1853. _Hesperomys texana_ Woodhouse, Proc. Acad. Nat. Sci.
Philadelphia, 6:242, type probably from vicinity of Mason,
Mason Co., Texas.
1909. _Peromyscus leucopus texanus_, Osgood, N. Amer. Fauna,
28:127, April 17.
_Distribution in Tamaulipas._--Over all of state.
This is the most common species of the genus _Peromyscus_ in
Tamaulipas. It and _Liomys irroratus_ are the two rodents most easily
trapped throughout the state. In general _P. l. texanus_ occurs in
forested and brushy areas especially under 1200 feet in elevation, as
was noted in the Sierra de Tamaulipas, where _P. l. texanus_ was taken
commonly at elevations of up to 1200 feet. Above this elevation the
species was rare and _P. pectoralis_ and _P. boylii_ were more abundant
than at lower elevations. The three specimens of _P. l. texanus_ from
12 kilometers north and four kilometers west of Ciudad Victoria were
trapped in a line of 110 traps set near tree stumps. Small burrows in
the ground were noted here. The forest at this locality was composed of
mesquite, ebony, acacias, a few yuccas and "nopales" (= cactuses); the
ground was covered by cat claw.
Of the many young taken, 15 specimens were saved from Ejido Santa
Isabel where _P. leucopus_ was abundant in an area of chaparral
consisting of wild "tomate," "zapote," "huizache" and "salvadora." Most
of the specimens caught at this locality were taken between 7:30 and
9:30 p. m. in traps baited with a mixture of rolled oats, peanut butter
and banana. Specimens from 53 kilometers north of El Limon were taken
along with _Liomys irroratus_; the specimen from two kilometers west of
El Carrizo was trapped near a dead mesquite log. _Reitrodontomys
fulvescens_ was taken in the same area. Four specimens of _P. leucopus_
were taken at Rancho Pano Ayuctle, around a big pile of old firewood in
an abandoned sugar mill. At the locality six miles north and six miles
west of Altamira, _P. leucopus_ was found in cultivated fields and
along the grassy roadsides; in the vicinity of Tampico specimens were
taken in an area of forested cactus-thorn. The specimen from seven
kilometers south and two kilometers west of San Fernando was found in a
trap set at the base of "nopal" cactus, which was surrounded by bushes
and small trees (10-12 feet high).
Breeding records are as follows: Rancho Pano Ayuctle, on February 15,
one female carried 2 embryos of 23 mm. in crown-rump length; Jaumave,
July 26 to 29, five females, averaging 4.6 (3-6) embryos of 7 (3-15)
mm., two females lactating, one on May 25 and the other on July 26;
Ejido Santa Isabel, on January 20 to 25, three females lactating; Soto
la Marina, on May 16, one female lactating.
Average weights were as follows: from Jaumave four pregnant females,
28.0 (25-33), eight males, 23.4 (21-27); from the Sierra de Tamaulipas,
eight females non-pregnant, 21.2 (18-26), 14 males, 22.0 (19-27); from
6 mi. N, 6 mi. W Altamira, six males, 23.5 (21-27).
All specimens examined from Tamaulipas are assigned to _P. l. texanus_
because their coloration is pale. Even so the color varies some
according to locality; specimens from Rancho Pano Ayuctle and the
Sierra de Tamaulipas have much of the cinnamon color that is
characteristic of _P. l. incensus_ from farther south, but even so
specimens from the two localities last mentioned are paler than those
from Veracruz that are typical _incensus_.
Goldman (1942:158) reported specimens from Altamira as _P. l.
incensus_, in which subspecies Ingles (1959:397) included specimens
from two miles west of Tampico, but specimens examined from the same
area do not differ from individuals from far north thereof; for this
reason I identify specimens from these localities as _texanus_. Osgood
(1909:131) and Hooper (1953:7) also referred specimens from the
southern part of Tamaulipas to _texanus_. These two authors examined
156 specimens and did not find any intergradation between _texanus_ and
_incensus_, but to me, the cinnamon tones of specimens from Rancho Pano
Ayuctle and the Sierra de Tamaulipas, suggest intergradation between
the two subspecies.
Osgood's (1909:265) measurements of _P. l. texanus_, from Brownsville,
Texas, and those of 40 specimens from different localities in
Tamaulipas are about the same except that the anterior palatine
foramina average longer in Tamaulipas. Baker's (1956:262) specimens
from Coahuila, averaged larger even than Tamaulipan specimens. Another
difference between Osgood's measurements and Baker's was the shorter
3.4 (3.0-3.7) maxillary tooth-row in Tamaulipan specimens.
Hooper (1953:7) recorded specimens from General Teran, as in
Tamaulipas; actually this locality is in Nuevo Leon.
_Records of occurrence._--Specimens examined, 149: 4.5 mi. S
Nuevo Laredo, 1; 3 mi. SE Reynosa, 2; 7 km. S, 2 km. W San
Fernando, 1; Villa Mainero, 1700 ft., 1; Rancho Santa Rosa,
25 km. N, 13 km. W Cd. Victoria, 260 m., 2; 9.5 mi. SW
Padilla, 800 ft., 2; 15 mi. N Cd. Victoria, 2; 4 mi. N La
Pesca, 1; Soto la Marina, 11; La Pesca, 1; 12 km. N, 4 km. W
Cd. Victoria, 3; 7 km. NE Cd. Victoria, 1; Sierra de
Tamaulipas, 10 mi. W, and 2 mi. S Piedra, 1200 ft., 31;
Ejido Eslabones, 10 mi. W, 2 mi. S Piedra, 1200 ft., 6;
Jaumave, 20; Ejido Santa Isabel, 2 km. W Pan-American
Highway, 2000 ft., 15; 53 km. N El Limon, 12 km. S Rio
Guayalejo, 5; Rancho Pano Ayuctle, 25 mi. N El Mante, 3 km.
W Highway, 300 ft., 16; Rancho Pano Ayuctle, 6 mi. N Gomez
Farias, 300 ft., 7; 8 km. W, 10 km. N El Encino, 400 ft., 3;
8 mi. N Tula, 4500 ft., 2; 2 km. W El Carrizo, 3; 6 mi. N,
6 mi. W Altamira, 9; 16 km. N Tampico, 1; 7 km. N Tampico, 3.
Additional records (Osgood, 1909:131, unless otherwise
noted): Nuevo Laredo; Mier; Camargo; near Bagdad; Sierra San
Carlos (Hooper, 1953:7); Matamoros-Victoria Highway
(_ibid._); Charco Escondido (Baird, 1858:464); Hidalgo; Cd.
Victoria; 10 mi. NE Zamorina (Hooper, 1953:7); Gomez Farias
(Goodwin, 1954:12); Chamal (_ibid._); Tula (Hooper, 1953:7);
Antiguo Morelos (_ibid._); Altamira (Goldman, 1942:158); 2
mi. W Tampico (Ingles, 1959:397); Tampico.
=Peromyscus boylii=