Meeting Abstract
The role of prey or host shifting as a driver of diversification in large clades of marine taxa is poorly studied within a phylogenetic framework. Cladobranchs occupy a number of marine environments including coastal reefs, where diversity is highest, but also the deep sea and highly specialized pelagic and neustonic niches. However, difficulties in reconstructing the phylogeny of Cladobranchia have limited the ability of researchers to test whether prey preference has any effect on diversification within this group. To address issues with reconstructing the phylogeny of Cladobranchia, we identify and resolve the major lineages within Cladobranchia using RNA-Seq data, and use ancestral state reconstruction and diversification analyses to better understand the evolution of prey preferences and prey switching, and test for possible association with diversification. These analyses have resolved several questions regarding the evolutionary relationships within Cladobranchia, including a monophyletic Arminida to the exclusion of Janolus and Dirona, and a clearly non-monophyletic Dendronotida. In addition, the results of the present study indicate that clades within Cladobranchia are closely allied with prey preference, but there are very few prey shifts across the evolutionary history of this group. Diversification analyses indicate little support for the hypothesis that prey shifting leads to diversification. Future research on Cladobranchia would benefit from broader taxon sampling, and combined analyses of diet preferences and prey switching, diversification, and characters that may be correlated with diversification in this group.
