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Archaeornithes

plural noun
Ar·​chae·​or·​ni·​thes | \ -ˈȯrnəˌthēz, -ˌȯrˈnī(ˌ)thēz\

Definition of Archaeornithes

: a subclass of Aves comprising the earliest and most primitive of fossil birds, retaining distinctive reptilian characters, and including the two genera Archaeornis and Archaeopteryx

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History and Etymology for Archaeornithes

New Latin, from archae- + -ornithes

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