QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Werner, Y. L. Articles by Saunders, J. C. Search for Related Content PubMed PubMed Citation Articles by Werner, Y. L. Articles by Saunders, J. C.

Effects of age and size in the ears of gekkonomorph lizards: middle-ear sensitivity

Yehudah L. Werner^1,3,*, Petar G. Igi², Merav Seifan³ and James C. Saunders¹

¹ Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania, PA 19104, USA
² University of Chicago — Pritzker School of Medicine, 924 E 57^th Street, Chicago, IL 60637, USA
³ Department of Evolution, Systematics and Ecology, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel

View larger version (189K): [in a new window]   Fig. 1. Right-side ear of freshly dead adult Eublepharis macularius (Nikon Multiphot Macrophotography system). The tympanic membrane (TM) has been completely exposed surgically. The four processes of the extracolumella spreading on the inside of the TM are clearly seen through. A, location of the microbead opposite the columella-extracolumella shaft (hidden from view); B, location of the microbead at the tip of the pars inferior of the extracolumella; C, location of the microbead on the free sector of the TM; H, hinge of the extracolumellar mechanical lever; PAA, anterior process; PAP, posterior process; PS, superior process. Scale bar, 3 mm.

View larger version (14K): [in a new window]   Fig. 2. Correlation (r=0.88) of the maximum velocity of tympanic membrane vibration (mms-1), with animal rostrum—anus (RA) length, among nine samples of gekkonomorph lizards. Sample codes are explained in Table 1. The line describes the linear regression, maximum velocity=0.95+3.081x10-2RA.

View larger version (14K): [in a new window]   Fig. 3. Correlation (r=0.806) of the frequency at which tympanic membrane vibration reaches peak velocity (kHz), with pars inferior length among nine samples of gekkonomorph lizards. Sample codes are explained in Table 1. The line describes the linear regression, peak frequency=5.369-1.354xpars inferior length. The correlation of the peak frequency with extracolumella anchorage length (combined lengths of pars superior and pars inferior) is r=0.805 and this regression equation is peak frequency=5.41-1.095xanchorage length.

View larger version (13K): [in a new window]   Fig. 4. Correlation (r=0.813) of the peak bandwidth of the tympanic membrane transfer function (octave range of frequencies achieving at least half the velocity of the peak), with animal rostrum—anus (RA) length, among nine samples of gekkonomorph lizards. Sample codes are explained in Table 1. The line describes the linear regression, peak width=3.219-2.51x10-2RA.

View larger version (23K): [in a new window]   Fig. 5. (A) The averaged raw (unsmoothed) transfer function for juvenile Eublepharis macularius. Values are means + 1 S.E.M. This variability was typical of all the curves reported here. (B) Averaged peak-to-peak velocity functions of the tympanic membrane, measured at the junction of the columella, for the eublepharid triad.

View larger version (24K): [in a new window]   Fig. 6. Averaged peak-to-peak velocity functions of the tympanic membrane, measured at the junction of the columella, for the diplodactyline triad.

View larger version (23K): [in a new window]   Fig. 7. Averaged peak-to-peak velocity functions of the tympanic membrane, measured at the junction of the columella, for the gekkonine triad.