Chitinozoan diversity in the East Baltic Silurian: first results of a quantitative stratigraphic approach with CONOP

Chitinozoans are among the most common and stratigraphically useful microfossils in the Silurian. We examine their regional diversity pattern in the Baltoscandian basin using constrained optimisation (CONOP), based on distributional data of 189 species in 15 sections. The CONOP-derived taxonomic richness curve provides close approximation to the standing diversity, complementing previous analyses and revealing finer details. The results show distinct diversity peaks in the Telychian and Homerian with regional maximum of 25-30 species. Major crises occurred in the early Sheinwoodian and late Homerian, coincident with carbon isotope excursions. The Ludfordian pattern remains controversial awaiting extension of the data-set.