Southeast Asia allowed the varanids to spread into what is now the Indonesian archipelago. Based upon DNA sequences of three nuclear and two mitochondrial genes, cladistic analysis identifies V. salvadorii as a member of a species cluster that includes the lace monitor (V. varius) and the Komodo dragon (Varanus komodoensis). Morphological considerations suggest that Varanus priscus was also a member of the group. Monitors apparently colonized Australasia from Asia about 32 Mya; the varius clade then arose about 17 Mya. The Torres Strait separating New Guinea from Australia is less than long, a distance that could have been covered fairly easily with island hopping. Distribution The largest of the seven species of monitors found on the island of New Guinea, V. salvadorii occurs in both the state Papua New Guinea and the Indonesian region of West Papua. It inhabits the high and low canopies of the lowland rainforests and coastal mangrove swamps, sometimes venturing out of these areas during floods in the rainy seasons. No detailed field investigation data are available for V. salvadorii, so the full extent of its range is unknown. Its remote and generally inaccessible habitat is an obstacle to detailed study of this monitor in its natural habitat. Biology and morphology The most characteristic feature of V. salvadorii is its blunt, bulbous snout, which makes it look different from every other monitor on New Guinea, and suggested the common name "tree crocodile". The body of the lizard is dark green with rings of yellow spots. The tail is banded yellow and black and is extremely long, more than twice as long as the snout-to-vent length. Its teeth are long, straight, and sharp. Its claws are prominent and strongly curved. No clear external sexual dimorphism is seen. Various descriptions are mutually inconsistent, but agreement exists that V. salvadorii is unique among extant varanid species, in that the animal's tail is much longer than the snout-to-vent length in both juveniles and adults. One figure gives the tail as two-thirds longer, whereas another states that the tail is 210% of the animal's body length. At hatching, V. salvadorii is about long. Reports of the maximal length vary greatly and are the subject of much dispute. It possibly attains the greatest length among extant species of lizards, although it is considerably less massive than the Komodo dragon. Specimens are known to reach at least in length. but it has been