Chitinozoa z ordoviku a siluru pražské a velšské pánve: vliv biologie a ekologie chitinozoí na jejich použití v biostratigrafii

Vodička, Jakub

Chitinozoans have a great potential for biostratigraphic correlation of Ordovician through to Devonian marine sedimentary sequences. However, the question of chitinozoan biological affinities remains unresolved. Consequently, also the question of their palaeoecology and mode of life is a matter of discussion. Incorrect interpretation of both these questions can influence the accuracy of chitinozoan-based correlation. Four peer-review studies dealing with chitinozoan biostratigraphy, paleoecology and biological affinities are presented in this thesis. Studied chitinozoan material originated from two areas, the Prague Basin (Czech Republic) and the Welsh Basin (U.K.). Exceptionally preserved chitinozoan clusters with parallel oriented vesicles have been described from the Ordovician rocks of the Welsh and the Prague basins. These clusters have been termed P-clusters and interpreted as remains of an egg mass and support the interpretation of chitinozoans as eggs of unknown metazoans, the chitinozoophorans. The material figured in previous contributions proves the presence of P-clusters in all three chitinozoan families, spanning from the Ordovician to the Devonian and across the palaeo-globe. The P-clusters indicate that a benthic phase must have been included in the chitinozoan spreading cycle....

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