Molecular phylogeny of the deep-sea penaeid shrimp genus Parapenaeus (Crustacea: Decapoda: Dendrobranchiata)

The commercial deep-sea penaeid shrimp genus Parapenaeus contains 15 species, three subspecies and two forms in the Indo-West Pacific and the Atlantic. Novel nucleotide sequence data from five different genes (COI, 16S, 12S, NaK and PEPCK) were collected to estimate phylogenetic relationships and taxonomic status amongst all but one subspecies in this genus. The phylogenetic results only support two of the four species groups previously proposed for this genus and indicate an evolution direction of the genital organs from simple to complex. The present results suggest that Parapenaeus originated in the shallow waters of the West Pacific with subsequent migration to the deep sea and the Atlantic. The molecular data reveal that there was probably misidentification of females between Parapenaeus australiensis and Parapenaeus ruberoculatus, with females previously assigned as P.australiensis likely being the females of P.ruberoculatus, while material identified as P.australiensis forma nodosa being the true P.australiensis females. On the other hand, Parapenaeus longipes forma denticulata truly represents a variation of the same species, while the subspecies Parapenaeus fissuroides indicus warrants a specific rank.