An expedition to a remote part of northern Australia has uncovered three new vertebrate species isolated for millions of years, with scientists calling the area a “lost world”.

Conrad Hoskin from James Cook University and a National Geographic film crew were dropped by helicopter onto the rugged Cape Melville mountain range on Cape York Peninsula earlier this year and were amazed at what they found.

It included a bizarre looking leaf-tail gecko, a gold-coloured skink -- a type of lizard -- and a brown-spotted, yellow boulder-dwelling frog, none of them ever seen before.

“The top of Cape Melville is a lost world. Finding these new species up there is the discovery of a lifetime -- I’m still amazed and buzzing from it,” said Dr Hoskin,