Birds

Nature 461, 601-602 (1 October 2009) | doi:10.1038/461601a; Published online 30 September 2009Palaeontology: Feathered dinosaurs in a tangle Lawrence M. WitmerThe fossil described by Hu et al.1 isassigned to the family Troodontidae, whichtogether with the closely relatedDromaeosauridae and Avialae comprise theParaves (itself a subgroup of the theropoddinosaurs). One significant aspect ofAnchiornis is that it predatesArchaeopteryx, the iconic 'first bird', bysome 5 million to 10 million years. Anotheris that it shows that basal members of allthree of the Paraves groups — Anchiornis,Microraptor and Pedopenna — had longpennaceous feathers on their lower legs andfeet, as well as on their hands and tail. Theimplication is that avian evolutionconceivably went through a 'four-wing'stage. Numbers are approximate ages ofthe geological divisions in millions of yearsago.Even more significantly, Anchiornis is older (by 5 million to 10 million years) than the iconic 'firstbird' Archaeopteryx, which comes from younger Jurassic rocks in Germany.25