Clusters of small cylindrical pellets occur sporadically in Ordovician strata in Bohemia. They are assigned to the ichnogenus Tomaculum and occur in lenticular or elongated accumulations. Similar accumulations are associated with body fossils including the cephala of the trilobites Ormathops atavus, Pricyclopyge binodosa, and Parabarrandia crassa. The clusters are situated under the glabella and in the anterior parts of the cephalon but their exact position is variable in different cases. Accumulations of pellets have also been studied inside shells of hyoliths, bellerophontids, and echinoderm thecae. They probably represent the faeces of either scavengers feeding on soft parts or organisms using cephalic shields and other shells as hiding places. An interpretation of these pellets as trilobite eggs is highly improbable.

Key words: Ichnofossils, pellets, palaeoecology, taphonomy, trilobites, Ordovician, Bohemia.

Jana Bruthansová [jana.bruthansova@nm.cz], Department of Palaeontology, National Museum, Václavské nám. 68, 115 79 Prague 1, Czech Republic; Petr Kraft [kraft@natur.cuni.cz], Charles University, Institute of Geology and Palaeontology, Albertov 6, 128 43 Prague 2, Czech Republic.