It's a pars pro toto if you will.
I'd never heard synecdoche called that. Interesting.
That said, it's really weird to have a word for "monkeys and apes" other than the biological term "simians." That said, Americans generally can't distinguish among monkeys and apes, and a significant number of Americans believe they're unrelated. [sigh]
Well, the reason we do it is not because we have a word for both. We just have a word for monkeys that we use for the whole group, probably because the words look alike anyway. Monkeys (EN) = Apen (NL), Apes (EN) = Mensapen (NL), you can see the confusion.
And that's what "pars pro toto" means: A part for the whole.
Another example is the sentence: "Torturer isn't a problem if there's no Village."
Here I don't specifically mean the Village from the base set, but basically any card that reliably gives extra actions.
The reverse is a "totum pro parte" where you use the whole for a part.
Example: "Netherlands beat Hungary in the World Cup qualification."
I don't mean that 17 million Dutch people took on 10 million Hungarians.
It just means that a team of 11+ (substitutes) football players with a Dutch passport beat a team of players with the Hungarian nationality.