Cochlear Labyrinth Volume in Euarchontoglirans: Implications for the Evolution of Hearing in Primates

Using high resolution X-ray computed tomography data we examined the relationship between cochlear labyrinth volume and body mass in extant, non-primate euarchontoglirans, and in two fossils, to allow for comparison with the results of Kirk and Gosselin-Ildari (2009). Modern primates have significantly higher cochlear labyrinth volumes relative to body mass than other euarchontoglirans, which may be related to a downward shift in the highest and lowest audible frequencies over the course of primate evolution, and to the relative increase in brain size observed in Euprimates. Anat Rec, 294:263-266, 2011. (C) 2010 Wiley-Liss, Inc.