11003-99022 Tuatara (Sphenodon punctatus) male sharing burrow with fairy prion chick. This tuatara was once recognised as a separate species and named Gunthers tuatara (Sphenodon guntheri) for a short period from 1989 onwards. This population of approximately 400 characteristically small, strongly marked individuals are confined to North Brother Island in the Marlborough Sounds. However a re-examination of the genetic bases used to distinguish this species of tuatara has concluded they only represent geographic variants, and so only one species should be recognized. North Brother Island.