More than a decennium ago , fossil excavator unearthed the 50 - million - twelvemonth - old remains of a chicken - sized hoot in a former lakebed in Wyoming . Now , researcher let on that the unusually preserved fossils go to a never - before - date species . They named itCalciavis grandei , and it ’s related to modern - day ostrich , kiwis and emus . It was described in theBulletin of the American Museum of Natural Historylast calendar week .
skirt fossils that old are exceedingly rare . They ’re hollow , more fragile than most mammal osseous tissue , and very likely to be crushed during the preservation cognitive process . " These are stunningly preserved fossils , ” Virginia Tech ’s Sterling Nesbitt said in astatement . One of them is a nearly complete , articulated skeleton with soft tissue ( include feathers ) , and the other specimen is a well - preserved but disarticulated skeleton in the cupboard .
Nesbitt and Julia Clarke from the University of Texas at Austin psychoanalyse both individuals , which were discovered in Warfield Springs at the Fossil Butte Member of the Green River Formation , near Kemmerer , Wyoming . This fogey lakebed – which dates back to the previous former Eocene 51.66 million years ago – is a well - known site for ancient Pisces , crocs , turtles , mammals , and other bird .
The new species was about the size of a chicken , and like chicken , it was mostly flat coat - abode and vanish in unretentive burst to escape predators as involve . It was a stuffy relative of today ’s ostriches of Africa , kiwis of New Zealand , and tinamous , which are found in Central and South America .
" The young bird record us that the razz group that includes the largest flightless birds of today had a much full distribution and longer evolutionary account in North America , " Nesbitt say . " Back whenCalciaviswas awake , it lived in a tropical surroundings that was ample with tropical spirit and this is in stark direct contrast to the high - desert environment in Wyoming today . " It likely went out when tropical forests disappear across the continent .
The novel genus name combines “ calx , ” Latin for stone , with “ avis , ” Latin for chick , and the species name honour paleontologist Lance Grande .
Images in textbook : Calciavis grandei fossils by Sterling Nesbitt ( middle ) and Rick Edwards / American Museum of Natural History ( bottom )
