Contrasting patterns and connections of rock and biotic diversity in the marine and non-marine fossil records of North America

Abstract

Macrostratigraphy uses packages of continuous sedimentation that are bound by hiatuses of non-deposition, erosion, or alternations between environments/lithologies to characterize spatiotemporal patterns of sedimentation. Previous work has linked the macrostratigraphy of marine shelf environments to many different macroevolutionary patterns in the marine animal fossil record. Here we use an improved macrostratigraphic database for North America, combined with fossil occurrence data in the Paleobiology Database, to show that macroevolutionary and macrostratigraphic patterns are correlated more strongly in marine environments than in non-marine environments. We also test the hypothesis that the temporal distribution of lithological diversity (measured as evenness, similar to ecological evenness based on the number of lithostratigraphic units with a given lithologic type within each time interval) has a relationship to genus-level taxonomic diversity in both the marine and non-marine realms. Uneven sampling of lithologies and their corresponding depositional environments can bias our perception of taxonomic diversity by causing taxa from poorly sampled environments to be underrepresented in the fossil record. Our results show a negative correlation between lithologic evenness and marine vertebrate generic richness — less even sampling of lithologies corresponds to a higher observed taxonomic richness, and no correlation with lithologic evenness and non-marine diversity measures. This suggests a difference in the relationship between biologic and sedimentary processes at work in the marine and non-marine realms, and possibly differences in the magnitude of the bias imposed by the rock record on the underlying biologic patterns.