Dressed down

Gregory Nemec

Gregory Nemec

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Modern penguins wear tuxedos, but 36 million years ago, the penguin named Inkayacu paracasensis—“the water king”—favored a less formal look.

“Their dress was more business-casual,” says Yale paleontologist Jakob Vinther, who helped analyze the fossil feathers of the earth tone–clad species recently discovered in Peru.

These early penguins were also “humongous,” says Vinther: five feet tall and about 100 pounds. The largest living species, the Emperor penguin, is only three to four feet tall and averages 66 pounds. “But while the colors were wrong, and it had this very odd, elongated beak, it was clearly penguin-like—flightless, fully aquatic, and well-adapted to swimming.”

Vinther, who has pioneered techniques for discerning the colors of dinosaurs and other fossil species, examined tiny pigment-bearing bodies called melanosomes in the feathers of I. paracasensis and found that they looked quite different from those of modern penguins. Vinther uses differences in melanosome shape, size, and distribution to determine nature’s palette in feathers, skin, and scales. Surprisingly, Inkayacu’s melanosomes bore less resemblance to those in any of the 17 modern penguin species Vinther’s team examined than to those found in other modern birds. The ancient bird, he says, had a grayish back and a red-brown underside. (The study appeared in Science.)

Why remains a mystery, but Vinther and his colleagues suspect that the differences reflect lifestyle. The black-and-white patterning of modern penguins provides a measure of camouflage in the water. The extra melanin, which makes feathers black, might also help strengthen the wings of a bird that essentially flies through the ocean. But Inkayacu’s grey and brown tones could have been an advantage to a bird still tied somewhat to the land, or, at least, to a rocky coast and shallower waters.

“This fossil is a good intermediate form between primitive and modern penguins,” says Vinther. “A lot has happened since this guy was swimming around.”  

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