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RE: Dino coloration and more...



About dino coloration, Ronald Orenstein wrote:

>Not to mention fishes (like piranhas), many lizards and frogs (eg the large
>horned frogs of the genus Ceratophrys).
>>
>There is no reason to suppose that bright colours in animals are necessarily
>linked to flowers (think of fishes, for example, or poison arrow frogs).

I believe I specifically mentioned poison frogs as "animals that have no need
of stealth." If you want to include insectivores in the "predator" category, I
guess we should, but insects aren't widely known for being that observant.
They make up for it with quick reflexes and tough little bodies. 
        As for fishes, I was really referring to terrestrial flora/fauna. Of
course the underwater world has plenty of bright colors, and lots of fauna
that look at first glance like flora.

>Further, there is no reason to suppose that non-flowering plants lacked
>bright colours - besides leaves of many flowering plants, consider fungi
>(yes, true, they aren't realy plants) or the cones of cycads, the arils of
>some conifers etc.

Very true. Again, I was speaking in generalizations -- I would still expect
the world of the Mesozoic to be PRIMARILY greens and browns. Of course
there will be exceptions -- probably too many to list -- without changing the
basic dominant color scheme.

In his last "bipedal" posting, Tom Holtz mentioned Dale Russell's "dinosauroid",
and it reminded me of something that always bothered me about it. This hypo-
thetical critter is somebody's idea of what the dinos might have evolved into, 
given the chance, right? Well, they had the chance, and a bloody long one, too!
150 million years, give or take a few dozen million, is a lot more time than it
took us to evolve to our current state of degeneracy (once we got started!). 
        Let's face it -- there simply wasn't a survival imperative requiring
the dinos to develop intelligence and humanoid bodies. They never evolved
because they didn't need to -- they were already masters of the world.

Jeffrey Martz wonders why it takes a finer grain of stone to preserve feather
impressions than those of scales. I suggest that it's a simple matter of
resolution in the medium -- the barbs, etc of feathers are much finer details
than are scales, and it takes a smaller unit of resolution ("foxel"? = "fossil
pixel") to show it. A flight feather might easily have fifteen or twenty
lines/cm, where scales would rarely approach that size. To effectively show a
feature, I would guess that you would need grain about half the size of the
feature -- and sand rarely gets that fine in nature.
        I also think Nathan M.'s suggestion about determining the general
frequency of feather preservation is a great idea. Has anyone done anything
like this?

Finally, Darren Naish was asking about pics of early crocodilians. I have a
book called, "The MacMillan Illustrated Encyclopedia of Dinosaurs and
Prehistoric Animals." It has a two-page spread (pp. 98-99) illustrating early
crocodiles: Terrestrisuchus, Gracilisuchus, Protosuchus, Bernissartia,
Metriorhyncus, Teleosaurus, Pristichampus, and the well-known
Deinosuchus. Unfortuantely, a lot of the illustrations in this book are not up
with current theory, so I have no way of knowing how accurate the pix are.

Wayne Anderson