Global climate model comparisons of niche evolution in Turritelline gastropods across the end-Cretaceous mass extinction

Paleo-Ecological Niche Modeling (PaleoENM) aims to map the distributions
of extinct species using paleo-coordinates of fossils and local
environmental data. While General Circulation Models (GCMs) have been
widely used to estimate climate conditions in deep time, they have
primarily been applied to the terrestrial vertebrate record. Furthermore,
variations in paleo-elevation models used in GCM construction can
significantly influence the outcomes of PaleoENM. This study addresses two
main objectives: (1) to investigate whether changing climatic factors
drove niche shifts following the end-Cretaceous mass extinction in the
shelly marine invertebrate group, the tower snails (Turritellidae:
Turritellinae), and (2) to compare the effects of two different
paleo-elevation models on the results of GCM-based predictions of species
distribution. Fossil occurrence data from the Maastrichtian and Danian
time periods were obtained from the Paleobiology Database, supplemented by
museum collections and published literature. Environmental data were
extracted from atmosphere-ocean General Circulation Model (GCM)
simulations using the HadCM3L model, applying two different sets of
paleogeographic and CO2 boundary conditions: Scotese-based and
Getech-based. Additional sedimentology and depositional environment data
were sourced from the Paleobiology Database (PBDB). We predicted the
distributions of Turritellines using the maximum entropy (MaxentMaxEnt)
algorithm and performed niche similarity analysis using principal
component analysis and kernel density estimation. We found significant
differences in the spatial arrangement of suitable habitats between the
Maastrichtian and Danian time periods across GCMs. The results also showed
that the Getech-based GCM outperformed the Scotese-based GCM in terms of
model metrics. Niche overlap across both time periods was high, with niche
similarity and equivalency being higher than expected by chance within
both GCMs. Our results also suggest that differences in elevation model
boundary conditions led to variations in the predicted distribution and
niche patterns. This study provides a novel approach to understanding
ecological resilience and niche change in invertebrate taxa after mass
extinction events. It also explores the robustness of varying GCM boundary
conditions on PaleoENM studies and offers a framework for future
paleoecological research on fossil invertebrate taxa.