Probing the ecology and climate of the Eocene Southern Ocean with sand tiger sharks Striatolamia macrota

During the Eocene, the Earth climate system transitioned from greenhouse to icehouse conditions. Central to many explanations is the Southern Ocean—where tectonic configurations influenced oceanic gateways, ocean circulation reduced heat transport, and/or greenhouse gas declines prompted glaciation. To date, few studies have explored the implications of this climate transition on high latitude, marine vertebrates. Seymour Island near the Antarctic Peninsula preserves a rich, diverse fossil assemblage in the Tertiary Eocene La Meseta (TELM) Formation (Fm). We examine teeth of Striatolamia macrota, an extinct (†) sand tiger shark that is abundant throughout the La Meseta Fm. to discern ecological and environmental characteristics. Body size is an integrative ecological trait often tracked through time and space. †Striatolamia macrota body size distributions indicate no shifts during TELMs 2-5 based on anterior tooth crown height (n=450, mean=19.6 ± 6.4 mm, total body length 88-389 cm). Si...