Coues Rice Rat
_Oryzomys aquaticus_ Allen, Bull. Amer. Mus. Nat. Hist., 3:289, June 30, 1891. (Type from Brownsville, Cameron County, Texas.)
_Oryzomys couesi aquaticus_ Goldman, N. Amer. Fauna, 43:39, September 23, 1918.
_Specimens examined_, 2 as follows: 36 km. N and 10 km. W Ciudad Victoria, 1 km. E El Barretal, on Rio Purificacion, 1; 70 km. [by highway] S Ciudad Victoria and 6 km. W of the [Pan-American] highway [at El Carrizo], 1.
_Remarks._--The specimens, all immatures, are slightly darker than topotypes of _O. c. aquaticus_, seemingly tending toward the darker _O.
c. peragrus_ Merriam to the southward. These records of occurrence extend the known range of this subspecies approximately 210 miles to the southward and increase the possibility of continuous distribution between _O. c. aquaticus_ and _O. c. peragrus_.
The male obtained south of Ciudad Victoria was taken on January 12, by William J. Shaldach, Jr., 200 yards within the tunnel of a mine at an elevation of approximately 2600 feet. This was in the Sierra Gorda, which is a part of the Sierra Madre Oriental.
~Oryzomys rostratus rostratus~ Merriam
Rice Rat
_Oryzomys rostratus_ Merriam, Proc. Washington Acad. Sci., 3:293, July 26, 1901. (Type from Metlaltoyuca, Pueblo, Mexico.)
_Specimen examined_, 1 from 70 km. [by highway] S Ciudad Victoria and 2 km. W El Carrizo.
_Remarks._--This immature male is paler than specimens of _O. r.
rostratus_ from the state of Veracruz. This locality extends the known range of this species northward a distance of approximately 100 miles.
Previously it had been recorded from only as far north as Alta Mira, Tamaulipas (Goldman, N. Amer. Fauna, 43:54, September 23, 1918). This specimen was trapped on February 16 in a rodent runway in dense gra.s.s in a fallow cane field.
~Oryzomys fulvescens engraciae~ Osgood
Fulvous Rice Rat
_Oryzomys fulvescens engraciae_ Osgood, Jour. Mamm., 26:300, November 14, 1945. (Type from Hacienda Santa Engracia, northwest of Ciudad Victoria, Tamaulipas, Mexico.)
_Specimens examined_, 5 from 70 km. [by highway] S Ciudad Victoria and 2 km. E El Carrizo.
_Remarks._--These specimens are referred to _O. f. engraciae_ on the basis of their pale color and narrow interorbital s.p.a.ce. They were taken in runways in dense gra.s.s in fallow cane fields.
~Sigmodon hispidus toltecus~ (Saussure)
Hispid Cotton Rat
[_Hesperomys_] _toltecus_ Saussure, Revue et magasin de zoologie, _ser._ 2, 12:98, 1860. (Type from mountains of Veracruz, Mexico.)
_Sigmodon hispidus toltecus_ Bailey, Proc. Biol. Soc.
Washington, 15:110, June 2, 1902.
_Specimens examined_, 23 as follows: 36 km. N and 10 km. W Ciudad Victoria, 1 km. E El Barretal, on Rio Purificacion, 1; 70 km. [by highway] S Ciudad Victoria and 2 km. W El Carrizo, 22.
_Remarks._--Among named kinds of _Sigmodon_ this series most closely approaches _S. h. toltecus_ to the southward. The specimens are slightly lighter in color of the upper parts than are examples of this same subspecies from 8 km. NW of Potrero, Veracruz, but in other ways are similar. The single specimen from 36 km. N and 10 km. W Ciudad Victoria is a skull only, but seems closest to _S. h. toltecus_. As is often the case with collections of _Sigmodon_, this series contains mostly immatures.
Cotton rats were found abundantly in cultivated areas. Local farmers stated that these rats were destructive to sugar cane by girdling the stems one and one-half inches above the ground.
~Neotoma micropus micropus~ Baird
Baird Wood Rat
_Neotoma micropus_ Baird, Proc. Acad. Nat. Sci.
Philadelphia, p. 333, April, 1855. (Type from Charco Escondido, Tamaulipas, Mexico.)
_Specimens examined_, 2 from 7 km. S and 2 km. W San Fernando.
