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Re: THE WONDERFUL WORLD OF SALAMANDERS
From: "Nicholas R. Longrich" <longrich@phoenix.Princeton.EDU>
> Do we really have that much good evidence on salamanders and
> frogs? Can we even identify them past the generic level, or even
> past the subfamily level? I've heard something to the effect that
> there are no complete frogs known from the late K of NA.
I am not in a position to judge on my own.
Archibald doesn't say much about frogs - there is at most one frog
species in his faunal tabulation. He counts 8 or so species of
salamanders in the Hell Creek and Fort Union faunas. He claims to
have rejected indeterminate fragments in his tabulations (that is
why he lists no snakes, for instance).
> scenario #1: Not a single species of frog, toad, newt, salamander,
> caecilian etc. went extinct at the K/T boundary. They all made it
> through. There was not any decline in the number of individuals in
> a species, either.
It is quite possible for there to have been a substantial decline in
numbers and yet few no extinctions. (Scenario #1.5 :-)
Archibald's data make no characterization of abundance, except for a
simple binary discrimination of "rare" versus "not rare". Thus, the
data as presented cannot say anything about any decline in numbers,
or lack thereof.
Also, Archibald treats the presence of a Fort Union *descendent* as
a survival, even if the older species is not actually attested in
> scenario #2: Frogs, toads, newts, salamanders, etc. got a good
> thrashing at the K/T for the same reason(s) as dinosaurs. Most
> species went extinct- in fact, only a relatively few individuals
> from ONE species of each genera/subfamily (as the case may be)
> managed to survive. In the depopulated post K/T world, however,
> their large reproductive potential allowed the individuals to
> repopulate or even create new species in the vacuum left. Very
> soon after the K/T, frogs and salamanders were thriving and
> These are just for the sake of argument, of course. My question
> is: is the evidence of fossil amphibians good enough to
> distinguish between these two extreme scenarios?
I am not sure. I think Archibald would say the evidence tends to
favor scenario #1 or #1.5.
Another issue, of course is whether pattern of salamander survival
is restricted to the Hell Creek and Lance, or is worldwide. There
is no evidence on that issue yet.
The peace of God be with you.