Primate needs way of working with group after ruin (8)
I believe the answer is:
marmoset
'primate' is the definition.
(marmoset is a kind of primate)
'way of working with group after ruin' is the wordplay.
'way of working' becomes 'mo' (I've seen this in other clues).
'with' is a charade indicator (letters next to each other).
'group' becomes 'set' (set is a kind of group).
'after' is a charade indicator (letters next to each other).
'ruin' becomes 'mar' (I've seen this before).
'mo'+'set' is 'moset'.
'moset' after 'mar' is 'MARMOSET'.
'needs' acts as a link.
(Other definitions for marmoset that I've seen before include "Somme rat? (anag)" , "Small New World monkey" , "Arms me to (anag) - animal" , "Little monkey" , "Monkey with claws" .)