These ancestral forms of bats are documented on almost all continents during the Lower Eocene (~ 54.8 to 49 But): in North America, in Europe, en Australie, South Asia and possibly South America . These forms involve 6 extinct families and are commonly named Eochiroptera . These are morphologically recognizable by traits of the skeleton, the skull or teeth that are not found on current species . Fossils of North Africa, up to now, attested from very diverse bat fauna includes forms derived exclusively from the Lower Eocene (Morocco, Egypt, Tunisia).
Aina hizi za baba wa popo ni kumbukumbu juu ya karibu mabara yote wakati Chini Eocene (~ 54.8 kwa 49 Lakini): katika Amerika ya Kaskazini, na Ulaya, sw Australie, Asia ya Kusini na pengine Amerika ya Kusini . Hizi aina kuhusisha 6 familia haiko na ni kawaida aitwaye Eochiroptera . Hizi ni morphologically kumtambua na sifa ya mifupa, fuvu au meno ambayo si kupatikana kwenye aina ya sasa . Fossils ya Afrika Kaskazini, hadi sasa, limedhibitishwa kutoka bat fauna tofauti sana ni pamoja na aina inayotokana peke kutoka Eocene Lower (Morocco, Misri, Tunisia).