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Nemegt and Wangshi etc



  To Jonathan,

Protoceratopsid remains are also known from the Wangshi; Bayan Mandahu-a Djadokhta correlative- has them as well as Pinacosaurus in common.

The Nemegt fauna apparently extended well beyond the Nemegt basin, and not just outer units like Gurilin Tsav. The Dinosauria mentioned an unnamed unit in Heilongjiang i.e. not the Tsagayan, but very close, with Saurolophus "kryschtofovici" and "A. periculosus", considered of Nemegtian age by Lucas. This suggests the differences between the Nemegt and Tsagayan were the result of time or succession, not distance.

Yes, Euoplocephalus and Edmontonia persisted from the Judithian to the Edmontonian, despite obvious environmental changes as the area became more inland with regression. (I don't think faunal changes were yet great; generally there was continuity until the Lancian.)In contrast, I don't know of any environmental changes in the Barungoyotian areas adjacent to Nemegtian ones, by the time of the Nemegt deposition, but the once ubiquitous Pinacosaurus is apparently absent in those habitats.

True, different NA hadrosaurs preferred different regions e.g. the near marine Edmontosaurus and lambeosaurs farther inland. I note, however, that Saurolophus and Hypacrosaurus? (=Barsboldia?) extended from NA all the way to Asia. I can't understand why none of the Tsagayan hadrosaurs-probably essentially those of the Wangshi series-were present in the Nemegtian areas. Why just the American immigrants? After all, there were hadrosaurs in Mongolia in the Barungoyotian period which preceded he c Edmontonian age of Saurolophus. I get the impression the Asian hadrosaurs (which seem primitive to Godefroit) must have been supplanted.

                  Cheers -Tim




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