Avialae

Avialans Temporal range: Middle Jurassic–Present, 150.8–0 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N Earliest 165 Ma if Anchiornithidae are members[2]
Fossil specimen of Jeholornis prima
Collage of four extant birds. Clockwise from top-left: Spanish imperial eagle (Aquila adalberti), common ostrich (Struthio camelus), mallard (Anas platyrhynchos), and common kingfisher (Alcedo atthis)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Pennaraptora
Clade:	Paraves
Clade:	Avialae Gauthier, 1986
Subgroups
†Alcmonavis †Cretaaviculus †Dalianraptor †Fukuipteryx †Gargantuavis? †Jixiangornis †Tingmiatornis? †Yandangornis †Zhongornis †Jeholornithiformes Avebrevicauda Paul, 2002 †Omnivoropterygiformes? Pygostylia Possible avialans †Anchiornithidae †Scansoriopterygidae †Archaeopteryx †Balaur †Hesperonychus †Overoraptor †Rahonavis †Wellnhoferia †Yixianosaurus

Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used (see below).

Archaeopteryx lithographica, from the late Jurassic Period Solnhofen Formation of Germany, is usually considered the earliest known avialan which may have had the capability of powered flight;^[3] a minority of studies have suggested that it might have been a deinonychosaur instead.^[4] Several older (but non flight-capable) possible avialans are known from the late Jurassic Tiaojishan Formation of China, dated to about 160 million years ago.^[5][6]