My favorite term in genetics is "the mouse"
Ha! Ha!_My_ favorite term is "the fly". That's always *Sophophora melanogaster*, not even any other of the 1400-odd former *Drosophila* species.
No, actually, it gets yet better, when *S. melanogaster* is treated as completely representative of "invertebrates"...
Wait! Better still! "Higher eukaryotes". That's all eukaryotes except yeast. *Saccharomyces* and *Schizosaccharomyces*, just as a reminder, are secondarily unicellular ascomycetes, more closely related to chanterelles than to bean rust.
And there's the Nature paper on the ancestral vertebrate karyotype which reconstructs the ancestral _osteichthyan_ karyotype... and says "tetrapod" when it means "sarcopterygian" (not "tetrapodomorph"; "sarcopterygian"!)...