| Agamids | |
|---|---|
| Male Mwanza Flat-headed Rock Agama (Agama mwanzae), in the Serengeti, Tanzania | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Lacertilia |
| Infraorder: | Iguania |
| Family: | Agamidae |
| Subfamilies | |
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6, see text |
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Agamids, lizards of the family Agamidae, include more than 300 species in Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Phylogenetically they may be sister to the Iguanidae, and have a similar appearance. Agamids usually have well-developed, strong legs. Their tails cannot be shed and regenerated like those of geckoes, though a certain amount of regeneration is observed in some.[1][2] Many agamid species are capable of limited change of their colours to regulate their body temperature.[3] In some species, males are more brightly coloured than females[4] and colours play a part in signaling and reproductive behaviours.[5] Although agamids generally inhabit warm environments, ranging from hot deserts to tropical rainforests, at least one species, the Mountain Dragon, is found in cooler regions.
This group of lizards includes some more popularly known, such as the domesticated bearded dragon and the uromastyx.
One of the key distinguishing features of the agamids is their teeth, which are borne on the outer rim of the mouth (acrodont), rather than on the inner side of the jaws (pleurodont). This feature is shared with the chameleons, but is otherwise unusual among lizards. Agamid lizards are generally diurnal, with good vision, and include a number of arboreal species, in addition to ground and rock-dwellers. They generally feed on insects and other arthropods (such as spiders), although some larger species may include small reptiles or mammals, nestling birds, flowers or other vegetable matter in their diets.[6] The great majority of agamid species are oviparous.[7]
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There have been very few studies of the Agamidae with the first comprehensive assessment by Moody (1980) followed by a more inclusive assessment by Frost and Etheridge (1989). Subsequent studies were based on mitochondrial DNA loci[8][9][10] (using allozymes), and sampling across the Agamidae. Few other studies focused on clades within the family, but the Agamidae have not been as well investigated as the Iguanidae.
The agamids show a curious distribution. They are found over much of the Old World, including continental Africa, Australia, Southern Asia and sparsely in warmer regions of Europe. They are however absent from Madagascar and from the New World. The distribution is the opposite of that of the iguanids, who are found in just these areas but absent in areas where agamids are found. A similar faunal divide is found in between the boas and pythons.
Among the Agamidae, six subfamilies are generally recognized:[11]
The chameleons of the sister family Chamaeleonidae are sometimes discussed as subfamily Chamaeleoninae and subfamily Agaminae (referring to Agamidae, not the Agaminae mentioned above).