THE DISTAL EFFECTS OF AVAILABLE SUITABLE HABITAT ON EXTINCTION POTENTIAL IN CEPHALOPODS AND OTHER MOLLUSKS ACROSS THE K/PG IN THE ATLANTIC COASTAL PLAIN

The Cretaceous/Paleogene (K/Pg) boundary extinction is the latest of the big five mass extinctions to have occurred in Earth’s history, killing ~ 70% of marine species and leading to the current day biota. Extinction patterns are often attributed to geographic range size (i.e., amount of suitable habitat, SH) as well as proximity to the impact site. Here we investigate changes in the size of predicted abiotic SH in cephalopods and other molluscan genera across the K/Pg boundary in the relatively distal Atlantic Coastal Plain (ACP). We compare these results to a similar study looking at extinction patterns in the the same taxa in the Gulf Coastal Plain (GCP). Abiotic SH in the latest Maastrichtian and early Danian was characterized using sedimentological proxies for environment (e.g., substrate conditions and carbonate contribution). These data were combined with taxon occurrences derived from fieldwork and the Paleobiology Database, and analyzed using PaleoEcological Niche Modeling (PaleoENM). Models of predicted SH were trained in the latest Maastrichtian, then projected into the Danian to estimate the availability and size of a taxon’s SH after the extinction interval. Several surviving and non-surviving genera (Turritella, Eutrephoceras, and Nuculana vs. Discoscaphites, Sphenodiscus, and Baculites, respectively) were modeled to test whether survivorship was associated with changes in the size of available SH in the Danian. Preliminary results suggest that there is no correlation between changes in SH and survivorship in the ACP. In contrast, previous work in the GCP showed that genera with increased SH tended to survive the extinction, and genera with decreased predicted SH area were more likely to go extinct. These results suggest that biogeographic processes that influence extinction at the K/Pg boundary may be dependent on proximity to the impact site.