摘要
On the basis of a worldwide review of Claraia , Pseudoclaraia and Eumorphotis , especially their important species , two range zones are recognized:the Pseudoclaraia wangi range zone —— Upper Griesbachian——and the Claraia stachei- C. aurita - Eumorphotis multiformis acme zone——Upper Griesbachian to Lower Smithian This result revises both the tradition-al Chinese concept regarding these fossils as limited in Lower Scythian and the viewpoint of some Eurasian researchers who hold Eumorphotis multiformis to be Upper Scythian .The paleogeographical distribution of the three genera is controlled primarily by temperature (latitude) and secondarily by physiographic separations .Distribution of these fossils is subdivided into four realms and five provinces . The Eastern Asia province of the Tethys realm is suggested as the source area of these fossils .The striking contrast between the composition of the species along the southern and northern margins of the Tethys , together with other distributional characters ,supports the plate tectonic theory .
On the basis of a worldwide review of Claraia , Pseudoclaraia and Eumorphotis , especially their important species , two range zones are recognized:the Pseudoclaraia wangi range zone —— Upper Griesbachian——and the Claraia stachei- C. aurita - Eumorphotis multiformis acme zone——Upper Griesbachian to Lower Smithian This result revises both the tradition-al Chinese concept regarding these fossils as limited in Lower Scythian and the viewpoint of some Eurasian researchers who hold Eumorphotis multiformis to be Upper Scythian .The paleogeographical distribution of the three genera is controlled primarily by temperature (latitude) and secondarily by physiographic separations .Distribution of these fossils is subdivided into four realms and five provinces . The Eastern Asia province of the Tethys realm is suggested as the source area of these fossils .The striking contrast between the composition of the species along the southern and northern margins of the Tethys , together with other distributional characters ,supports the plate tectonic theory .
