Brachyura, 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 : 643

Hosts: Brachyura and Calianassoidea.

Genera: Drepanorchis Boschma, 1927 (five spp.), Heterosaccus Smith, 1906 (15 spp.), Loxothylacus Boschma, 1928 (29 spp.), Ptychascus Boschma, 1933 (two spp.), Sacculina (167 spp., see below); Sesarmaxenos Annandale, 1911 (two spp.).

Remarks: The family comprises taxa that originate at node 17 in Figure 3. The high support values for both node f and g in Figure 2 show that the Sacculinidae as defined until now is polyphyletic and must be split into two monophyletic taxa, viz. an amended Sacculinidae and the new family Polyascidae . These two species clusters appeared already in the study by Glenner & Hebsgaard (2006) and have been confirmed with high support by all subsequent analyses of the ‘sacculinid’ species concerned ( Glenner et al., 2010; 2020; Høeg et al., 2019). A morphology-based diagnosis for Sacculinidae was given by Øksnebjerg (2000), but there seems at present to be no possibility that such characters can separate Sacculinidae and Polyascidae . From Figure 3, it follows that the amended Sacculinidae should with certainty comprise the type species Sacculina carcini , Sacculina upogebiae Shiino, 1943 and the species of Heterosaccus , Loxothylacus , Ptychascus and Sesarmaxenos . Loxothylacus is monophyletic, as already shown by Glenner et al. (2008). Before our revision, the genus Sacculina contained 172 recognized species (WoRMS, 2019). By default, we include all species of that genus (167) in Sacculinidae , except the five (see p. 13) that have been shown specifically by molecular data to belong in the new family Polyascidae . Molecular data are still not available for the monotypic genus Drepanorchis . Both Ptychascus and Sesarmaxenos infest freshwaterinhabiting hosts ( Feuerborn, 1931; Boschma, 1933; Andersen et al., 1990) and in Figure 3 are nested in Heterosaccus , but further analysis must clarify whether these remarkable genera should be subsumed in the latter genus ( Glenner et al., 2020).