Diapsida

A reptile lineage with a two-opening temporal skull organization inferred in its ancestry. Modified descendants can lose or close these openings; turtles illustrate why present-day hole counts do not determine ancestry.

A member of the turtle lineage, whose shell and skull underwent substantial modification. Molecular and fossil evidence support a diapsid origin, with living turtles commonly recovered as sister to archosaurs.

A Middle Triassic stem relative of turtles combining modified ribs and ventral skeletal elements with temporal anatomy supporting a diapsid origin.

The clade comprising the most recent common ancestor of living crocodilians and birds and all its descendants, including extinct dinosaurs. Being sister to this clade does not make turtles archosaurs.

The avian total group: Aves and all extinct archosaurs more closely related to them than to living crocodilians. Under standard relationships this includes pterosaurs and nonavian dinosaurs.

A member of the dinosaur lineage, including birds. Restricting the word to extinct nonavian forms excludes descendants.

A member of the theropod lineage of dinosaurs, within which birds are nested. The hands and integument of nonavian relatives inform comparisons of avian origins.

A name used for a more restricted avian-lineage clade than Panaves. Definitions have included a branch-based bird-versus-deinonychosaur rule and an apomorphy-based flight rule; the definition must be specified in comparative work.

A nonavian tyrannosauroid dinosaur represented by skeletons with preserved filamentous feathers.

A member of the avian lineage of theropod dinosaurs. The extent of the named group can differ between crown-based and broader fossil usages.

A toothed latest Cretaceous bird outside the living-bird crown group. Its preserved pterygoid bone supplies evidence for a mobile palatal arrangement before the crown divergence.

A toothed Late Cretaceous bird outside Aves in crown usage, important for comparisons of the avian skull.

A Late Jurassic avian-lineage theropod dinosaur outside the living-bird crown group under standard relationships.

Used here for the crown group of birds: the last common ancestor of living palaeognaths and neognaths and all descendants. Broader historical definitions also occur and should be stated explicitly.

The crown-bird lineage containing Galloanserae and other living birds outside Palaeognathae. Taxonomic membership and possession of a particular mobile palate are different claims.

The clade containing landfowl and waterfowl.

The crown-bird lineage containing ostriches, emus, kiwis, tinamous and relatives. Its palaeognathous palate is an anatomical specialization, not evidence that its members are ancestors of neognaths.

A corvid used in studies of food caching and experience-dependent cache protection.

A corvid, including Corvus corax, used in studies of social information and caching.

A radiation of Galápagos and nearby finches important in studies of ecological divergence, song and hybridization.

The owl called Tyto alba in the cited sibling-negotiation experiments.

The bird studied in experiments on flexible deceptive alarm mimicry.

A member of the living crocodilian lineage, including crocodiles and their closest living relatives. birds are its living sister lineage within Archosauria.

A member of the lineage containing the tuatara and squamates such as lizards and snakes.

A living representative of the rhynchocephalian lineage. Including this branch helps test alternatives for turtle placement rather than equating all lepidosaur diversity with lizards.