"This was a highly unusual observation and indicated that the tuatara genome is an odd combination of both mammalian and reptilian [including bird] components.".

Throughout that huge amount of time, tuatara have remained the sole members of the archaic reptilian order known as Rhynchocephalia.

The sex of future tuatara depends heavily on the temperature surrounding the eggs, and global warming could lead to too many males being born, sending the reproductive cycle into an imbalance.

The authors of the new study say tuatara "remain imperilled owing to their highly restricted distribution, threats imposed by disease and changes in sex ratios induced by climate change that could markedly affect their survival.".

"This partnership - which, to our knowledge, is unique among the genome projects undertaken to date - had a strong practical focus on developing resources and information that will improve our understanding of the tuatara and aid in future conservation efforts," the authors write