Proavis

The term "Proavis" was first coined, although under the form "Pro-Aves", by English osteologist and zoologist William Plane Pycraft in "The Origin of Birds", a 1906 article published in the magazine Knowledge and Scientific News.

Pycraft's "Pro-Avis" (singular of "Pro-Aves") was arboreal, as suggested Professor Osborn six years before, in 1900, in an article dealing with the hypothetical common ancestors of dinosaurs and birds.

[7] In the following years, as of 1913, Danish artist and amateur zoologist Gerhard Heilmann also used and popularised the term Proavis, this time presenting the public with more accurate and anatomically probable drawings.

[9] In 1991 and 1996 "proavis" or "protoavis" models were proposed by respectively Samuel Tarsitano[10] and Alan Feduccia,[11] both adherents of the "thecodont" hypothesis about the origins of birds.

He thought they must have represented an intermediate ecological stage, in which the hindlimbs still had largely cursorial adaptations whereas the arms had been elongated in order to climb.

[13] When in 2013 Aurornis was described, at the time the most basal known member of the Avialae, the group consisting of birds and their closest relatives, the Italian paleontologist Andrea Cau remarked it bore an uncanny resemblance to Paul's "proavis".