FOSSIL INVERTEBRATES FROM THE MONTBROOK VERTEBRATE SITE (LEVY COUNTY, FLORIDA)

The Montbrook Fossil Site was discovered near Williston (Levy County, Florida) in 2015 and continues to be excavated by research personnel and volunteers from the Florida Museum of Natural History (FLMNH). The site is posited to be an alluvial environment but may have cut through older strata, as freshwater and marine fossils, both vertebrate and invertebrate, are intermixed with the predominantly terrestrial vertebrate assemblage. Vertebrate fossils found at the site are late Miocene-early Pliocene in age with occasional Eocene taxa, while invertebrate fossils are late Eocene (Ocala Limestone) and Miocene (Hawthorn Group) in age. Furthermore, three sediment cores have been collected at the site by the Florida Geological Survey (FGS). Detailed analysis of the lithology and reconstruction of the paleo-environment, however, remains a work in progress.

While widely known for the vertebrate fossil assemblage, thousands of invertebrate fossils have been picked from bulk sediment samples collected from the site. These invertebrates include small bivalves (e.g., cardiids and arcids) and gastropods (e.g., naticids and turritellids), crustaceans (e.g., crabs and shrimp), and bryozoans.

Here, we provide a preliminary account of the invertebrate taxa found from these samples. Occurrence data from the FLMNH Invertebrate Paleontology (IP) database show the invertebrate fauna to be low diversity consisting of 25 families. Preservation of the invertebrates ranges from moldic (most of the molluscan taxa) to body fossils (crustaceans and bryozoans). Callianassid shrimp dominate the taxa identified thus far. Many of the invertebrates found in these samples reflect nearshore to marine environments, in contrast to the predominantly terrestrial vertebrate fossils. Processing of additional invertebrates, through picking of sediment samples and improved taxonomic determinations, may contribute to the overall reconstruction of the paleo-environment at the site.