[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Faunal list (Was Re: Selective Extinction)

"Peter Von Sholly" wrote:
> An old and often asked question about the final dinosaur extinction is why
> certain animals went and others didn't.<snippage>

There is no clear trend in extinction patterns, except for the following
points noted by Laurie Bryant (1989), and many others since her work:

1) Aquatic vertebrates faired relatively well across the bounday.

2) Mammals got clobbered, but still some very different taxa
got across unscathed (multi's, metatherians and eutherians squeaked by).

3) Big land verts. *all* went caput.

4) Most small land verts. went belly-up too.

The common view now is that burrowing animals had a fair chance of survival,
(mammals, boids), AND that if one was aquatic, survival was in one's favor, too
(crocodylians/alligators made it. So did turtles and champsosaurs).

Simply counting large-sized taxa (i.e., taxa bigger than
your thumb) across the boundary isn't (in my opinion, at least)
a very good way of studying the problem.  An "ecosystem approach" is
the best way to get to the root of the problem.  

I am putting together a full ("full" as is reasonably possible in such a 
"ecosystem life-list" for the Montana portion of the Hell Creek Formation.
This list will be eternally under construction. The list is meant to be a
"snap-shot" of Maastrichtian life in one geographic locality (Montana).
The list as it stands now is large, and in my not so humble opinion,
very informative as to showing the wonderfully-rich diversity of life just
before the terminal event.
Taxa included/will be included are all of the published:
1) dinosauria; 2) amphibians; 3) fish; 4) lizards+snake; 5) crocodylomorphs;
6) mammalia; 7) turtles; 8) champsosauria; 9) invertebrates; 10) plants;
11) nannofossils (freshwater rads, if any, etc.)

Everything is done except plants (which may a hard job, as most published Hell 
plant material comes the collection by Kirk Johnson from the Dakotas, ergo it 
be on the list; anyone???), and microfossils (I know of no work on Hell Creek
Formation non-marine nannofossils of Montana; anyone???).  Further, I am having 
hard time deciding whether to include pollen taxa in with plant impression 
(the reason being that pollen blows in from thousands of KM away from the MT 
Hell Cr.
area, and it may not represent plants in the "Montana Hell Creek Ecosystem").
I am leaning towards listing only plant impression fossils.

I will post the files to the dino-list in a couple days.  As the text file
is large, it will be posted in small packets, which then
can be cemented back together at your end.  The list is undoubtably
incomplete, so I welcome additions/corrections.  If you do submit such,
please include a published reference where I can check-out the info.
And remember, this isn't a Maastrichtian flora and fauna list; rather,
it's a "Montana Hell Creek Formation Ecosystem list".  Hell Creek life
from the Dakotas, or from the Lance Formation, can't be included!
p.s.  Anyone want to do the same for the Tullock Formation?  :-)