The auditory bulla of Dipodomys deserti (Rodentia) and evidence of its adaptive significance

Abstract

The Osseous structure of the auditory bullae of the desert kangaroo rat, Dipodomys deserti, has been studied. The most significant modifications of this structure are the relatively free suspension of the bony labyrinth, the inflated character of the mastoid and tympanic bones, the enlarged tympanic membrane and elongated manubrium and an intrincate articulation of the malleus and incuso.

Evidence based upon habitat selection and the degree of specialization of this species would seem to indicate that these features have accompanied other adaptations as an important supplement. It seems likely that auditory perception has been an adaptation of selective value in the evolution of Dipodomys deserti.