Re: Sauropod necks????

[don ohmes <d_ohmes@yahoo.com>]

Thanks for the ref! It led me to this site--
"http://www.geocities.com/mesozoicdinosaurs/dinopapers.html#dinosaurs";
If your "library" is lackin', check it out ASAP. I'll
be loading up. Apologies to folks who already know it
is there. Comments below:

--- Jura <pristichampsus@yahoo.com> wrote:

> If sauropods were feeding about in swampy areas,
> wouldn't one expect them to have feet that were more
> adapted to a muddy environment (webbing, splayed
> toes,
> etc.)?

Swamp areas:
I think of a swamp as an wet area with seasonally
shallow to non-existent standing water. If this is
what you mean, I more envision them as lake or river
dwellers, with adjacent swampy areas accessible to
longnecks, I mean long necks. 

Enlargement of footprint:
No, I wouldn't. When you are that big, "webs and
splayed toes" are an invitation to injury (in my
opinion).

> Also, didn't Witmer (2001), pretty much put to rest,
> the oft held belief that sauropod nostrils opened at
> the top of the skull?

Looking at Fig. 1A-- Even if the nostril is in
position (a), I don't see anything that obviates a
semi-aquatic lifestyle. Sort of reminds me of an
alligator.

> Witmer, L.M. 2001.  Nostril position in dinosaurs
> and
> other vertebrates and its significance for nasal
> function. Science 293: 850-853.
> 
> Jason
> 
> 
> --- don ohmes <d_ohmes@yahoo.com> wrote:
> > Other reasons for "liking" a retro hypothesis:
> > 
> > 1. Alligators can stay under water for 2 hours.
> > Achievable dive time increases with body mass.
> > Perhaps
> > sauropods couldn't breath while mostly submerged
> > like
> > hippos, but they may have only needed to "surface"
> 3
> > or 4 times a day. Another positive selective
> vector
> > relative to size. 
> > 
> > 2. A sauropod standing in water at a depth such
> that
> > the base of the neck is at the surface of the
> water
> > could be able to (at least) partially inflate it's
> > lungs. If the neck is then "floated", a large arc
> of
> > water column could be foraged at low cost and the
> > nostril position is (finally!) clearly
> advantageous.
> > 
> > 3. Given the length of their legs, and their
> > presumable power, they may have been difficult to
> > bog
> > down, even when fully emerged from water. Given
> mud
> > overlain by shallow water, they may have gained
> some
> > locomotive advantage from the long neck and tail
> > (rocking side-to-side, increased "flotation", and
> > forward momentum from the tail).
> > 
> > --- don ohmes <d_ohmes@yahoo.com> wrote:
> > 
> > > Finally someone responds to this (thanks,
> David):
> > > 
> > > You are in line with concensus thought on this.
> > > However, current research indicates an earlier
> > > origin
> > > for angiosperms (as early as ~340 mys BP, in my
> > > readings), and there is literature discussing an
> > > aquatic origin of same. So as an old farm boy
> who
> > > has
> > > spent many hot days acquiring biomass, I am
> > willing
> > > to
> > > reconsider a retro hypothesis, even though it
> > might
> > > be
> > > a stretch.
> > > 
> > > You see, I, like the individual who supposedly
> > > invented the hypothetical shell-less molluscs
> > (from
> > > Colbert, if memory serves) have a hard time
> > squaring
> > > the probable daily amounts of forage the largest
> > > sauropods required (assuming mass specific
> > > nutritional
> > > values have not changed) with the physical
> > equipment
> > > they had to work with.
> > > 
> > > "Facts"? In os veritas. The rest is best
> guesses,
> > > right? 
> > > 
> > > Don
> > > 
> > > --- David Marjanovic <david.marjanovic@gmx.at>
> > > wrote:
> > > 
> > > > ----- Original Message -----
> > > > From: "don ohmes" <d_ohmes@yahoo.com>
> > > > Sent: Sunday, May 22, 2005 12:13 AM
> > > > 
> > > > > I like the idea of hydrilla or some aquatic
> > weed
> > > > with
> > > > > similar interwined growth habit as a primary
> > > food
> > > > > source. [...]
> > > > >
> > > > > Hydrilla seems to grow best in water 1-2 m
> > deep,
> > > > and
> > > > > will utilize every cc of water column. So no
> > > need
> > > > to
> > > > > move tree to tree, hold the head up, pull
> back
> > > to
> > > > > strip leaves, or separate/swallow twigs,
> just
> > > wade
> > > > > through it like a teenager sucking up a
> giant
> > > > plate of
> > > > > spagetti. Only practical way I see to obtain
> > the
> > > > truly
> > > > > incredible bulk the biggest probably needed.
> > Any
> > > > > thoughts?
> > > > 
> > > > Several.
> > > > 
> > > > - *Hydrilla* and most other water weeds are
> > > > angiosperms, and thus 
> > > > unavailable in the Jurassic. I don't know
> enough
> > > > about ferns like 
> > > > *Salvinia*, but AFAIK they don't get this
> > > > productive...
> > > > - So much water may not have been available
> in,
> > > for
> > > > example, the Morrison Fm 
> > > > environment.
> > > > - The neck length of *Dicraeosaurus* should
> > > suffice
> > > > for this lifestyle. So 
> > > > why do sauropods vary so much in neck length?
> > > > 
> > > > Beautiful hypothesis, ugly facts... :-] 
> > > > 
> > > > 
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> 
> "I am impressed by the fact that we know less about
> many modern [reptile] types than we do of many
> fossil groups." - Alfred S. Romer
> 
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