fossils

Weird fossil of the week: Inkayacu

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Nick
Garland

Founder and Editor
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Julio
Lacerda

Staff Artist and Writer
Thirty-six million years ago, during the Eocene Epoch, a group of giant penguins swam the world's southern oceans.

Imagine an emperor penguin, the biggest of all living penguins at 3 feet tall. Seems pretty tall for a penguin, right? Now imagine a penguin that's on average 5 feet tall and you have the giant penguin Inkayacu paracasensis.


The fossils of Inkayacu were first found in Peru and described in 2010. The "Water King" wasn't the tallest of fossil penguins, though. That title goes to the 6-foot-tall Palaeeudyptes klekowskii, discovered in 2014 in Antarctica.


However, what Inkayacu lacks in height, it makes up in feathers. It had unusual coloration for a penguin. As researchers uncovered Inkayacu's left forearm bones, they revealed a swath of fossilized feathers.


Over the past few years, paleontologists have learned that under high magnification they can find remnants in fossils of what are called melanosomes. A melanosome is an organelle within animal cells responsible for producing the protein melanin, which is what gives mammal hair its color and what gives bird (and other dinosaur) feathers their color.


Now finding a melanosome is extraordinary but how in the world do you know what color it produces? The shape of a melanosome is indicative of the color it produces. So, finding feathers and viewing the melanosomes allowed researchers to discover that the colors of Inkayacu were unlike modern penguins. Instead of a penguin tuxedo characteristic of those species alive today, Inkayacu had feathers that were mostly gray and reddish-brown.


Not only that, but Inkayacu's feather melanosomes were more similar to other living birds than today's penguins. Inkayacu and the emperor penguin share a common ancestor but modern penguins evolved giant, broad grape-cluster melanosomes that made their feathers more resistant to wear. This was possibly due to the demands of having an aquatic habit or even as the penguins evolved different coloration to escape new prey.


One thing's for certain, though. Inkayacu is one weird penguin.

5c3e0c5dff4b84c2d89b8da7be5adf3e

Nick
Garland

Founder and Editor


http://sulc.us/6qicy
http://www.eartharchives.org/articles/weird-fossil-of-the-week-inkayacu/