D3220: (2nd Place) A new species of Illinichernes (Pseudoscorpiones: Chernetidae) in Oregon from burrows of mountain beaver (Mammalia: Aplodontidae: Aplodontia rufa)

Shallow subterranean arthropod collections in Oregon from Mountain Beaver (Mammalia: Aplodontidae: Aplodontia rufa) burrows for ectoparasites resulted in what we determined to be an undescribed pseudoscorpion species in the genus Illinichernes (Chernetidae). The collections included 488 individuals: 129 males, 71 females, including 17 with egg sacs, and 289 nymphs. Specimens were collected on four different collection dates: 16 December 1981 (190 specimens), 19 July 1982 (86 specimens), 14 August 1982 (114 specimens), and 17 August 1982 (98 specimens). This new species is separated from its congeners by an apophysis on the dorsal surface of the chela hand present in males and females, measurements of the pedipalps, placement of movable finger trichobothria, and chela length. Of the two species in the genus Illinichernes, I. distinctus and I. stephensi, the latter was recently described by Benedict and Malcolm in 1982 from collections of leaf litter in hollows of living maple, beech, and madrone trees in western Oregon. We provide a complete species description that includes illustrations of both sexes, immature stages, and egg sacs; measurements; and a diagnostic key separating the new species from the two described. Notes are also provided on potential interactions with Mountain Beaver and other potential burrowing mammals.