Desert iguana

For the extinct genus, see Desertiguana.

Desert iguana
A desert iguana near Amboy Crater, California
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Iguania
Family:	Iguanidae
Genus:	Dipsosaurus
Species:	D. dorsalis
Binomial name
Dipsosaurus dorsalis (Baird and Girard, 1852)

The desert iguana (Dipsosaurus dorsalis) is an iguana species found in the Sonoran and Mojave Deserts of the Southwestern United States and northwestern Mexico, as well as on several Gulf of California islands.

Taxonomy

The species was first described in the Proceedings of the Academy of Natural Sciences of Philadelphia, by Spencer Fullerton Baird and Charles Frédéric Girard, in 1852 as Crotaphytus dorsalis. It was reclassified two years later as Dipsosaurus dorsalis by Edward Hallowell. The generic name comes from a combination of two Greek words meaning "thirsty lizard": "Dipsa" (δίψα) for "thirsty", and "sauros" (σαῦρος) for "lizard". The specific name, "dorsalis", comes from the Latin word dorsum meaning "spike", in reference to a row of enlarged spiked scales on the middle of the lizard's back which form a crest that extends almost to the tip of its vent. Dipsosaurus contains two species, D. dorsalis, and D. catalinensis. Genetic evidence supports Dipsosaurus being the most basal extant member of Iguanidae, diverging during the late Eocene, about 38 million years ago.

There are two peninsular and one continental subspecies of the desert iguana.

Description

The desert iguana is a medium-sized lizard which averages 41 cm (16 in) in total length but can grow to a maximum of 61 cm (24 in) including the tail. They are pale gray-tan to cream in color with a light brown reticulated pattern on their backs and sides. Down the center of the back is a row of slightly enlarged, keeled dorsal scales that become slightly larger farther down the back. The reticulated pattern gives way to brown spots near the back legs, turning into stripes along the tail. The tail is usually around 1+1⁄2 times longer than the body from snout to vent. The belly is pale. During the breeding season, the sides become pinkish in both sexes.

Habitat

Their preferred habitat is largely contained within the range of the creosote bush, mainly dry, sandy desert scrubland below 1,000 m (3,300 ft). They have a significant presence in the Sonoran and Mojave deserts. They can also be found in rocky streambeds up to 1,000 m. In the southern portion of its range, these lizards lives in areas of arid subtropical scrub and tropical deciduous forest.

These lizards can withstand high temperatures and are out and about after other lizards have retreated into their burrows. They seek shade when their body temperature is in the low-forties (Celsius), and seek the protection of a burrow when their body temperature reaches the mid-forties (Celsius). They burrow extensively and if threatened will scamper into a shrub and go quickly down a burrow. Their burrows are usually dug in the sand under bushes like the creosote. They also often use burrows of kit foxes and desert tortoises.

Reproduction also plays a role in where these lizards are found. It is believed that the high temperature environment helps with successful hatching of eggs. The eggs often hatch between temperatures of 28 and 38 degrees Celsius.

Diet and reproduction

Mating takes place around May–June. Only one clutch of eggs is laid each year, with each clutch having 3-8 eggs. The hatchlings emerge around September.

Desert iguanas are primarily herbivorous, eating buds, flowers, fruits and leaves of many annual and perennial plants. They are especially attracted to the flowers and leaves of the creosote bush and alfalfa. They also eat insects, especially ants, crickets and mealworms, as well as the feces of other herbivores. Predators of these iguanas and their eggs are birds of prey, foxes, rats, long-tailed weasels, and snakes.

References

• Frost, D.R. and R.E. Etheridge (1989) A Phylogenetic Analysis and Taxonomy of Iguanian Lizards (Reptilia: Squamata). Univ. Kansas Mus. Nat. Hist. Misc. Publ. 81
• 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: 38 pp.
• Hancock, T. V., & Gleeson, T. T. (2007). Contributions to Elevated Metabolism during Recovery: Dissecting the Excess Postexercise Oxygen Consumption (EPOC) in the Desert Iguana (Dipsosaurus dorsalis). Physiological and Biochemical Zoology, 81(1), 1–13.
• Revell, T. K., & Dunbar, S. G. (2007). The energetic savings of sleep versus temperature in the Desert Iguana ( Dipsosaurus dorsalis) at three ecologically relevant temperatures. Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 148(2), 393–398.
• Valdivia-Carrillo, T., García-De León, F. J., Blázquez, M. C., Gutiérrez-Flores, C., & González Zamorano, P. (2017). Phylogeography and Ecological Niche Modeling of the Desert Iguana (Dipsosaurus dorsalis, Baird & Girard 1852) in the Baja California Peninsula. The Journal of Heredity, 108(6), 640–649.

External links

• Desert Iguana Pictures Archived 2009-09-03 at the Wayback Machine
• Arizona-Sonora Desert Museum: Desert Iguana (Dipsosaurus dorsalis)
• San Diego Natural History Museum: Dipsosaurus dorsalis (Desert Iguana)