The Collaborative International Dictionary of English v.0.48:

Syndyasmian \Syn`dy*as"mi*an\, a. [Gr. syndyasmo`s a pairing,
   fr. syndya`zein to pair.]
   Pertaining to the state of pairing together sexually; -- said
   of animals during periods of procreation and while rearing
   their offspring. --Morgan.
   [1913 Webster]