Parasites preserved in primeval iceberg? (4)
I believe the answer is:
lice
'parasites' is the definition.
(lice are parasitic insects)
'preserved in primeval iceberg?' is the wordplay.
'preserved in' indicates the answer is hidden within the clue.
'LICE' can be found hidden inside 'primeval iceberg'.
(Other definitions for lice that I've seen before include "Parasitic insects" , "Crawlers" , "Bloodsucking insects" , "Wingless bloodsucking parasites" , "Bloodsucking parasitic insect" .)