan de Orizaba, Veracruz. Thomas thought that beatae was related to aztecus, but the differences relied on by him to distinguish the two are the same as those that distinguish aztecus from boylii. Osgood (1909:153) placed beatae in synonymy under P. b. levipes because Mount Orizaba (type locality of beatae) is "relatively very near" Mount Malinche (type locality of levipes), and Thomas had not compared beatae with levipes. Xometla, on the east side of the Volcan de Orizaba, is approximately 56 miles east of the Tlaxcalan part of Mount Malinche and is situated where the Tropical Life-zone begins, whereas Mount Malinche is in the Austral Life-zone on the Mexican Plateau; the difference in habitat between the two places is great. Topotypes of levipes differ from two topotypes of beatae in the same fashion as do other specimens of levipes (from San Luis Potosi) from other specimens of beatae (from Veracruz). Unfortunately, the topotypes of beatae lack external measurements and are subadults, but their coloration agrees with that of other specimens that are here referred to beatae.

Hall and Kelson (1959:634, map 364) incorrectly mapped the distribution of levipes in Veracruz. There are at least two places named Xuchil in the state of Veracruz and Hall and Kelson (loc. cit.) unfortunately plotted the one at lat. 20 deg. 42' N, long. 97 deg. 42' W whereas the specimens actually were collected at the Xuchil on the pleateau south of the Volcan de Orizaba (18 deg. 53' N, 97 deg. 14' W) in the west-central part of Veracruz. The specimens from Xuchil are P. b. beatae.

Intergradation in color between the two subspecies levipes and beatae is seen in specimens from Jalapa and Zacualpan (3 km. N, also others from 3 km. W), Veracruz. Intergradation between these two subspecies possibly will be found elsewhere along the Sierra Madre Oriental.

Specimens examined.--Total 60 as follows: VERACRUZ: 1 km. E Jalancingo, 6500 ft., 2; 2 km. S Jalancingo, 2; 6 km. SSE Altotonga, 8000 ft., 8; 1 km. W Las Vigas, 8500 ft., 2; Las Vigas, 8500 ft., 13; 2 km. E Las Vigas, 8000 ft., 5; 3 km. E Las Vigas, 8000 ft., 8; 5 km. E Las Vigas, 7 (TAM); 5 km. N Jalapa, 4500 ft., 2; Jalapa, 1 (USNM); 10 km. SE Perote, N slope Cofre de Perote, 10,500 ft., 1 (TAM); Xometla Camp, Mt. Orizaba, 8500 ft., 2 (BM); Sta. Barbara, Mt. Orizaba, 12,000 ft., 1 (BM); Xuchil, 6 (CM).

#Peromyscus boylii ambiguus# new subspecies

Type.--Male, adult, skin and skull, No. 33092, United States National Museum, from Monterrey, Nuevo Leon; obtained on February 17, 1891, by Wm. Lloyd, original number 377.

Geographic distribution.--Eastern Coahuila, central Nuevo Leon, and the Sierra San Carlos, Tamaulipas.

Diagnosis.--Size small for the species; tail averaging longer than head and body (90-114%); dorsal coloration ochraceous, slightly darker middorsally; cheeks and lateral line Capucine Orange; skull small; supraorbital border rounded; anterior palatine foramina short.

Comparisons.--P. b. ambiguus differs from P. b. levipes in smaller size, longer tail relative to length of head and body, smaller incisive foramina, brighter and paler color, and relatively broader interorbital region. From P. b. beatae, P. b. ambiguus differs in being smaller in all parts measured and paler.

Remarks.--Osgood (1909:155) reported as P. b. levipes 37 specimens from Monterrey and 18 from Cerro de la Silla, Nuevo Leon, but noted that they were "aberrant." I have examined those same specimens and can hardly decide to which species, P. boylii or P. pectoralis, they belong. Everything considered I, as did Osgood, opine that the specimens are P. boylii. However, I do not rule out the possibility that in this area there is an unnamed species, because I find an unusually wide range of variation in such cranial characters as size of the bullae, width and form of the pterygoid fossa, and shape of the braincase. Extremes of these characters are not constantly associated except in one specimen (33124 USNM), which is the smallest of all the adults examined. It has small bullae, a short rostrum, widely spreading zygomatic arches anteriorly, and a narrow pterygoid fossa, but does not differ externally from the other specimens. Additional material from this area is needed in order to make out the systematic position of these mice.

Because of the wide range of variation in some of its characters, P. b. ambiguus is difficult to diagnose. Nevertheless, its small external and cranial size, short anterior palatine foramina, and bright color seem to separate it from other subspecies of P. boylii in the eastern part of the range of the species. These differences are most conspicuous when specimens from the northernmost part of the range of levipes are compared with specimens of ambiguus.

The specimens from the Sierra San Carlos, Tamaulipas, closely resemble levipes in color, but are referred to ambiguus on the basis of small size, as also are the two specimens from 12 km. E San Antonio de las Alazanas, Coahuila.

TABLE 1. MEASUREMENTS (IN MILLIMETERS) OF PEROMYSCUS

A: Number of specimens B: Total length C: Length of tail-vertebrae D: Length of hind foot E: Per cent length of tail to head and body F: Greatest length of skull G: Zygomatic breadth H: Interorbital constriction I: Length of nasals J: Palatine slits K: Maxillary tooth-row