Three new species of the fairy shrimp Eubranchipus Verill, 1870 (Branchiopoda: Anostraca) from northern Japan and far Eastern Russia

Abstract

Background Small crustaceans in the order Anostraca that lack a carapace are commonly referred to as fairy shrimps. Eubranchipus is an Anostracan genus distributed across the Holarctic region. E. uchidai has been recorded only in Japan and has been considered the only species of Eubranchipus in the region. Results We obtained fairy shrimps from three previously unsampled locations (Shiretoko and Chokai in Japan, and Khanka in Russia). Each specimen shares morphological similarities with E. uchidai, but can be discriminated by the second antenna of males and the genital morphology of females. Based on these specimens, we describe three new species of fairy shrimp: Eubranchipus asanumai n. sp. from the banks of the Shiretoko Five Lakes (Japan: Hokkaido), Eubranchipus hatanakai n. sp. from the base of Mt. Chokai (Japan: Yamagata) and Eubranchipus khankanus n. sp. from the banks of Lake Khanka (Russia: Primorsky). Phylogenetic analysis of mitochondrial DNA reveals significant differences from other known Eubranchipus species, including E. uchidai. Conclusion Both morphological and molecular analyses show that the three new species are similar to E. uchidai but constitute distinct species. Pronounced differences in female morphological features correspond to variability of the amplexus structure previously reported in the genus.