USING NETWORK MODELING TO ASSESS BIOGEOGRAPHIC AND MACROECOLOGICAL PATTERNS IN THE LATE CRETACEOUS WESTERN INTERIOR SEAWAY AND GULF COASTAL PLAIN

The Western Interior Seaway (WIS) and Gulf Coastal Plain (GCP) are characterized by a dense fossil record of a wide variety of marine invertebrate faunas spanning the Late Cretaceous that experienced significant abiotic shifts across several habitat types over approximately 45° latitude. These basins represent closely spaced regions with distinct normal and non-normal marine conditions, potentially influencing invertebrate dispersal and macroecology. Taxon distributions and the resulting paleocommunity structures produced across these spatiotemporally varying environments are important factors in understanding the influence of changing environments on both modern and ancient systems. We utilize a set of relatively novel quantitative methods, including network modeling, to reassess marine invertebrate provinciality as well as the distribution and communication of functional entities “grouped” into paleocommunities. These analyses are significant in that they represent a detailed and broad-scale assessment of regional macroecological patterns across approximately 18 Ma of geologic history that includes regional habitat differences and experienced significant abiotic fluctuations, including sea level shifts, but that does not include a major biotic upheaval akin to a mass extinction event. These analyses therefore explore macroecological and biogeographic patterns during a “background” interval of abiotic and biotic change, relevant to understanding baseline aspects of biogeography and functional diversity.