MACROSTRATIGRAPHY AND THE NON-MARINE FOSSIL RECORD OF NORTH AMERICA

Variability in the stratigraphic record is linked to empirical patterns of diversity, mass extinction and other macroevolutionary phenomena in the fossil record. However, the extent to which the structure of the stratigraphic record distorts real macroevolutionary patterns (Bias Hypothesis) versus reflects Earth systems processes that also influence biological evolution (Common Cause Hypothesis) remains somewhat controversial. Mounting evidence supports the Common Cause Hypothesis in the marine realm, where tectonics and climate interact to influence both stratigraphy and macroevolution. However, the expectations of the Common Cause Hypothesis in non-marine environments remain largely undefined. Changes in continental flooding driven by climate and tectonics fundamentally alter the types and distributions of marine habitats, but are not expected to directly influence the stratigraphy of inland terrestrial environments. Here we present a test of the Common Cause and Bias Hypotheses for the Cretaceous through Neogene non-marine record of North America using the Macrostrat and Paleobiology Databases (PaleoDB). The dataset consists of 2,077 non-marine packages of sediment (deposited continuously at ~ 1-3 myr resolution and separated from other packages by hiatuses or by marine sediments) distributed across 648 geologic columns. The paleontological data consists of 10,673 PaleoDB collections representing 2,130 non-marine genera. An analysis of the paleontological completeness of the non-marine rock record shows that genus richness is not correlated with the proportion of sampled non-marine rock units. Moreover, neither origination nor extinction rates significantly co-vary with any macrostratigraphic quantities. These results do not support the Common Cause Hypothesis or the Bias Hypothesis. Instead, they suggest that stratigraphic architecture in the non-marine rock record may simply impart additional noise to macroevolutionary signals in the non-marine fossil record.