USING ANCESTRAL STATE RECONSTRUCTION FROM MODERN TO RECONSTRUCT PALEOECOLOGY: WHEN DOES IT WORK (AND WHEN DOES IT NOT)?

A common motivation among ecologists and evolutionary biologists is measuring and explaining biological diversity. evolutionary biologists turn to phylogenetic methods to address diversity-related questions, but paleontologists warn that methods that do not use fossil data make dangerous, often false, assumptions. Unfortunately, the fossil record itself is incomplete, making empirical studies of paleoecology difficult.

Paleontological data show species geographic range sizes to be heritable and that some lineages have a higher propensity to speciate than others, resulting in greater standing diversity. These tendencies bear implications for the long-term survival of the lineages that possess them. Here, we use the current phylogenetic method of likelihood-based ancestral state reconstruction (ASR) on genera in the Rosales (Angiosperms: Eudicots) to infer paleo-patterns of species richness and geographic range size. We then ground-truth our investigation against the known fossil record of these genera. Our primary goal is to evaluate the efficacy of ASR to recover paleo-patterns in studies on groups with poor fossil records (unlike the Rosales, which do).

Preliminary results using BiSSE-ASR (BiSSE = Binary State Speciation and Extinction) at inferring paleorichness and paleorange size are not statistically significantly better than random guessing. However, because ASR reconstructs common ancestors while paleobotanists are hesitant to assign fossils to cladograms unless they belong to living genera, the failure of ASR may owe in part to the incomplete fossil record than to ASR. Another ASR algorithm, BioGeoBEARS, is capable of incorporating both living and fossil data into its analysis, and for the Rosales likely offers a better reconstruction of the past. Final results of BiSSE-ASR (modern data only) will be compared to those of BioGeoBEARS (modern and fossil data) at the meeting.