Part 23 (2/2)
1909. _Peromyscus boylii levipes_, Osgood, N. Amer. Fauna, 28:153, April 17.
_Distribution in Tamaulipas._--Central and southern parts of state.
Weights of 19 males and 18 females from the Sierra Madre Oriental are, respectively, 25.2 (22-30) and 23.6 (20-29); weights of eight males and five females from the Sierra de Tamaulipas are 24.9 (22-32) and 29.6 (24-31).
_Records of occurrence._--Specimens examined, 54: Sierra Madre Oriental, 8 mi. S, 6 mi. W Victoria, 4000 ft., 37; 5 mi. S, 3 mi. W Victoria, 1900 ft., 2; Ejido Eslabones, 10 mi. W, 2 mi. S Piedra, 1200 ft., 1; Sierra de Tamaulipas, 11 mi. W, 8 mi. S Piedra, 2000 ft., 13; 2 km. W El Carrizo, 1.
Additional records: Rancho del Cielo (Hooper, 1953:7); 3 mi.
NW Acuna (_ibid._); Rancho Viejo (Goodwin, 1954:12); Santa Maria (_ibid._); Joya de Salas (_ibid._).
=Peromyscus pectoralis=
White-ankled Mouse
_Peromyscus pectoralis_ and _P. boylii_ are closely related morphologically and seem to occupy the same habitat. In the Sierra Madre Oriental, according to the field notes of the collector (Heinrich, June 6 to August 5, 1953), individuals of _P. pectoralis_ had a pinkish coloration on the mouth and forefeet produced by the juice of the ”nopal” cactus fruit, on which obviously the mice feed, whereas only a few specimens of _boylii_ were thus discolored. It was noted that _boylii_ was feeding on acorns. Furthermore, the two species may differ in time of breeding; in August, males of _pectoralis_ had the testes well developed when those organs were small in _boylii_ collected at the same locality.
A specimen from 53 kilometers north of El Limon, was shot at a height of 10 feet on a concrete underpa.s.s. Other specimens were taken in a trap line that yielded _Peromyscus boylii_, _P. leucopus_ and _Liomys irroratus_.
Two subspecies of _P. pectoralis_ occur in Tamaulipas: _P. p. collinus_ is widely distributed in the central and western parts of the state and _P. p. eremicoides_ occurs only in the western ”corner” of the state.
=Peromyscus pectoralis collinus= Hooper
1952. _Peromyscus pectoralis collinus_ Hooper, Jour. Mamm., 33:372, August 19, type from San Jose, 2000 ft., Sierra San Carlos, 12 mi. NW San Carlos, Tamaulipas.
_Distribution in Tamaulipas._--Along the central and western mountains.
A female obtained on January 21 at a place 53 kilometers north of El Limon, contained three embryos. A lactating female was taken on August 2 in the Sierra Madre Oriental. Males, as previously noted, had well-developed testes in August. The weights of 17 males and 20 females from the Sierra de Tamaulipas were, respectively, 26.6 (24-33), and 25.6 (21-31) grams.
Measurements of specimens from different localities in Tamaulipas averaged about the same, except that those of specimens from Palmillas, averaged smaller. The small size suggests intergradation between the subspecies _collinus_ and _eremicoides_. The latter occurs to the west and differs from _collinus_ in smaller size, more grayish coloration, completely white tarsal joint and relatively longer tail. Hooper (1952:374) reported specimens from Jaumave as intergrades between the two subspecies before mentioned and Osgood (1909:164) identified two specimens from there as _eremicoides_. In the present account, individuals from Palmillas and Jaumave are referred to _collinus_.
_Records of occurrence._--Specimens examined, 101: 7 km. SW La Purisima, 1; Sierra Madre Oriental, 5 mi. S, 3 mi. W Victoria, 1900 ft., 12; Sierra Madre Oriental, 8 mi. S, 6 mi. W Victoria, 4000 ft., 16; Sierra de Tamaulipas, 2 mi. S, 10 mi. W Piedra, 1200 ft., 36; Sierra de Tamaulipas, 3 mi.
S, 14 mi. W Piedra, 1200 ft., 14; 14 mi. N, 6 mi. W Palmillas, 5500 ft., 1; Palmillas, 4400 ft., 3; 53 km. N El Limon, 12 km. S Rio Guayalejo, 5; Joya Verde, 35 km. SW Victoria, 3800 ft., 9; 10 km. N, 8 km. El Encino, 400 ft., 1; 8 km. NE Antiguo Morelos, 500 ft., 3.
Additional records (Hooper, 1952:374, unless otherwise noted): Sierra San Carlos (Marmolejo, 1700 ft., San Jose, 2000 ft., Tamaulipeca, 1500 ft., La Vegonia, 2900 ft.); Villagran, 1300 ft.; Cd. Victoria; near Jaumave, 2400 ft.; Sierra de Tamaulipas, near Acuna, 1600 ft.; La Joya de Salas (Goodwin, 1954:12).
=Peromyscus pectoralis eremicoides= Osgood
1904. _Peromyscus att.w.a.teri eremicoides_ Osgood, Proc. Biol.
Soc. Was.h.i.+ngton, 17:60, March 21, type from Mapimi, Durango.
1909. _Peromyscus pectoralis eremicoides_, Lyon and Osgood, Bull. U. S. Nat. Mus., 62:128, January 28.
_Distribution in Tamaulipas._--Known only from Miquihuana and vicinity of Tula.
The two specimens from Miquihuana are typical _P. pectoralis eremicoides_ in external and cranial measurements. Specimens from nine miles southwest of Tula are characteristic of _eremicoides_ in cranial measurements but the tail is shorter than usual for this subspecies, in this respect approaching _P. p. lacia.n.u.s_.
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