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dinosaur eyeballs



     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)
     
       But what about the other dinosaur species?  Do we have any clues 
     about eyeballs of ceratopsians like the orbital-bone-socket-thingies?  
     Or did saurapods have any special depth-of-field specialisations to 
     help them gain detailed images of their environment (being so far 
     above the ground and all)?
     
        Would the herbivorous dinosaurs shown more of a 
     mammalian-herbivore-type eye construction?  Would they have more 
     closely resembled birds rather than, say, cows?   Mammals have gotten 
     fancy with pupil shapes, with equine and goat horizontal slits, cats' 
     vertical slits, and whales' just being plain 'ol big.  Would the 
     dinosaur species' have shown as wide a variety of shapes, or would 
     they have been more limited as to shape?  I'm not aware of much 
     variety in the shape of birds' pupils; owls and parrots both still 
     have round pupils.
        
        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?
        
        I am assuming that the eyeballs would be colorful, as birds and 
     reptiles share colorful pupils as a trait, but I've noticed that 
     reptiles (especially the carnivorous ones) blend eye color in with 
     their camouflage patterns, while birds tend to have eyeballs colored 
     for display.   Which would be more likely for dinosaurs?
     
     (I've been very fond of using eye-stripes in my recreations of T rex 
     and other therapods-a very widely used adaptation of camouflage found 
     throughout the animal kingdom: cheetahs use 'em, tropical fish, hawks, 
     snakes, and South American aboriginal hunters (though these are 
     painted on).
     
     Betty Cunningham
     (Flyinggoat@aol.com) closing this account at the end of the month
     (bcunning@nssi.com) work
     (bettyc@flyinggoat.com) new account starting at the end of the month