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Re: possible ceratopsian feeding behaviour?



Stephan Pickering (stefanpickering2002@yahoo.com) wrote:

<I believe that environmental stresses caused the ceratopsians to be able
to displace sauropods, derived as well as from the biomass of the animals
(a long sauropod could not navigate its way very well in an evergreen
woodland).>

  This may or may not be possible, but there is some corroboration for it:
there is only one level where sauropods and ceratopsians co-occur, that is
the Aguja/Big Bend strat which bear both *Alamosaurus* and
*Pentaceratops*, and both are large animals. Absence of large sauropods
from other levels has never been explained adequately. Some theories have
been dominance of other large herbivores may have controlled the habitat,
much as elephants do today, or environmental effects of seasonal changes.
However, one must determine what the two ate for there to be an effect of
competition and therefore displacement. Sauropods are so much larger than
ceratopsians, and since few sauropods are found in wetlands areas with the
exception of some of the early Late Cretaceous forms from Africa (but this
may be depositional) whereas ceratopsid at least are regularly found in
wetlands areas. In fact, the last sauropod in North America previous to
*Alamosaurus* (an immigrate from South America seems to be the best source
of it (based on phylogenetics) but it is also possible to be one of those
Campanian immigrants from Asia) occured prior to the first sizeable
ceratopsids, from the Berriasian to Albian of the Mountain States, being
the Cedar Mountain fauna (*Venenosaurus*, *Cedarosaurus*, etc.). In fact,
ceratopsids diversify in North America and start getting big only in the
Campanian, well after sauropods are no longer present.

<Plant toxic defenses, an area wonderfully analyzed in the work of Fred
Provenza, could have been prevalent during the transitional stages when
sauropods were driven from the ecosystems taken over, as it were, by
ceratopsians and hadrosaurs.>

  Hadrosaurs and sauropods prevail together in several levels, including
the Maastrichtian of Romania, the Campano-Maastrichtian of Mongolia, and
the Maastrichtian of Patagonian Argentina; ceratopsids are restricted
entirely to North America barring the possible relevance, though
challenged, of the nature of such Asian forms like *Asiaceratops* and
*Turanoceratops*.

  On to plant toxins, many closely related plants produce varying levels
of toxins, including some which are harmless or non-threatening, and it is
not possible to determine toxicity by any standard we have today of
extinct plants, especially since palynomorphs and impressions do not
preserve the appropriate data. Carbonized remains of plants from
lagerstätt similarly show only that: carbon.

<Using some adjusted mathematical formulae, could not one reasonably
estimate, e.g., the amount of food intake that would be required by a
sauropod, or an ankylosaur, or a stegosaur, or a ceratopsian?>

  There is considerable work in the 1980's by guys like Farlow and Bakker
on food intake values of per mass matter to keep an animal alive given
certain periods of time, including herbivores (mostly Farlow based on
extent biomechanical and organic processing cycle models and simple
caloric calculations) and carnivores (a lot of Bakker using then-current
Serengeti-influenced models). To calculate, one must have a value to gross
mass, and also in a way estimate "herd" or group size if more than one
individual is useful. Thus, lotsa variables.

<These multi-tonne animals were eating voraciously...but how much? I have
seen how a herd of rhinos can decimate acres of plants,>

  Are you sure these were rhinos? Rhinos are not herding animals, no
species I'm aware of can tolerate more than its mate during the season, or
its own young. Rhinos in the keep of zoos represent unhealthy, and
unnatural, social groupings.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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