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RE: "Baby"ramus and Age of the Barun Goyot, Djadoktha and Nemegt Formations




Gera Mirantsev wrote:

   I do not think that it hands at the private collection. I saw
Alioramus cervicals at the PIN collection. Some cervicals are attached
to holotype.

Is this new 1m-long _Alioramus_ skull also in the PIN collection? Or just the cervicals?


Faunal turnover e.g. Pinacosaurus-Saichania-Tarchia. The presence of Saurolophus and a tyrannosaur closest to Tyrannosaurus in the Nemegt argues for a younger age than that of the Djadokhta.

I could be missing something here, but... if two formations in different parts of the world show closely related species, why does this mean that the two formations must be contemporary? Taxa are not just parachuted into two different continents. If two species are sister taxa, then the lineage must have branched somewhere, with at least one of the two taxa originating in some place other than where it ended up.


I agree with Mickey &c: using dinosaurs for biostratigraphic dating is a very bad idea. Just look at how similar _Brachiosaurus_ is to _Sonorasaurus_, even though the two are widely separated chronologically.

Cheers

Tim