RE: Sauropod Trunks: Nuh-uh!

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

> -----Original Message-----
> From: Ralph Miller III [SMTP:gbabcock@best.com]
> Sent: Wednesday, November 18, 1998 12:46 AM
> To:   Dwight.Stewart@VLSI.com; 'MGibb21521@aol.com'; dinosaur@usc.edu
> Subject:      Sauropod Trunks: Nuh-uh!
> 
> 
> And it makes for a typically amusing Robert Bakker illustration on page
> 141
> of _The Dinosaur Heresies_.  In his 1986 book, Dr. Bakker claims that the
> idea of trunked dinosaurs had been floating around for half a century (in
> paleontological journals, no citations given).  While Bakker states that
> the trunk remains a possibility, he finds problems with the hypothesis. 
> For one thing, sauropods, unlike elephants, do not appear to be descended
> from a lineage of animals which feature a complex of lip muscles (whence
> the lips are derived).  Nor does Bakker see scars from big trunk muscles
> near the edges of sauropod nares.  He seems to favor the nose flute
> hypothesis (as depicted on page 145), but admits that there is some
> mystery
> surrounding the faces and noses of "brontosaurs," as he calls them.
        #################################

        Yes; that illustration is rather "Dr. Seussian". :-).  But now that
you mention it;
        I DO recall Dr. Bakker's objections to the trunk hypothesis.
        ###################################

> Another objection to the sauropod trunk should be the pointlessness of it.
> 
> Elephants have massive, bulky heads mounted atop short necks, so the need
> for a long trunk to reach up to high branches or down to low branches is
> intuitively obvious, whether the elephant is knocking down a tree to get
> at
> the foliage or leaving the tree standing in place.  Needless to say,
> sauropods are built along very different lines, with an awesome reach and
> the ability to rear up to feed on high branches.  What is the adaptive
> advantage for developing a trunk on such an animal?
        ###################################

        Okay, I see your point.  Logical.
        ###############################

> Furthermore, the elephant has only grinding molars (and tusks, of course),
> so it requires something other than teeth (the trunk) to draw food into
> the
> mouth.  As in many other mammals, with their cropping incisors and their
> grasping lips and tongues followed by grinding molars, there is a
> decoupling of the feeding and grinding processes.  The same is true of
> many
> ornithischian dinosaurs, with their cropping beaks up front and grinding
> or
> dicing teeth aft.  In sauropods, it is believed that the grinding may have
> occurred much further aft within gastrolith-laden crops and gizzards (as
> indicated by the _Seismosaurus_ specimen).  The teeth were therefore
> employed to merely collect, rather than to grind up the food.  So, unlike
> the elephant, the sauropod has teeth up front, which could be peg-like for
> raking the twigs and leaves into the mouth (as in _Apatosaurus_), or
> spatulate and chisel-like, for cropping the twigs off (as in
> _Camarasaurus_).  This would seem to be a sufficient and expedient method
> for ingesting the massive quantities of vegetation that these giants must
> have required, and the capacious guts could continually digest the food
> once it comes down the pike, aided by the usual assortment of acids,
> microbes, and what have you.  Again, I fail to see the point of a sauropod
> trunk.  Display?
> 
> David Norman writes in _The Illustrated Encyclopedia of Dinosaurs_ that
> the
> enormous nostrils of _Brachiosaurus_ may have accommodated a strong sense
> of smell, a resonating device, or "a cooling surface for the blood."  Or
> some combination of these, I should think.  The snorkel hypothesis is
> definitely out.  At least we can agree on something!
> 
> -- Ralph Miller III     gbabcock@best.com 
> 
> Who nose?
        ###################
        Perhaps it was all three(?): strong olfactory senses, resonating
device, & a cooling
        surface?  Have any  auditory models of a sauropod skull ever been
done; similar
        to the work done on PARASAUROLOPHUS?

        Dwight