The oldest known penguin genus discovered in New Zealand rocks dating to about 60 million years ago is Waimanu.
Waimanu lived during the Paleocene, shortly after the mass extinction that ended the Cretaceous Period. Its fossils were found in the Waipara Greensand near the Waipara River on New Zealand’s South Island. The genus name means “water bird” in Māori.
Waimanu differs from modern penguins in having a more slender body and wings that were not yet specialized for underwater flight. Even so, its bones show that penguin-like birds had already become strong swimmers very early in their evolutionary history.
The oldest known Waimanu fossils are roughly 60–62 million years old. This does not mean Waimanu was necessarily the first penguin; it is simply the earliest penguin genus currently known from fossil evidence. Later fossil penguins became far more diverse, including giant species that were much taller than living penguins.