The Structure of the Middle Ear in Egyptian fruit bat (Rousettus aegyptiacus)

The purpose of this study is to provide a more detailed anatomic description of the middle ear in Egyptian fruit bat (Rousettus aegyptiacus). The tympanic bullae of both sides (۶ middle ears) of ۳ Egyptian fruit bats were dissected under light microscopy. The malleus by its very long anterior process is fused to the margin of the ring-like tympanic bone. The incus is composed of a well-developed body and two processes of unequal size. The base of the stapes penetrates deep into the oval window, to which it is firmly attached by an annular ligament. The tensor tympani is a well-formed fusiform muscle and inserted by a single tendon into a very rudimentary muscular process located at the junction of the neck and root of the manubrium. The stapedius is another muscle that originates from the stapedial fossa and is inserted into a tubercle on the head of the stapes. In conclusion, the middle ear structure of R. aegyptiacus shows similarities to other Pteropodidae, but also several significant differences that have evolved to fully adapt to echolocation of this species of the bat.

Keywords:

Anatomy , Middle auditory system , Egyptian fruit bat