Pennsylvanian Eugeneodontid Shark Tooth

The late Pennsylvanian and early Permian dark shale deposits of the Midwest have produced some exceptional examples of fossils of the elasmobranches, the grouping to which sharks and rays belong. These horizons are the result of deep water deposits during marine transgressions into the interior of the continent that are known as cyclothems. These black shales represent deposition in a low to no oxygen environment which allowed for exceptional preservation of specimens that were free from predation and scavenging. This is a fine example of a tooth from a Eugeneodontid shark known as Campodus. These sharks may have been plankton feeders. The teeth do not have the sharp edges suited for tearing flesh, and the tiny ridges across the crown of the tooth do not suggest they were suited for crushing shells of invertebrates. Some teeth have been found that were 100 mm across, indicating a giant some 12 meters in length.