I’m in, Sian, from the apes! (6)

I believe the answer is:

simian

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'from the apes' is the definition.
I can't tell whether this definition defines the answer.

'i'm in sian' is the wordplay.
'i'm' becomes 'im' ().
'in' is an insertion indicator.
'im' going inside 'sian' is 'SIMIAN'.

Can you help me to learn more?

(Other definitions for simian that I've seen before include "Primate" , "Ape; apelike" , "Of monkeys and apes" , "To do with or looking like a monkey" , "Like an ape or monkey" .)

I've seen this clue in the Sydney Morning Herald.

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