Rare fossil bird deepens mystery of avian extinctions

Today's birds descend from a small number of bird species living before the dinosaur extinction. Some of the birds that went extinct, the enantiornithines, were actually more common than and out-competed modern bird ancestors. Analysis of a newly described fossil, the most complete known from the Americas, demonstrates, too, that the enantiornithines were as agile and strong in flight as the ancestors of modern birds. But after the cataclysm that wiped out most of the dinosaurs, only one group of birds remained: the ancestors of the birds we see today. The 75-million-year-old fossil, from a bird about the size of a turkey vulture, is the most complete skeleton discovered in North America of what is called enantiornithines, or opposite birds. Discovered in the Grand Staircase-Escalante area of Utah in 1992 by University of California, Berkeley, paleontologist Howard Hutchison, the fossil lay relatively untouched in University of California Museum of Paleontology at Berkeley until doctoral student Jessie Aderholt learned about it in 2009 and asked to study it