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Re: Paralititan (mangrove swamps)



Hi all
One interesting aspect of this system is the sense of scale - that
whatever applied to the dynamics of the mangrove lowlands, it would
apply over truly vast tracts.  One "reoccurring fluke" involves
invocation of hurricane-like storm cells, which may or may not apply to
the eastern half of the African landmass.  Even if you posit that there
were major storms raising hell there, not at all clear whether you can
infer uniformitarian effects at such large scales Larger forested
lowlands are indeed vulnerable to storm surges, with demonstrably
enormous motive force not later found in the sedimentary record except
as "fluke" sized particles like cars, cows.  However, larger scale
cypress-tupelo forests in the Gulf have been shown to suffer little in
medium-size hurricanes, with noticeable absence of outrageous Lacovaran
"gravels".  A further complication is the possibility that large-animal
conduits might have been afforded by estuarine channels, making
megafaunal highways as inroads into the mangrove swamps.  This situation
accrues in chesapeake area as well as Mobile Bay and the Mississippi
Delta.  So gravel-moving events would in this case not have to transport
(possibly floater) carcasses all that far, and down the steepest
paleotopographic gradient at that.  

All this to agree with Ken that there sure are a lot of viable
scenarios!  makes it the more fascinating

Jeff.

_____________________
Jeffrey Alan Bartlett
Graduate Student in Paleoecology
Center for the Exploration of the Dinosaurian World
North Carolina State University

jabartle@unity.ncsu.edu
(919) 515-7648






Ken Kinman wrote:
> 
> Josh,
>       I agree that one likely scenario is that Paralititan and its predator
> may have been primarily a part of the mangrove ecosystem.
>       But on the other hand, perhaps they were primarily a part of an
> ecosystem further inland (lacking anoxic mud that would have preserved
> them).  Perhaps Paralititans occasionally wandered into mangrove swamps (or
> forced by population pressures?) and sometimes got stuck there and died (and
> less sticky version of La Brea tar pits??).
>       Who knows, maybe their predators were even smart enough to learn that
> if they chased Paralititan towards the swamps, it was an easier way to make
> a kill.  In that case, Paralititan may have hated the swamp, but the
> predator loved it as a means to an easier meal (whether they actually chased
> them into the swamp or not).
>       Just speculating on other possible scenarios that might also fit the
> facts (but you know a lot more of the details than I do).   What type of
> habitat would one have found inland from these swamps, and would they be far
> less favorable for fossil preservation?
>                        ------Ken
> ********************************************************
> >From: Josh Smith <smithjb@sas.upenn.edu>
> >Reply-To: smithjb@sas.upenn.edu
> >To: kinman@hotmail.com
> >CC: dinosaur@usc.edu
> >Subject: Re: Paralititan (mangrove swamps)
> >Date: Tue, 05 Jun 2001 10:25:45 -0400
> >
> >Ken Kinman wrote:
> >
> > > Tracy and Josh,
> > >       Aren't the soils (muds) of mangrove swamps usually anoxic and
> > > therefore an unusually ideal area for fossil preservation?
> > >       If so, couldn't it be a fluke of preservation.  In other words,
> > > perhaps Paralititan usually lived in other habitats, but only got
> >fossilized
> > > if one happened to wander into such a swamp and died there.
> > >       I don't have any firm conviction either one way or the other
> > > (non-theropods don't interest me much).  Just playing devil's advocate
> >for
> > > the sake of discussion.
> > >                         ---Ken
> >
> >     If it is a fluke of preservation, then it was a reoccurring fluke,
> >because
> >by far most of the fossils we have produced from Bahariya so far are coming
> >from the same sorts of environments.  The Bahariya Formation
> >stratigraphicaly
> >proximal to Stromer's "saurier" beds appears to record the existence of a
> >big
> >"mangrove coastline" in the Cenomanian, and this is by far one of the most
> >productive "units" in the Bahariya sequences.
> >     Bahariya records a very low energy regime.  There doesn't appear to be
> >enough energy in the system to move around gravel the size of _Paralititan_
> >(as
> >our coastal geologist Ken Lacovara loves to term in, but to Lamanna's
> >pain).
> >Moreover, Ken is convinced that the water depths in the "Bahariya
> >mangroves"
> >would have been too shallow for the beast to actually float around.  This,
> >combined with the evidence at the quarry that CGM 81119 was scavenged
> >indicates
> >that not only this individual, but whatever was munching on it (most likely
> >a
> >carcharodontosaurid according to my analyses) walked into the mangrove
> >under
> >their own power.  Did they live there, or were they just walking through?
> >Who
> >the hell knows for sure?  However, it is most parsimonious to presume, give
> >the
> >frequency that we find large vertebrate bones in these sequences, that we
> >have
> >the record of a fauna that at least didn't hate mangroves, so I would say
> >they
> >very well might have lived there.  It wasn't just _Paralititan_ that was
> >running around in this environment, but the theropods in the Bahariya as
> >well,
> >as far as we can tell.
> >
> >-Josh
> >
> >--
> >Josh Smith
> >Department of Earth and Environmental Science
> >University of Pennsylvania
> >471 Hayden Hall
> >240 South 33rd Street
> >Philadelphia, PA  19104-6316
> >(215) 898-5630 (Office)
> >(215) 898-0964 (FAX)
> 
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