Pinna and chimpanzee questions

[Kevin Austin <kevin.austin@xxxxxxxxxxxx>]

Regarding azimuth estimation, somewhere I read another term for the  
ridge in the pinna called the antihelix -- the "Darwinian ridge",  
although I can find no such reference with Google. Is this structure  
more complex in humans than in chimpanzees (for example)? http://158.130.17.5/~myl/languagelog/archives/chimp.jpg

The abstract http://www.news.cornell.edu/releases/Dec03/chimp.life.hrs.html 
 notes that chimpanzees also do not have the same frequency response  
as humans:

   Mutations in alpha tectorin result in poor frequency response of  
the ear,
   making it hard to understand speech. ... The large divergence  
between
   humans and chimps in alpha tectorin, he says, could imply that  
humans
   needed to tune the protein for specific attributes of their sense of
   hearing. This leads Clark to wonder whether one of the difficulties
   in training chimpanzees to understand human speech is that their  
hearing
   is not quite up to the task. Although studies of chimpanzee  
hearing have
   been done, detailed tests of their transient response have not been
   carried out.


What is the effect of plastic surgery on azimuth response?
http://www.plasticsurgery4u.com/procedure_folder/revision_otoplasty/revise_overfoldedantihelix.htm


Best

Kevin