Avialae

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).

Jixiangornis is a genus of basal avialan dinosaurs from the Early Cretaceous. Like later avialans, it had no teeth, but it also had a long tail, unlike modern birds. Since teeth were still present in some more derived short-tailed avialans, Jixiangornis seems to have evolved its toothlessness independently of modern birds. The long forelimb (131% of hindlimb length) indicates at least some aerial ability. Jixiangornis is currently known only from a single specimen, a complete but juvenile skeleton. The fossil was found in the Yixian Formation near Beipiao City, western Liaoning, China.

Dalianraptor (meaning "Dalian thief") is a dubious, possibly chimeric, genus of theropod dinosaurs from the Jiufotang Formation of China, dating to the Early Cretaceous. It was initially believed to have been a possible dromaeosaurid before it was described in 2005.

Alcmonavis is a basal genus of avialan dinosaur that during the Late Jurassic lived in the area of present Germany. The only named species in the genus is Alcmonavis poeschli. Its only known fossil was originally reported as a specimen of Archaeopteryx.

Baminornis (meaning "Fujian Province bird") is an extinct genus of basal avialans from the Late Jurassic (Tithonian age) Nanyuan Formation of China. The genus contains a single species, Baminornis zhenghensis, known from a partial skeleton. Baminornis was initially identified as the oldest known avialan to bear a fused pygostyle, but later research cast doubt on the identification of this structure, claiming it could instead be part of the synsacrum.

Gargantuavis (meaning 'gargantuan bird') is an extinct genus of large, primitive bird containing the single species Gargantuavis philoinos. It is the only member of the monotypic family Gargantuaviidae. Its fossils were discovered in several formations dating to 73.5 and 71.5 million years ago in what is now northern Spain, Southern France, and Romania. Gargantuavis is the largest known bird of the Mesozoic, a size ranging between the cassowary and the ostrich, and a mass of like modern ostriches, exemplifying the extinction of non-avian dinosaurs was not a necessary condition for the emergenc

Yandangornis is a genus of theropods (possibly avialans) from the Late Cretaceous Tangshang Formation of China. It lived 81.5 million years ago in what is now China. The type species, Y. longicaudus, was formally described by Cai and Zhou in 1999.

Zhongornis (meaning "intermediate bird") is a genus of primitive maniraptoran dinosaurs that lived during the Early Cretaceous. It was found in rocks of the Yixian Formation in Lingyuan City (China), and described by Gao et al. in 2008.

Fukuipteryx is an extinct genus of basal avialan dinosaurs found in Early Cretaceous deposits from Japan's Kitadani Formation. It contains one species, Fukuipteryx prima.

Tingmiatornis (meaning "bird that flies") is a genus of flighted and possibly diving ornithuran dinosaur from the High Arctic of Canada. The genus contains a single species, T. arctica, described in 2016, which lived during the Turonian epoch of the Cretaceous.