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Re: MR's comment on dino vision



At 09:10 AM 1/3/97 +1030, you wrote:
><Snip>
>>
>> [ dinosaurs probably had better color vision
>>   than most mammals and may have been sensitive to optical polarization
>>   as well.  The latter would be particularly helpful in allowing an
>>   animal to see under the surface of the water because the polarization
>>   of reflected light would be different from the polarization of light
>>   transmitted from under the water's surface.  -- MR ]
>
>How can we know *anything* about dinosaurs' color vision &/or
>sensitivity to optical polarization?

Extant Phylogenetic Bracket method: if both the living ingroup (birds) and
living outgroups (crocs, lepidosaurs, and turtles, in this case) demonstrate
a particular soft tissue structure, behavior, etc., the most parsimonious
explanation (given no other data to the contrary) is that the extinct taxa
we are interested in (dinosaurs) also possessed said soft tissue structure,
behavior, etc.  Since living reptiles (including birds) have more
sophisticated color vision than mammals, it is more parsimonious to accept
that dinosaurs did as well.

>d science (and bad science, too).  While I am a paleontologist,
>I make no pretensions about being a dinosaurologist.  Therefore I will need
>help, and send this note as a general request for input from the community
>of dinosaur specialists.  I will likely use Lucas' book as a text.

Ouch.  See Holtz.  1995.  Journal of Vertebrate Paleontology 15:210-212.
for a review of Lucas' book.  The second edition fixes some of these
problems, but many remain.  I have used both Lucas and the Two Daves
textbook (see below) for 100-level non-major classes, and find that my
students are not overwhelmed by the dramatically larger amount of
information provided by the Two Daves.

>I have
>the big *Dinosauria* volume.  I'll have about 14 weeks, twice weekly, to
>share with something like 60 students.  Advice is appreciated, syllabi would
>be much appreciated, and other suggestions as well.  Thanks,

Suggestion: go with Dave Fastovsky & Dave Weishampel's Evolution and
Extinction of Dinosaurs (Cambridge) rather than Lucas' textbook: it is
VASTLY closer to the current understanding of dinosaur paleontology.

I can fax you syllabi from past classes, if you'd like.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"To trace that life in its manifold changes through past ages to the present
is a ... difficult task, but one from which modern science does not shrink.
In this wide field, every earnest effort will meet with some degree of
success; every year will add new and important facts; and every generation
will bring to light some law, in accordance with which ancient life has been
changed into life as we see it around us to-day."
        --O.C. Marsh, Vice Presidential Address, AAAS, August 30, 1877