Pa turns up with his little creature (5)
I believe the answer is:
aphis
'little creature' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'pa turns up with his' is the wordplay.
'turns up' is a reversal indicator.
'with' says to put letters next to each other.
'pa' written backwards gives 'ap'.
'ap'+'his'='APHIS'
Can you help me to learn more?
(Other definitions for aphis that I've seen before include "Small insect" , "Plant louse" , "Greenfly" , "sucker?" , "Sap-sucking garden pest" .)