Six new native gecko species have been discovered during the course of a two-decade long research program by the Queensland Museum and Griffith University.

Key points: Genetic testing has revealed six new species of native gecko, which also have subtle differences to the Asian house gecko

Genetic testing has revealed six new species of native gecko, which also have subtle differences to the Asian house gecko The "new" geckos, which are found mostly in northern Australia, have smooth tails and fewer claws than their famous cousins

The "new" geckos, which are found mostly in northern Australia, have smooth tails and fewer claws than their famous cousins New species are identified in Australia quite frequently, according to one reptile expert

The university's Dr Paul Oliver, who is also a senior curator at Queensland Museum, said identifying the new species required painstaking detective work.

"Part of the reason these common species have been undiscovered for so long is that they're very hard to tell apart," he said.

Tail tips from the creatures were analysed to identify the genetic differences.

"Although we can't tell them apart, [other geckos] certainly can," he said.

This native Geyhra arnhemica was discovered almost four hours east of Katherine, in the Northern Territory, at the Wongalara Sanctuary. ( Supplied: Stephen Zozaya )

The story in a tail

Despite being as common as the Asian house gecko, which can be found in many homes across Australia, native geckos have three distinct differences:

Asian house geckos make the famous gecko "clicking" sound, but their Australian cousins are much quieter

Asian house geckos make the famous gecko "clicking" sound, but their Australian cousins are much quieter Asian house geckos have spikes on their tails, while the six native geckos share smooth tails

Asian house geckos have spikes on their tails, while the six native geckos share smooth tails Native geckos do not have a claw on their first toe, whereas Asian house geckos have claws on all their toes

The Gehyra lapistola can be found in bushland, like this one that was spotted in the NT's Fish River. ( Supplied: Steven Richards )

Where to find the new species

The newly discovered Australian geckos, according to Dr Oliver, are fairly widespread.

"They're basically dotted across northern Australia, from Broome to as far south as Brisbane," he said.

The Northern Territory is home to the Geyhra arnhemica and the Gehyra chimera, found in rocky ranges towards the Top End.

Gehyra gemina occurs widely through the northern deserts of Western Australia and Northern Territory, with the Geyhra chimera and Geyhra calcitectus found mainly in the Kimberley region.

North-west Queensland has the Gehyra lauta, better known as the "ghost gecko" for its pale appearance, and it can also be seen in bushland in the north-eastern Northern Territory.

If you find a gecko a long way away from people in the bush, Dr Paul Oliver said the probability is that it's a native gecko.

Gehyra lauta — better known as the "ghost gecko" — has been spotted in north-west Queensland and the Northern Territory. ( Supplied: Mark Hutchinson )

New discoveries nothing new

Steve Wilson, the author of the Guide to Australian Reptiles, said new species were constantly being identified by researchers and wildlife enthusiasts each year.

"We had about 1,100 Australian reptile species, and over the past three years we've had another 80 added to that," Mr Wilson said.

Mr Wilson said there were two common ways to identify new species of animals.

"One is to turn over a rock and say, 'That's a new lizard that no-one has ever seen before,'" he said.

"The other way is to look at a species that has a wide distribution and genetically test them [and they] turn out to be different, which is what's happened with this new discovery."

Mr Wilson says anyone who finds an unusual animal should take a photo of it and the location and send them to the Queensland Museum.