Washington: Paleontologist have unearthed fossils of what they say the tallest ever penguin species that lived in what is now New Zealand some 27 million years ago.
The lanky bird that stood as high as 4.2 feet was also slimmer than modern penguins, with a long beak and flippers.
The researchers, who named the bird "Kariuku", hope that their finding will add to knowledge about the evolution of giant penguins.
According to them, most of New Zealand at that time was underwater, with only today`s mountaintops emerging from the sea. That made for excellent coastal nesting for the penguin species, LiveScience reported.
The new fossil specimens were found beginning in the 1970s, and researchers have continued to turn up bones from the animals as recently as two months ago, said study author Daniel Ksepka, a paleontologist at the North Carolina State University.
The find expands the known diversity of ancient New Zealand penguins, Ksepka said. "In the past we would have thought there were one or two species living in the area. Now we know there were five."
According to the researchers, who detailed their findings in the Journal of Vertebrate Paleontology, Kariuku grebneffi was the largest of at least five penguin species that lived in New Zealand during that period.
The bird had unusually long flippers and a slim build, though its legs and feet were as short and stumpy as those of penguins today, they said.
Ksepka and colleagues are using these ancient penguins to study everything from brain evolution to how the animals regulate their temperatures in frigid waters.
"Penguins are so interesting," Ksepka said.
"They`re so different than other birds that there`s a lot we can do in the fossil record to try to understand how they became what they are," he added.