Biogeography of Ordovician Chitinozoa

Biogeographic differentiation of chitinozoans may help explain some of the problems associated with correlating the microfaunas of Quebec with those of southwest Europe, North Africa, and the Baltic region of Scandinavia. This differentiation becomes evident when comparisons are made with the respective regional zonation, vertical stratigraphic distribution charts, and microfaunal assemblages.

An assessment of the number of species in common between chitinozoan assemblages of different regions, and the similarity coefficient thus obtained, indicates affinities among the microfaunas of North Africa, southwest Europe, Great Britain, and Bohemia; these regions were situated in high latitudes during the Ordovician. Similarly, microfaunas from eastern Canada, Australia, Spitsbergen, and the United States, which occupied subequatorial latitudes, have many feature in common. Faunas from the Baltic region of Scandinavia appear to have occupied an intermediate position.