Ornithurine

Part of speech: adjective

Definitions

1. A type of extinct bird that exhibits characteristics of both modern birds and reptiles
2. an ancient avian group recognized for traits indicating their evolutionary transition
3. a classification that highlights features similar to modern birds while retaining primitive aspects

Etymology: Ornithurine comes from the scientific name Ornithurae, a group of birds that includes modern birds and their closest extinct relatives. The Greek roots are "ornis", meaning bird, and "oura", meaning tail. The name refers to the tail skeleton, which in these birds is shortened and fused into a structure called the pygostyle, rather than the long bony tail seen in earlier feathered dinosaurs such as Archaeopteryx. The suffix "-ine" is the ordinary English adjective ending used to turn a group name into a description, so ornithurine simply means "belonging to the Ornithurae." Words of this kind were coined in the 19th and 20th centuries, when palaeontologists needed precise names for branches of the bird family tree; the ancient Greeks had no such terms.