Elliptic Fourier analysis on the tympanic bullae in three Meriones species (Rodentia, Mammalia): its application in biosystematics

Abstract. The size and shape of the auditory bullae are investigated across three species of Meriones, in order to determine the biosystematic value of bulla characteristics in species recognition. This study is based on outline (geometric morphometric) with elliptical Fourier and eigenshape analysis of tympanic bullae in: (a) the suprameatal triangle, (b) the mastoid, (c) the auditory meatus, and (d) the ventral view of bullae. The results show that characters of the auditory meatus separate these three species from each other. The shape of different parts of the bullae within each species is also shown to vary such as in two populations of M. persicus. The shape of organs is important in the interaction between the organism and its environment. Tympanic bullae variation is similar in the Geno population of M. persicus (Geno is located in south of Iran), and in M. libycus which lives in similar climates. The results of this analysis of tympanic bullae differ from the characters described by CORBET (1978).