Re: Wrong Reconstructions

[Jason Brougham <jaseb@amnh.org>]

Jaime,

The acoustic apparatus of owls depends on lateral bullae, but also on fleshy 
facial disks, as illustrated by scanner images here:

http://digimorph.org/specimens/Tyto_alba/

If any troodontid had an analogous structure, then couldn't the sound waves be 
conducted down the external auditory meatus, regardless of the position of the 
parasphenoid bullae? I believe that Drs. Mateus and Castanhinha demonstrated 
that Troodontids do have an  asymmetrical meatus geometry that is analogous to 
owls.

> 
> 
>   Owl auditory bullae are large, very large, and extend largely to the 
> external margins of the skull, such that the ear is essentially flush with 
> the skull of the head. In a facial disk, this permits the sound to transfer 
> directly into the funnel without being redirected at an angle before entering 
> the auditory canal. Troodontids (or at least the Dinosaur Park skulls) lack 
> the auditory bullae seen in owls, and the otic region is confined to within 
> the braincase and between the quadrates, rather than extended poteriorly and 
> lateral to them. This makes the case of a troodontid facial disk highly 
> unlikely. I must say, however, that the restoration is fantastic and you 
> should go ahead with it anyways!
> 
> Cheers,
> 
> Jaime A. Headden
> The Bite Stuff (site v2)
> http://qilong.wordpress.com/
>