title: Optical and tomographic imaging of a middle ear malformation in the bullfrog (Rana catesbeiana).
abstract: Using a combination of in vivo computerized tomography and histological staining, a middle ear anomaly in two wild-caught American bullfrogs (Rana catesbeiana) is characterized. In these animals, the tympanic membrane, extrastapes, and pars media (shaft) of the stapes are absent on one side of the head, with the other side exhibiting normal morphology. The pars interna (footplate) of the stapes and the operculum are present in their normal positions at the entrance of the otic capsule on both the affected and unaffected sides. The pattern of deformity suggests a partial failure of development of tympanic pathway tissues, but with a preservation of the opercularis pathway. While a definitive proximate cause of the condition could not be determined, the anomalies show similarities to developmental defects in mammalian middle ear formation.
authors.affiliation: Department of Psychology, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Seth S
authors.initials: SS
authors.lastname: Horowitz
authors.forename: Andrea Megela
authors.initials: AM
authors.lastname: Simmons
authors.forename: Darlene R
authors.initials: DR
authors.lastname: Ketten
mesh_terms: D000818:Animals; D004432:Ear, Middle / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005260:Female; D008297:Male; D011892:Rana catesbeiana / Q000002:abnormalities* / Q000502:physiology; D012886:Skull / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D013199:Stapes / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014432:Tympanic Membrane / Q000002:abnormalities / Q000473:pathology; D014828:Vocalization, Animal