Ursa Minor last seen in Banana Republic (4)
I believe the answer is:
cuba
'republic' is the definition.
(Cuba is an example)
'ursa minor last seen in banana' is the wordplay.
'ursa minor' becomes 'cub' (I can't explain this - if you can you should believe this answer much more).
'last seen in' suggests the final letters.
The final letter of 'banana' is 'a'.
'cub'+'a'='CUBA'
Can you help me to learn more?
(Other definitions for cuba that I've seen before include "Island country involved in a 1962 missile crisis" , "West Indian island" , "Largest Caribbean island" , "Guantanamo Bay location" , "Long rum-based drink" .)