The Australian Water Dragon (Intellagama lesueurii) is Australia's largest species of dragon lizard, with two distinct subspecies being recognised, namely the Eastern Water Dragon (Intellagama lesueurii lesueurii) and the Gippsland Water Dragon (Intellagama lesueurii howittii). These two subspecies are readily distinguished from one another by distinct colour and pattern differences, although these are sometimes obscured by dirty or stained skin (e.g by iron oxide bacteria).* For detailed descriptions of subspecies colours and patterns and how to tell them apart, see individual subspecies in the field guide.
Good ways to identify Intellagama lesueurii, even when the colours and patterns are obscured or the animal is young, are transverse rows of enlarged scales across the back and limbs (see accompanying image); an enlarged dorsal crest that continues onto the tail, becoming two low ridges in the distal portion; and a vertically compressed tail. This latter feature is an adaption to riparian habitats, that enable it to swim efficiently, both above and below the water.
* If you're unsure or unable to determine which subspecies it is, perhaps due to dirty or stained skin e.g from iron oxide bacteria (see field guide for example), thus obscuring the distinctive colours and patterns, then Intellagama lesueurii is a safer option.
No sightings currently exist.