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Re: Late night thoughts: Pathetica and Interspersal
----- Original Message -----
From: "Tim Williams" <firstname.lastname@example.org>
Sent: Thursday, June 21, 2007 4:08 AM
No, David didn't say that at all. What he said was that after a dramatic
increase in size that occurred early in their evolution (from
_Anchisaurus_-sized to _Isanosaurus_-sized and beyond), sauropods had
essentially hit their maximum size by the Middle Jurassic.
No, not that either. I said that after a drastic increase in the size
_range_, into both directions, with -- in sum -- _no trend_, the smallest
ones (like *Anchisaurus*) died out, and the bigger ones kept diversifying,
though neither the minimum nor the maximum size changed much from the MJ
I read your response a few times, and I still can't figure out how my
response is different to your response. This is a distinction without a
Easy: you said there was "a dramatic increase in size that occurred early in
their evolution (from _Anchisaurus_-sized to _Isanosaurus_-sized and
beyond"; I said there was no such increase, only diversification. I didn't
mention that *Anchisaurus* comes out as the result of a dwarfing event; the
first sauropod is reconstructed as larger. The same, incidentally, holds
even for *Saturnalia* and the first sauropodomorph.
I do agree that the maximum size didn't get pushed much after the Middle
Jurassic, except by *Amphicoelias fragillimus* (which is not in my sample,
but then neither are any footprints).