Animal-Plant Relationships and Paleobiogeography of an Eocene Seagrass Community from Florida

Abstract

An excellent example of a preserved seagrass community occurs in the late Middle Eocene Avon Park Formation of west-central, peninsular Florida. This fossil assemblage provides some of the first detailed information about the evolutionary development of animal/seagrass interactions, and in addition, documents the pre-Miocene existence of seagrasses in Florida. The most common seagrasses present are species of Thalassodendron and Cymodocea. A strong Tethyan paleobiogeographic connection, previously noted among the Eocene molluscs of Florida, is also supported by the seagrasses and dugongs. We hypothesize that this assemblage of seagrasses was much more widespread in the Neotropics during the Paleogene and into the Neogene. Their absence now can be explained by the changing circulation patterns and cooling initiated by the closing of the Panamanian Isthmus and/or the onset of Plio-Pleistocene glaciation