Description of the bark beetle associated nematodes Micoletzkya masseyi n. sp. and M. japonica n. sp. (Nematoda: Diplogastridae)

Micoletzkya masseyi n. sp. and M. japonica n. sp. from bark beetles Orthotomicus caelatus and Dryocoetes uniseriatus , respectively, are described based on morphology and molecular data. Both species are gonochoristic and can be cultured monoxenically on bacteria. Micoletzkya masseyi n. sp. is differentiated from other species of the genus by a very short male tail, P6-P8 genital papillae arranged in a triangle and with P7 being closer to P8 than to P6, and a conoid female tail to a sharp terminus. Micoletzkya japonica n. sp. is distinct from other Micoletzkya species by the arrangement of its male papillae such that P6 and P7 are close to each other and P8 is positioned apart from them, a conoid male tail with a spicate terminus, and a small gubernaculum ( ca 11 μm in length). Phylogeny of the genus was inferred using nucleotide sequences of 18S rRNA, 28S rRNA, COI, and two ribosomal protein genes. Biological data for the new species are presented and the associations between Micoletzkya species and bark beetles are discussed.