Inferred placoderm bite marks on Devonian crinoids from Poland

Crinoid ossicles bearing plausible placoderm bite marks are described from the Middle Devonian (Eifelian) of central Poland (Holy Cross Mountains). Damage to the ossicles includes a series of regularly spaced, shallow and crater-shaped indentations, which are circular or slightly oval in outline. The dimension and spacing of these damage match the jaw morphology of certain placoderms probably belong to Coccosteidae (Arthrodira). The present discovery constitutes possible evidence of predator-prey interaction in the Middle Devonian. During this time, referred to as the Middle Palaeozoic marine revolution, diversification of durophagous predators occurred, which resulted in increases in defensive adaptations among prey taxa including crinoids (such as: thickening calyx plates, reduction of viscera and increase of spinosity).