Though they were plentiful and were successful marine predators, sharks did not fossilize well in the Smoky Hill Chalk. Unlike bony fish such as Xiphactinus, shark bone is cartilage and requires special conditions to be preserved as a fossil. Most sharks are described by the shape of their teeth and individual sharks’ teeth are found in abundance. There are many shark genera represented in the Kansas Cretaceous. The three main types are Cretoxyrhina, Squalicorax, and Ptychodus.
Cretoxyrhina (kree-tox-ee-rye-nuh) was the largest shark in the Niobrara Sea, some reaching a length of twenty feet. Their teeth are long and smooth and can measure over two inches. It was undoubtedly a ferocious predator.
Squalicorax (squay-luh-kore-ax) was a smaller genus, averaging less than ten feet long. The teeth of Squalicorax are curved and have sharp, serrated edges. More sharks’ teeth are found of this type than any other in the Smoky Hill Chalk.
Ptychodus (tie-ko-dus) was an odd shark that had dense, crushing teeth that were used to break clam shells so that they could get to the meat. Ptychodus are mainly found in lower strata of the Smoky Hill chalk.
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