A Brief Peek at Penguin History and a Svelte Species Discovered

King Penguins would have been dwarfed by the ancient Kairuku. Photo: Sean Mack via wikimedia commons

Everybody loves penguins. Flightless, awkward on land, yet elegant in the water, it’s hard to imagine how this strange bird came about. In fact, as avian paleontologist Dan Ksepka reveals, the penguin has a long, storied history and this week, another chapter was unveiled when scientists announced the discovery of Kairuku penguins.

Penguins are an evolutionary puzzle. Explaining how these strange, diving birds with scale-like feathers came about is a challenge. Watch a penguin and it seems improbable that they’re related to high-soaring seabirds. Touch a penguin and you feel something more akin to a damp “chubby dog,” to borrow Ksepka’s description, than the light feather-fluff of most birds.

How much do we know about ancient penguin history? “Quite a lot, actually,” says avian paleontologist Dan Ksepka, of North Carolina State University.

Ksepka’s love of birds led him to penguin fossils while in graduate school. He’s been piecing together penguin history ever since and splits his time between fossil studies on weekdays and bird-watching on the weekend.
As Ksepka notes on his blog, March of the Fossil Penguins, there are fifty known species of extinct penguin in the fossil record. These fossils have been found throughout the Southern Hemisphere in locations where modern penguins exist today.

Scientists suspect these water birds originally came fromNew Zealand, where paleontologists have unearthed many penguin fossils including the oldest Waimanu penguins. New Zealand’s isolation, islands, and lack of native mammals —save bats— made it an ideal spot for penguin proliferation and developing new species.
Fossils belonging to Waimanu penguins date back more than 60-million years. A primitive penguin, Waimanu was slender and could fold back its wings. It’s likely that Waimanu was a descendent of an ancient petrel-penguin ancestor, though without older fossils we can’t be sure.

This week, Ksepka and colleagues at the University of Otago, New Zealand, published their discovery of a new species of now-extinct svelte penguins, Kairuku.

Reconstruction of Kairuku waitaki with a stranded Waipatia dolphin in background. Artwork by Chris Gaskin. Owner and copyright owner: Geology Museum, University of Otago. Used with permission.

Kairuku lived in New Zealand 27-million years ago. At the time New Zealand made an especially ideal habitat, with much of the South Island covered in 20-30 meters of water, creating more islands and warm, shallow waters.

Using three skeletons, the scientists reconstructed Kairuku, whose name is Maori for “diver who returns with food.” The reconstruction revealed a tall and slim bird, with a long narrow beak and flippers. At 4.2 feet, Kairuku was nearly a foot taller than the modern Emperor penguin.

Kairuku was not, however, an ancestor of modern penguins. Instead, Ksepka describes the Kairuku as a “side experiment” of evolution, successful for millions of years, then dying out.

In the case of Kairuku, their size hints that they occupied the niche of modern seals and sea lions. When these mammals arrived, the Kairuku may have been out-competed into extinction. Another explanation for their disappearance is changing climate. Whatever the reason, environmental shifts eliminated the elegant Kairuku, while other species thrived.

“What happened to the giant penguins is still a mystery,” Ksepka says.

For more on penguin research, read Hugh Powell’s “Penguins Offer Insight into Climate Change”  for Audubon magazine. Penguins are also popular on the Perch, read on for Rachel Nuwer’s post on Emperor penguin huddle research and a remarkable video of a penguin escaping a killer whale.

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