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

Abstract

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.

Keywords::

• chitinozoans
• Silurian
• Baltica
• biodiversity
• quantitative stratigraphy
• CONOP9

Acknowledgements

The authors are grateful to Thijs Vandenbroucke and an anonymous reviewer for their most useful comments and corrections. The study was supported by the Estonian Research Council (projects ETF9039 and SF0140020s08) and Archimedes Foundation. This is a contribution to the IGCP project 591.