Mazon Creek Fossil Fauna
Higher Crustaceans - Class Malacostraca
Marine-Estuarine Shrimp and Lobsters
Fossil shrimp were first reported from the Mazon Creek area around 1860, but prior to the opening of Pit 11 the diversity was remarkably small. Now, they are divided into robust non-marine and marine-estuarine groups. These fossil arthropods are preserved in full-body detail or as exoskeleton molts.
Tyrannophontes theridion, A. Jansen, Braidwood, IL
Mamayocaris jaskowskii is a moderate-sized crayfish-like animal, probably a scavenger or low-level carnivore, and is a member of the marine Essex Biota.