Pakudyptes Hakataramea Photo: Supplied
A fossil of a penguin that lived in Otago millions of years ago has shed light on the evolution of penguins.
It has been named the Pakudyptes Hakataramea.
Researchers say the penguin was very small - about the same size as the little blue penguin, the smallest in the world - with anatomical adaptations that allowed it to dive.
Lead author Dr Tatsuro Ando, formerly a PhD candidate at the University of Otago - Ōtākou Whakaihu Waka and now at the Ashoro Museum of Palentology in Japan, collaborated with researchers from Otago, Okayama University of Science and Osaka University.
They looked at three bones in the wing, a humerus, femur and ulna - and Dr Ando said Pakudyptes fills a morphological gap between modern and fossil penguins.
"In particular, the shape of the wing bones differed greatly, and the process by which penguin wings came to have their present form and function remained unclear," he said.
The humerus and ulna highlight how penguins' wings have evolved.
"Surprisingly, while the shoulder joints of the wing of Pakudyptes were very close to the condition of the present-day penguin, the elbow joints were very similar to those of older types of fossil penguins.
"Pakudyptes is the first fossil penguin ever found with this combination, and it is the 'key' fossil to unlocking the evolution of penguin wings."
Co-author Dr Carolina Loch said analysis of the internal bone structure, with comparison with data on living penguins, shows these penguins had microanatomical features suggestive of diving.
Modern penguins have excellent swimming abilities, largely due to their dense, thick bones that contribute to buoyancy during diving.
Loch said fossil penguins were usually large, about 1m in height.
"Penguins evolved rapidly from the Late Oligocene to Early Miocene and Pakudyptes is an important fossil from this period. Its small size and unique combination of bones may have contributed to the ecological diversity of modern penguins," she said.
