Meeting Abstract
P3.142 Wednesday, Jan. 6 Reconstruction of the Rhinolophid Vocal Tract PEDERSEN, Scott*; RIEDE, Tobias; NGUYEN, Son; LU, Hongwang; MA, Jianguo; YAN, Zhen; HE, Weikai; ZHANG, Zhiwei; WANG, Fuxun; MUELLER, Rolf; PEDERSEN, ; PEDERSEN, ; South Dakota State University, Brookings; University of Utah, Salt Lake City; Institute of Ecology & Biological Resources, Hanoi; Shandong University, Jinan; Shandong University, Jinan; Shandong University, Jinan; Shandong University, Jinan; Shandong University, Jinan; Shandong University, Jinan; Virginia Tech, Dalton scott.pedersen@sdstate.edu
One-third of extant microchiroptera emit their echolcative calls through their nose. The evolution of this complex morphological innovation required a substantial redesign of the microchiropteran head, literally reinventing much of the rostrum. Several of these modifications supercede the mechanical demands imposed on the skull by other cranio-dental adaptations (e.g., durophagy). The rostrum and vocal tract of Rhinolphus are the most extensively modified examples of this nasal emitting innovation within the Order. Sound is produced in the larynx and filter characteristics of the sub- and supraglottal vocal tract shape the source signal. Previously, source and filter were modeled as if they were linearly coupled. Those linear models of the supraglottal vocal tract in rhinolophoids suggested that the differential developmental dynamics of the mid-face directly effected fixed cavity resonances thereby imposing restrictions on what sound levels and frequency profiles are permitted by the supraglottal vocal tract in different rhinolophoids. Recently, we reopened this line of inquiry readdressing the physics of the enormous sound levels produced by some species. The airways of several Rhinolphus were reconstructed by micro-computer tomography in order to quantify vocal tract dimensions. We evaluate the resonant mechanics of this complicated system and test linear and nonlinear numerical models of the sub- and supraglottal vocal tract. Our goal is to simulate a signal with realistic acoustic output power and efficiency. Preliminary data indicate that linear transfer functions are insufficient to explain the functioning of this sophisticated acoustic device.
