1. Institute of Paleobiology Polish Academy of Sciences ul. Twarda 51/55 00‐818 Warszawa Poland
2. Institute of Geological Sciences National Academy of Science of Ukraine O. Gonchar Street 55‐B 02054 Kyev Ukraine
3. Oles Honchar Dnipropetrovsk National University 72, Gagarin Avenue Dnipropetrovsk 49010 Ukraine