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Re: Article: T. rex Had "some of the best vision in animal history"
I haven't read the JVP paper yet, but I do have a couple of questions on
Dr. Stevens' very interesting research:
Orbit size estimate: In extant reptiles and birds, how "tight" is the
correlation between calculated orbit diameter (as done by the "party
balloon" test in the Stevens paper) and the animal's actual eyeball
diameter? Is there any type of consistent ratio that fits this
relationship across taxa? And are there any extant exceptions to this
rule (e.g., animals with a huge orbit with a small eyeball; or with a
small orbit with a huge eyeball)?
Bulging eyes vs. "normal set" eyes: Most birds don't have bulging eyes
(eyes projecting outward from the plane of the orbit), but some reptiles
do (chameleons, for instance). Kent appears to have the eyeballs set in
about the normal "birdy" configuration, with the outer surface of the
eyeball flush with the outer surface of the margins of the orbit. But
how certain is the placement of _T. rex's_ eyeballs? Could they instead
have been bulging? This would have greatly widened the BFoV.
Fancy head gear: At least one tyrannosauroid had some stupendous snout
rackage (_Guanlong_). In fact, many (all?) tyrannosaurids have nasal
bones that are both rugose and permeated with foraminae (to various
degrees), suggesting an anchoring point for some type of integument. If
_T. rex_ had fleshy (or spiny keratinous or feathery) nose
ornamentation, it could block some of the BFoV (unless this hypothesized
integument was usually stowed in a "non-flared" state).
On Sun, 02 Jul 2006 10:58:35 -0400 (EDT) Danvarner@aol.com writes:
> See Kent's page with images at his website. Be sure to click on
> Minott's website while you are there, too. DV