"Proto-birds" (extinct)
- See also Archaeopterygiformes and Deinonychosauria, and Origin of birds.
This category contains very early fossils that some consider the earliest evidence of birds, and others which are agreed to be maniraptoran theropods of controversial placement in regard to birds. Most scientists consider them closely related to birds, and some find them avian enough to include in the birds outright. In any case, these forms demonstrate that feathered wings and other "avian" features were not limited to true birds, but first evolved in more basal lineages of theropods.
This assemblage is by no means monophyletic: the Late Cretaceous Rahonavis has by now been quite firmly established to represent a vicariant endemic Malagasy line of unenlagiine Dromaeosauridae. It was about as advanced as Archaeopteryx – though only half its age. The Scansoriopterygidae, on the other hand, may come as close to an actual "proto-bird" as anything yet known to science.
- "Protoavis" (Late Triassic) – a nomen dubium
- "Palaeopteryx" (Late Jurassic) – a nomen dubium
- Oviraptorosauria
- e.g. Caudipteryx (Early Cretaceous)
- Therizinosauria
- e.g. Beipiaosaurus (Early Cretaceous)
- Alvarezsauridae/Parvicursoridae
- e.g. Shuvuuia (Late Cretaceous)
- Dromaeosauridae
- e.g. Microraptor (Early Cretaceous)
- e.g. Rahonavis (Late Cretaceous)
- Archaeopterygidae – Dromaeosauridae?
- Anchiornis (Middle Jurassic) – tentatively placed here
- Archaeopteryx (Late Jurassic)
- Wellnhoferia (Late Jurassic) – probably synonym of Archaeopteryx
- Xiaotingia (Late Jurassic)
Read more about this topic: List Of Fossil Birds