Verification of the cryptic species Penaeus pulchricaudatus in the commercially important kuruma shrimp P. japonicus (Decapoda:Penaeidae) using molecular taxonomy

The kuruma shrimp Penaeus japonicus Bate, 1888 (Decapoda:Penaeidae) is economically important in the global shrimp market. It was regarded as the only species in the subgenus Marsupenaeus. However, our previous molecular analyses revealed two cryptic species (Forms I and II) in this species complex. In this study, we confirm the phylogenetic relatedness between the two cryptic species; revise their taxonomic status; and review their range distribution. The name Penaeus pulchricaudatus Stebbing, 1914 (with type-locality off the eastern coast of South Africa), previously considered as a junior synonym of P. japonicus, is fixed for Form II through a neotype selection. P. japonicus (Form I) is only confined to the East China Sea (including Japan, its type-locality) and the northern South China Sea. P. pulchricaudatus is widely distributed in the South China Sea, Australia, the Red Sea, the Mediterranean, and the western Indian Ocean. Phylogenetic analysis shows that P. japonicus is genetically homogeneous yet P. pulchricaudatus exhibits a strong phylogeographical structure. The Mediterranean stock of P. pulchricaudatus originated from the Red Sea population, supporting the Lessepsian migration hypothesis. The presence of two closely related cryptic species in the P. japonicus species complex provides important insights into fishery management and aquaculture development.