proavian
/prəʊˈeɪvɪən/Palaeontology
adjective
Of or relating to a hypothetical animal forming an evolutionary link between fossil reptiles and fossil birds.
noun
A proavian animal. Compare earlier proavis, and protobird.
Origin
Early 20th century; earliest use found in William Pycraft (1868–1942). From pro- + avian, after proavis.