A Study of Skull Structure in the Desert Monitor, Varanus Griseus (Daudin, 1803) (Sauria: Varanidae)

 The monitor lizards (the Varanidae Family) are an ancestral group of the Anguimorph reptiles. The monitor lizards, crocodiles, and pythons are the largest living ectothermic predators. The varanid lizards are distributed in Africa, South and Southeast Asia, the Indonesian archipelago, and Australia. The genus Varanus encompasses three species in Iran. The species studied in this survey include Varanus griseus and Varanus nesterovi. In the present study, samples kept in the laboratory of Razi University of Kermanshah and a body of Varanus griseus were used. To study the skeleton, two methods of a) removing the skeletal components and photographing them, and b) using the CT-scan method were used. The Varanus skull contained 39 components of braincase as well as 12 elements of the lower jaw and hyoid apparatus. The comparison of the skulls showed that the skull of Varanus griseus and Varanus nesterovi had no significant difference except in the form of the nasal bones. The characteristic of the skull in some lizards is an important diagnostic key among various species including Varanus griseus and Varanus V. nesterovi. The similarity in skull structure in the two studied species is probably the result of their close relationship as well as the very similar method of nutrition.