Meeting Abstract
Cnidarians are a stunning group of animals with diverse ecologies, life histories, and morphologies. Relationships within the cnidarian tree of life have been the subject of controversy for many years and the position of several nodes, especially within the Anthozoa, remain unresolved. This project aims to clarify the relationships among and within cnidarian lineages by combining transcriptome data from 32 newly sequenced taxa in Actinaria, Ceriantharia, and Octocorallia with previously published sequence data from 63 additional taxa. We use an innovative approach that combines a backbone phylogeny estimated from hundreds of loci across 95 taxa with a single-locus 18s phylogeny comprising over 900 taxa. To produce our phylogenomic data set, we assembled RNA sequence data into taxon-specific transcriptomes in Trinity, identified orthogroups across taxa in OrthoFinder, and used a novel pruning approach to remove paraphyletic and monophyletic duplicates from orthogroups. Our resulting data matrix contains 101 genes with 15,286 aligned amino acid sites for 89 cnidarian and 6 outgroup taxa with 78% occupancy. To generate the 18s data set, we mined Genbank for all previously published cnidarian 18s sequences. We use the backbone phylogenomic tree to infer deep nodes and to constrain the 18s sequences, producing the most comprehensive cnidarian phylogeny to date. Deployed together, these data sets will enable the resolution of deep and shallow phylogenetic relationships among cnidarian taxa. These resolved relationships can serve as the foundation for trait-based analyses, and will improve our understanding the evolutionary history of cnidarian innovations.
