Oral Presentation- Symposium 12th International Mammalogical Congress

Fossilised birth-death priors on phylogenies given rate heterogeneity in the fossil record of carnivoran mammals (#187)

Peter Wagner 1
  1. University of Nebraska, Lincoln, Lincoln, Nebraska, United States

Estimates of origination, extinction and sampling rates allow us to put prior probabilities on the divergence times of clades within phylogenies.  Although these are easy to estimate given homogenous rates over time, origination, extinction and sampling all vary from one time interval to the next. Moreover, these rates can vary within the same clades on different continents.  Additionally, sampling rates vary among taxa within clades simply because most species occupy relatively few areas whereas some occupy many areas. “Fossilized birth-death” models can be modified to accommodate these variations over time, space and taxa.  I present an example here with North American and Eurasian Carnivora. Carnivora are one of the few known examples of a clade in which turnover rates differ between North America and Eurasia as well as over time. Carnivoran sampling rates also have been shown to vary over time, and to typically show lognormal distributions among species. Phylogenies are ideally suited for accommodating geographic variation in rates because phylogenies simultaneously allow us to estimate probabilities of unsampled lineages being present in different areas. Thus, the prior probability of a branch given Eurasian or North American rates can be weighted by the probability that the lineage was present in either area. Notably, the greatest effect on divergence priors comes from rate heterogeneity over time; however, there are small effects of biogeographic and taxonomic heterogeneities, and the ability to accommodate them should provide added confidence in the final results.