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Giant penguins once marched on equatorial South America when the Earth's climate was much warmer than it is today, scientists have discovered.
One species of penguin with a fearsomely long beak stood 1.5m tall - more than 30cm taller than the emperor penguin today. It lived about 36 million years ago, according to a study of its fossilised bones.
A second newly discovered species lived about 42 million years ago and, at 70cm tall, was about the same height as a living king penguin. But instead of living in the frosty habitat of Antarctica, the penguin lived off the balmy coast of southern Peru, just like its earlier extinct cousin.
Julia Clarke, a palaeontologist at the North Carolina State University in Raleigh, said Earth was then much warmer than now but the discovery of tropical penguins so near the equator should not come as a surprise.
"We tend to think of penguins as being cold-adapted species, even the small penguins of equatorial regions today, but the new fossils date back to one of the warmest periods in the last 65 million years of Earth's history.
"The evidence indicates that penguins reached low latitude regions [near the equator] more than 30 million year prior to our previous estimates," Dr Clarke said.
The new species of giant penguin, named Icadyptes salasi, is just 30cm short of the biggest known penguin species, Nordenskjoeld's giant penguin, which grew 1.8m tall and lived between 30 and 40 million years ago.
The second new species of penguin living in Peru is Perudyptes devriesi, which had a slightly longer beak than living penguins of the same size. But the beak of I. Salasi was unusually elongated and sharply pointed.
Strong muscle attachments to the bones around the bird's neck suggest the penguin used its powerful beak to catch and subdue its prey of fish or squid. But over time the beak of all penguins became shorter and blunter.
Penguins are a group of flightless birds superbly adapted to underwater swimming and life in a cold climate.
They evolved from a common ancestor that lived about 80 million years ago off the coasts of New Zealand and Byrd Land in Antarctica, which were then geographically closer to one another due to moving nature of the Earth's plate tectonics.
About 20 species of penguin are alive today. The largest live in and around Antarctica and a few smaller species live as far north as the tip of South Africa and the Galapagos Islands in the Pacific Ocean. No penguins are in the northern hemisphere.
But the new species do not offer hope for penguins today in the face of global warming, it seems.
"These Peruvian species are early branches off the penguin family tree that are comparatively distant cousins of living penguins," Dr Clarke said.
"The data from these new fossil species cannot be used to argue that warming wouldn't negatively impact living penguins."
The study of the two extinct species of Peruvian penguin is published in the current issue of the journal Proceedings of the National Academy of Sciences.
- Independent
