1. Department of Natural and Cultural Resources, University of Ferrara, C.so Porta Mare 2, I-44100 Ferrara, Italy; Department of Paleobiology and Botanical Garden, University of Modena and Reggio Emilia, V.le Caduti in guerra 127, I-41100 Modena, Italy; and Department of Pharmaceutical Sciences,University of Ferrara, v. Fossato di Mortara 17/19, I-44100 Ferrara, Italy