Intergradation occurs between L. i. texensis and L. i. pretiosus in southeastern Tamaulipas as noted previously by Hooper (1953:5). Individuals from Altamira and one mile south thereof are small and dark as in pretiosus, but cranial measurements are as in texensis to which they are here assigned. Specimens from the vicinity of Tampico are typical texensis.
Average weight of the specimens from three different localities are as follows: Soto la Marina, seven males, 42.7, 14 females, 36.9; Sierra de Tamaulipas, 12 males, 47.3, 20 females, 40.7; Sierra Madre Oriental, eight males, 45.5, nine females, 37.0 grams.
The specimens reported by Ingles (1959:394) from two miles south of El Mante as L. irroratus are here referred to texensis on geographic grounds.
Records of occurrence.—Specimens examined, 121: 7 km. S, 2 km. W San Fernando, 7; 7 km. SW La Purisima, 1; Rancho Santa Rosa, 25 km. N, 13 km. W Cd. Victoria, 260 m., 2; 36 km. N, 10 km. W Cd. Victoria, 1; 15 mi. N Cd. Victoria, 2; 4 mi. N La Pesca, 5; Soto la Marina, 25; Sierra Madre Oriental, 5 mi. S, 3 mi. W Cd. Victoria, 1900 ft., 18; Sierra de Tamaulipas, 2 mi. S, 10 mi. W Piedra, 1200 ft., 36; Sierra de Tamaulipas, 3 mi. S, 10 mi. W Piedra, 1200 ft., 1; Ejido Santa Isabel, 2 km. W Pan-American Highway, 2000 ft., 3; Rancho Pano Ayuctle, 25 mi. N, 3 km. W El Mante, 300 ft., 1; Rancho Pano Ayuctle, 6 mi. N Gómez Farías, 300 ft., 8; 10 km. N, 8 km. W El Encino, 400 ft., 1; 2 km. W El Carrizo, 6; 53 km. N El Limón, 4; 8 km. NE Antiguo Morelos, 2; Altamira, 1; 1 mi. S Altamira, 3; 10 mi. NW Tampico, 1; 7 km. N Tampico, 2.
Additional records: Hidalgo (Goldman, 1911:59); Matamoros (ibid.); Bagdad (ibid.); Sierra de San Carlos (Hooper and Handley, 1948:20); 3 mi. W Soto la Marina (Hooper, 1953:5); [Cd.] Victoria (Goldman, 1911: 59); Acuña (Hooper and Handley, 1948:20); Mesa de Llera (Hooper, 1953:5); Gómez Farías (Goodwin, 1954:9); 2 mi. S Cd. Mante (Ingles, 1959:394); Antiguo Morelos (Hooper and Handley, 1948:20).
Castor canadensis mexicanus V. Bailey
Beaver
1913. Castor canadensis mexicanus V. Bailey, Proc. Biol. Soc. Washington, 26:191, October 23, type from Ruidoso Creek, 6 mi. below Ruidoso, Lincoln Co., New Mexico.
Distribution in Tamaulipas.—Probably in the Río Grande drainage.
The beaver has been reported in Tamaulipas only from Matamoros (Baird, 1858:355—three specimens) and from 12 miles below, south of, Matamoros (V. Bailey, 1905:124). In Tamaulipas the beaver may occur only in the Río Grande drainage.