Shell repair and mode of life of Praenatica gregaria (Gastropoda) from the Devonian of Bohemia (Czech Republic)

Repaired shell injuries occuring in less than four per cent of examined specimens of the platyceratid gastropod Praenatica gregaria (Barrande, in Perner 1903) from the Lower Devonian (Pragian) of Bohemia probably result from non–lethal predatory attacks. The low frequency may reflect the resistance of the large, smooth, rapidly expanding shell to attack, but a high rate of fatal attacks could produce the same pattern. The habit of some platyceratid gastropods living on echinoderm calices may provide a refuge from benthic predators, but conclusive evidence for this mode of life in P. gregaria or the general assumption of platyceratid coprophagy is lacking.