Meeting Abstract
The tube-dwelling family Chaetopteridae are unique among annelids in their remarkably tagmatized body plan. Their three-part bodies have allowed morphological specialization for diverse mucus-net filter feeding strategies that vary considerably across the four genera and ~100 species comprising the family. Recent phylogenetic analyses have recovered Chaetopteridae as one of the earliest diverging lineages, sister to all other Annelida except Magelonidae and Oweniidae. Despite recent progress, current understanding of chaetopterid phylogeny is limited by low taxon and gene sampling, low gene tree congruence, and poor support at key nodes. Phylogenomic approaches offer solutions to these issues. Here, we employ a target capture approach to better resolve the phylogeny of Chaetopteridae. Four published chaetopterid transcriptomes and the Capitella teleta genome were used to identify homologous exon regions for capture probe design. RNA probes were synthesized for 790 exon regions and used for target capture of dual-indexed libraries for 46 taxa. Post-capture libraries were pooled and paired-end sequenced using Illumina MiSeq with a 600 cycle kit. Sequence data were assembled and aligned for phylogenetic analysis. In addition to the full dataset, three data subsets (25%, 50% and 75% taxon occupancy) were used for phylogenetics. Concatenated, partitioned Bayesian and Maximum Likelihood (ML) phylogenetic analyses were performed for each dataset, as well as species tree analyses under ML. Of 790 targeted regions, 604 usable loci were recovered. The phylogenies are highly congruent among analyses and generally well-supported. The genera Chaetopterus and Mesochaetopterus were recovered as well-supported sister groups, while paraphyly was confirmed in Spiochaetopterus and Phyllochaetopterus. The implications of the phylogeny for taxonomy and body plan evolution are discussed.
