Meeting Abstract
In 1997, seminal papers were published by Kristian Fauchald and Greg Rouse that help clearly define families of polychaetous annelids and provided an overarching phylogenetic hypothesis that helped focus systematic research within the group. Fostered by this work, understanding of annelid phylogeny has changed dramatically. Molecular and genomic tools were used to test many hypotheses laid out in the 1997 papers. Sipunculids, echiurids, vestimentiferans, pogonophorans, and myzostomids all used to be considered separate phyla and are now known to be nested within annelids, and clitellates are recognized to be derived polychaetes. Here I will discuss recent and novel transcriptomic data in reference to higher-level annelid phylogeny, as well as the role transcriptomics and genomics has played in bringing about this new understanding. Discussion will be focused on placement of groups that were traditionally placed outside of “Polycheata”. Magelonidae and Owenidae are sister to all other annelids and clitellates are allied with terebelliform annelids. Interestingly, the non-segmented sipunculids are sister to the homonomously segmented amphinomids. This novel understanding has profound implications for how we view segmentation across animal groups. Although, segmentation used to be considered a character of considerable phylogenetic value, it is an evolutionarily plastic feature that is likely dictated by functional constraints.
