Different views in the interpretations of the host adoption within the neodermatan phylogenetic framework. The relative sequence in the acquisition of invertebrate/vertebrate hosts by three major groups of the Neodermata is illustrated by numerical order (not to scale). (A) 'Vertebrate first' hypothesis; (B) 'Mollusc first' hypothesis (modified ); (C) the interpretation of the present study.
Park et al. BMC Evolutionary Biology 2007 7:11 doi:10.1186/1471-2148-7-11