Someone over at t'other place made a plausible suggestion of the Dodo, which is pretty much a byword for an extinct organism.

TBH, I think all the dinosaurs us 1970s kids had models of (T. Rex, Brachiosaurus (Brontosaurus), Triceratops, Stegosaurus) are probably better known than the Archeopteryx and, thanks to Jurassic Park, you can probably add Velociraptors to that list as well.