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New Fossil Penguin Species Enhances Understanding of Evolutionary History
While it may seem that penguins lack functional wings, these features are significant in understanding their evolutionary past. Recent research on a fossil species known as Pakudyptes hakataramea sheds light on the transition from extinct penguins to their modern relatives. This study, published on July 31 in the Journal of the Royal Society of New Zealand, emphasizes the evolutionary role of their wing structures, which have adapted to facilitate quicker swimming.
The Pakudyptes species thrived in what is now the South Island of New Zealand approximately 24 million years ago. Measuring at just 9.8 inches tall and weighing about 2.2 pounds, it is recognized as one of the smallest penguin species ever documented, akin in size to the modern little blue penguin (kororā).
[Related: This human-sized penguin isn’t even the largest ancient penguin we know about.]
Notably, despite its diminutive size, Pakudyptes possessed adaptations suited for diving, emphasizing its aquatic capabilities early in the penguin lineage. The research team, comprising scientists from the University of Otago and several Japanese universities, investigated the humerus, femur, and ulna of this fossil. These bones were unearthed during fieldwork, conducted by the late paleontologist Ewan Fordyce, in the Hakataramea Valley, located in Canterbury.
The study reveals that Pakudyptes serves as a crucial link in understanding the morphological evolution from ancient to contemporary penguins.
“The distinct shape of the wing bones provides valuable insight into how penguins’ wings evolved, but the specific mechanisms behind this transformation had remained uncertain,” noted Tatsuro Ando, a co-author of the study from the Ashoro Museum of Paleontology.
Analysis of the humeral and ulnar structures indicates an intriguing evolutionary blend. “Notably, while the shoulder joints of Pakudyptes align closely with those of present-day penguins, the elbow joints exhibit characteristics similar to earlier fossil varieties,” added Ando, emphasizing the significance of this find in revising our understanding of penguin wing evolution.
The internal structure of the fossil was examined in conjunction with data from living penguins. Researchers determined that Pakudyptes possessed specific bone microanatomical features indicative of diving capabilities. Modern penguins are recognized for their adeptness in swimming, a trait supported by denser bones that influence buoyancy during dives.
Unlike contemporary relatives, the bone cortex of Pakudyptes was relatively robust, yet its medullary cavity remained open, mirroring the characteristics of the little blue penguin that typically forages in shallow waters.
The dive-specific adaptations of Pakudyptes result from the unique composition of its skeletal structure. The configurations of the humerus and ulna reveal attachment points for musculature, elucidating how these wings facilitated underwater movement.
[Related: Poop stains reveal four previously unknown Emperor penguin colonies.]
Although extinct penguin species were generally larger—some measuring up to 6 feet tall—Pakudyptes stands as an exception with its significantly reduced size. Such size variations highlight the rapid evolutionary changes that occurred during the Late Oligocene to Early Miocene periods.
“The evolution of penguins during this time was marked by swift diversification, and Pakudyptes plays a vital role in understanding that trajectory,” remarked Carolina Loch from Otago’s Faculty of Dentistry. “The distinctive size and skeletal composition of Pakudyptes may have influenced the ecological variety observed in modern penguin species.”
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