A small fossil penguin plays a major role in the bird’s evolutionary history, an international study has found.
Published in the Journal of the Royal Society of New Zealandthe study describes a new species of fossil penguin that lived in Otago about 24 million years ago.
Named Pakudyptes hakatarameathe 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, former PhD candidate at the University of Otago – Ōtākou Whakaihu Waka and now at the Ashoro Museum of Palentology in Japan, worked with researchers from Otago, Okayama University of Science and Osaka University.
Dr. Ando’s inspiration for the article came from conversations with the late Professor Ewan Fordyce, his supervisor and mentor at Otago.
Researchers analyzed three bones – a humerus, femur and ulna – found by Professor Fordyce in the Hakataramea Valley, South Canterbury.
says Doctor Ando Pakudyptes fills a morphological gap between modern and fossil penguins.
“The shape of the wing bones in particular varied enormously, and the process by which penguin wings acquired their current shape and function remained unclear,” he says.
The humerus and ulna highlight how penguins’ wings evolved.
“Surprisingly, the shoulder joints of the wing are gone Pakudyptes were very close to the condition of the current penguin, the elbow joints were very similar to those of older species 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, from Otago’s Faculty of Dentistry, says analysis of internal bone structure carried out at the Faculty of Dentistry, compared with data on living penguins from Okayama University of Science, shows that these penguins had microanatomical features that thinking about diving.
Modern penguins have excellent swimming abilities, largely due to their dense, thick bones that contribute to buoyancy while diving.
In Pakudyptesthe bone cortex was fairly thick, although the medullary cavity, which contains bone marrow, was open, similar to what we see in the modern little blue penguin, which tends to swim in shallow water.
The power for Pakudyptes diving and swimming comes down to the distinctive combination of his bones.
Bones such as the humerus and ulna reveal areas where muscles and ligaments attach, showing how the wings were used to swim and maneuver underwater.
Dr. Loch says fossil penguins were usually large, about 1 meter tall.
“Penguins evolved rapidly from the late Oligocene to the early Miocene and Pakudyptes is an important fossil from this period. The small size and unique combination of bones may have contributed to the ecological diversity of modern penguins.”
