Re: Dinosaur parasites

[Phil Bigelow <bigelowp@juno.com>]

On Sun, 30 Apr 2006 13:36:02 -0700 (PDT) "Robert J. Schenck"
<nygdan@yahoo.com> writes:
> 
> 
> --- Dann Pigdon <dannj@alphalink.com.au> wrote:
> 
> > I seem to remember that many intestinal
> > parasites picked up by
> > herbivores are via eating grass with either
> > eggs or larvae on it. 
> There is, for example, a species of parasite that
> infects ants, and "takes over" their behaviour. 
> It makes them crawl to the top of grass blades
> and cling on with their pinchers, to make them
> more likely to get eaten by grazzing cattle (the
> next step in the parasite life cycle).  In fact,
> this organism is so specific that it will
> 'relinquish' control during noon-time, when the
> sun is very high, so that the ant can return to
> normal behaviour to avoid dying from the heat.
> 
> > It would be interesting to compare the plant
> > material in the infected
> > Iguanodon coprolites with that of other,
> > apparently healthy coprolites
> > from other Iguanodontids
> [...]snip
> >(ie. attempts at
> > self-medication).
> 
> Or even to get a better idea of mesozoic
> ecosystems. Often parasites are species specific
> too.  If the droppings can be correlated
> reasonably to a population, then it might be
> possible to determine how many species were in
> that population, by looking at species of the
> parasite (of course, sometimes the parasite
> species are 'cryptic' also).  Or it might even be
> possible to look at the parasite as markers of
> different species between formations.


A palynologist friend once told me that there can be many tens of fossil
worm egg cases, protozoa cysts and bacteria spores in a one gram sample
of Hell Creek Fm. mudstone (that's a *randomly collected* sample).  Few
palynologists are studying these microfossils, because their taxonomic
affinities are hard to pin down. (these non-pollen fossils are put in
either the "other" category or "unknown" category).

There is a much richer fossil diversity and fossil number at the
microscopic level in plain ol' Mesozoic dirt than there is at the
macroscopic level.  How many fairies can dance on the head of a pin? 
Apparently, when it comes to terrestrial nanofossils, the answer is
"quite a few".

<pb>
--
"We recognize, however dimly, that greater efficiency, ease, and security
may come at a substantial price in freedom, that law and order can be a
doublethink version of oppression, that individual liberties surrendered,
for whatever good reason, are freedoms lost." - Walter Cronkite, preface
to the 1984 edition of George Orwell's _1984_.