Ratites (flightless birds) and Tinamous (Chicken-like bird from Americas) were the first to split off from the other birds so I suppose you could argue they'd b

Ratites (flightless birds) and Tinamous (Chicken-like bird from Americas) were the first to split off from the other birds so I suppose you could argue they'd be the most dinosaur-y evolutionarily. All birds are technically Dinosaurs as far as taxonomy is concerned.