RE: Sauropods and lung development

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

Yet, there were long necked predators in the sea.  I'm thinking primarily of
the long necked Plesiosaurs.

Dwight

        -----Original Message-----
        From:   James Norton [SMTP:JNorton@MAILBOX.UNE.EDU]
        Sent:   Thursday, September 24, 1998 8:05 AM
        To:     dinosaur@usc.edu; ottscay@uwyo.edu
        Subject:        re: Sauropods and lung development

        >>> Scott A Hartman <ottscay@uwyo.edu> 09/23/98 08:25pm >>>
        >>>Interestingly, outside of of the Saurischia (avian and non),
        there are very few terrestrial animals that evolve long necks.>>>

        I've been toying with this observation for some time now.  In my
opinion,
        bipedality, long necks, and a parabronchial lung co-evolved
        simultaneously, yielding an active cursorial predator with a
        three-pronged attack system (Mouth and clawed hands) or maybe
        five-pronged, if you include clawed feet.   Allometry supports the
        observation that mammals and birds of similar sizes have very
different
        neck lengths and ventilatory parameters, and when I think of the
most
        efficient mammalian predators I can't picture any with long necks.
The air
        sac system and parabronchial lung effectively cancelled out the
potential
        disadvantage of increased tracheal dead space, and then could have
        been secondarily modified for weight reduction in sauropods and
        increased gas exchange efficiency in theropods and birds.  The
        predatory advantage in having the head at the end of a long and
flexible
        neck is as yet unproven, but could only have been an advantage if
the
        respiratory system supported it.

        JM Norton