ACKNOWLEDGEMENTS

Many colleagues contributed to the realisation of this paper: The writer warmly thanks Prof. A. J. Boucot (Oregon State University) and Prof. R. E. Crick (UTA) for the encouragement, useful advice, and remarks in various steps of the work. Dr. J. Kríz, Š. Manda (Czech Geological Survey), and Prof. G. N. Kiselev (St. Petersburg University) kindly provided useful papers by Czech and Russian authors respectively. Many thanks also to Drs. S. Kovács (Eötvös Loránd University, Budapest), H. P. Schönlaub (Austrian Geological Survey, Wien), and Prof. G. B. Vai (Dept. of Earth and Environmental Sciences, Bologna University) for information on northeastern Hungary and Carnic Alps Geology respectively. Dr. T. Engeser (Freie Universität zu Berlin) gives me free usage of his 1997-99 «Data Retrieval System Nautiloidea» in CD-ROM. Mr. G. Leonardi (Modena and Reggio E. University) helped with graphics and diagrams. Thanks also to anonymous PE reviewers for suggestions and invaluable checking of the MS. Last but not least, many thanks are due to Dr. Norman MacLeod (Dept. Palaeontology, The Natural History Museum, London) for his kindness in calculation of the Probabilistic Faunal Index Similarity. The present research is funded by MIUR grants (resp. Prof. E. Serpagli) and by the scientific cooperation project n°23 -ES 1 (2002-2005) between Czech Rep. and Italy (resp. Dr. P. Štorch and Prof. E. Serpagli)