A rare Kimberley snake thought to have been the same species as one found in the Northern Territory has been identified as a separate unique species.

The Kimberley death adder, acanthophis cryptamydros, is a small, well-camouflaged snake about 50 centimetres long, with a diamond-shaped head typical of the death adder.

Although the snake had been identified in the Kimberley some years ago, herpetologists believed those specimens were examples of the more well-known northern death adder.

But WA Museum curator of herpetology Paul Doughty said a student from Bangor University in the UK made the discovery by comparing genetic material from the different species.

"To our surprise, the snakes from the Kimberley turned out to be more closely related to desert death adders and the Pilbara death adder," he said.

Dr Doughty said a team of researchers then moved on to the physical characteristics of the snakes, using abut 20 examples of the species that had been previously collected, as well as 15 specimens of the Northern Territory snake.

"Myself as a museum person, we have lots of things in jars we can take out and look at under microscopes," he said.

"We had a good look at those but we didn't have enough specimens from the Top End, so we got the NT Museum to send a few down so we could line them up and compare them.

"They are very similar, but there are enough differences there to be able to say, 'Ok yes I can see the difference there, this is what's going on'.

"That was sort of the protracted eureka experience, which is often the case with these biological discoveries."

'They do pack a punch'

The Kimberley death adder is considered to be a rare species, with very few encountered.

Dr Doughty said in his years of studying snakes in the region, he had only ever seen one in the wild.

He said that was in keeping with the ambush nature of death adders, all of which are highly venomous.

"They do pack a punch," Dr Doughty said.

"They're very accurate strikers because their whole thing in life is to sit there and say to the world, 'I'm invisible, I'm not really here'.

"And then an unfortunate lizard or mammal wanders by and when that happens they're going to strike, deliver their venom, and get their food that way.

"If they miss they're not built for speed, so the prey animal would flee and they'd be stuck without a meal."