Icaronycteris

Icaronycteris is an extinct genus of microchiropteran (echolocating) bat that lived in the early Eocene, approximately 52.2 million years ago. Four exceptionally preserved specimens are known from the Green River Formation of North America. There is only one thoroughly described species of bat in the genus, I. index, [1 ] although fragmentary material from France has also been tentatively placed within Icaronycteris as the second species I. menui.[2 ]

Information
http://en.wikipedia.org/wiki/Icaronycteris