From editor or global species database
Classification Zrzavý et al (2009) suggest the traditional "Scolecida" and "Canalipalpata" are both polyphyletic, forming instead two clades: one including Cirratuliformia and the "sabelloid-spionoid clade" (incl. Sternaspis, Sabellidae-Serpulidae, Sabellariidae, Spionida s. str.), the other ("terebelloid-capitelloid clade") including Terebelliformia, Arenicolidae-Maldanidae, and Capitellidae-Echiurida.
Sabellariidae lie outside Sabellida and have Spionida affinities according to Capa et al (2012) [details]