The Collaborative International Dictionary of English v.0.48:

Petauristidae \Petauristidae\ prop. n.
   A natural family of Old World flying squirrels.

   Syn: subfamily Petauristidae.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Petauristidae
    n 1: Old World flying squirrels [syn: Petauristidae,
         subfamily Petauristidae]