Paul Oliver, a PhD student, has completed a detailed genetic study of the Australian gecko genus Diplodactylus and found that the lizard, once thought to be a single widespread species, was actually about eight different species.

"Many of these species are externally very similar, leading to previous severe underestimation of true species diversity," he said.

His study, detailed in Proceedings of the Royal Society: B, found more than twice the recognised number of gecko species, bringing the number from 13 to 29.

With a much narrower, more restricted habitat than previously thought, Mr Oliver said the various species were possibly much more vulnerable to environmental change.

"One of the major problems for biodiversity conservation and management is that many species remain undocumented," he said.

"This completely changes how we look at conservation management of these species.

"Even at a basic inventory level, this shows that there is a lot of work still to be done.

"It will require considerable effort and expense, but with potentially rich returns."