Functional Anatomy of the Middle Ear of Insectivores

Light microscopy was used to investigate the anatomy of [he middle ears of some representative members of the lnsectivora, concentrating on fossorial species. An augmented version of an existing model of the middle ear of mammals (1) was used to examine the audition in air of the animals studied. A second model was used to predict the nature of bone conduction by ossicular inertia in these species, Within the family Chrysochloridae (golden moles) there are genera (e.g. Ch~sospa/~r, Ereolilalpa and Chrysochlori$ that have middle ears which appear to be very poorly adapted (o the impedance-matching function required for efficient air hearing. me models suggest that the structure of the relatively enormous ossicles in golden moles of [hese genera is primarily adapted towards transmission of ground vibrations, via a mechanism of inertial bone conduction. Other fossorial marrunals, including golden moles of the genus At?tb/ysott~~/s,do not show such adaptations. me evolution of hearing in subterranean mammals is discussed.