Re: sclerotic rings

[stssram@st.unocal.com (Bob Myers)]

On Feb 22, 22:15, Nicholas Roy Longrich wrote:
} Subject: Re: sclerotic rings
> 
>       On the subject of eyes, I recall that some birds have a pair of focal 
> points (fovea) in the eye, and so are able to set up a binocular system 
> with each  eye. This would seem to be a convenient arrangement for the 
> predatory dinosaurs, who didn't get around to binocular vision until 
> pretty late in their history. More untestability. 
>-- End of excerpt from Nicholas Roy Longrich

Wouldn't this only work for very short range distance estimation?  I could
see where it might work out for a small animal like a bird, if the bird
needed to do a lot of close range distance estimation, but I'm a little
skeptical of larger animals.

Hmmm... How does eye size vary with animal size, particularly in the
dinosaur/aves clade?  If eye linear dimensions (and therefore the binocular
separation) expand with body size linear dimensions, I suppose that scales
up.  I've always has the impression that eye size does not scale that way,
though, that if you double the size of the animal, in general the size of
the eye is less than doubled - but I have no evidence to support this.





-- 
Bob Myers                         Unocal Tech. & Ops. I. S. Support
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