NORTH-WESTERN JOURNAL OF ZOOLOGY 10 (2): 374-381 ©NwjZ, Oradea, Romania, 2014 Article No.: 141506 http://biozoojournals.ro/nwjz/index.html Sexual dimorphism and natural history of the Western Mexico Whiptail, Aspidoscelis costata (Squamata: Teiidae), from Isla Isabel, Nayarit, Mexico Raciel CRUZ-ELIZALDE1, Aurelio RAMÍREZ-BAUTISTA1, *, Uriel HERNÁNDEZ-SALINAS1,2, Cynthia SOSA-VARGAS3, Jerry D. JOHNSON4 and Vicente MATA-SILVA4 1. Centro de Investigaciones Biológicas (CIB), Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo, Km 4.5 s/n, Colonia Carboneras, Mineral de La Reforma, A.P. 1-69 Plaza Juárez, C.P. 42001, Hidalgo, México. 2. Instituto Politécnico Nacional, CIIDIR Unidad Durango, Sigma 119, Fraccionamiento 20 de Noviembre II, Durango, Durango 34220, México. 3. Laboratorio de Herpetología, Escuela de Biología, Benemérita Universidad Autónoma de Puebla, C. U. Boulevard Valsequillo y Av. San Claudio, Edif. 76, CP. 72570, Puebla, Puebla, México. 4. Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, USA. *Corresponding author, A. Ramírez-Bautista, E-mail:
[email protected] Received: 25. April 2014 / Accepted: 13. June 2014 / Available online: 16. October 2014 / Printed: December 2014 Abstract. Lizard populations found in insular environments may show ecological and morphological characteristics that differ from those living in continents, as a result of different ecological and evolutionary processes. In this study, we analyzed sexual dimorphism, reproduction, and diet in a population of the whiptail lizard, Aspidoscelis costata, from Isla Isabel, Nayarit, Mexico, sampled in 1977 and 1981. Males and females from Isla Isabel showed no sexual dimorphism in many morphological structures, such as snout-vent length (SVL), but they did in femur length (FL) and tibia length (TL).