1. Department of Geology, University of Tartu, Ravila, Tartu, Estonia
2. Department of Earth Sciences, The College of Wooster, Wooster, OH, USA
3. Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russia
4. Institut für Geologie, Universität Hamburg, Hamburg, Germany
5. Department of Geology, Tallinn University of Technology, Tallinn, Estonia