Sheltered preservation in Ordovician trilobites

Abstract. Articulated holaspid specimens of Placoparia Hawle and Corda, 1847 Eoharpes Raymond, 1905 entombed inside cephalopod conchs under the remains large illaenid, asaphid, cyclopygid dalmanitid trilobites from Middle Ordovician Šárka Formation Prague Basin (Czech Republic) are described discussed. Two such samples were also found in overlying Dobrotivá Middle/Late age. Four articulated juvenile exoskeletons preserved a cephalon trilobite Degamella Marek, 1961 represent first record shelter strategy non-holaspid trilobites. The sheltered preservation could be explained by hiding behaviour associated with danger predation, storm disturbances, seeking for food or high vulnerability after moulting. It is obvious that deliberately entered restricted space skeletal parts conchs. These exceptional finds provide new insight life some benthic classified as cases “frozen” behaviour.