Pirusaccus, Lutzen, 1985

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 : 646

Genera: Pirusaccus (one sp.).

Remarks: Until now, this monotypic genus was the only rhizocephalan not assigned to a family. It differs morphologically from both ‘akentrogonids’ with colonial externae ( Polysaccidae and Thompsoniidae ) and from the two other families ( Chthamalophilidae and Duplorbidae ) with spermatogenic islets. This argues for erection of a new family to recognize its uncertain position and unique character combination. Pirusaccus is a deep-sea form sampled only once; therefore, prospects are poor for obtaining material for molecular analysis. The larvae might offer valuable information, but the specimens described by Lützen (1985) were unfortunately not berried. In our composite phylogeny ( Fig. 3), we suggest that the unique sexual system, with spermatogenic islets, is a synapomorphy for a clade comprising Pirusaccidae , Duplorbidae and Chthamalophilidae .