A primitive Emballonurid bat (Chiroptera, Mammalia) from the Earliest Eocene of England

Jerry J. Hooker

A new genus, Eppsillycteris, is erected for Adapisorex? allglicus COOPER, 1932, from the earliest Eocene Blackheath Beds of Abbey Wood, London, England. Various derived character states indicate that it belongs to the order Chiroptera (bats) rather than to the extinct "insectivore" family Adapisoricidae. Other derived character states are shared with fossil and modern members of the family Emballonuridae. Placement of the new genus in this family extends the record of the Emballonuridae back in time by about 10 million years. It is the earliest record of a modern bat family and one of the earliest bats. This implies that the differentiation of at least some modern bat families took place in the Palaeocene, where no authenticated records of bats yet exist. The primitive characters of the earliest bats make the family Nyctitheriidae an unlikely stem group for the order Chiroptera. A tentative plausible alternative exists in some unnamed upper molars from the Palaeocene of Walbeck, Germany. Wyollycteris chalix, described as a bat from the Late Palaeocene of Wyoming, U,S.A., fits better in the family Nyctitheriidae.