Varanus (Odatria)

Odatria was coined by John Edward Gray in 1838 as a genus name. Odatria is the most species diverse subgenus of monitor lizards, with 22 different species. The subgenus also includes two species complexes represented by the spiny-tailed monitor and the Timor monitor. Alternatively, Vidal et al. 2012 splits Odatria into two species groups represented by the spiny-tailed monitor and the black-headed monitor. In the past, tree monitors such as the green tree monitor have sometimes been included within Odatria as well as Euprepriosaurus, but now form their own subgenus Hapturosaurus. A 2020 phylogenomic study by Brennan et al. found that Odatria is most closely related to much larger Australian monitor lizards from the subgenus Varanus, which includes the largest living lizard, the Komodo dragon, as well as the monotypic subgenus Papusaurus of which the crocodile monitor is the only member of. Together, Odatria, Varanus, and Papusaurus form a monophyletic clade of Indo-Australopapuan monitors. The same study found the black-palmed rock monitor, Odatria glebopalma, the largest species within Odatria, to be sister to the rest of Odatria During the early-mid Oligocene, the genus Varanus dispersed in two directions. The southeastern dispersion into Indo-Australia likely occurred shortly after the collision of the Asian and Australian tectonic plates, which created a connection between Sahul and Sundaland, i.e., an Indonesian land bridge that would have facilitated the dispersal of monitor lizards into Australia. The existence of this land bridge also likely allowed the Indo-Australopapuan clade including many Odatria species to disperse back into Indonesia. == Phylogeny ==

Species groups Vidal et al. 2012 separated Odatria into two species groups; the V. acanthurus group included V. acanthurus, V. baritji, V. brevicauda, V. bushi, V. caudolineatus, V. eremius, V. gilleni, V. kingorum, V. primordius, and V. storri, while the V. tristis group included V. auffenbergi, V. glauerti, V. glebopalma, V. mitchelli, V. pilbarensis, V. scalaris, V. semiremex, V. similis, V. timorensis, and V. tristis. To maintain monophyly in light of Brennan et al. 2020, V. glebopalma would be excluded from the V. tristis group, and more species would be included as in the following: V. acanthurus group - (V. acanthurus, V. baritji, V. brevicauda, V. bushi, V. caudolineatus, V. eremius, V. gilleni, V. kingorum, V. primordius, V. sparnus and V. storri) V. tristis group - (V. auffenbergi, V. glauerti, V. hamersleyensis, V. mitchelli, V. pilbarensis, V. scalaris, V. semiremex, V. similis, V. timorensis, and V. tristis) ==Ecology==

Behaviour The genus is diverse in terms of behaviour, and includes terrestrial, arboreal, and semiaquatic species. Many are saxicolous, i.e., they are strongly associated with rocky habitats, while some others prefer forests. Diet Orthopteran insects and other species of lizards make up the mainstay of the diet for most species. One species, the rusty desert monitor, consumes a particularly large amount of lizard prey with lizards such as various species of Ctenotus accounting for up to 70% of their diet by weight. Larger species such as black-palmed rock monitors are also known to prey on other dwarf monitors. In captivity, wild caught individuals may suffer more from the effects of parasites due to the stressful process of being taken from the wild and being shipped elsewhere. ==Conservation and captivity==

Under the EPBC Act, the export of live Australian Odatria species for commercial purposes is prohibited. Illegal trade of these species still persist, as many dwarf monitor species are in great demand in the pet trade. In Australia, monitor lizards are threatened by the invasive cane toad, as they have no natural immunity to the toad's toxins when ingested. Captive breeding for the pet trade has been successful in many such species however and lessens the pressure on wild populations. Some such as the often captive bred ridge-tailed monitor are popular pet lizards, in some cases as a "beginner monitor" to train those who are aspiring to eventually keep larger and less forgiving monitor lizard species. == Species ==