A specimen (56924) from La Pesca differs from all other specimens of N. micropus examined in being smaller, having a conspicuously shorter rostrum, broader intraorbital canal, and lower broader braincase. External measurements of this specimen are as follows: 347; 155; 39; —. Its cranial measurements are: greatest length, 44.8; basilar length, 34.3; zygomatic breadth, 23.6; interorbital constriction, 6.2; incisive foramina, 6.5; length of maxillary tooth-row, 8.7; width of mesopterygoid fossa, 4.1.
Records of occurrence.—Specimens examined, 58: 4 mi. SW Nuevo Laredo, 900 ft., 14; 4-1/2 mi. S Nuevo Laredo, 1; 3 mi. SE Reynosa, 1; 3 mi. S Matamoros, 2; 33 mi. S Washington Beach, 1; San Fernando, 180 ft., 1; 7 km. S, 2 km. W San Fernando, 2; 12 mi. NW San Carlos, 1300 ft., 4; 9-1/2 mi. SW Padilla, 800 ft., 3; 3 mi. N Soto la Marina, 3; Soto la Marina, 500 ft., 12; 4 mi. N La Pesca, 3; 1 mi. E La Pesca, 1; La Pesca, 2; 3 mi. NE Guemes, 1; 7 mi. NE Cd. Victoria, 1; Cd. Victoria, 6.
Additional records (Goldman, 1910:28, unless otherwise noted): Nuevo Laredo; 10 mi. S Nuevo Laredo (Booth, 1957:15); Camargo; Matamoros; Bagdad; 40 mi. S Matamoros (Hooper, 1953:9); Sierra San Carlos (El Mulato, Tamaulipeca) (Dice, 1937:254); San Fernando (J. A. Allen, 1891:224); Forlón.
Microtus mexicanus subsimus Goldman
Mexican Vole
1938. Microtus mexicanus subsimus Goldman, Jour. Mamm., 19:494, November 14, type from Sierra Guadalupe, southeastern Coahuila.
Distribution in Tamaulipas.—Reported only from mountains near Miquihuana (Goldman, 1938:495).
Canis latrans
Coyote
In Tamaulipas two and possibly three subspecies of Canis latrans occur. C. l. texensis is known only from the northwesternmost part of the state, and C. l. microdon occurs from Camargo south to Nicolás. Hall and Kelson (1959:845) guessed that C. l. cagottis would be found in the southern third of the state; as yet specimens from there have not been obtained and the subspecific identity of the coyotes there, if any are present, remains in doubt.