Car-sized sauropod coprolites (was Re: Lava and dinosaurs)

[Gigi and Ralph <gbabcock@best.com>]

Rik Hill wrote:

>  Something like Seismosaurus must have created
> stools the size of a small automobile, no? (etc.)

Stools the size of a small automobile, no.

You can see a photograph of a putative sauropod coprolite mass at:
<www.cc.emory.edu/Geoscience/HTML/Dinocopro.htm>.  As the web page
explains, large herbivores (elk, for example) often produce small pellets,
rather than large chunks of dung.  The 40 cm diameter coprolite on display
(from the Morrison, Utah) is apparently an amalgamation of several
pellets.  You must bear in mind the limitations of the non-avian dinosaur
cloaca and associated pelvis. Like the eggs, the dinosaur feces must pass
between the narrow space between the spine and the ischia, the latter of
which contact distally.  Extant birds may have ischia which spread widely
apart, facilitating the passage of much larger eggs -- relatively speaking
-- out of the body.  This is why a kiwi can produce an egg which weighs
one third as much as its entire body whereas sauropods produced eggs only
about the size of soccer balls!  (Note how the female human pelvis
required remodeling to permit the passage of big brained babies).  I'm
sorry, but I don't see anybody driving a car through the cloaca of a
sauropod.  That's gotta hurt!       ~%^&

On the other hand, Dr. Robert Bakker speculated that sauropods had the
pelvic capacity to deliver 500 pound babies (oh, really?), so they should
have been able to egest better than little fecal pellets, had there been a
strong selection pressure to do so.  (We now know that titanosaurs did
indeed lay eggs, and there is no evidence for live birth in any
dinosaur).  Maybe the pellets are just more expedient when you don't want
the strain of egesting large intact fecal masses to slow down your
ingestion of large fodder masses.  (Nothing personal; I'm using the term,
"You," in the general sense).  It slows you down, you know?  _Maiasaura_
coprolites have been found as large as 24cm x 33cm x 34cm; the big _T.
rex_ coprolite (which had lost some material to erosion) was about 44cm x
16cm, or the size of a loaf of bread, hence about the size of a bread
box.  Perhaps there are larger such gems yet to be discovered, but that's
about the size of it for now.

For more free fecal fun on the web, search on "coprolite" or "coprolite
Chin," but be sure to start your day off right with the following:

<www.calacademy.org/calwild/archives/fall98/horizon.htm>
<http://darwin.apnet.com/dinosaur/chin.htm>
<http://geology.wr.usgs.gov/king-sizedcoprolite.html>

Any corrections graciously accepted.

-- Ralph W. Miller III     gbabcock@best.co

Quoth Spinal Tap: "Big bottom, drive me out of my mind.  How could I leave
this behind?"