Functional Morphology of the Nasal Complex in the Harbor Porpoise (Phocoena phocoena L.)
Article first published online: 20 MAR 2009
Copyright © 2009 Wiley-Liss, Inc.
The Anatomical Record
Volume 292, Issue 6, pages 902–920, June 2009
How to Cite
Huggenberger, S., Rauschmann, M. A., Vogl, T. J. and Oelschläger, H. H.A. (2009), Functional Morphology of the Nasal Complex in the Harbor Porpoise (Phocoena phocoena L.). Anat Rec, 292: 902–920. doi: 10.1002/ar.20854
- Issue published online: 22 MAY 2009
- Article first published online: 20 MAR 2009
- Manuscript Accepted: 3 NOV 2008
- Manuscript Received: 19 OCT 2008
- Graduiertenförderung (Johann Wolfgang Goethe University)
- German Academic Exchange Service (DAAD)
- epicranial complex;
- sound generation;
Toothed whales (Odontoceti, Cetacea) are the only aquatic mammals known to echolocate, and probably all of them are able to produce click sounds and to synthesize their echoes into a three-dimensional “acoustic image” of their environment. In contrast to other mammals, toothed whales generate their vocalizations (i.e., echolocation clicks) by a pneumatically-driven process in their nasal complex. This study is dedicated to a better understanding of sound generation and emission in toothed whales based on morphological documentation and bioacoustic interpretation. We present an extensive description of the nasal morphology including the nasal muscles in the harbor porpoise (Phocoena phocoena) using macroscopical dissections, computer-assisted tomography, magnetic resonance imaging, and histological sections. In general, the morphological data presented here substantiate and extend the unified “phonic lips” hypothesis of sound generation in toothed whales suggested by Cranford et al. (J Morphol 1996;228:223–285). There are, however, some morphological peculiarities in the porpoise nasal complex which might help explain the typical polycyclic structure of the clicks emitted. We hypothesize that the tough connective tissue capsule (porpoise capsule) surrounding the sound generating apparatus is a structural prerequisite for the production of these high-frequency clicks. The topography of the deep rostral nasal air sacs (anterior nasofrontal and premaxillary sacs), narrowing the potential acoustic pathway from the phonic lips to the melon (a large fat body in front of the nasal passage), and the surrounding musculature should be crucial factors in the formation of focused narrow-banded sound beams in the harbor porpoise. Anat Rec, 292:902–920, 2009. © 2009 Wiley-Liss, Inc.