The Lake Eyre dragon (Ctenophorus maculosus) is an agamid lizard that lives only on the barren, vegetation-free, salt crust of several dry lake basins in South Australia

Question

The lizards burrow into moist sediment beneath the crust to escape the extreme heat of midday, and they feed on insects and plant debris that blows onto the salt crust from the vegetation surrounding the lake basins. All of the lizard's water is derived from its food; there is no water for it to drink. Describe the ecological and physiological characteristics that allow the Lake Eyre dragon lizard to survive in such an inhospitable environment.

Answer 1

Metabolism and growth: The food supply is limited at all times and there are probably periods of severe food shortage. The low metabolic rate and high efficiency of secondary production that characterize ectotherms allow the Lake Eyre dragon lizard to survive under these conditions.
Water balance: The Lake Eyre drazon lizard minimizes the evaporative water loss through the skin and lungs by burrowing into moist soil beneath the salt crust and uricotely contributes to water conservation. (Students could logically propose that a nasal salt gland helps to conserve water, but this is not the case—Ctenophorus lack nasal salt glands.) (L. C. Hazard. 2004 . Sodium and potassium secretion by iguana salt glands: Acclimation or adaptation? In A. Alberts et al. (eds.), Iguanas: Biology and Conservation. Berkeley, CA: University of California Press, 84-93 . R. Pedler. 2009 . Distribution and Ecology of the Lake Eyre Dragon (Ctenophorus maculosus). Port Augusta, SA: South Australian Arid Lands Natural Resources Management Board)