Before black tie

Sophia Akl
23 January 2012

Ever wonder why penguins are so “well-dressed”? In fact, the black and white tuxedo-like “look” of the modern day penguin is a departure from that of a prehistoric predecessor.

Palaeontologist Julia Clarke, along with her team from the University of Texas at Austin, recently discovered that instead of sporting black and white feathers, a penguin species from more than 36 million years ago, in fact, had grey and reddish-brown feathers.

Fossils of the species Inkayacu paracasensis (which means “water king”) were unearthed by Clarke’s team in Peru in 2007, along with two other species of prehistoric penguins. Just recently, they uncovered fossilized feathers from the wing of the water king penguin. By comparing the size and shape of a pigment-containing portion of cells, called melanosomes, from the water king's feathers with those found in the feathers of modern day penguins, they were able to determine its colouring.

Did You Know?
Melanosomes contain melanin, a dark pigment that is present in the eyes, hair and skin of animals.

According to Clarke, the team found that the top of the prehistoric penguin’s wing was grey and the underside reddish-brown, although they did not have enough feathers to determine what the rest of its body looked like.

Did You Know?
The water king penguin was 1.5 meters tall (approximately five feet), which is twice the size of the largest modern-day penguin!

Why is this discovery important?

From studying the Inkayacu fossil, researchers found that the characteristics that make penguins such good swimmers (like wing and feather shape) appeared early in penguin evolution, whereas their present-day colour evolved much more recently.

Researchers have a few different ideas as to why penguins’ colouring has changed over time. One reason may be to protect themselves against predators, such as seals. From a seal’s vantage point in the water below, a penguin’s white belly helps it blend in with the sky above, making it harder to find. Another reason for the colour change could be due to the fact that penguins spent more and more time in the water. Clarke’s team found that the melanosomes in modern day penguins are larger than those found in the Inkayacu fossil, which could make the feathers stronger and more resistant to “wear and tear”.

The fossils found in Peru have extraordinarily well preserved scales and feathers, which could help researchers uncover more about penguin evolution and potentially about other marine animals as well.

Learn More!

National Geographic article

http://www.futurity.org/science-technology/giant-penguin-fossil-found-in-peru/

References:

Clarke, J. A., D. T. Ksepka, R.Salas-Gismondi, A. J. Altamirano, M. D. Shawkey, L. D’Alba, J. Vinther, T. J.DeVries and P. Baby. 2010. Fossil evidence for evolution of the shape andcolour of penguin feathers. Science. 330 (6006): 954-957.

Solomon, E. P., L. R. Berg and D. W. Martin. 2002. Biology. Brooks / Cole, 6thedition.

Willmer, P., G. Stone and I. Johnson. 2000.Environmental Physiology of Animals. Blackwell Science.

Article first published December 24, 2010.

Photo credit:Illustration courtesy Katie Browne, U.T. Austin

Sophia Akl

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