An international team of researchers has recently unearthed fossil bones in New Zealand from two newly described penguin species (Kumimanu fordycei and Petradyptes stonehousei). According to the experts, the former is the largest penguin that ever lived, weighing over 150 kilograms (more than three times the size of the largest living penguins).
The fossils were discovered between 2016 and 2017 in 57-million-year-old beach boulders in North Otago, on New Zealand’s South Island. Analyses revealed the fossils as being between 59.5 and 55.5 million years old, thus dating about five to ten million years after the mass extinction that wiped out all the non-avian dinosaurs.
By using lasers to create digital models of these penguins’ bones and comparing them to other fossil species, modern penguins, and birds such as auks, the researchers estimated that K. fordycei was most likely an enormous bird, weighing up to 154 kilograms (in comparison, emperor penguins – the largest living species of penguins – weigh between 22 and 45 kilograms). The other species discovered, named by the scientists Petradyptes stonehousei, weighted about 50 kilograms.
“Fossils provide us with evidence of the history of life, and sometimes that evidence is truly surprising,” said study co-author Daniel Field, an expert in Earth Sciences at the University of Cambridge. “Many early fossil penguins attained enormous sizes, easily dwarfing the largest penguins alive today. Our new species, Kumimanu fordycei, is the largest fossil penguin ever discovered – at approximately 350 pounds, it would have weighed more than [basketball player] Shaquille O’Neal at the peak of his dominance!”
According to the scientists, these penguins grew to such titanic proportions because it made them more efficient in the water. “Size conveys many advantages. A bigger penguin could capture larger prey, and more importantly it would have been better at conserving body temperature in cold waters. It is possible breaking the 100 lb size barrier allowed the earliest penguins to spread from New Zealand to other parts of the world,” explained study lead author Daniel Ksepka, an Ornithology curator at the Bruce Museum.
“When we start thinking of these finds not as isolated bones but as parts of a whole living animal then a picture begins to form,” added co-author Daniel Thomas, a senior lecturer in Zoology and Ecology at Massey University of New Zealand. “Large, warm-blooded marine animals living today can dive to great depths. This raises questions about whether Kumimanu fordycei had an ecology that penguins today don’t have, by being able to reach deeper waters and find food that isn’t accessible to living penguins.”
“Kumimanu fordycei would have been an utterly astonishing sight on the beaches of New Zealand 57 million years ago, and the combination of its sheer size and the incomplete nature of its fossil remains makes it one of the most intriguing fossil birds ever found. Hopefully future fossil discoveries will shed more light on the biology of this amazing early penguin,” Field concluded.
The study is published in the Journal of Paleontology.
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By Andrei Ionescu, Earth.com Staff Writer
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