Samplings of Millipedes in Japan and Scarab Beetles in Hong Kong result in five new Species of Pristionchus (Nematoda: Diplogastridae)

The authors describe five new species of from Japan and Hongkong. Scarab beetle samplings in Hongkong identified sp. n. and sp. n., representing the first beetle-associated species from China. Surprisingly, samplings of millipedes in Japan revealed a previously unknown association of nematodes with these arthropods. Specifically, the authors found three previously known species, , , and on Japanese millipedes. In addition, the authors found three new species on millipedes, which are described as sp. n., sp. n., and , sp. n., the latter of which was also found on stag beetles. These species are most closely related to , , and and belong to the species-complex. The authors describe all species based on morphology, morphometrics, and genome-wide sequence analysis. Mating experiments indicated that all species are reproductively isolated from each other and in contrast to the species of the “ species-complex ” they do not form F1 hybrids.