Scientists have discovered an ancient penguin that bridges the gap between extinct giant human-sized penguins and their modern relatives.
The human-sized penguins whizzed through Southern Hemisphere waters more than 60 million years ago.
Fossil records show that the birds swam alongside smaller forms, similar in size to some species that live in Antarctica today, after the dinosaurs were wiped off the planet.
The newly described Kupoupou stilwelli has been found on the geographically remote Chatham Islands in the southern Pacific near New Zealand’s South Island.
Scientists say it appears to be the oldest penguin known with proportions close to its modern relatives.
Next to its colossal human-sized cousins, including the recently described monster penguin Crossvallia waiparensis, Kupoupou was comparatively small
While it may have been an expert swimmer, like its modern-day relatives the penguin had short legs that meant it would have waddled on land.
It lived between 62.5 million and 60 million years ago at a time when there was no ice cap at the South Pole and the seas around New Zealand were tropical or subtropical.
Flinders University PhD palaeontology candidate and University of Canterbury graduate Jacob Blokland, who made the discovery, said: “Next to its colossal human-sized cousins, including the recently described monster penguin Crossvallia waiparensis, Kupoupou was comparatively small – no bigger than modern King penguins which stand just under 1.1 metres tall.
“Kupoupou also had proportionally shorter legs than some other early fossil penguins.
“In this respect, it was more like the penguins of today, meaning it would have waddled on land.
“This penguin is the first that has modern proportions both in terms of its size and in its hind limb and foot bones (the tarsometatarsus) or foot shape.”
Published in the Palaeontologica Electronica journal, the animal’s scientific name acknowledges the indigenous Moriori people of the Chatham Island Rekohu – with Kupoupou meaning “diving bird” in Te Re Moriori.
It's not impossible that penguins lost the ability to fly and gained the ability to swim after the extinction event of 66 million years ago, implying the birds underwent huge changes in a very short time
According to the researchers, the discovery may even link the origins of penguins themselves to the eastern region of New Zealand.
University of Canterbury adjunct Professor Paul Scofield, senior curator of natural history at the Canterbury Museum in Christchurch, said: “We think it’s likely that the ancestors of penguins diverged from the lineage leading to their closest living relatives – such as albatross and petrels – during the Late Cretaceous period, and then many different species sprang up after the dinosaurs were wiped out.
“It’s not impossible that penguins lost the ability to fly and gained the ability to swim after the extinction event of 66 million years ago, implying the birds underwent huge changes in a very short time.
“If we ever find a penguin fossil from the Cretaceous period, we’ll know for sure.”