A new
paper supports the traditional relationship of dromaeosaurid ('raptors') and troodontid theropods as the closest relatives of birds, but also supports the status of the controversial anchiornithine theropods as the earliest birds.
The authors
say theirs is the most comprehensive study of feathered dinosaurs and early birds into the evolutionary relationships of dinosaurs at the origin of birds. They used an analytical pipeline to search for evolutionary trees, and estimated how each species may have crossed the stringent thresholds for powered flight.