Gerrhonotus imbricatus imbricatus Wiegmann
Gerrhonotus imbricatus Wiegmann, Isis von Oken, 21:379, 1828.—México. Type locality restricted to México, Distrito Federal, by Smith and Taylor (1950b:201).
Gerrhonotus imbricatus imbricatus, Dunn, Proc. Acad. Nat. Sci. Philadelphia, 88:475, October 20, 1936.
Acuaro de las Lleguas (9); Cerro Barolosa (4); Cerro Tancítaro (36); Dos Aguas (22); Paracho; Sierra Patamba; Tinguidín; Zacapu.
Specimens from the Sierra de Coalcomán are noticeably different from those inhabiting the mountains rising from the Mexican Plateau. Of 45 specimens from Cerro Tancítaro and adjacent areas on the Mexican Plateau and in the Cordillera Volcánica, 15 have twelve longitudinal rows of dorsal scales and 30 have fourteen rows. Of seven specimens from the state of México, 5 have twelve rows and 2 have fourteen; of nine specimens from central Veracruz, 8 have twelve rows and one has fourteen; of six specimens from Hidalgo, 5 have twelve rows and one has sixteen; of two specimens from Guanajuata, one has fourteen and the other has sixteen rows. All of the 35 specimens from the Sierra de Coalcomán have sixteen rows. Furthermore, these specimens have the superciliary row extended anteriorly, so that the anterior superciliary is in broad contact with the loreal. Specimens from Cerro Tancítaro have a shorter superciliary row, so that the anterior superciliary is not in broad contact with the loreal. These characters were used by Tihen (1949:220) to distinguish Gerrhonotus imbricatus ciliaris from G. imbricatus imbricatus. According to Tihen, the subspecies G. imbricatus ciliaris ranges from Guanajuato and Hidalgo northward to Chihuahua and Coahuila, whereas the nominal subspecies occurs from Michoacán and Hidalgo southward to Oaxaca. Specimens from the Sierra de Autlán in Jalisco are like those from Cerro Tancítaro; consequently, there seems to be no connection between the populations of G. imbricatus ciliaris in the mountains of the northern part of the Mexican Plateau with the ciliaris-like individuals found in the Sierra de Coalcomán. The acquisition and study of additional material from throughout the range of the species is necessary to clarify the picture of geographic variation. Until then, I prefer to consider all of the specimens from Michoacán as Gerrhonotus imbricatus imbricatus.
The largest specimen is a male having a snout-vent length of 136 mm. Two juveniles collected in July 24, 1960, have snout-vent lengths of 36 and 42 mm. A specimen having a snout-vent length of 127 mm. and a tail length of 145 mm. was regurgitated by a Crotalus pusillus, which had a body length of 550 mm.
Gerrhonotus imbricatus imbricatus is an inhabitant of coniferous forests. In the Cordillera Volcánica it occurs from 1500 to 3500 meters at the top of Cerro Tancítaro. In the Sierra de Coalcomán it occurs from 2100 to 2700 meters. On July 4, 1955, a pair was found in copulation beneath a pine log at 2700 meters on Cerro Barolosa. The male was lying on top of the female and was holding her head firmly in his jaws; the male's tail was curled under the female's tail, so that the cloacae were in contact.
Serpentes
Typhlops braminus (Daudin)
Eryx braminus Daudin, Hist.... des reptiles, 7:279, 1803.—Vazagapatam, India.