Figure 2. Summary of relationships involving the aculiferan taxa. (A) Monophyly of Aculifera, Aplacophora and Conchifera (Scheltema 1993); (B) Adenopoda hypothesis placing Caudofoveata as sister group to all other molluscs and Testaria monophyletic (Salvini- Plawen 1980); (C) Hepagastralia hypothesis placing Solenogastres as sister group to all other molluscs and Testaria monophyletic (Salvini-Plawen and Steiner 1996; Haszprunar et al. 2008); (D) monophyly of Aplacophora and of its sister group, Testaria (Waller 1998); (E) a version of the Serialia/Dorsoconcha/Variopoda (Giribet et al. 2006; Stöger et al. 2013) hypothesis; (F) summary tree summarizing the phylogenetic hypotheses of Kocot et al. (2011) and Smith et al. (2011).