Phylogenomic analyses unravel annelid evolution

The annelids, or segmented worms, comprise one of the largest and most diverse animal phyla, found everywhere from the soil to the ocean bed. Their evolutionary relationships are poorly understood, and a reconstruction of annelid evolutionary history would be welcome. To that end, Struck et al. present a new phylogenomic analysis of 34 annelid taxa. Notable features include a division of most annelids into the Sedentaria and the Errantia, reviving a neglected 150-year-old hypothesis that the annelids developed as two major groups or clades, one specialized for a sedentary way of life and the other for a more active lifestyle.