Lead researcher Lachie Scarsbrook said the geckos found on Cook Strait’s Brothers and Trios Islands were previously regarded as the same species as the Duvaucel’s living on islands off the northeastern coast of the North Island.
However, scientists have known for years that there were differences between the southern and northern lineages.
"The Brothers and Trios Islands geckos are smaller, have different colours and patterns on their bodies and possess unique genetic signatures, which are all the ingredients needed to describe a new species," Mr Scarsbrook said.
"It wasn’t until we used cutting-edge ancient-DNA techniques to reconstruct the diversity in now-extinct North and South Island mainland populations, that we realised just how different they really are — over five-million years to be exact."
The new species has been named te mokomoko a Tohu (Hoplodactylus tohu) — after Tohu Kakahi, one of the first recognised pacifists, for his work in the decades leading up to the invasion of Parihaka.
"This has elevated their threat classification, with both Duvaucel’s gecko and te mokomoko a Tohu now receiving critically endangered status on the International Union for Conservation of Nature red list.
"While these islands have proved a sanctuary from rats and other introduced predators over the past few centuries, the effects of changing climate, as well as predator incursion, pose significant risks to the survival of te mokomoko a Tohu."
Mr Scarsbrook said further studies using these novel DNA techniques were "desperately needed" to inform evidence-based conservation management, leading to effective guardianship practices.
"Scientists, conservationists and tangata whenua cannot hope to save species from extinction if we don’t know what species are out there.
"Our ancient DNA research on Hoplodactylus geckos has only just scratched the surface of what we know about the diversity of geckos, skinks, frogs and tuatara at the time of human arrival in Aotearoa, and how it has changed in the time since."
