extinction before K-T

[Fet, Victor]

Well, of course we don't know that it was exactly K-T event --- there
are so few Mesozoic fossils we just cannot tell

We know, however, that there are four major extant clades of orthostern
scorpions (with a Carboniferous outgroup), with hypothesized divergence
in early Mesozoic; two of them quite diverse (and only one of those,
Buthidae, possessing mammal-specific toxins) while two others are
monogeneric Asian relicts (one of them known from Cretaceous).

Victor Fet
Department of Biological Sciences
Marshall University
Huntington, WV 25755-2510 USA
ph. (304) 696-3116, fax (304) 696-3243
http://www.science.marshall.edu/fet/euscorpius/Fet.htm

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Hi Victor,
     I would certainly agree that many major scorpion groups died out
*before* the K-T extinction (most well before the Cretaceous even
began).  I suppose some families of scorpions could have gone extinct
the end of the Cretaceous, but with so few fossils (mostly from the
Middle Cretaceous?), how would you know that the end-Cretaceous
extinction did them in?  Whatever scorpion families existed at the end
of the Cretaceous, I still suspect a majority of them survived (although
with fewer genera than before the extinction).  Not a *catastrophic*
extinction like that which wiped out the vast majority of families of
birds at the end of the Cretaceous.  Birds just barely made it through.
  ---Cheers,
           Ken Kinman
P.S.  Are mammal-specific neurotoxins of scorpions effective against
certain clades of mammals, or against mammals in general?  If the
latter, then such toxins could have easily developed during the very
long Mesozoic history of mammals.