(CN) – Scientists have discovered the missing link between modern penguins and their ancient ancestors who lived more than 60 million years ago, identifying a new species Monday that lived beside its human-sized penguin cousins.
In a paper published in the journal Palaeontologia Electronica, researchers pieced together the fossils of the newly described Kupoupou stilwelli penguin found in the Chatham Islands near New Zealand's South Island in the Pacific Ocean.
The species, with proportions more in line with modern penguins, appears to be the oldest link between the two. Research scientists said it lived between 60 - 62.5 million years ago when the waters around New Zealand were tropical.
Jacob Blokland, Flinders University palaeontology doctoral candidate, discovered the existence of the ancient species after examining fossils collected from the island.
"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 (3.6 feet) tall," Blokland said in a statement.
Blokland said the species had shorter legs than other early penguins, giving it a distinctive waddle that modern penguins are known for.
"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," he said.
The name of the newly discovered species is taken from the language of the native Moriori people of Chatham Island. Kupoupou means "diving bird" in the native language of Te Re Moriori.
Paul Scofield, professor at the University of Canterbury and co-author, said the species gives supporting evidence that ancient penguins went through rapid evolution.
"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," Scofield said.
Fossils of ancient species of penguins showed evidence that they were capable of flight, differing from penguins of today.
"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," Scofield said.