One of the two new species, Kumimanu fordycei, weighed up to 160 kg and may have been the largest penguin ever to have lived, according to Bruce Museum paleontologist Daniel Ksepka and his colleagues from New Zealand, the United Kingdom and the United States.
Life reconstructions of Kumimanu fordycei and Petradyptes stonehousei. Image credit: Simone Giovanardi.
In their study, Dr. Ksepka and co-authors nine new penguin specimens from the Moeraki Formation of the South Island, New Zealand.
They assigned the largest specimen to a new species, Kumimanu fordycei, which had a live body mass in the range of 148 and 160 kg.
The second new species, Petradyptes stonehousei, was represented by five specimens.
The anciet bird was slightly larger than the living emperor penguin (Aptenodytes forsteri).
Both new species lived during the Late Paleocene epoch, between 60 and 55 million years ago.
“Kumimanu fordycei and Petradyptes stonehousei show that penguins got very large early in their evolutionary history, millions of years before they fine-tuned their flipper apparatus,” the paleontologists said.
They also observed the two species retained primitive features such as more slender flipper bones and muscle attachment points that resemble those of flying birds.
To estimate the size of the species, they measured hundreds of modern penguin bones and calculated a regression using flipper bone dimensions to predict weight.
“The penguins were so large as it made them more efficient in the water,” Dr. Ksepka said.
“A bigger penguin could capture larger prey, and more importantly it would have been better at conserving body temperature in cold waters.”
The massive size and placement of Kumimanu fordycei close to the root of the penguin tree provide additional support for a scenario in which penguins reached the upper limit of their body size very early in their evolutionary history.
“It is possible their size allowed the earliest penguins to spread from New Zealand to other parts of the world,” Dr. Ksepka said.
Source: sci.news
