Specimens from southern Michoacán have fewer ventrals and caudals than do those from the northern part of the range; three males and three females have, respectively, 178, 182, 182, 185, 186, and 188 ventrals, and 27, 28, 29, 22, 29, and 29 caudals. Klauber (1952:81) gave the following data for Crotalus basiliscus (based on specimens from the entire range, except Oaxaca): ventrals in males, 179-201 (191.4), in females, 185-206 (197.6); caudals in males, 26-36 (30.7), in females, 21-29 (24.4). Klauber (1952:84) remarked that the one specimen that he had seen from Apatzingán had fewer ventrals and caudals than most other specimens. The low numbers of ventrals and caudals in specimens from Michoacán, as compared with more northern populations, may be indicative of a trend in the reduction of the numbers of these scutes from north to south. The southernmost examples of Crotalus basiliscus (Crotalus basiliscus oaxacus from Oaxaca) have 172-175 ventrals and 21 caudals (Gloyd, 1948).
In Michoacán Crotalus basiliscus basiliscus has been found in arid habitats on the coast, in the Tepalcatepec Valley, and in the lower parts of the Sierra de Coalcomán. All specimens are from localities below 1070 meters in elevation.
Crotalus durissus culminatus Klauber
Crotalus durissus culminatus Klauber, Bull. Zool. Soc. San Diego, 26:65, August 8, 1952.—El Sabino, Michoacán, México.
El Sabino (18).
These specimens are part of the type series and were collected by Hobart M. Smith near the upper limits of the arid scrub forest at an elevation of about 1050 meters on the lower slopes of the Cordillera Volcánica at the northern edge of the Tepalcatepec Valley. They were discussed in detail by Klauber (1952:66-70).
Crotalus intermedius intermedius Troschel
Crotalus intermedius Troschel, in von Müller, Reisen in Vereiningten Staaten, Canada und Mexico, vol. 3, p. 613, 1865.—Type locality unknown.
Crotalus intermedius intermedius, Klauber, Bull. Zool. Soc. San Diego, 26:9, August 8, 1952.
Cerro Tancítaro.