Glenner, Høeg & Noever & Rees & Crandall & Glenner, 2020

Høeg, Jens T., Noever, Christoph, Rees, David J., Crandall, Keith A. & Glenner, Henrik, 2020, A new molecular phylogeny-based taxonomy of parasitic barnacles (Crustacea: Cirripedia: Rhizocephala), Zoological Journal of the Linnean Society 190, pp. 632-653 : 644

Genera: Polysaccus (two spp.).

Remarks: Both species have elongated, colonial externae. The family is represented here only by Polysaccus japonicus and is situated in a cluster ( Fig. 3, node 7) that also contains some former akentrogonid families: Polyascidae and Sacculinidae . The closest ally may be Clistosaccidae ( Glenner et al., 2010) , but the precise position is uncertain, explaining the polytomy at node 7 in Figure 3. It further complicates the situation that the only two species, Polysaccus japonicus and Polysaccus mediterraneus , deviate in larval morphology to an extent that puts doubt on the monophyly of the genus, hence also the family ( Glenner et al., 2010; Høeg et al., 2019). The third segment of the antennule in Polysaccus japonicus has a specialized pointed shape that suggests its use in antennular penetration. In contrast, the antennule in Polysaccus mediterraneus is similar to that found among peltogastrid species. Unfortunately, no molecular data are available for the type species, Polysaccus mediterraneus , meaning that a solution must await future additional data.