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re:extinction events in Mesozoic



To underscore Thomas Holtz's comments:

I'm not sure that sauropods readdy we(try really went) extinct in the Maastricht
Ve noted before, there are a slew (slough?) of sauropod remains
in the Maastrichtian of West Texas, and I'm not convinced that they re-emnigrate
re-emigrated from S. America.   The same taxa are common in N. Mexico and
to a lesser extent in Wyoming.  Thus sauropod extinction is greatly
exaggerated.

  There was apparently a major late Triassic event among a wide variety
of tetrapods, but I'm not the one to tabulate taxa involved there.  As
I see the record, nothing else noteworthy occurred during the Mesozoic
except, of course, the K/T thoing.  Indeed, the *lack* of a significant
mass extinction event post end-Triassic and prior to the K/T is
noteworthy, since that contains ca 180 Million years of tranquility.

 In fact, to beat sauropods to death, they have a funny way of being
around with few body fossils.  For example, in the Late Cretaceoius
of eastern US we have a single set of caudal veretbrae from North Carolina
(_Hypsibema crassicaudata_), and a single, isolated caudal from NJ. Period.
Are we to assume a single critter wandered or swam over from Texas or
New Mexico?  More likjely thie (awful typos today:() their habitat
was somehow cryptic: perhaps piedmont of Appalachioans or something
of the sort.  Ditto for the Paluxy beds: tracks mean trackmakers,
and there was clewarly a big population.

How do 10+tonne animals disappeart so easily from the record?

david schwimmer
schwimm@uscn.cc.uga.edu