Abstract

Integration of newly available Chinese data for the biogeography of the Silurian and Devonian makes possible a number of globally sigificant advances. The Early Silurian, the Llandoverian, can now be shown to have been moderately provincial rather than cosmopolitan, as considered earlier. The Uralian-Cordilleran Region defined previously for the Late Silurian can now be shown with Chinese information to have been in existence with a co-occurring North Atlantic Region since the beginnings of the Silurian and to have been somewhat more provincial than the Late Silurian. The view of Late Silurian provincialism with two major regions is further substantiated with the help of Chinese data. For the Early Devonian, it is now possible to define a South China Region that includes the bulk of the Yangtze Platform Region of South China plus adjacent Tonkin in North Vietnam. The boundary of the South China Region is present in central Yunnan and extends in an approximately north-south direction. The South China Region is still prominent during the lower, Eifelian half of the Middle Devonian. Relatively cosmopolitan Devonian conditions affect China by the latter, Givetian half of the Middle Devonian, as is also the case in most other parts of the world except for eastern North America and the Southern Hemisphere Malvinokaffric Realm. The Chinese Upper Devonian is cosmopolitan in a manner similar to that of the rest of the World. It is notable during the Lower Devonian that the nonmarine vertebrate fauna is unusually provincial and very distinct from faunas known in Europe and North America, as well as from those present in northern Asia. It is suggested that previous distinctions between Lower Devonian Uralian and Mongolo-Okhotsk Regions are more likely provincial or even subprovincial. The presence of the atrypacean genus Tuvaella in the Silurian of east-central Asia is shown to represent the restricted occurrence of a single genus, rather than being indicative of a major biogeographic unit. However, it may indicate the presence of a subprovincial unit or of an endemic center.

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