[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Sauropod necks????
Uh, not quite totally retro:
I want to make it clear that I don't see the long
necked sauropods as incapable of terrestrial
locomotion, or incapable of utilizing terrestrial
--- don ohmes <email@example.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.
> sauropods couldn't breath while mostly submerged
> 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
> 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 <firstname.lastname@example.org> 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
> > to
> > reconsider a retro hypothesis, even though it
> > be
> > a stretch.
> > You see, I, like the individual who supposedly
> > invented the hypothetical shell-less molluscs
> > Colbert, if memory serves) have a hard time
> > the probable daily amounts of forage the largest
> > sauropods required (assuming mass specific
> > nutritional
> > values have not changed) with the physical
> > they had to work with.
> > "Facts"? In os veritas. The rest is best guesses,
> > right?
> > Don
> > --- David Marjanovic <email@example.com>
> > wrote:
> > > ----- Original Message -----
> > > From: "don ohmes" <firstname.lastname@example.org>
> > > Sent: Sunday, May 22, 2005 12:13 AM
> > >
> > > > I like the idea of hydrilla or some aquatic
> > > with
> > > > similar interwined growth habit as a primary
> > food
> > > > source. [...]
> > > >
> > > > Hydrilla seems to grow best in water 1-2 m
> > > 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
> > > truly
> > > > incredible bulk the biggest probably needed.
> > > > 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... :-]
> > >
> > >