Researchers studying a rare and endangered species of penguin have uncovered a previously unknown species that disappeared about 500 years ago.

The research suggests that the first humans in New Zealand hunted the newly found Waitaha penguin to extinction by 1500, about 250 years after their arrival on the islands. But the loss of the Waitaha allowed another kind of penguin to thrive -- the yellow-eyed species that now also faces extinction, Philip Seddon of Otago University, a co-author of the study, said yesterday.

The team was testing DNA from the bones of prehistoric modern yellow-eyed penguins for genetic changes associated with human settlement when it found some bones that were older - and had different DNA.