NEW CALCITIC-SHELLED MARINE INVERTEBRATES FROM THE EOCENE OCALA LIMESTONE EXPOSED IN TWO NORTH FLORIDA CAVES (JACKSON BLUE SPRING AND CATACOMBS)

Two caves, Jackson Blue Springs and Catacombs, developed in the middle to late Eocene Ocala Limestone in northern Florida, recently yielded fossil marine invertebrates never before reported from that formation. All were originally calcitic-shelled taxa; aragonitic-shelled taxa were preserved as molds only. New species discovered include decapod crustaceans [Families: Callianassidae and Ctenochelidae (shrimps) and Parthenopidae, Majidae and Mithracidae (crabs)], irregular echinoids [genera: Tarphypygus and Rhyncholampas], and articulate brachiopods [genus: Argyrotheca]. Tarphypygus, an extinct genus, is known only from fossil deposits in Cuba and Jamaica. Additionally, abundant disarticulated ossicles of goniasterid asteroids, ophiuroids, and crinoids, along with poriferan spicules were recovered. Jackson Blue Spring in Jackson County is a high flow water-filled cave. Fine-grained clays and coarse grained sands containing some of the above-mentioned taxa were removed from the cave floor in 1-liter Nalgene® water bottles. Catacombs Cave in Marion County is a water table cave and in addition to collecting fine-grained clays from the cave floor, exposed specimens on the cave walls were removed in remote areas. In both instances, great care was taken to minimize impact to the cave's environment. Florida's protected cave environments with their slowly eroding limestones provide a rare opportunity to collect and document new and rare fossil marine invertebrates (especially ones with multi-component skeletons) that rapidly changing surface exposures (e.g., quarries, river banks and bottoms) typically do not.