A spiral-horned African antelope (5)
I believe the answer is:
nyala
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a spiral-horned african antelope</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for nyala that I've seen before include "Ruminant" , "Spiral-horned antelope" , "wild animal" , "Antelope of southern Africa" , "South African native" .)