Here's a subtle and fun one I ran into yesterday. For reasons I won't get into, I was thinking of having a character think of the scientific name of the orangutan. I looked it up, and the Bornean orangutan is Pongo pygmaeus. Reading a little further, I saw that the current classification of orangutans into two species was established in 1996 (and is still under discussion). So my character, in 1951, probably would not have produced the name Pongo pygmaeus. She would have come up with whatever it might have said in, say, an issue of National Geographic or American Scientist in the 40s. I've done a bit more digging but haven't yet determined what that might be. The original classification by Linneaus was Simia satyrus. Might that have changed by the 40s? It's likely. So there's probably some third name which is the name that my character would think of.

There's a 2014 book called Wild Man from Borneo: A Cultural History of the Orangutan that will probably answer my question. It's not really worth a great investment at this point, however. The scene might change - I've already waffled many times on whether it's an orangutan or a baboon - or be cut completely. And it's not the kind of anachronism that even nonegenarian readers (should I be lucky enough to have any) would catch, unless they happen to have been taxonomists of primate species. It's good to know that the answer is findable, but I'm trying to set it aside for now - the manuscript says Simia satyrus for now. Maybe my character read Linneaus....