Local and global abundance associated with extinction risk in late Paleozoic and early Mesozoic gastropods

Ecological theory predicts an inverse association between population size and extinction risk, but most previous paleontological studies have not confirmed this relationship. The reasons for this discrepancy between theory and observation remain poorly understood. In this study, we compiled a global database of gastropod occurrences and collection-level abundances spanning the Early Permian through Early Jurassic (Pliensbachian). Globally, the database contains 5469 occurrences of 496 genera and 2156 species from 839 localities. Within the database, 30 collections distributed across 7 stages contain at least 75 specimens and 10 genera – our minimum criteria for within-collection analysis of extinction selectivity. We use logistic regression analysis to assess the relationship between abundance and extinction risk using global and local measures of population size and stage-level extinction patterns in Early Permian through Early Jurassic marine gastropods. We find that global genus occu...