A tiny fossil penguin plays a huge role in the evolutionary history of penguins, an international study shows.
Published in the Journal of the Royal Society of New Zealand, the study describes a new species of fossil penguin that lived in Otago about 24 million years ago.
Named Pakudyptes hakataramea, 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 Ph.D. candidate at the University of Otago — Ōtākou Whakaihu Waka and now at the Ashoro Museum of Paleontology in Japan, collaborated with researchers from Otago, Okayama University of Science, and Osaka University.
Dr. Ando’s inspiration for the paper came from discussions 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.
This small penguin fils the gap between modern and fossil penguins
Dr. Ando says 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 says.
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, from Otago’s Faculty of Dentistry, says an analysis of the internal bone structure conducted at the Faculty of Dentistry, compared with data on living penguins provided by the Okayama University of Science, 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.
In Pakudyptes, the bone cortex was reasonably 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 waters.
The ability of Pakudyptes to dive and swim comes down to the distinctive combination of its bones.
Bones, such as the humerus and ulna, show areas for the attachment of muscles and ligaments, which reveal how the wings were used to swim and maneuver underwater.
Dr. Loch says fossil penguins were usually large, about 1 m 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.”
This article is republished from University of Otago. Read the original article.
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