FOSSIL ASSEMBLAGE SLABS AND MULTISPECIES SPECIMENS: HIDDEN DATA IN FOSSIL INVERTEBRATE COLLECTIONS

Fossil invertebrate collections often have high levels of biodiversity that can be seen in specimens with attached parasites and epibionts, and also in assemblage slabs, a single slab of rock with two or more (sometimes hundreds or thousands of) individual specimens. Assemblage slabs may be the result of communities buried quickly (storm deposits, submarine landslides, etc.) or deposition of current sorted or time averaged fossils. In either case, the abundance and diversity of fossils represent paleoecological and paleoenvironmental data that should be preserved when digitized.

The fossil invertebrate collection at the Field Museum is organized systematically and assemblage slabs are commonly stored together under their own category. However, interns working in our digitization projects have encountered both assemblage slabs and epibionts and their hosts stored under individual species names without any indication of the other species present. This hides diversity and potentially important fossils and data. To address this, we have created categories in our database to mark these as multispecies specimens, so that they can be searched and in the future fully described and digitized.

Digitizing our collections is an opportunity to make these specimens and data more accessible. The Yale Peabody Museum uses the Inselect software while digitizing assemblage slabs. This software provides an easy method to divide an image of a fossil assemblage slab into separate images and records. This allows each individual organism to be counted in the overall biodiversity of the slab. These records can all be linked to each other in the database.