Cat identified by old church group (6)
I believe the answer is:
ocelot
'cat' is the definition.
(ocelot is a kind of cat)
'old church group' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'church' becomes 'ce' (abbreviation for Church of England).
'group' becomes 'lot' (lot is a kind of group).
'o'+'ce'+'lot'='OCELOT'
'identified by' acts as a link.
(Other definitions for ocelot that I've seen before include "Animal in the loo etc." , "American wild cat" , "Wild creature" , "Type of American wildcat" , "Send animal to Cole" .)