Scientists from south Australia first to break old records (10)

'scientists from south australia' is the definition.
'zoologists' can be an answer for 'scientists' (zoologist is a kind of scientist). I am not certain of the 'from south australia' bit.

'first to break old records' is the wordplay.
I cannot quite understand how this works, but
'first' could be 'ist' (ist resembles 1st) and 'ist' is present in the answer.
'old' could be 'o' (abbreviation as in OT - Old Testament) and 'o' is located in the answer.
'records' could be 'logs' (logging is a kind of recording) and 'logs' is found within the leftover letters.
The remaining letters 'zo' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?