Usage in sentence:
Person A: Ooh - look at that crow!
Person B: Well, actually, as someone who is a scientist who studies crows, I am telling you, specifically, in science, no one calls jackdaws crows. They're not the same thing. If you're saying "crow family" you're referring to the taxonomic grouping of Corvidae, which includes things from nutcrackers to blue jays to ravens. It's not one or the other, that's not how taxonomy works.
Person A: Are you always such an XXX?
"Pedant" is close, but not quite.
It would be a mix of "know-it-all", "condescending" and "arrogant".