Introducing Inkayacu, the First Fossil Penguin with Feathers

Today, an important  fossil penguin discovery was announced in the journal Science.  A new Peruvian penguin has been added to the panthenon of extinct species.  This fossil species was larger than the living Emperor Penguin and lived near the Equator, but that is only a small part of the story.  This fossil is goundbreaking because it is the only fossil penguin ever discovered with preserved feathers. I was fortunate to be involved in this study myself, so it seems like a good opportunity to provide some behind-the-scenes details of how a fossil goes from the desert to the museum to (hopefully) the popular imagination. Over the next two weeks, I’ll be posting some more details of the new fossil and what it means for our understanding of penguin evolution.  Today, we can start with the basics.

Soft tissue structures like skin and feathers are rarely preserved in the fossil record.  Feathers are even more rarely preserved in marine settings – most of the famous feathered fossils like the Liaoning dinosaurs and the Green River birds are from freshwater lakes. Nevertheless, the feathers of Inkayacu are preserved in remarkably good condition.  In the image below, a pair of Inkayacu feathers are compared to a feather from a living Emperor Penguin.   The rachis, or shaft, of the feather is clearly visible and shows the characteristic flattened shape of a modern penguin feather. Even the fine barbs branching off the rachis are visible.  And it doesn’t end there – under a scanning electron microscope, even microscopic melanosomes, intracellular structures that impart color to feathers, are visible.  This reveals a lot about Inkayacu, and we’ll delve into that a few posts down the road.  Note that even though we are dealing with a giant, roughly 5 foot long (swimming length) penguin the fossil feathers shown below are small, like those of living penguins, reaching about 3cm each.

Fossil feathers of Inkayacu compared to a modern Emperor Penguin feather. Note the flattened shape of the feather shaft, the fine preservation of the barbs and the similar darkened tips in two specimens.

The new species is named Inkayacu paracasensis. “Inkayacu” means “Water King” in the Quechua language, while “paracasensis” refers to the Reserva Nacional de Paracas, the national park where the fossil was found.  The nickname of the new fossil has long been Pedro, after a TV character popular in Peru.  The skeleton itself is exquisitely well preserved after lying buried in silt and sandstone in the desert for 36 million years.  In fact, it would be quite a big deal if only the bones were found – giant penguin skulls and skeletons are still very rare, and the skeleton of Inkayacu is remarkably complete.  These bones will be given their due in a follow-up post.

Reconstruction of Inkayacu paracasensis diving. Artwork by Katie Browne.

This is a good opportunity to thank the institutions that supported this research.  Our team is very grateful to the National Science Foundation and the National Geographic Society Expeditions Council for funding the fossil fieldwork in Peru and back in the lab that helped make the Inkayacu project a reality.

To read the full story, follow this link to the original paper: http://www.sciencemag.org/cgi/content/abstract/science.1193604

Reference:

Julia A. Clarke, Daniel T. Ksepka, Rodolfo Salas-Gismondi, Ali J. Altamirano, Matthew D. Shawkey,, & Liliana D’Alba, Jakob Vinther, Thomas J. DeVries, Patrice Baby (2010). Fossil Evidence for Evolution of the Shape and Color of Penguin Feathers Science : 10.1126/science.1193604 (Pre-print PDF at Science Express)