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Re: Age of the Barun Goyot, Djadoktha and Nemegt Formations
Again, Norman considered S. angustirostris and S.
osborni to be virtually indistinguishable.
This only (!) works as an argument if you assume a certain fixed speed of
morphological evolution _and_ disregard stabilizing selection. In other
words, your argument is built upon two speculations.
Apples and oranges. Turnover among large dinosaurs
How do you know?
Saurolophus is unknown from the Campanian
or late Maastrichtian.
In North America, yes... at least so far...
I think armchair geologists
Was Shuvalov an armchair geologist? Or Sukhanov,
Martinson, Russell, or Jerzykiewicz? They all
expressed views on the age of the Nemegt simlar to
mine, based on all the evidence.
There is so little evidence, in any direction, that the armchair is not a
meaningful distinction in this case.