Short reptile in half of China (4)
I believe the answer is:
croc
'short reptile' is the definition.
(short for crocodile; 'short' asks for an abbreviation)
'half of china' is the wordplay.
'half of' indicates taking half.
'china' becomes 'crockery' (I've seen this before).
'crockery' cut in half is 'CROC'.
'in' acts as a link.
(Other definitions for croc that I've seen before include "Large predatory reptile (colloq.)" , "Snapper" , "Predatory reptile (abbr)" , "Small reptile" , "Long-tailed reptile (abbr)" .)