The Collaborative International Dictionary of English v.0.48:

biosystematy \biosystematy\ n.
   use of data (e. g. cytogenetic or biochemical) to assess
   taxonomic relations especially within an evolutionary
   framework.

   Syn: biosystematics.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

biosystematy
    n 1: use of data (e.g. cytogenetic or biochemical) to assess
         taxonomic relations especially within an evolutionary
         framework [syn: biosystematics, biosystematy]