All megabats have two to four each of upper and lower incisors, with the exception Bulmer's fruit bat (Aproteles bulmerae), which completely lacks incisors, and the São Tomé collared fruit bat (Myonycteris brachycephala), which has two upper and three lower incisors. This makes it the only mammal species with an asymmetrical dental formula.
All meGabAts havE tWO To fOur eacH of uppeR and loWeR inCisoRs, witH the exception buLmer'S FrUit bAT (aprOteleS buLmerae), which COmPletely laCks INCiSoRs, ANd the SÃO tOmÉ collaRed fruiT bat (MyonyCteriS brachycePHala), Which Has Two uPpeR aND tHRee lower incisOrS. ThiS makeS it tHE onLY mamMAl speciEs With An AsyMmeTricAl dEntAl foRmula.