Salvadora mexicana Günther, Ann. Mag. Nat. Hist., ser. 3, 12:349, 1863.
Apatzingán (12); Capirio (2); El Sabino (5); Huetamo; La Placita; La Playa (4); Lombardia; Nueva Italia; Ojos de Agua de San Telmo; Oropeo; Río Cancita, 14 km. E of Apatzingán; Santa Ana.
This is one of the most abundant snakes in the arid lowlands of the Tepalcatepec Valley; observations indicate that it probably is equally abundant on the coastal lowlands. Near Apatzingán as many as five of these snakes have been seen in one-half hour. The snakes seem to be equally abundant and active in the dry season and in the rainy season. Most individuals were seen on the ground, but two were found in low trees. On several occasions Salvadora mexicana was observed in pursuit of lizards on the ground. Captured individuals regurgitated Cnemidophorus costatus zweifeli, Cnemidophorus deppei infernalis, Sceloporus horridus oligoporus, Sceloporus pyrocephalus, and Urosaurus gadowi.
Salvadora mexicana inhabits only the arid scrub forest at elevations from sea level to about 1000 meters.
Sibon nebulatus (Linnaeus)
Coluber nebulatus Linnaeus, Systema naturae, ed. 10, 1, p. 222, 1758.—Africa (in error). Type locality restricted to Jicaltepec, Veracruz, México, by Smith and Taylor (1950a:349).
Sibon nebulatus, Taylor, Univ. Kansas Sci. Bull., 26:473, November 27, 1940.
Aquila.
The one specimen from Michoacán was collected by Peters (1954:30) in tropical semi-deciduous forest on the coastal foothills of the Sierra de Coalcomán. As presently known, the range of this species in western México extends from Chiapas to Nayarit. Throughout this region the species avoids scrub forest; this may explain its absence in the Balsas-Tepalcatepec Valley.
Sonora michoacanensis michoacanensis (Dugès)