Description of a new subterranean species of Plutomurus (Collembola: Tomoceridae) from the Nanatsuoguchi Mine, central Honshu, Japan with notes on Plutomurus yamatensis

A new species of Plutomurus Yosii, 1956, P. asuwaensis sp. nov., from the Nanatsuoguchi Mine in Fukui, central Honshu, Japan, is described and illustrated. The new species is clearly distinguished from all other congeners by the combination of following characters: absence of eyes, number of prelabral chaetae, and shape of the claws. Morphological observation of topotypes of P. yamatensis Yosii, 1956 from Gansuiji-Shonyudo Cave showed that the number of prelabral chaetae differs from its previous description. Phylogenetic positions of the new species and P. yamatensis are estimated within the genus based on the sequences of the mitochondrial cytochrome c oxidase subunit I. The obtained phylogeny indicates that P. asuwaensis sp. nov. belongs to a unique lineage, and thus corroborates its distinct species status revealed by morphological examination.