Old primates OK fitness class being introduced

I believe the answer is:

ape-men

I'm a little stuck... Click here to teach me more about this clue!

'old primates' is the definition.
'ape-men' can be an answer for 'primates' (I have seen 'Primitive primates ' mean 'ape-men' so perhaps 'primates' could also mean 'ape-men'). I am not certain of the 'old' bit.

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for ape-men that I've seen before include "Early humans" , "Multiple Tarzans" , "Primitive primates" , "Extinct primates" , "Extinct human ancestors" .)

I've seen this clue in The Telegraph.

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