Discussion of Phylogenetic Relationships
Sipunculidea (Sipunculidae , Golfingiiformes), Sipunculidae (Sipunculus , Xenosiphon , Siphonosoma , Siphonomecus , Phascolopsis), and Phascolosomatidae (Phascolosoma , Apionsoma , Antillesoma) of Cutler (1994) are most likely not monophyletic (Maxmena et al. 2003, Schulze et al. 2007).
