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Re: dinosaur eyeballs



At 3:13 PM 8/10/95, Cunningham, Betty wrote:
>     I was just wondering......
>
>       We know how closely the maniraptors and birds are related, but does
>     this give us an idea of how soft tissues (other than skin) might have
>     looked, such as eyeballs?
>
>        I suppose that the therapods and other carnivourous dinosaurs would
>     have similar eye-color and construction to birds, especially since
>     some evidence of those eyeball-socket-bone-things have been supposed
>     for some species.  This would mean round pupils for the most part, not
>     snake-like or cat-like vertical slits.  (as in JP's raptors)

        I've always personally favored the look of dinosaur eyeballs as
drawn bird-like -- that is, large, round, slightly protruding all-black
orbs, like one sees in birds.  There are whites to the eyes in birds, but
they're hidden by the surrounding flesh.

>        What about inner and outer eyelids?  Did dinosaurs blink?  Did
>     dinosaurs blink twice?   Snakes don't blink, but they are much more
>     primitive a form than a dinosaur is, and the demands on their eyeballs
>     aren't as important to a snake's survival as they have developed other
>     senses more important than sight (to a snake).   Birds (some) have
>     inner eyelids for whatever reason.  Is this an extremely advanced
>     trait?  How likely would it be for a dinosaur to have the same needs
>     for an inner eyelid as a bird?

        Birds blink and crocodilians blink; thus, on both sides of the
dinosaur lineage you have blinkers (left and right!  8-)  ), and so I would
assume that dinosaurs blinked, too.




Jerry D. Harris
Schuler Museum of Paleontology
Southern Methodist University
Box 750395
Dallas  TX  75275-0395
jdharris@lust.isem.smu.edu
        (Compuserve:  73132,3372)

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