REVIEW OF VERTEBRATE DIVERSITY IN THE COON CREEK FORMATION LAGERSTÄTTE (LATE CRETACEOUS) OF WESTERN TENNESSEE

The Coon Creek Formation (terminal Campanian – Early Maastrictian) Lagerstätte is internationally recognized for its abundant and diverse invertebrates, especially mollusks and decapod crustaceans; however, the vertebrate fauna has received less attention until recently. The Coon Creek consists of a two predominant lithofacies. A lower sequence of micaceous, glauconitic, clayey-sand and sandy-clay beds contains the classic Coon Creek Fauna dominated by invertebrates. The overlying lithofacies is a dark, micaceous, shale dominated by trace fossils, gastropods and a wide variety of vertebrates. Six shark taxa include Heterodontus sp., Squatina hassei, Odontaspis serratus, Scapanorhynchus r. texanus, Otodus appendiculatus, and Squalicorax p. pristodontus, three rays (Ischyrhiza m. mira, Brachyrhizodus wichitaensis?, and Rhombodus binkhorsti). Chimaeroids include Ischyodus bifurcatus and Edaphodon sp. Turtles are represented by Bothremys cooki and Toxochelys latiremis. As many as five mosasaur taxa occur belong to Prognathodon overton, the only record of this taxon outside of the Western Interior, Plioplatecarpus depressus, Halisaurus platyspondylus, Globidens dakotensis, and Mosasaurus hoffmannii. Other marine reptiles include the marine crocodilian Eothoracosaurus mississippiensis and the plesiosaur Cimoliasaurus magnus. Flying reptiles are represented by a newly found azhdarchid pterosaur. A single hadrosaur tooth represents terrestrial taxa. Fish taxa are represented by teeth and bone of Hadrodus priscus, Anomoeodus robustus, Saurodon leanus, Pachyrhizodus, Enchodus (2 sp), Stratodus apicalis, Hoploberyx insculptus, and Cylindracanthus cretaceus. Pertinent information on the Coon Creek vertebrates has also been obtained through fish otoliths or earstones, which are part of the acoustico-lateralis system. Ten actinopterygians representing at least nine families have been identified. Otoliths add an albulid (bonefish), a pterothrissid (bonefish), a congrid (conger eel), an ariid (sea catfish), a chlorophthalmid (greeneyes), a trachichthyid (roughies), two apogonids (cardinal fishes), a pempherid (sweepers), and a perciform to the assemblage.