Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) in Southwestern New Mexico:population Genetics, Morphology, and Ecology Inthree Contact Zones

Abstract

have long been interested in the scientific research being conducted in their neighborhood, reflecting their concerns for nature and the future of their land. Bill Sr. has donated significant specimens to scientific collections, and all of the Millers have assisted our research in the Southwest in important ways. In addition, we thank them for good advice, several rescues, and much hospitality. Our work and our lives have been enriched and improved by our association with the Millers. 4 NO. 246 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY

Barriers to Sympatry Between Avian Sibling Species (Paridae: Baeolophus) in Local Secondary Contact

“…For example, it is crucial in such analyses to distinguish between secondary contact and in situ differentiation when explaining patterns of variation where species overlap. Although these two processes may be difficult to distinguish using clinal analysis of single-locus traits (Endler 1977;Harrison 1993;Durrett et al 2000), evidence for secondary contact is provided by concordant clines of different traits, especially some that are known to be neutral (Barton and Hewitt 1981;Dessauer et al 2000). Similarly, tracking the timing of secondary contact relative to the history of isolation is critical for explaining current patterns and processes.…”

“…Studies of closely related taxa, especially where they occur in secondary contact along ecotones, provide a valuable framework for examining distributional limits and evolutionary barriers to gene exchange (e.g., Harrison and Arnold 1982;Latta and Mitton 1999;Dessauer et al 2000). The common association between secondary contact zones and environmental gradients can be explained by a balance between dispersal and selection (Barton and Hewitt 1985), the latter acting either on genotype-specific responses to the environment (Endler 1977) or on fitness of intermediate genotypes Hewitt 1981, 1985).…”

Laboratory Hybridization Among North American Whiptail Lizards, IncludingAspidoscelis Inornata Arizonae × A. tigris marmorata(Squamata: Teiidae), Ancestors of Unisexual Clones in Nature

“…For A. inornata, we have examined 115 bone marrow cells at mitotic metaphase from 21 individuals (including both sexes) from widespread localities representing four subspecies, including seven specimens of A. i. arizonae from the vicinity of Willcox, Cochise County, Arizona, all of which were karyotypically identical to each other (e.g., Lowe et al, 1970;Cole et al, 1988). For A. tigris sensu lato, we have examined at least 40 specimens also from widespread localities representing various subspecies, all of which are karyotypically identical to each other, excepting for the sex chromosomes that distinguish males and females (e.g., Cole et al, 1969;Lowe et al, 1970;Dessauer et al, 2000;Taylor et al, 2001;Cole et al, 2007). For A. neomexicana, which has a diploid karyotype consistent with its hybrid origin of A. t. marmorata × A. inornata, we have examined about 175 cells at mitotic metaphase from more than 30 individuals from throughout its geographic range (Cole et al, 1988;Manning et al, 2005).…”

“…Methods of preparing homogenates, conducting electrophoresis (except we used vertical gels), localizing specific proteins, and scoring gel phenotypes, as well as the abbreviations for specific gene loci, followed Harris and Hopkinson (1976), Murphy et al (1996), and, particularly for lizards of the genus Aspidoscelis, Dessauer et al (2000).…”

“…This species originated as a result of hybridization between Aspidoscelis tigris marmorata (♀) × Aspidoscelis inornata (♂) (for reviews, see Neaves, 1969;Neaves and Gerald, 1969;Brown and Wright, 1979;Parker and Selander, 1984;Cole et al, 1988;Dessauer and Cole, 1989), for which two comments on the scientific names of the parental forms are pertinent: (1) some authors disagree with applying names of modern taxa to ancestral events, but the ancestral hybridization could have happened only a few hundred or a few thousand years ago and the genetic signature of the ancestors is clear-we have no basis for calling them anything else; and (2) some authors today treat A. t. marmorata as a species separate from A. tigris (we follow Dessauer et al, 2000) and some treat A. inornata arizonae (see below) as a species separate from A. inornata (we follow Wright and Lowe, 1993, with respect to considering arizonae as part of inornata).…”