Delcourt’s gecko is the largest known gecko in the world that is only known from a single specimen in the Natural History Museum of Marseille. Like many historical specimens from the 19th century, its provenance is unknown. Based on its similarity to geckos from New Zealand, it was suggested that it had lived in Aotearoa and may have been the inspiration for the kawekaweau of Māori legend.

However, doubts have been raised as to whether this giant gecko was really from New Zealand as no fossil bones of Delcourt’s gecko have been found, with the suggestion that it may in fact be part of the New Caledonian gecko radiation. New Zealand and New Caledonian geckos are cousins and share evolutionary tupuna.

Using ancient DNA Matthew Heinicke and colleagues have shown that Delcourt’s gecko is in fact part of the New Caledonian radiation, which has repeatedly spawned giant geckos, and is not from New Zealand.

This does not mean that the kawekaweau is dead in the water. There are large lizard bones in New Zealand’s fossil record that need genetic reassessment that could be from the kawekaweau, and newly developed non-destructive ancient DNA techniques will finally allow us to answer these questions.

The study my Matthew Heinicke and colleagues is a beautiful example of using ancient DNA to resolve long standing debates in natural history. Who knows what other mysteries are hiding in museum collections waiting to be solved.