Molecular and morphological methods are used to describe the rhizocephalan Briarosaccus hoegi sp. nov. from Russian waters of the Sea of Japan, parasitizing the stone crab Hapalogaster dentata (De Haan, 1849). Briarosaccus hoegi sp. nov. has minor differences by gross morphology from the closely related species B. tenellus, parasitizing H. mertensii in British Columbia and Alaska. Briarosaccus hoegi sp. nov. and B. tenellus are identified as distinct species by genetic markers. These two species have different hosts and different areas of distribution. Moreover, nauplii of Briarossacus hoegi sp. nov. have naupliar eyes not present in B. tenellus larvae. The presence/absence of larval eyes may be a clear character separating the two species. The prevalence of Briaroaccus hoegi sp. nov. on H. dentata in Peter the Great Bay is about 6%.
Rhizocephala, Briarosaccus, Lithodidae, DNA analysis, Histology, SEM, Peter the Great Bay
