Heterohyus is an extinct genus of apatemyid from the early to late Eocene. A small, tree-dwelling creature with elongated fore- and middle fingers, in these regards it somewhat resembled a modern-day aye-aye.
Three skeletons have been found at the early Eocene site at Messel Pit, Germany[1]
McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN0-231-11013-8