Chitinozoan diversity dynamics in the East Baltic Silurian

The species diversity of chitinozoans has undergone considerable changes throughout the East Baltic Silurian. Well-pronounced diversity maxima occur in the sedgwickii, murchisoni bohemicus, testis, and formosus zones and in the middle Pridoli; innovation maxima fall in the turriculatus, flexilis, radians, scanicus, and formosus zones. The major extinction events took place in the sedgwickii, riccartonensis, testis, and balticus zones. Most of these events were closely related to the transgression-regression phases of the Silurian Baltic Basin, global sea-level fluctuations, and evolutionary changes in the chitinozoan assemblage.