Star gundog ultimately turned up antelopes (4)
I believe the answer is:
gnus
'antelopes' is the definition.
(gnu is a kind of antelope)
'star gundog ultimately turned up' is the wordplay.
'star' becomes 'sun' (Sun is an example).
'ultimately' says to take the final letters.
'turned up' is a reversal indicator.
The final letter of 'gundog' is 'g'.
'sun'+'g'='sung'
'sung' reversed gives 'GNUS'.
(Other definitions for gnus that I've seen before include "South African antelopes" , "Strange guns for the beasts" , "Large African antelopes" , "Snug (anag) -- wildebeest" , "African runners" .)