Meeting Abstract

4.5  Friday, Jan. 4  Form and Function of the Odontocete Ear ARY, WJ*; CRANFORD, T; BERTA, A; KRYSL, P; San Diego State University; San Diego State University; San Diego State University; Univ. of California, San Diego williamjamesary@gmail.com

Toothed whales (odontocetes) have a sound reception apparatus that is specialized for underwater hearing and works in tandem with their biosonar system. The apparatus is composed of the internal acoustic pinnae and the bony tympanoperiotic complex (TPC). The internal pinnae are made of special acoustic fats and other tissues that form a waveguide, bringing sounds from the environment to the TPC, which contains the middle ear bones. The sound reception apparatus functions to filter and/or amplify incoming sounds depending on their utility to the animal. Across species, odontocete TPCs have a variety of shapes. These shapes are linked to function. We CT scanned TPCs from 8 species across the Odontoceti. Geometric Morphometrics techniques characterized the shapes of the TPCs. Vibrational analysis based on finite element models provided a family of “natural” or resonant frequencies for each TPC. These resonant frequencies provide insight into the animals’ sense of hearing and the potential effects of anthropogenic sound.