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Re: Cretaceous Mammals




Ralph Chapman wrote:

> RE Our lack of looking for those mammals...
>
> I don't know any dinosaur paleontologist who doesn't look very hard to
> try and find not only mammals, but all other aspects of the fauna as well.
>

    As a "so-called" dinosaur paleontologist I second Ralph. Dinosaurs are part
of a diverse biota and to reconstruct the environment any paleontologist worth
his salt looks at everything. We cannot be experts on everything, but I know
that I try to drag every warm body I can into my field area. I'm always trying
to sucker in palynologists, palyobotanists, geochemists. paleomag. types, and
sedimentologists into getting involved in my projects. The complete job
requires a holistic view of the world.    However, individually people publish
papers on their own areas of expertise. I've got a great thesis here on
Morrison isotope geochem., how many folks on this list are going to read it.
How many (and I know there are a few) read the fossil mammal literature.

>  We all want lots and lots
> of mammals if, for anything, to show just how pathetic the group was
> during the day of dinosaur ;-). And besides, dinosaurs are still more
> diverse, species-wise.

    Not much so; perhaps a preservational bias.    At the Fruita Paleo Area
(Late Jurassic), there are at least 12 mamal species represented by skulls and
it is clear they vastly out number dinosaurs in abundance if not biomass (8-)).
Basically dinos and mammals fill different guilds. Dinos the big carnivore
herbivore guild and mammals the nocturnal insect-eater & seed-collector guild,
which most mammal species still do today. Small dinos are rare (Echinodon &
compsognathid size) and a diversity of cursorial crocs make up the bulk of
small predators (skunk- fox sized). Lizards and sphenodontids are the diurnal
insect-eater & seed-collectors.

    My work with Cifelli and Eaton show that the Cretaceous mammals shared
similar diversity and relative abundance. Mammals were a major players
throughout the Mesozoic, they just did not fill the roles of large animals
until dinosaurs went extinct.

Jim Kirkland
Dinamation

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