1. Geological Faculty; Lomonosov Moscow State University; Leninskie Gory 1 Moscow 119899 Russia
2. Geological Institute of the Russian Academy of Sciences; Pyzhevsky Lane 7 Moscow 119017 Russia
3. Borissiak Paleontological Institute of the Russian Academy of Sciences; Profsoyuznaya St. 123 Moscow 117647 Russia
4. Department of Geology; Université de Liège; 14 Allée du 6 Août Liège 4000 Belgium
5. Institute of Paleobiology; Polish Academy of Sciences; Twarda 51/55 PL-00-818 Warsaw Poland
6. Department of Earth Sciences; University of Oxford; Oxford OX1 3AN UK