Revision of the generic system for the swimming crab subfamily Portuninae (Decapoda: Brachyura: Portunidae) based on molecular and morphological analyses

Swimming crabs of the genus Portunus are revised based on analysis of three genetic markers (COI, 16S and H3) and a morphological comparison. The analyses reveal the polyphyletic composition of Monomia, Portunus and Xiphonectes and the paraphyly of Achelous. Portunus, in our revised composition, is restricted to 13, Monomia to ten and Xiphonectes to 14 species. Other species are transferred to Achelous (28) and Cycloachelous (nine) or to newly established genera. Four new genera are separated from Xiphonectes and one new genus from Monomia. The systematic composition of the portunid subfamily Portuninae now comprises 11 genera: Arenaeus, Allomonomia gen. nov., Cavoportunus, Callinectes, Cycloachelous, Eodemus gen. nov., Incultus gen. nov., Monomia, Portunus, Trionectes gen. nov. and Xiphonectes. The genus Lupella is synonymized with Achelous (Achelouinae). Xiphonectes pulchricristatus and Xiphonectes spinipes are placed in Alionectes gen. nov., Portunus ponticus is transferred to Lupocycloporus (both Lupocyclinae), and Monomia euglypha is now placed in Cycloachelous (Portuninae). Portunus mokyevskyi is considered a junior synonym of Scylla tranquebarica (Necronectinae). Xiphonectes leptocheles is confirmed as a valid species. Cycloachelous granulatus unispinosus is also considered a valid species and is to be treated as Cycloachelous unispinosus.

Automated summary

Swimming crabs of the genus Portunus were revised based on genetic markers and morphological comparison, leading to the discovery of polyphyletic and paraphyletic composition of several genera. The revised composition divided Monomia, Portunus, and Xiphonectes into new genera, and the subfamily Portuninae now consists of 11 genera.