Integrative taxonomy of Janirella (Isopoda: Asellota: Janirellidae), with descriptions of two new species and an amended classification of the genus

Abstract We describe two new Janirella species, Janirella scutum sp. nov. and Janirella spinoscutum sp. nov., collected at depths of 2893–3176 m on the landward slope of the Japan Trench, northwestern Pacific. These species differ from congeners in having an ovoid body with dorsal spines on each pereonite; the pleotelson with two pairs of short and one pair of long lateral projections; and the posterior projection on the pleotelson shorter than pleotelson length. They differ from one another in the number and size of dorsal spines on the pereonites. We determined partial sequences for the cytochrome c oxidase subunit I (COI) gene for the two new species and seven other Janirella species and constructed a COI-based maximum-likelihood tree of Janirella. In the tree, the subgenus Parjanirella was monophyletic but embedded within a paraphyletic group of species in the subgenus Janirella. Based on this result, we propose the elimination of subgenus ranks in Janirella.