The study of morphology and anatomy of tympanic bullae in the genus Meriones and its adaptation role using histological techniques and electron microscope

Structure of hearing organ especially middle ear has different specialization that provides response to wide range of sound frequencies. In this research external morphology and internal anatomy of tympanic bullae was studied using histological techniques and electron microscope in three species of genus Meriones (M. persicus، M. libycus، and M. crassus). Our results indicated adaptive value of tympanic bullae characters as well as increasing in the volume of tympanic bullae in the genus Meriones. This part is larger in M. crassus and M. libycus that live in desert habitats. Also it was seen that tympanic bullae in desert species has penumatization. Maximum penumatization of this part is occurred in desert species. In addition، middle ear ossicles have less hardness and more volume that increase reception possibility for higher sound frequencies. These characters enhance the ability of adaptation with desert environment such as; escape from predators، finding mate and returning to house.