FIGURE 1 in Segmented worms (Phylum Annelida): a celebration of twenty years of progress through Zootaxa and call for action on the taxonomic work that remains

FIGURE 1. Schematic representation of main branchings in the phylogeny of the Annelida, showing relationships of major subgroups. Traditional Polychaeta are all Annelida minus Clitellata, and traditional Oligochaeta are all Clitellata minus Hirudinea. Families per higher-level sub-taxon are listed in alphabetical order. In "oligochaetes" the upper group represents basal taxa, mostly aquatic, the lower group represents the Crassiclitellata (true earthworms); the middle group (3 families) includes earthworm-like worms; together with Crassiclitellata it forms the Metagynophora Jamieson, 1988. Acanthodrilidae here include Benhamiidae and Octochaetidae. Phylogeny based on Weigert & Bleidorn (2016), Struck (2019) and Erséus et al. (2020), for further phylogenetic resolution of families see these references. Taxa noted with vertical text and with dashed lines indicate paraphyletic groups (sedentariate polychaetes, oligochaetes). Taxa denoted with a dashed line and question mark are considered Annelida incertae sedis and are currently debated in terms of their phylogenetic position (see discussion in Struck et al. 2019; Capa & Hutchings 2021); some additional aberrant taxa (Lophotrochozoa incertae sedis) are not included. Data on numbers of species primarily derived from Pamungkas et al. (2019), Read & Fauchald (2021), WoRMS Editorial Board (2021), Handbook of Zoology, Annelida (Purschke et al. 2019a, b; 2021) and DriloBASE (2021).