Parthenogenetic Aspidoscelis Neomexicana (Sauria: Teiidae) and Syntopic Congeners in Presidio County, Texas (Report‪)‬

Although the parthenogenetic whiptail lizard Aspidoscelis neomexicana (sensu Reeder et al., 2002) is a well-studied member of the herpetofauna of New Mexico (e.g., Christiansen, 1971; Cole et al., 1988; Walker et al., 1992; Manning et al., 2005), practically nothing is known about its biology in Texas. Specifically, information is needed on distributional ecology of this parthenogen in the Rio Grande Valley southeast of its documented presence at several sites in El Paso, El Paso Co., Texas (Cordes et al., 1989; Dixon, 1987, 2000). The first record of A. neomexicana in Presidio County was reported by Axtell (1966) based on a specimen in the University of Kansas Museum of Natural History (KU 40264) from 36.8 km N, 83.2 km W Marfa. Subsequent authors, however, have expressed doubt about the origin of this specimen (Wright, 1971; Dixon, 1987, 2000) or used it to map the distribution of A. neomexicana southeastward along the Rio Grande in Texas and Chihuahua, Mexico (Cole et al., 1988; Persons and Wright, 1999). Prior to the present report, Cordes et al. (1989, 1990) reported two individuals of this species from a site within the floodplain of Rio Grande in Presidio County that is 225 km SE El Paso. Those specimens confirmed the presence of A. neomexicana in the county as reported by Axtell (1966) and documented the lowest elevation and southernmost geographic distribution for the species. Extensive field work along the Rio Grande in Presidio County by the senior author has revealed A. neomexicana at three sites in assemblages of whiptail lizards of unexpected composition. This paper adds to knowledge of the biology of this species at the southern terminus of its range and reports ecologically significant records for parthenogenetic A. exsanguis and other congeners near the Rio Grande in Texas and Chihuahua.