Kupoupou stilwelli: New Species of Paleocene Penguin Bridges Gap in Penguin Family Tree
Paleontologists in New Zealand have uncovered the fossilized bones from an extinct penguin that swam the oceans between 62.5 and 60 million years ago. Dubbed Kupoupou stilwelli, the ancient bird is the oldest penguin known with proportions close to its modern relatives.
Kupoupou stilwelli lived during the Paleocene epoch at a time when there was no ice cap at the South Pole and the seas around New Zealand were tropical or subtropical.
Numerous skeletal remains of the prehistoric penguin were recovered from the Takatika Grit of Chatham Island, part of the Chatham Islands located about 535 miles (860 km) off the east coast of New Zealand’s mainland.
The fossils were analyzed by Flinders University paleontologist Jacob Blokland and his colleagues.
“Next to its colossal human-sized cousins, including the recently described monster penguin Crossvallia waiparensis, Kupoupou stilwelli was comparatively small — no bigger than the modern king penguin (Aptenodytes patagonicus) which stands just under 3.6 feet (1.1 m) tall,” Blokland said.
“It 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.”
The discovery of Kupoupou stilwelli may link the origins of penguins themselves to the eastern region of New Zealand — from the Chatham Island archipelago to the eastern coast of the South Island, where other most ancient penguin fossils have been found.
“The study provides further support for the theory that penguins rapidly evolved shortly after the period when dinosaurs still walked the land and giant marine reptiles swam in the sea,” said Dr. Paul Scofield, from the University of Canterbury and the Canterbury Museum in Christchurch.
“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.”
Jacob C. Blokland et al. 2019. Chatham Island Paleocene fossils provide insight into the palaeobiology, evolution, and diversity of early penguins (Aves, Sphenisciformes). Palaeontologia Electronica, article number: 22.3.78; doi: 10.26879/1009