Meeting Abstract

45-4   14:15 - 14:30  Commonality of phylogenetic reticulation in an adaptive radiation DeBaun, D*; Raxworthy, C; Burbrink, F; American Museum of Natural History; American Museum of Natural History; American Museum of Natural History ddebaun@amnh.org

A fundamental assumption of evolutionary biology is that speciation follows a bifurcating process; species are formed from the splitting of one lineage into two. However, hybrid speciation and introgression are becoming more widely documented in many animal groups. Hybrid inference studies have been historically limited to small sets of taxa, so explorations of the prevalence of reticulation within a single large group remains unexplored. We study the phylogeny of an adaptive radiation of 108 gemsnakes in Madagascar (Pseudoxyrhophiinae) to identify instances of introgression. Using a combination of network inference methods, we find nine reticulation events within the approximately 22-million-year evolutionary history of the gemsnakes. These reticulations occur in areas of high genetic conflict, where we see disagreement between conventional species tree inference methods. Notably, the hybridization events were not concentrated at any particular time or within any clades, in a radiation that created all standing generic diversity at constant rates throughout the Miocene. The pattern of reticulate evolution is consistent with these diversification rate estimates, suggesting that hybridization was one of the mechanisms by which the group radiated. Future research will seek to understand the genomic consequences of these hybridizations and understand more complex patterns of gene flow for the group.