Analysis of Hybridization between Two Subspecies of the Desert Whiptail Lizard, Cnemidophorus tigris

Phylogeography of the Western Lyresnake (Trimorphodon biscutatus): testing aridland biogeographical hypotheses across the Nearctic–Neotropical transition

“…Remington described this area as a suture zone between distinct Sonoran and Chihuahuan desert biota based largely on work detailing hybridization between Sonoran and Chihuahuan forms of the western whiptail lizard Aspidocelis (Cnemidophorus ) tigris (Dessauer et al . 1962; Zweifel 1962; Wright & Lowe 1967, 1968). Dessauer et al .…”

An Evaluation of Narrow Hybrid Zones in Vertebrates

“…In some cases, inferences based on geological data or events recorded in historical times, were made as to the time when secondary contact was established. These complexes include two ecologically distinct morphs of sticklebacks, Gasterosteus aculeatus, in British Columbia (Hagen, 1967); toads, Bufo woodhousei x B. fowleri, in Texas (Meacham, 1962); anurans, Geocrinia laevis x G. victoriana, in Victoria (Littlejohn, Watson, and Loftus-Hills, 1971;Littlejohn and Watson, 1973, 1974; anurans, Litoria ewingi and L. paraewingi, in Victoria (Watson, Loftus-Hills, and Littlejohn, 1971;Watson, 1972;Gartside, 1972;Littlejohn, 1976); whiptail lizards, Cnemidophorus tigris gracilis x C. t. marmoratus, in Arizona and New Mexico (Zweifel, 1962;Dessauer, Fox, and Pough, 1962); leopard lizards, Crotaphytus wislizenii X C. silus, in California (Montanucci, 1970); chromosomal races of the Sceloporus grammicus complex of iguanid lizards in Mexico (Hall and Selander, 1973); orioles, Icterus galhula galbula X I. g. bullockii (Sibley and Short, 1964;Rising, 1970Rising, , 1973, flickers,Colaptesauratus auratus x C. a. cafer (Short, 1965), and towhees, Pipilo erythrophthalmus erythrophthalmus x P. e. arcticus (Sibley and West, 1959), on the Great Plains; grackles, Quiscalus quiscula quiscula X Q. q. versicolor, in eastern and southeastern United States (Huntington, 1952;Yang and Selander, 1968); titmice, Parus bicolor x P. atricristatus, in Texas (Dixon, 1955); towhees, Pipilo erythrophthalmus X P. ocai, in Mexico (Sibley, 1954) (Thaeler, 1968).…”

“…The hybrid populations occur primarily in the narrow belt of transitional oak-hickory forest sandwiched between pine-oak forest to the east and blackland prairie to the west (Meacham, 1962). Zweifel (1962) noted that the narrow secondary intergradation zone between Cnernidophorus tigris gracilis and C. t. rnarrnoratus is correlated with the specific and subspecific range limits of several forms with which these two lizards are geographically and ecologically associated. Lowe ( 1955) described the general vicinity of these hybrid populations as a complex ecotone between the Sonoran Desert and more eastern biotas.…”

Chromosome Studies of Pocket Gophers, Genus Thomomys. I. The Specific Status of Thomomys umbrinus (Richardson) in Arizona

“…Presumably this occurred as the two species came into contact following changes in the vegetation in the present area of sympatry. Present hybridization between other groups of vertebrates (for example, Cnemidophorus- Zweifel, 1962;Lowe and Wright, 1966) and plants (for example, oaks-Tucker, 1963) in the same general area has been attributed to these factors also.…”