Antelope in national park around middle of trail (5)
I believe the answer is:
nyala
'antelope' is the definition.
(nyala is a kind of antelope)
'national park around middle of trail' is the wordplay.
'national' becomes 'n' (abbreviation listed in Chambers).
'park' becomes 'lay' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'around' shows that the letters should be reversed in order.
'middle of' says to take the centre.
The middle letter of 'trail' is 'a'.
'lay' back-to-front is 'yal'.
'n'+'yal'+'a'='NYALA'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for nyala that I've seen before include "African animal" , "Spiral-horned antelope" , "Antelope of southern Africa" , "beast" , "wild animal" .)