The Collaborative International Dictionary of English v.0.48:

Serotine \Ser"o*tine\, n. [F. s['e]rotine, fr. L. serotinus that
   comes or happens late.] (Zool.)
   The European long-eared bat (Vesperugo serotinus).
   [1913 Webster]

WordNet (r) 3.0 (2006):

serotine
    n 1: common brown bat of Europe [syn: serotine, European
         brown bat, Eptesicus serotinus]