Science The new family tree, compiled using information from fossils and from genetic analyses of modern birds, also reveals that this lineage underwent a major burst of evolution after an asteroid slammed into Earth about 66 million years ago and killed off the rest of their dinosaurian kin. By Sid Perkins
'“This is one of the most comprehensive studies that attempts to date when these evolutionary divergences happened,” says Luis Chiappe, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California, who wasn’t involved in the new research.
'Modern birds, a group called Neornithes (a name that combines neo and a variant of ornis, the Greek words for “new” and “bird,” respectively) are the most diverse and widespread vertebrates on Earth today. Previous studies that used only information from genetic analyses of current species have suggested that birds arose anywhere from 72 million to 170 million years ago. But the new study, which includes anatomical data extinct species preserved in the fossil record, narrows that window considerably, says Joel Cracraft, an ornithologist at the American Museum of Natural History in New York City.
'He and museum colleague Santiago Claramunt, also an ornithologist, didn’t include well-known ancient birds such as Archaeopteryx and Confuciusornis, which belonged to lineages that eventually died out. They only looked at species that belonged to the three major groups of birds alive today: Palaeognathae (ostriches and their close relatives), Galloanseres (waterfowl, pheasants, and their close kin), and Neoaves (all other birds).'