Bulletin of the American Museum of National History. Named Calciavis grandei, the newly discovered species is believed to have been roughly the size of a chicken. The creature was probably a predominantly ground dwelling bird, again, much like a chicken according to the authors, only engaging in short bursts of flight to evade predators. The species was partially named after renowned archaeologist Lance Grande, who had studied fossil fish in the same lake the new species was discovered in. The first part of the name is comprised of calci, meaning hard or stone, and avis, the Latin for bird. Fossil diggers unearthed two Calciavis fossils in the Green River Formation in Wyoming, a site usually considered a hotbed for fossilised fish. The Calciavis fossils date back to the Eocene Epoch, between roughly 56 million and 30 million years ago. Nesbitt, and his co-author Professor Julia Clarke, believe the fossils fit into the extinct group of early Palaeognathae birds, the Lithornithidae. They explain that the extinct bird is a close relative of ostriches, kiwis and tinamous now living in the southern hemisphere. Calciavis likely went extinct following the disappearance of tropical forests in North America. The creature’s discovery offers fresh insight into the chronology and distribution of tropical birds on the continent. “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,” Nesbitt said. “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 discovery of such a spectacularly well preserved example of a new species has the potential to greatly aid the interpretation of both bird fossils discovered decades ago, and those found in the future. “This spectacular specimen could be a ‘keystone’ that helps interpret much of the sparse fossils of birds that once lived in North America millions of years ago,” said Nesbitt. For more information: American Museum of Natural History ]]>
