Polyacrodus sp. Middle Triassic, Upper Muschelkalk (Ladinian), Upper Silesia, Poland A beautifully preserved specimen of a shark tooth crown, Polyacrodus sp., belonging to the order Hybodontiformes. My observations indicate that the teeth of these sharks are significantly less numerous in the Ladinian sediments of Upper Silesia than those of other hybodonts. This is the only…