Hapturosaurus, sometimes known as the tree monitors, is a subgenus of lizards, consisting of slender-bodied arboreal monitor lizards mostly found in the tropical rainforests of Indonesia and Papua New Guinea.
The type species is the green tree monitor, originally designated by Hermann Schlegel in 1844 as Monitor prasinus. Robert Mertens placed tree monitors within the subgenus Odatria in 1942. In 1988, tree monitors were instead placed within Euprepriosaurus alongside the mangrove monitors.[1] Nevertheless, there was a distinction between mangrove and tree monitors that was clear even then, so Euprepriosaurus was commonly considered to consist of two species complexes, i.e., the V. indicus complex and the V. prasinus complex. In 2016, Yannick Bucklitsch, Wolfgang Böhme, and André Koch found the two species complexes sufficiently morphologically, ecologically, and biologically distinct, and so all species within the V. prasinus complex were moved under a newly erected subgenus, i.e., Hapturosaurus. Hapturosaurus diverged from Euprepriosaurus during the late Miocene.[2]
The name Hapturosaurus is derived from the Greek words "haptein" (to grasp), "ouros" (tail), and "sauros" (lizard), in reference to the prehensile tails of tree monitors.[2]
All species are highly arboreal. In captivity, tree monitors demonstrate the capacity to play, in the form of destructive behaviour such as systematically shredding the leaves on plants with teeth and claws.[3] Play-like behaviour is also documented in other less closely related monitor species, such as Komodo dragons.[4]
Tree monitors are primarily insectivorous, but also consume other small invertebrates such as spiders, or occasionally small mammals, lizards or the nestlings and eggs of birds. In captivity they are occasionally seen eating plants although the gut contents of wild individuals were not reported to contain plant matter.[5] This may however be a result of accidentally ingesting leaves when playing with them, which is documented in captivity.[3]
Captive hatchling often refuse food for more than two weeks, although force feeding may be recommended before then and until they begin feeding by themselves.[5]