RE: [RE: [Re: Sauropod Trunks]]

["Stewart, Dwight" <Dwight.Stewart@VLSI.com>]

> -----Original Message-----
> From: archosaur@usa.net [SMTP:archosaur@usa.net]
> Sent: Tuesday, November 17, 1998 10:32 PM
> To:   Dwight.Stewart@VLSI.com
> Cc:   dinosaur@usc.edu
> Subject:      Re: [RE: [Re: Sauropod Trunks]]
> 
> Dwight.Stewart@VLSI.com wrote:
> > 
> 
> > 
> 
> 
> Well, that's kind of a grey area. Many of the large reptiles died out
> already,
> plus many mammals are medium to small creatures.
> 
> If we look at a 17 ft Nile crocodile, it ends up standing at around the
> same
> height as an 9ft lion. Both are predators and in such cases, be they
> reptiles
> or mammals, the height stays about the same for both. It just seems to be
> a
> constraint of modern times. Most living predators don't stand much taller
> than
> 3 or 4 feet (these must be very modern times, since Megalania and
> Purussaurus
> would have had something to say on that)
        #############################################################

        The exception would be omnivores, such are bears.  A Polar bear can
stand as tall as 5 feet at the shoulder & 9 feet when standing on it's hind
legs.  But, I believe you are right about modern
        predators if you don't count us. :-)
        ###########################################################

> Now in the herbivore category we get the bigger animals. Since everyone
> already knows about the largest mammals, I'll just go to the reptiles, the
> largest reptile herbivores (and tallest reptiles) are Aldabra and
> Galapagos
> tortoises. Animals that are often seen in a posture that is very sauropod
> like
> in design, with the neck held in a nice S curve to the body.
> 
> These turtles don't seem to find that much trouble with keeping their long
> necks held so much higher than their bodies and they only have a 3
> chambered
> heart.
        ######################################################

        Point taken, but still much shorter than many tall living birds &
mammals.  But I have seen Galapagos
        tortoises doing what you are describing.
        ###############################################

> Now when moving, their heads become more level to their bodies, but when
> at
> rest or surveying the terrain, they keep their necks held high. I could
> see
> the same for sauropods. Keeping the neck rather low while walking and then
> high while resting and feeding.
        #################################################

        Yes, but I think there was probably species variation.  I think
Diplodocidae were very likely to
        walk this way.  It's more difficult to envision a Brachiosaurus
doing this.

        ####################################################


> Then of course their is the ever so strange Tanystropheus and
> Keichousaurs.
> Have to wonder how they positioned those necks and how they kept the blood
> flow going.
> 
> All these questions.
> 
> Archosaur J
        ########################################

        You've picked two fascinating creatures there! :-)  Has it ever been
decided if Tanystropheus is a kind of primitive Euryapsid or not?  It DOES
have a LONGGG neck!  I know next to nothing about
        the Keichousaurus, except that it was found in Triassic starita in
China.  I assume it had a long neck too?

        Dwight