Study On The Molecular Systematics Of The Superfamily Palaemonoidea Rafinesque,1815(Crustacea, Decapoda, Caridea)

Palaemonoidea Rafinesque,1815is one of the most speciose superfamilies ofCaridea, Decapoda, Crustacea. Since it was established, several classification schemesof Palaemonoidea have been proposed and modified. However, the currentclassification of Palaemonoidea is still in dispute. In this study, one mitochondrialgene (16S rDNA) and three nuclear genes (histone3,18S rDNA and28S rDNA) wereused to explore the phylogenetic relationships among the subgroups of thesuperfamily Palaemonoidea, including eight families with26affiliated genera. Basedon the combined data with both maximum likelihood and Bayesian inference analyses,the results support the monophyly of Anchistioididae, Hymenoceridae andKakaducarididae. In contrast, Gnathophyllidae is suggested to be paraphyletic andPalaemonidae is shown to be a polyphyletic group. Especially, our analyses revealthat the studied subfamily Palaemoninae species could be approximately divided intothree clades, and the branchiostegal groove is the probable morphological evidence ofthe environmental transition from sea to fresh water. Besides, for some of thePalaemonoidea families, their taxonomic status is obscure. A revision of theclassification of Palaemonoidea and a reevaluation of its constituent taxa appear to benecessary despite the systematics of the subfamily Pontoniinae is still undetermined.The genus Periclimenes Costa,1844is the most species-rich genus in thesubfamily Pontoniinae. Recent studies have suggested that it might be a polyphyletictaxon and could be further subdivided. In this study, three protein-coding nucleargenes (enolase, NaK and PEPCK) and one mitochondrial ribosomal gene (16S rDNA)were used to analyse the phylogenetic relationships among the genera of thePericlimenes complex, includes the genus Periclimenes and15related genera, i.e.Ancylomenes, Brucecaris, Crinotonia, Cuapetes, Harpiliopsis, Harpilius, Laomenes,Leptomenaeus, Manipontonia, Palaemonella, Periclimenella, Philarius, Phycomenes,Unguicaris and Vir. Based on both independent and combined data analyses, theresults support that the genus Periclimenes is a polyphyletic group. Furthermore, thestudied Periclimenes species could be divided into several independent groups, andthe taxonomic status of P. commensalis, P. brevicarpalis and P. digitalis may need tobe reconsidered. Besides, the majority of the related genera of Periclimenes aresuggested to be monophyletic. Our analyses also reveal that these generaapproximately form two main clades, despite some deep relationships are still obscure.In this study, a variety of gene sequences were used to analyse the systematicstatus of the superfamily Palaemonoidea for the first time, providing molecularevidences for its phylogenetic studies and further classification. Besides, severalnuclear protein-coding genes were utilized to explore the phylogenetic relationshipsamong multiple genera of the subfamily Pontoniinae for the first time, which enrichesthe application of the nuclear protein-coding genes on the molecular phylogeneticstudies and provide new insights into the classification for the traditionalmorphological taxonomy.