VERTEBRATE BITES AND SCATS IN MARINE CRETACEOUS DEPOSITS: INFORMATION FROM EXTANT TEETH, MUSCLES, GUTS AND SPHINCTERS

General information about predatory and feeding behavior of ancient vertebrates in marine facies can be inferred from simple presence of bite traces on coeval bones and coprolites. More specific insights are based on detailed biology and behavior of modern analogs. For bite traces, variables may include tooth morphologies, jaw muscle strength, tooth positions and lability. Coprolites, as the product of digestive and excretory systems which rarely fossilize, must be based on information inferred from analogs. Additionally, coprolites of terrestrial tetrapods in marine deposits are likely allochthonous, and the original sites of deposition must be considered.

Late Cretaceous bite marks in Southeastern marine deposits are most evident on larger-surfaced, denser bones such as turtle carapaces and plastrons, and dinosaur limb bones. However, they have also been found on mosasaur and dinosaur vertebrae, plesiosaur metapodials, and even crocodylian jaws. The majority of such traces derive from selachians and crocodylians, which were favored by nearshore environments of deposition. Coprolites in marine deposits tend to favor the same taxa that produce most bite traces, also reflecting the bias toward their origin and preservation. Detailed knowledge of crocodylian bite strength and prey selection comes from observation of modern species. Similarly, detailed knowledge of shark feeding, digestion and excretion involves actualistic processes and observations. However, not all obvious marine coprolites are readily correlated with modern forms, and may involve extinct, indeterminable taxa.