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Rare fossil offers glimpse of birds that lived millions of years ago

Calciavis grandei
FLIGHTLESS: Calciavis grandei was about the size of a chicken. Image courtesy of Velizar Simeonovski.

A 50-million-year-old fossil has revealed that a close relative of today’s ostriches, kiwis, and tinamous once lived in North America.

The specimen is exceptionally well preserved and completely intact, preserving soft tissues and feathers as well as bones. It was unearthed more than a decade ago in Wyoming’s Green River Formation, a former lakebed famous for producing scores of complete fish-skeleton fossils.

Paleontologists Sterling J. Nesbitt, of Virginia Tech, and Julia A. Clarke, of the University of Texas at Austin, named the new species Calciavis grandei, combining calci, meaning hard or stone, with avis, which is Latin for bird. The word grandei honors a well-known fellow paleontologist.

“The new bird shows us that the bird group that includes the largest flightless birds of today had a much wider distribution and longer evolutionary history in North America,” says Nesbitt. “Back when Calciavis was alive, it lived in a tropical environment that was rich with tropical life, and this is in stark contrast to the high-desert environment in Wyoming today.”

The scientists described the find in the Bulletin of the American Museum of Natural History on June 30.


A version of this article appeared in the October 2016 issue of BirdWatching. Subscribe.


Read the report

The anatomy and taxonomy of the exquisitely preserved Green River Formation (early Eocene) lithornithids (Aves) and the relationships of Lithornithidae. (Bulletin of the American Museum of Natural History, no. 406). Nesbitt, Sterling J,; Clarke, Julia A. 2016-06-30. Abstract and PDF.

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