"Protobird" is an informal term that has been used by some

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

s when discussing animals that, while technically classified as non-avian

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s, possess many features normally associated with

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s. All protobirds are

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

. Zhou and Farlow (2001), for example, used the term "protobird" for primitive members of the clade

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 Deinonychosauria, deinonychosaurs, though ...

. In this sense, protobirds would include animals like '' Confuciusornis'', '' Sapeornis'', and the

Enantiornithes The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct Avialae, avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teet ...

. These animals were small, flying, feathered, and closely related to birds. The authors restricted the term "bird" to refer only to

Aves Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...

, which they used to mean only modern ("crown group") birds.Zhou, Z. and Farlow, J.O. (2001). "Flight Capability and habits of Confuciusornis." Pp. 237-245 in ''New Perspectives on the Origin and Early Evolution of Birds''. Peabody Museum of Natural History, Yale University, New Haven, USA.

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

used the term "protobird" in a wider sense in 1988, to refer to the extremely bird-like non-avian dinosaurs (

Maniraptora Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Dromaeosauridae, Troodontidae, ...

), including oviraptorosaurs, troodontids, and dromaeosaurids.Paul, Gregory S. (1988). ''Predatory Dinosaurs of the World.'' New York: Simon and Schuster. 464 pp. Paul speculated that these forms were so bird-like they probably had

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...

s, an idea later proven by fossil evidence.

References

Dinosaurs {{dinosaur-stub

See also

References