A New Subspecies of Lizard, Cnemidophorus sacki, from Michoacán, México

by William Edward Duellman

Ecology.—In the arid Tepalcatepec Valley Cnemidophorus sacki zweifeli lives at elevations of 160 to 1300 meters. In the lower parts of the valley the lizards live primarily in open scrub forests, characterized by deciduous trees offering only partial shade from the sun, especially during the prolonged dry season. Common trees in this scrub forest are Acacia cymbispina, Cercidium plurifoliolatum, Mimosa distachya, and Prosopis juliflora.

During the dry season (November through May) adult males apparently aestivate; several large series collected in the winter include only subadults and females. This absence of males is corroborated by personal observations in the Tepalcatepec Valley in April and May. In the summer rainy season the lizards are active in the morning and again in the late afternoon; only Cnemidophorus calidipes is active during the heat of the midday. In some areas of the scrub forest Cnemidophorus sacki zweifeli is found in association with Cnemidophorus communis communis. Throughout the scrub forest C. sacki zweifeli occurs with C. deppei infernalis. In some of the more dense scrub forest, where C. sacki zweifeli is not so abundant as in the more open forest, it has been taken with C. lineatissimus exoristus. In the open Acacia-Cercidium associations on the valley floor C. sacki zweifeli occurs with C. calidipes.

This subspecies is not restricted to the scrub forest. On the lower slopes of the Cordillera Volcanica in Michoacán C. sacki zweifeli has been collected in open pine-oak forest near Zirimicuaro and Ziracuaretiro.

Distribution.—Cnemidophorus sacki zweifeli inhabits the valley of the Río Tepalcatepec in Michoacán and probably extreme southwestern Jalisco, and the western part of the Balsas Basin in Michoacán. No specimens have been seen from extreme western Guerrero, but C. s. zweifeli may occur there.

Specimens examined.—Catalogue numbers are preceded by abbreviations of the name of the institution as listed in the acknowledgements.

Cnemidophorus sacki occidentalis, 22 specimens, as follows: Jalisco: 8 km. E of Ameca, UMMZ 102045; 7 km. SE of Ameca, UMMZ 102046; Autlán, UMMZ 102044, 102219-21; 7 km. ESE of El Arenal, UMMZ 114736 (2); San Gabriel, UMMZ 102040, 102042-3. Michoacán: 2 km. ESE of Jiquilpan, UMMZ 117557 (3). Nayarit: Ixtlán del Río, UMMZ 104747; San José de la Conde, UMMZ 102047 (4); 5 km. N of Santa Isabel, UMMZ 102048-50.

Cnemidophorus sacki sacki, 108 specimens, as follows: Guerrero: Chilpancingo, UMMZ 72426 (8), 73937 (7), 88422 (4); 8 km. W of Chilpancingo, UMMZ 119144 (4); 5 km. N of Iguala, UMMZ 114712 (11); 15 km. N of Iguala, UMMZ 99039; Mexcala, UMMZ 114711 (10); 8 km. S of Taxco, UMMZ 114709 (2). Morelos: Amacuzac, UMMZ 114716; 3 km. S of Cuautla, UMMZ 99031 (9), 99917 (11): Río Cuautla, UMMZ 99038 (6); 5 km. S of Temixco, UMMZ 114718 (12); Puebla: 5 km. SE of Izúcar de Matamoros, UMMZ 112650 (4); 13 km. SE of Izúcar de Matamoros, UMMZ 117497 (2); 3 km. NW of Tehuitzingo, UMMZ 114714 (10); 1 km. N of Teyuca, UMMZ 114713 (6).

Cnemidophorus sacki zweifeli, 207 specimens, as follows: Michoacán: Apatzingán, CNHM 36966-8, 38969, 38971 (18), 38972 (50), UIMNH 36772-7, USNM 135967-8, 135970, 135972-3; 4 km. E of Apatzingán, UMMZ 85412; 6.5 km. E of Apatzingán, UMMZ 114731 (5); 5 km. W of Apatzingán, KU 29289-90, 29293-7; 10 km. W of Apatzingán, UMMZ 114730 (4); 12.3 km. S of Apatzingán, UMMZ 112647; 16 km. S of Apatzingán, KU 29298; 14 km. SSW of Apatzingán, KU 29735, 29746, 29750-2; 10 km. W of Buenavista, UMMZ 114719 (3); Capirio, UMMZ 112643, 114722 (2), 114733, 119536-50; 4 km. N of Capirio, UMMZ 112644 (3), 112645; 5.6 km. N of Capirio, UMMZ 114732; 2 km. S of Charapendo, UMMZ 112639 (12); Chinapa, UMMZ 119556 (2); Jazmin, UMMZ 114725 (2); between La Playa and Volcán Jorullo, UMMZ 104748 (2); Limoncito, UMMZ 119552 (3); 14 km. S of Lombardia, KU 29299-301, 29303, 29305-11; 6 km. SW of Nueva Italia, UMMZ 112640 (2); 2.7 km. S of Nueva Italia, UMMZ 112641 (4); 5 km. N of Nueva Italia, UMMZ 114721; Río Marquez, 10 km. S of Lombardia, UMMZ 112642, 112646; Río Marquez, 13 km. SE of Nueva Italia, UMMZ 114726; 6 km. N of Tafetan, UMMZ 119555 (18); 14.5 km. E of Tepalcatepec, UMMZ 114720 (2); 6 km. S of Tzitzio, UMMZ 99199, 99200 (2); 19 km. S of Tzitzio, UMMZ 99154; Volcán Jorullo, UMMZ 104449 (4), 104750; Ziracuaretiro, UMMZ 114724; 3 km. NW of Zirimicuaro, UMMZ 114723.

Acknowledgments.—For the loan of specimens under their care I am indebted to Doris M. Cochran, United States National Museum (USNM); Norman Hartweg, University of Michigan Museum of Zoology (UMMZ); Robert F. Inger, Chicago Natural History Museum (CNHM); and Hobart M. Smith, University of Illinois Museum of Natural History (UIMNH). I thank Ann S. Duellman, Richard E. Etheridge, Fred G. Thompson, Jerome B. Tulecke, and John Wellman for their assistance in the field, Lorna Cordonnier for the drawing reproduced as Figure 1, and Richard G. Zweifel for helpful suggestions and criticism. Field work in México was made possible by grants from the Penrose Fund of the American Philosophical Society and the Bache Fund of the National Academy of Sciences in co-operation with the Museum of Zoology of the University of Michigan.

Transmitted February 2, 1960.