CAPTURE-MARK-RECAPTURE ANALYSIS OF DIVERSIFICATION RATES IN LAURENTIA AND BALTICA DURING THE GREAT ORDOVICIAN BIODIVERSIFICATION EVENT

In order to get at a better understanding of diversification patterns through Earth history, we have to take into account possible controlling factors when modeling origination and extinction rates. However, not only are these driving factors complex but varying preservation and/or sampling probabilities in addition bias observed patterns of fossil diversity. Therefore it is important to account for the inherent incompleteness of the fossil record and the variation in our sampling of it. One way this can be done is by using capture-mark-recapture (CMR) approaches. Such approaches estimate origination and extinction rates simultaneously with sampling probabilities. Covariates, for instance different palaeocontinents, habitats or environmental data can be also included to explore their contributions to variation in diversification rates and differential sampling.

Preliminary estimates of origination and extinction rates for both Laurentian and Baltic genera through the Ordovician suggest slightly higher rates for Baltica. At the same time, genus richness estimates during the Lower to Middle Ordovician are higher on Laurentia.