Researchers from the University of Cambridge and an international team have unveiled two newly described penguin species, with one believed to be the largest penguin ever known, weighing over 150 kilograms—more than three times the size of today’s largest penguins. The discovery, published in the Journal of Paleontology, originated from fossils found in 57 million-year-old beach boulders in North Otago, New Zealand’s South Island. The senior author, Alan Tennyson from the Museum of New Zealand Te Papa Tongarewa, made the discovery between 2016 and 2017.
The team used laser scanners to create digital models of the bones and compared them to other fossil species, modern penguins, and flying diving birds. Through these comparisons, they estimated the newfound penguin’s weight, revealing it to be a remarkable 154 kg. This finding places these ancient penguins roughly five to 10 million years after the extinction event that wiped out non-avian dinosaurs. A fascinating discovery shedding new light on the history of penguins.
Dr. Daniel Field, a co-author from Cambridge’s Department of Earth Sciences, highlighted the surprising evidence that fossils offer in unraveling the history of life. The team’s discovery of Kumimanu fordycei, the largest fossil penguin ever found, amazed them. Weighing approximately 350 pounds, it would have been even heavier than basketball player Shaquille O’Neal during the peak of his dominance.
The new species was named Kumimanu fordycei to honor Dr. R. Ewan Fordyce, a renowned figure in the field and a generous mentor to many. First author Dr. Daniel Ksepka from the Bruce Museum in Greenwich, Connecticut, expressed gratitude for Dr. Fordyce’s field program, which revealed many iconic fossil species and inspired the penguin’s namesake.
Additionally, the team discovered multiple specimens of another penguin species, Petradyptes stonehousei, weighing 50kg, larger than today’s emperor penguins. The name reflects the preservation of the diving bird in a boulder, honoring the late Dr. Bernard Stonehouse, a pioneer in penguin biology.
These new species demonstrate that early in their evolutionary history, penguins reached impressive sizes, well before they refined their flipper apparatus. The two species exhibited primitive features, including slender flipper bones and muscle attachment points resembling those of flying birds. A remarkable insight into the fascinating world of ancient penguins.
According to Ksepka, the early penguins likely grew to massive sizes to gain several advantages in the water. Larger penguins would have been more efficient at capturing bigger prey and better at maintaining body temperature in cold waters. Crossing the 100 lb size barrier might have enabled the earliest penguins to expand from New Zealand to other regions around the world.
Dr. Daniel Thomas from Massey University in Auckland emphasized that viewing these fossils as parts of a whole living animal helps create a clearer picture. He suggested that Kumimanu fordycei might have had an ecology distinct from modern penguins, possibly enabling it to reach deeper waters and access food that remains beyond the reach of today’s penguins.
The sight of Kumimanu fordycei on the ancient beaches of New Zealand 57 million years ago would have been truly astonishing. Due to the incomplete nature of its fossil remains, it remains one of the most captivating fossil birds ever discovered, as expressed by Field, the Curator of Ornithology at Cambridge’s Museum of Zoology. The hope is that future fossil findings will provide more insights into the remarkable biology of this early penguin species.