Dipsosaurus dorsalis, the desert iguana, occurs in southeastern California, southern Nevada, southwestern Utah, western and south-central Arizona, eastern and southern Baja California, northwestern Mexico, and some of the Gulf of California islands. Desert iguanas live in the sandy flats and hummocks characteristic of the creosote woodlands of the Sonoran and Mojave deserts. The creosote bush provides food, shelter, and kangaroo rat burrowing sites that are readily used to escape predation and extreme heat. These lizards are primarily herbivorous, eating flowers, buds, fruits and leaves of many annuals and perennials, especially creosote. In addition to vegetation, insects, feces (mammal and lizard) and carrion have been reported in their diets.
The desert iguana is aptly named as it is more heat-tolerant than any other North American reptile. Dipsosaurus dorsalis both emerges and remains active later in the day than most lizards, and body temperatures of 45° C have been recorded -- well above lethal levels for most lizard species.
Dipsosaurus dorsalis is an iguanid lizard. Iguanids, the 'true iguanas', include eight genera (see also Ctenosaura pectinata, the Mexican spinytail iguana), and within these Dipsosaurus is generally thought to be near the base of the lineage. Iguanids are diagnosed in part by their flared and polycuspate teeth, which are visible in the animations above; these almost certainly reflect the desert iguana's primarily herbivorous lifestyle.
About the Species
This frozen specimen was collected in the vicinity of the intersection of Kelbaker Rd. and Rt. 66, San Bernadino County, California by J. Gauthier 21 May 2001. It was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Jessie Maisano of The University of Texas and Dr. Jacques Gauthier of Yale University. Funding for scanning was provided by an NSF grant (DEB-0132227) to Dr. Jack Sites of Brigham Young University. Funding for image processing was provided by a National Science Foundation Assembling the Tree of Life grant (EF-0334961), The Deep Scaly Project: Resolving Squamate Phylogeny using Genomic and Morphological Approaches, to Drs. Jacques Gauthier of Yale University, Maureen Kearney of the Field Museum, Jessie Maisano of The University of Texas at Austin, Tod Reeder of San Diego State University, Olivier Rieppel of the Field Museum, Jack Sites of Brigham Young University, and John Wiens of SUNY Stonybrook.
About this Specimen
The specimen was scanned by Matthew Colbert on 19 December 2002 along the coronal axis for a total of 660 slices. Each 1024x1024 pixel slice is 0.0468 mm thick, with an interslice spacing of 0.0468 mm and a field of reconstruction of 22 mm.
Avery, D. F., and W. W. Tanner. 1971. Evolution of the iguanine lizards (Sauria: Iguanidae) as determined by osteological and myological characters. Brigham Young University Science Bulletin, Biological Series 12:1-79,
de Queiroz, K. 1987. Phylogenetic systematics of iguanine lizards: a comparative osteological study. University of California Publications, Zoology 118:1-203.
Frost, D. R., and R. Etheridge. 1989. A phylogenetic analysis and taxonomy of iguanian lizards (Reptilia: Squamata). University of Kansas Museum of Natural History Miscellaneous Publication 81:1-65.
Frost, D. R., R. Etheridge, D. Janies, and T. A. Titus. 2001. Total evidence, sequence alignment, evolution of polychrotid lizards, and a reclassification of the Iguania (Squamata: Iguania). American Museum Novitates 3343:1–38.
Sites, J. W. Jr., S. K. Davis, T. Guerra, J. B. Vverson, and H. L. Snell. 1996. Character congruence and phylogenetic signal in molecular and morphological data sets: a case study in the living iguanas (Squamata, Iguanidae). Molecular Biology and Evolution 13:1087-1105.
Zug, G. R. 1993. Herpetology. Academic Press, San Diego.
Dipsosaurus dorsalis page from desertmuseum.org
Care sheet for desert iguanas
Three-dimensional volumetric renderings of the skull with the scleral ossicles, hyoid and jaw removed, and of the isolated left mandible. All are 2mb or less.