Oribatella (Acari, Oribatida, Oribatellidae) of western North America

摘要

The oribatid mite genus Oribatella (Oribatellidae) includes 18 species known previously from North America. Herein, we describe 11 new Oribatella species from montane, subarctic, forest and prairie habitats in western North America: O. abmi sp. nov.,O. banksi sp. nov., O. ewingi sp. nov., O. heatherae sp. nov., O. manningensis sp. nov., O. maryae sp. nov., O. oregonensis sp. nov., O. parallelus sp. nov., O. pawnee sp. nov., O. sintranslamella and O. yukonensis sp. nov. Descriptions of two species (O. heatherae and O. pawnee) include some developmental instars. That of O. yukonensis includes all instars; nymphs retain dorsocentral setae dm and dp, but the setal morphology changes between larva and nymphs. These immatures bear sclerotized areas on the hysterosoma. Adults of Oribatella oregonensis show distinct sexual dimorphism, with three notogastral setae arising from fused porose areas in the male. We provide new distribution records for Oribatella species previously known from North America, including O. arctica Thor, 1930, O. canadensis Behan-Pelletier and Earner, 2010, O.jacoti Behan-Pelletier, 2011 and O. reticulatoides Hammer, 1955, and remark on O. anomola Grabowski, 1970. We clarify description of the octotaxic system and the interlamellar region in species of Oribatella and discuss variability in hysterosomal sclerotization and setation in immatures. Finally, we give a key to adults of the 29 species of Oribatella now known from North America.