~Neotoma angustapalata~ new species
Tamaulipan Wood Rat
_Type._--Male, subadult, skin and skull; No. 36976, Univ.
Kansas Mus. Nat. Hist.; 70 km. [by highway] S Ciudad Victoria and 6 km. W of the [Pan-American] highway [at El Carrizo], Tamaulipas, Mexico; 14 January 1950; obtained by William J. Schaldach, Jr., original no. 578.
_Range._--Known only from the type locality; probably found in other localities along the humid, east face of the Sierra Madre Oriental in Tamaulipas.
_Diagnosis._--Size large (see measurements); upper parts dusky brown, paler on sides, individual hairs on middle of back tipped with black or with Light Pinkish Cinnamon (capitalized color term after Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912); head grayer especially on cheeks; underparts dusky (dark bases of white-tipped hairs exposed), hairs on throat and inguinal region of adult specimen white to base; outside of legs dusky gray; tail scaly in appearance and spa.r.s.ely covered with short, blackish hairs above and short, whitish hairs below; skull with auditory bulla large; external auditory meatus large; palatine region narrow; sides of interpterygoid fossa concave and broadly excavated near posterior end of molariform tooth-rows.
_Comparison._--_Neotoma angustapalata_ has been compared with _N. torquata_ (specimens from Veracruz and Puebla), _N.
navus_ (Coahuila), _N. mexicana_ (New Mexico), _N. micropus_ (Tamaulipas), _N. albigula_ (Coahuila), _N. ferruginea_ (Jalisco), and _N. distincta_ (from published description in Goldman, N. Amer. Fauna, 31:64, October 19, 1910). _Neotoma angustapalata_ differs from _N. micropus_ and _N. albigula_ in having a deep, instead of a shallow, anterointernal reentrant angle on the first upper molar and seems to belong to the _N. mexicana_ group of wood rats. _Neotoma angustapalata_ differs from _N. navus_, _N. mexicana_, _N.
torquata_, and _N. ferruginea_ in larger size, darker underparts, tail with spa.r.s.e, short hairs and scaly appearance, more broadly concave sides of interpterygoid fossa at posterior end of molariform tooth-rows, larger external auditory meatus, and narrower palatine breadth.
_Neotoma angustapalata_ differs from the description of _N.
distincta_ in having a faintly bicolored tail, no ochraceous pectoral band, broadly concave sides to interpterygoid fossa, and narrower palatine breadth.
_Remarks._--_Neotoma angustapalata_ is represented by two specimens; the type and another specimen, an adult male, no. 37062, with skin and broken skull. The description takes into account both of these specimens. The most significant characteristics of _N. angustapalata_ are its scaly-appearing tail with short, spa.r.s.e hairs, dusky underparts, broadly concave sides of the interpterygoid fossa at the posterior end of molariform tooth-rows, and the narrow palatine breadth. Among named kinds of _Neotoma_, the newly named species most closely resembles _N. torquata_ and _N. distincta_; however, it is geographically widely separated from these two species. _Neotoma navus_ of southeastern Coahuila is the only other member of the _N. mexicana_ group in northeastern Mexico.
These wood rats were taken in rocks and crevices at the base of a small hill in thick vegetation growing in deep humus. Schaldach termed the trapping site as "arid tropical tending toward humid tropical".
_Measurements._--The subadult, male holotype measures as follows: Total length, 325; length of tail, 154; length of hind foot, 36; length of ear from notch, 29; basilar length (of skull), 33.9; zygomatic breadth, 22.1; interorbital breadth, 5.7; length of nasals, 15.2; length of incisive foramina, 8.7; length of palatal bridge, 8.5; least breadth of palate between first upper molars, 2.7; greatest breadth of interpterygoid s.p.a.ce, 4.1; alveolar length of upper molariform tooth-row, 9.6. The adult, male, no. 37062, measures as follows: Total length, 380; tail vertebrae, 195; hind foot, 42; ear from notch, 31; interorbital breadth (of skull), 6.4.
_Specimens examined_, 2, from the type locality.
~Rattus rattus~ subsp.
Black Rat
_Specimens taken_, 2 from 70 km. [by highway] S Ciudad Victoria and 6 km. W of the [Pan-American] highway [at El Carrizo].
~Mus musculus~ subsp.
House Mouse