Onychonycteris known species, hence "Onychonycteris" meaning "clawed bat". The specific epithet is a tribute to the fossil prospector and preparator who discovered it, Bonnie Finney. "Onychonycteris finneyi" was the strongest evidence so far in the debate on whether bats developed echolocation before or after they evolved the ability to fly. "O. finneyi" had well-developed wings, and could clearly fly, but lacked the enlarged cochlea of all extant echolocating bats, closer resembling the old world fruit bats which do not echolocate. This indicates that early bats could fly before they could echolocate. However, an independent evaluation of the "Onychonycteris" reference fossil in
Animal echolocation below the photic zone. Further studies have found that echolocation below the photic zone could have been a predation adaptation to diel migrating cephalopods. Since its advent, there has been adaptive radiation especially in the family Delphinidae (dolphins) in which echolocation has become extremely derived. Two proteins have been found to play a major role in toothed whale echolocation. Prestin, a motor protein of the outer hair cells of the inner ear of the mammalian cochlea, has an association between the number of nonsynonymous substitutions and hearing sensitivity. It has undergone two clear episodes of accelerated protein evolution in cetaceans: