Pennsylvanian shark-cephalopod predation: a case study



A well-preserved portion of a body chamber of a coiled nautiloid (taxon uncertain) from the Kendrick Shale (Lower Pennsylvanian) of Floyd County, Kentucky, U.S.A., exhibits three comparatively large, nearly circular punctures and a circular indentation in the shell. These punctures are interpreted as representing an attack on the nautiloid by a cladodontid shark, most likely by the large symmoriid shark, Symmorium reniforme. We conclude that the punctures in the nautiloid body chamber were inflicted by three teeth in a single tooth file in the lower jaw of a specimen of 5. reniforme that was approximately 2.5 meters long. This nautiloid specimen is the first Paleozoic record of a chondrichthyan-cephalopod/ predator-prey relationship. We suggest, however, that this relationship was perhaps a common one and that other examples probably exist in collections of late Paleozoic ccphalopods. ?Paleozoic, Pennsylvanian, Symmorium reniforme, cephalopod. predation.